PART A

CHAPTER I

The Chemistry of Genus Cassia- A review.

Cassia (Leguminosae) is a large and predominantly tropical genus

of about 600 species of herbs, shrubs and trees with about 20

representatives in India. A few provide tanning materials of economic

value. Cassia auriculata cultivated in many parts of India is known as

Tanner's tree. 1,2 Some species like C.alata and C.fistula are ornamental.

Most species are reputed for their medicinal values and find extensive

use in traditional system of medicine all around the world. Cassia drugs

worth millions of rupees are exported annually from India.3 The

worldwide interest in the isolation of active ingredients from Cassia is

due to the commercial, economic and medicinal importance of these

species. This is evident from the amount of literature published on the

various species of Cassia annually.

This review makes an attempt to comprehend the chemistry of

Cassia by listing out the chemical components so far isolated in

literature. It acts as a pointer to the fact that the genus is a potential

source of secondary metabolites and they are categorised broadly as

1. Anthraquinones.

2. Anthrones and Oxanthrones.

3. Flavonoids.

4. Terpenes and Sterols.

5. Alkaloids.

6. Aliphatic compounds

Chapterl

7. Polysaccharides.

8. Miscellaneous compounds.

2

1. Anthraquinones.

The active principles of Cassia are anthraquinones. Rhein (2),

chrysophanol (3), physcion (4), aloe emodin (9) and emodin (lO)are

some of the important anthraquinones which have a wide spread

occurrence In Cassia speCIes. Anthraquinones including

bianthraquinones and their glycosides, their natural occurrence and

physical properties are listed in Table 1. Depending on the number of

hydroxyl groups present, they can be divided into (1) monohydroxy (2)

dihydroxy (3) trihydroxy (4) tetrahydroxy and (5) polyhydroxy

anthraquinones.

Biosynthesis of anthraquinone derivatives.3

Formation of anthraquinones in plants other than those belonging

to Cassia species are studied in detail. Biosynthesis of anthraquinone

derivatives has been shown to take place by two different pathways.

l.The acetate polymalonate pathway

In this pathway, anthraquinone derivatives are believed to be

formed as in Chart 1 and this is proved to take place in plants by

Leistner and Zenk.

Chapterl

Chart 1

3

acetylcoenzyme A

7COOHICH2CO.S.COA

malonylcoenzyme A

000

polyketo methylene

chain (C02dehydration ~

oemodin

Biosynthesis of emodin-The acetate polymalonate pathway

OH

TABLE 1

Anthraquinones from Cassia

n-'pO

"S.(1)..,

Sl.no Compound Molecular formula Source Part M.P.o C Reference

l. 1,8-dihydroxy anthraquinone (1) C14Hs0 4 Cassia jistula Fruit 313-6 112C. angolensis Stem bark 146

2. 1,8-dihydroxy anthraquinone -3-carboxylic ClsHs0 6 C.alata Leaves 309-10 50,113acid (Rhein) (2) C.obovata Leaves,pods 114

C.senna Leaves 115C.jistula Heartwood 116,117

Leaves 118C.siberianna Leaves 105C.reticulata Flowers 119c.tora Seeds 120C.fondosa - 121C.alata Leaves 122,123C.siamea Leaves,Bark 124C.nodosa Leaves 125C.javanica Leaves 126C. didymobotrya Whole plant 127

3. 3-methyl- 1,8-dihydroxy anthraquinone ClsH IOO4 C. obtusifolia Seeds 193-4 128(Chrysophanol) (3) C.senna Leaves 115

C.siamea Stem bark 130,131Root bark 132

.j:>.

Sl.no Compound

TABLE 1 (Contd.)

Molecular formula Source Part M.P.O C Reference

QPO

1:)

8"...,

-0eN45~

~

~.,;. -'.

r'~~/e~~

i ~~"- )~. /~.. k~"'~

~r

133124,135136137,69120,1314112314314489,14514614718,1481491501516,152,153,127155118,1571581596110966,160

193-4

SeedsFlowersWood,seedsStem barkHeart woodPods,seedsPod huskRootsHeartwoodWhole plantSeedsSapwoodRootsAerial partsRoots

HeartwoodLeavesLeavesRootsSeeds,leavesLeaves

Flower bud

C .marilandicaC occidentalis

CjaegiiCalataCtoraCsopheraCjavanicaCangolensisCgarettianaClaevigataCauriculataCabsusCsopheraC didymobotryaCmarginataC.fistulaCacutifoliaCmimosoidesCtorosaCpumilaCspectabilis

CsiameaClsH lO043-methyl-1,8-dihydroxyanthraquinone(Chrysophanol) (3)

3.

U1

TABLE! (Contd.) n::r-.po'0......

(1)

Sl.no Compound Molecular formula Source Part M.P.o C Reference .....

"I 3-methyl-l,8-dihydroxy ClsH lOO4 Cpudibunda Roots 63.).

anthraquinone (Chrysophanol) (3) Croxburghi Pods,fruit 92,161C corymbosa Leaves,fruit 162,163Cfikifiki - 129Cnomane Aerial parts 170Cglauca Stem bark 134,138Cfondosa - 121C abbreviata - 142Csingueana - 156Cjavanica - 126

4. 3-methyl-6-methoxy-l,8-dihydroxy C16H12Os C obtusifolia Seeds 206 128anthraquinone(physcion) (4) C occidentalis Seeds,flowers 164,169,

Roots 139C marilandica Leaves 136Cjaegii Leaves 141Cmimosoides Roots,seeds 166Csingueana Seeds 156Csenna Seeds 167Ctora Seeds 143Crogeoni Leaves 168Cspectabilis Aerial parts 169Csiamea Leaf 124,135,

Stem bark 130C. angolensis Stem bark 146

0\

TABLEt (Contd.) Q~

"0

Sl.no Compound Molecular formula Source Part M.P.o C Reference(;..,

4. 3-methyl-6-methoxy-l,8-dihydroxy C16H120S Cgarettiana Heart wood 147anthraquinone(physcion) (4) Claevigata Pods,seeds, 18,148

Roots 20Cjavanica Seeds 145Csophera Heartwood 151C marginata Seeds 155Cjistula - 118C acutifolia Roots 158Cnomane Seeds, 170

AerialpartsCtorosa Roots 61C.jloribunda - 16C spectabilis Flowerbud 66,160Cpumila Whole plant 171Cpudibunda Roots 63Cglauca Stembark,pods 134,138,172Cjikifiki - 129C abbreviata - 142Croxburghi Stembark 161C didymobotrya Pods 6

5. Obtusifolin (5) C16H120s C obtusifolia Seeds 237-8 128,1736. Obtusin (6) C1sH160 7 C obtusifolia Seeds 242-3 174,173

Ctora Seeds 1757. Chrysoobtusin (7) C19H lS0 7 C obtusifolia Seeds 214-5 174

-.l

TABLE! (Contd.) (J

~

Sl.no M.P.o C'""Q

Compound Molecular formula Source Part Reference ,-;.(TJ.,

7. Chrysoobtusin (7) C19H180 7 e.tora - 214-5 1738. Aurantio obtusin (8) Cl7H140 7 e. abtusifolia Seeds 265-6 1749. Aloe emodin (9) C15HlOOS e.obovata Leaves,pods 223-4 114

e.senna Leaves 115e.reticulata Flowers 119e. occidentalis Seeds 120e.alata Leaves,seed 122,123,

Fruit 176e.absus Roots 150e. didymobotrya Leaves, 153,177

Whole plante.grandis Leaves 178

Root bark -179e.acutifolia Roots 158e. corymbosa Leaves,fruits 162,163e.abbreviata - 142

10. 1,8,6-trihydroxy-3-methyl ClSHIOOS e. occidentalis Seeds,flower 254-5 139,69,anthraquinone (Emodin) (10) e.glauca Flowers 165

e.mimosoides Roots, seeds 166e.fondosa - 121e.lora Seeds, leaves 143,180e.alata Stem 123,181,182e. angolensis Stembark 146

00

TABLE 1 (Contd.) ():JP.:>

-0

Sl.no Compound M.P.o C(ti

Molecular formula Source Part Reference -:

10. 1,8,6-trihydroxy -3-~ethyl anthraquinone C1sHIOOS Cjavanica Rootbark 254-5 19(Emodin) (10) Seeds,leaves

Claevigata Roots 20Csophera Heart wood 151Cpumila Leaves 183,109Cnomane Aeria1parts 170Ctorosa Roots 61C obtusifolia - 184Csiamea Roots 133Cspectabilis Flowers 160Cabbreviata - 142C roxburghi Stem bark 161C didymobotrya Pods 6

II. Emodic acid (11) C1sHs0 7 C mimosoides Roots,seeds 363-5 16612. Fistulic acid (12) C17H 140 7 Cfistula Pods 18513. 1,3,5-trihydroxy-6,7-dimethoxy -2-methyl C17H 130 7 Ctora Roots 210 186

anthraquinone (13)14. 1,8-dihydroxy-2-methy1 anthraquinone (14) ClSH lOO4 C occidentalis Seeds 307-9 18715. 1,4,5-trihydroxy-7-methoxy-3- C16H 120 6 C occidentalis Seeds 285-7 187

methylanthraquinone (15)16. 1,5,8-trihydroxy-3-methy1 anthraquinone C16H120 6 Ctorosa Seeds - 74

(Xanthorin) (16)17. 1-hydroxy-3,8-dimethoxy-2-methy1 C17H14OS Crenigera Stem bark - 188

anthraquinone (17)

'-D

n::r-

TABLEt (Contd.)po'0......~...,~

Sl.no Compound Molecular formula Source Part M.P.o C Reference

18. 5-hydroxy emodin (18) C1sH lOO6 C.javanica Root bark >300 1919. 1,8-dihydroxy -3,5,7-trimethoxy-2- C17H140 7 Crenigera Seeds - 189

methylanthraquinone (19)20. 1,5,8-trihydroxy-6,7-dimethoxy -2- C 17H140 7 Crenigera Seeds - 189

methyl anthraquinone (20)21. Questin (21) C16H 12OS C obtusifolia Roots - 60,190

CUndheimeriana 97C occidentalis 81Ctorosa 77

22. Rubiadin (22) C1sH lOO4 Cjavanica Seeds - 14923. 1,3,6,7,8-pentahydroxy -4-methoxy-2- C16H12Og Cjavanica Seeds - 145

methyl anthraquinone (23)24. Sopheranin (24) C17H120 6 Csophera Heartwood - 15125. 1,3,8-trihydroxy-6-methoxy-2-methyl C16H120 6 Cmultijuga Roots - 191

anthraquinone (25)26. I-desmethyl-chrysoobtusin (26) ClgH1607 C obtusifolia Seeds - 19027. I-desmethylobtusin (27) C17H140 7 " " 190-28. I-desmethyl aurantio obtusin (28) C16H120 7 " " 190-29. 1,8-dihydroxy-3,6-dimethoxy-2-methyl- C19H160 6 Csophera Root bark 261 12

7-vinylanthraquinone (29)30. 1,3-dihydroxy-5,7,8-trimethoxy-2- C1gH160 7 " " 305 12

methylanthraquinone (30)31. O-methyl chrysophanol (31) C16H120 4 C obtusifolia Roots - 60

-0

()

TABLEt (Contd.)::r'$»'0......0.....

Sl.no Compound Molecular formula Source Part M.P.o C Reference

32. 1,3,5,8-tetrahydroxy-6-methoxy-2-methyl CI6H120 7 Cjavanica Stem bark - 9anthraquinone (32)

33. 1,3-dihydroxy-6,8-dimethoxy-2- C21H2006 Cmarginata Seeds 145 14.isopropenyl anthraquinone (33)

34. Fallacinol (34) C I6H 120 6 C didymobotrya Whole plant - 127,17735. Parietenic acid (35) C l6HlOO7 " " 127-36. Chrysophanol dimethylether (36) C 17H I40 4 Cpudibunda Roots 193-6 63

Csiamea Rootbark 13137. 1,3-dihydroxy-8-methyl anthraquinone CisH lOO4 C obtusifolia Seed 269 104

(8-methyl xanthopurpurin) (37)38. 5-hydroxy-l ,4,6,7-tetramethoxy-2-methyl Cl9HlS07 Cgreggi Roots 166-7 15

anthraquinone (38)39. 1,5,7-trihydroxy-4,6-dimethoxy-2-methyl C 17HI40 7 Cgreggi Roots 210-2 15

anthraquinone (39)40. 5,6-dihydroxy -1,4,7-trimethoxy-2- CisHIOO7 Cgreggi Roots 196-8 15

methyl anthraquinone (40)41. I-hydroxy-4,7-dimethoxy-5,6-methylene ClsHl40 7 " " 240-2 15

dioxy-2-methyl anthraquinone (41)42. 5,7-dihydroxy-l ,4,6-trimethoxy-2- C1sHl60S " " 192-4 15

hydroxymethyl anthraquinone (42)43. 4,5-dihydroxy-l ,6,7-trimethoxy-2-methyl C1sHl60 7 " " 192-'4 15

anthraquinone (43)44. 5,6-dihydroxy-4,7-dimethoxy-2-methyl C 17H I406 " " 15-

anthraquinone (44) --

(1::J

TABLEt (Contd.) P>"0......~....~

. Sl.no Compound Molecular formula Source Part M.P.o C Reference

45. 1-hydroxy-3-methyl-2,6,7,8-tetramethoxy- Cl9Hlg07 Clindheimeriana Roots 175-6 979,10-anthraquinone (45)

46. . 2-formyl-1 ,3,8-trihydroxy ClsHg06 Calata Stem >300 13anthraquinone (alatanol) (46)

47. 1,5-dihydroxy-3-methylanthraquinone (47) ClsHlOO4 Citalica Whole plant 191-3 11048. 1,5-dihydroxy-3-methoxy-7-methyl CI6H120S " " 189-90 110

anthraquinone (48)49. 1,4-dihydroxy-6,7,8-trimethoxy-2-methyl ClgH160 7 Cjavanica Stem bark - 193

anthraquinone (49)50. Alquinone (50) ClsHg06 Calata - - 19451. 1,3,5,8-tetrahydroxy-6,7-dimethoxy-2- C17H140g Cgrandis Roots - 195

methyl anthraquinone (51)52. 1,3,4,5-tetrahydroxy-7, 8- dimethoxy-2- C17H140g Cgrandis Pods - 196

ethylanthraquinone (52)53. 1,3 ,4-trihydroxy-6,7, 8-trimethoxy-2- C1gH160g Cgrandis Pods - 197

methyl anthraquinone (53)54. Kinopholone (54) C24HlgOg C didymobotrya Pods - 655. 1,5-dihydroxy-8-methoxy-2,3 -dimethyl - C17H140S Cgrandis Rootbark - 179

9,10-anthraquinone (55)56. Alaternin (56) ClsHlOO6 Ctora Seeds - 17557. 1-hydroxy-6,8-dimethoxy-2,3-dimethyl- ClgH160S Cgrandis Rootbark - 198

9,10-anthraquinone (57)58. 1,8-dihydroxy-6,7-dimethoxy-2-methyl- C17H140 6 Cnodosa Rootbark - 199

anthraquinone (58)__--------------- -tv

n:r-

TABLE! (Contd.) po'"0(p.,

Sl.no~

Compound Molecular formula Source Part M.P.o C Reference

59. 2-hydroxy-l,6,8-trimethoxyanthraquinone Cl7Hl406 Crenigera Stem - 200(59)

60. Xanthorin (60) CI6H 120 6 CZindheimeriana Roots - 9761. Digitolutin (61) C16H120 4 CgZauca Seeds 224-8 20162. 1,4,5-trihydroxy-7-methyl anthraquinone ClsHIOOS C obtusifoZia Roots - 60

(helminthosporin) (62)63. Rhein-8-monoglucoside (63) CZIHISOII CaZata Leaves,roots 183-5 176

Csenna Leaves,seeds 167,C acutifolia Fruits,roots 158,202,203Csieberiana Leaves 105

64. Aloe emodin glucoside (64) CZIH20010 CaZata Leaves 212 176,204Csenna Leaves 205,167Cacutifolia Pod valves 206,202,207

65. Chrysophanol glucoside (65) Cz1HzoOg CaZata - - 20466. 1,6-dihydroxy-3-methylanthraquinone-8- CZIHzoOIO Cjavanica Root bark - 19

O-a-L-rhamnopyranoside (66)67. 1,5,6-trihydroxy-3-methylanthraquinone - CZIH20011 Cjavanica Root bark - 19

8-0-a -L-rhamnopyranoside (67)68. I-hydroxy-6-methoxy-3-methyl CZSH340lS CZaevigata Pods - 18

anthraquinone-8-0-p-D-galactosyl-(l-74)-O-p-D-galactopyranoside (68)

69. 1,5,8-trihydroxy-6,7- dimethoxy-2- C23HZS0 13 Crenigera Seeds - 189methylanthraquinone -3-0-a -(-)rhamnopyranoside (69)

uJ

()::r

TABLEt (Contd.) po'"0......

(j)'"1-Sl.no Compound Molecular formula Source Part M.P.o C Reference

70. 1,5-dihydroxy -4,7-dimethoxy -2- C23H24012 Cjavanica Seeds - 145methylanthraquinone-3-0-a -L-rhamnopyranoside (70)

71. Physcion-8-0-a-L-arabinopyranoside (71) C22H22O lO Cmarginata Seeds - 20872. Emodin-8-0-a-L-arabinopyranoside (72) C21H20010 1/ " 208-73. I ,3-dihydroxy-2-methylanthraquinone -8- C21H20010 1/ " 155-

O-a-rharnnopyranoside (73)74. 1,3,8-trihydroxy-6-methoxy-2- C2sH33016 C multijuga Roots - 191

methylanthraquinone-3-0-rutinoside (74)75. Physcion-8-~-D-gentiobioside (75) C2sH33015 Ctorosa Seeds - 10876. Emodin-8-0-~-glucopyranoside (76) C21H200 9 C acutifolia Roots - 15877. 1,4-dihydroxy-8-methoxy-2-methyl C22H22011 Cnodosa Roots - 209

anthraquinone-3-0-~-D(+)glucoside (77)78. 8-hydroxy-6-methoxy-3-methyl C28H33015 Cglauca Stem - 210

anthraquinone-l-0-a-L-rharnnopyranosyl -(1-) 6)-~-D-glucopyranoside(78)

79. I-hydroxy-6,8-dimethoxy-2-methyl C23H24010 Csiamea Roots - 211anthraquinone-3-0-rutinoside. (79)

80. 2-0-~-D-glucopyranosyl-l,2,4, 8- C22H22011 Cgrandis Seeds - 212tetrahydroxy-6-methoxy-3-methylanthraquinone (80)

81. 3-0-~-D-glucopyranosyl-l ,3-dihydroxy- C24H26012 " " 212-6,7,8-trimethoxy-2-methyl anthraquinone(81)

-l:>.

()~

TABLEt (Contd.)p:>'0.-+(1).,-Sl.no Compound Molecular formula Source Part M.P.o C Reference

82. 6,8-dimethoxy-2-methylanthraquinone-3- C23Hz4OIO Csiamea Roots - 213O-~-D-galactopyranoside (82)

83. 1,5,8-trihydroxy-2-methylanthraquinone-3- C21 HZOO11 Csiamea Roots - 213O-~-D-galactoside (83)

84. 1,5,8-trihydroxy-6-methoxy-2-methyl C28H3Z017 Cauriculata Seeds - 214anthraquinone-3-0-~-D-galactopyranosyl(1-7 4)-O-~-D-mannopyranoside(84)

85. 1,2,4,8-tetrahydroxy-6-methoxy-3-methyl- C22Hz20 12 Cgrandis Seeds - 215anthraquinone-2-0-j3-D-glucopyranoside(85)

86. 3-hydroxy-6,8-dimethoxy-2-methyl C23H240 10 Cgrandis Seeds - 215anthraquinone-3-0-j3-D-glucopyranoside(86)

87. 1,3-dihydroxy-6,7,8-trimethoxy C23H240 12 Cgrandis Seeds - 215anthraquinone-3-0-~-D-glucopyranoside(87)

88. Emodin-8-0-sophoroside (88) C27H300 15 C angustifolia Leaves - 9889. 1,7,8-trihydroxy-4-methoxy-2-methyl C21H200 12 Cgrandis Pods - 216

anthraquinone-3-0-j3-D-galactopyranoside(89)

90. 1,3,4-trihydroxy-6,7,8-trimethoxy-2- C24H260 13 " " 217-methyl anthraquinone -3-0-j3-Dglucopyranoside (90) _ .. _- --- - -V1

n=:r"

TABLE 1 (Contd.)Pl

'"0......(D'""1-

Sl.no Compound Molecular formula Source Part M.P.o C Reference

9l. 3-methyl-6-methoxy-1 ,8-dihydroxy C22H2201O C occidentalis Seeds 141-3 218anthraquinone glucoside (91)

92. 8-hydroxy-3-methyl anthraquinone-l-~- C27H30014 Ctora Seeds - 143gentiobioside (92)

93. 3-hydroxy-6,8-dimethoxy-2-methyl C23H24011 Cauriculata Heartwood - 219anthraquinone-l-0-~-Dgalactoside (93)

94. Roxburghinol (94) ClsHl20S Croxburghi Leaves 211 895. 1,2-dihydro-l ,3-dihydroxy-6,8-dimethoxy- C17HI60 6 C.javanica Stem bark - 9

2-methylanthraquinone (95)

Bianthraquinones from Cassia

96. Cassiamin (96) C30HlS09 Csiamea Root bark 356-7 132,220,221,222

97. Siameamin (97) C30HlS06 Csiamea Trunk bark 323-5 222,220C occidentalis Leaves 140

98. 4,4'-bis(1,3,8-trihydroxy-2-methyl-6- C32H22012 Chirsuta Seeds >300 46methoxy anthraquinone) (98)

99. 5,5'-bis-T-methyl physcion (trachypone) C3~2001O C.trachypus Roots 252-4 223(99)

100. 4,4'-bis(l,3-dihydroxy-2-methyl-6,8- C34H260 12 Csiamea Roots 320 133dimethoxy anthraquinone) (100)

10l. 1,1 '-bis(4,5-dihydroxy -2-methyl C30H1sOs " " 330 133anthraquinone) (101)

102. Floribundone-l (5,7'-biphy~<;i()n) OO~) C32H22OIO C.jloribunda - >260 16 -0\

TABLEt (Contd.) n::;-po

'"0......

Sl.no Compound Molecular formula Source Part M.P.o C Reference(0.,

102. F1oribundone-1 (5,7'-biphyscion) (102) C32H22010 C multiglandulosa Seeds >260 4,5C corymbosa Roots 97

103. Floribundone-2 (103) C32H2409 C.jloribunda - - 16104. Torosaside A(5,7'-biphyscion-8-~-D- C 38H 330 16 Ctorosa Leaves 222-3 10

glucoside (104)105. Torosanin-9',10'-quinone (105) C32H26010 Cmultiglandulosa Leaves 222-5 4106. Anhydrophlegmacin-9',10'-quinone (106) C32H26010 " Seeds 187-9 4,5,79107. Sengulone(9(physcion-7'yl)5,10- C 32H 220 10 " " 188-92 4

dihydroxy-2-methoxy-7-methy1-1,4anthraquinone) (107)

108. Isosengulone C32H22010 Cmultiglandulosa Seeds 152-4 5(9(Physcion-7'y1)-5,10-dihydroxy-2-methyl-7-methoxy-1 ,4-anthraquinone)(108)

109. 5,10-dihydroxy-2-methyl-9- C31H2009 C didymobotrya Pods 150-2 6(physcion-7'yl)-lA-anthraquinone (109)

110. Presengulone (110) C32H 260 10 Csophera Seeds 193-5 7

--.l

Chapter 1 18

(I)R)::::Rs::::OR R2::::R3::::~::::Rs::::R6::::R7::::R

(2) R1 :::: Rs:::: OR R3 :::: COOR R2 ::::~ :::: Rs :::: R.s:::: R7 :::: H(3) R) :::: Rs:::: OR R3 :::: CH3 R2::::~ :::: Rs:::: R6 :::: R7:::: H(4) R) :::: Rs:::: OR R3 :::: CH3 R6:::: OCR3 R2::::~ :::: Rs:::: R7:::: H(5) R):::: OCR3 Rs:::: R2:::: OR R3:::: CR3 Rt:::: Rs:::: R.s:::: R7:::: H(6)R1 ::::R.s::::R7::::OCH3 Rs::::R2::::OH R3 ::::CH3 ~::::Rs::::H

(7) R):::: Rs:::: R6 :::: R7:::: OCH3 R2:::: OH R3:::: CH3(8) R1 :::: R7:::: OCH3 Rs:::: R2:::: R6:::: OH R3 :::: CH3 ~:::: Rs:::: H(9) R) :::: Rs:::: OR R3 :::: CR20R R2::::~ :::: Rs:::: R.s :::: R7:::: H(IO)R)::::Rs::::R6 ::::OH R3 ::::CH3 R2::::Rt::::Rs::::R7::::R(11) R):::: Rs:::: R6 :::: OH R3 :::: COOH R2::::~:::: Rs:::: R7:::: H(12) R) :::: OH R2= CH3 R3 = COOH R6 = R7 :::: OCR3 Rg ::::~ :::: Rs :::: H(13) R1= R3 = Rs :::: OH R2::::CH3 R6 :::: R7= OCR3 Rs::::~ :::: H(14) R1 :::: Rs= OH R2= CH3 R3 :::: Rt:::: Rs= R6 :::: R7:::: H(15) R j = Rt = Rs= OH R3 = CH3 R7:::: OCH3 Rs= R2:::: R6 :::: H(16) R1= Rs= Rs= OB R3= CI-h R6 = OCB3 R2=: Rt:::: R7=: H(17) R) = OH Rs:::: R3 :::: OCH3 R2:::: CH3 ~:::: Rs :::: R.s:::: R7:::: H(18) R) :::: Rs:::: Rs= R6 :::: OH R3 = CH3 R2::::~ :::: R7:::: H(19) R1= Rs= OH R3= Rs= R7= OCH3 R2::::~ :::: R.s =: H(20) R1 :::: Rs= Rs :::: OH R6 = R7:::: OCH3 R2:::: CH3 R3::::~ :::: H(21)R)::::R6 ::::OH Rs::::OCH3 R3 =CH3 R2 ::::Rt::::Rs ::::R7 =H(22) R) :::: R3:::: OR R2 :::: CH3 &r :::: Rs= R.s:::: R7:::: Rs:::: H(23) R):::: Rs:::: R3:::: R6 :::: R7= OH R2 :::: CH3 Rs:::: H ~:::: OCH3(24) R) :::: Rs:::: R3= R6 :::: OH R2:::: CH3 R7:::: -CH=:CH2 ~ =: Rs:::: H(25) R) :::: Rs= R3 = OH R2 :::: CR3 R.s:::: OCH3 ~:::: Rs :::: R7 :::: H(26) R) :::: R2 :::: OH Rs= R.s = R7:::: OCH3 R3:::: CH3 ~:::: Rs= H(27) R) :::: Rs= R2 = OH R3= CH3 R6= R7:::: OCH3 ~ = Rs= H(28) R) = Rs= R2 = R6 = OH R3= CH3 R7= OCH3 ~ :::: Rs= H(29) R1 :::: Rs:::: OH R2 = CH3 R3 = R6 :::: OCH3 ~ = Rs= H R7= -CH=CH2

(30) R1= R3= OH Rs:::: Rs= R7= OCH3 R2 = CH3 ~ :::: R6 = H(31)R)::::OCH3 Rs=OH R3::::CH3 R2::::Rt::::Rs::::R6 ::::R7=H(32)R1=Rs=R3=Rs=OH R2 =CH3 R6 =OCH3 &r=R7=R

Chapter 1 19

(33) R 1= R3 = OH R2 = -CH2CH=C(CH3)2 Rg = Rt; = OCH3~ = Rs= R7= H(34) R1 = Rg = OH R3 = CH20H Rt; = OCH3 R2 =~ = Rs= R7= H(35) R] = Rg = OH R3 = COOH Rt; = OCH3 R2 =~ = Rs= R7= H(36) R] = Rg = OCH3 R3 = CH3 R2 =~ = Rs = Rt; = R7= H(37) R] = R3 = OH Rg = CH3 R2 = ~= Rs= R6 = R7= H(38) R] =~ = R6 = R7= OCH3 R2 = CH3 Rs= OH R3 = Rg = H(39) R 1= Rs= R7= OH R2 = CH3 R4 = R6 = OCH3 Rg = R3 = H(40) R 1= ~ = R7= OCH3 R2 = CH3 Rs= Rt; = OH Rg =R3 =H(41) R1 = OH R2 = CH3 ~ = R7= OCH3 Rs = ~= -O-CH2-O- Rg = R3 = H(42) R 1= ~ = R6 = OCH3 Rs= R7= OH R2 = CH20H Rg =R3=H(43) R 1= R6 = R7= OCH3 ~ = Rs= OH R2 = CH3 Rg = R3 = H(44) R2 = CH3 ~ = R7 = OCH3 Rs= R6 =OH R1= Rg = R3 = H(45) R 1= OH Rg = R2 = R6 = R7= OCH3 R3 = CH3 ~ = Rs= H(46) R1= Rg = R3 = OH R2 = CHO ~ = Rs= R6 = R7 = H(47) R1= Rs= OH R3 = CH3 R2 = R4 = R6 = R7 = Rg = H(48) R1= Rs= OH R3 = OCH3 R7= CH3 Rg = R2=~ =~ = H(49) R1 =~ = OH Rg = R6 = R7= OCH3 R2 = CH3 R3 = Rs= H(50) R] = Rg = R2 = OH R3 = CHO ~ = Rs= ~ = R7= H(51) R1= Rg = R3 = Rs= OH R2 = CH3 R6 = R7= OCH3 ~ = H(52) R 1= R3 = ~= Rs= OH R2 = CH3 Rg=R7= OCH3 Rt;= H(53) R 1= R3 =~ = OH R2 = CH3 Rg = R6 = R7= OCH3 Rs= H(54) R1 = Rg = OH R3 = CH3 R2 = Rs= R6 = R7= H

~ = 2,4-dihydroxy-6-methoxy acetophenone(55) R 1= Rs= OH R2 = R3 = CH3 Rg = OCH3 ~= R6 = R7= H(56)R1 =Rg =R2 =R6 =OH R3 =CH3 ~=Rs=R7=H

(57) R 1= OH Rg = R6 = OCH3 R2 = R3 = CH3 ~= Rs= R7 = H(58) R1 = Rg = OH R2 = CH3 R6 = R7= OCH3 R3 = ~= Rs= H(59) R1 = Rt;= Rg = OCH3 R2 = OH R3 = ~= Rs= R7 =H(60)R]=Rg=Rs=OH R3 =CH3 Rt;=OCH3 R2=~=R7=H

(61) R1= OCH3 R2 = OH R3 = CI-h Rg = ~ = Rs= Rt;= R7 = H(62) R1 = ~ = Rs= OH R7= CH3 Rg = R2 = R3 =~ = H(63) R1 = OH R2 = ~ = Rs= R6 = R7= H R3 = COOH Rg = O-glucose(64) R 1= OH R2 = R4 = Rs= R6 = R7= H R3 = CH20H Rg = O-glucose(65) R1= OH R2 =~ = Rs= R6 = R7= H R3 = CH3 Rg = O-glucose(66) R1 = R6 = OH R2 = ~= Rs= R7= H R3 = CH3

Rg = O-cx-L-rhamnopyranose(67) R 1= Rs= R6 = OH R2 = R4 = R7= H R3 = CH3

Rs= O-cx-L- rhamnopyranosc( 68) R 1= OH R3 = CH3 R6 = OCH3 R2 =~ = Rs= R7= H

Rg = ~-D-galactosyl-(1-7 4)-O-~-D- galactopyranose.

Chapter 1 20

(69) R] = Rs= Rg= OH R2 = CH3 R6 = R7= OCH3 ~=HR3=O-a-rhamnopyranose

(70) R] =Rs= OH R2 = CH3 ~=R7= OCH3 ~=Rg=H

R3=O-a-rhamnopyranose(71) R] = OH R3= CH3 ~ = OCH3 Rg= O-a-L-xylopyranose

R2 = ~= Rs= R7= H(72) R] = ~ = OH R3= CH3 Rg= O-a-L-arabinopyranose R2=~ = Rs= R7= H(73) R] = R3= OH R2= CH3~ = Rs=~ = R7= H Rg= O-a-arabinopyranose(74) R] = Rg= OH R2 = CH3 R6 = OCH3 R3= O-rutinose ~ = Rs= R7= H(75) R] = OH R2= ~ = Rs= R7= H R3= CH3 ~ = OCH3 Rg= O-gentiobiose(76) R] = R6 = OH R3= CH3 R2 = ~ = Rs= R7= H Rg= O-glucopyranose(77) R] = ~= OH R2= CH3 Rs= R6 = R7= H Rg= OCH3

R3= O-~-D-glucopyranose

(78) R3= CH3 ~= OCH3 Rg= OH R2= ~= Rs= R7= HR] = O-a-I-rhamnopyranosyl (1-76)-~-D-glucopyranose

(79) R] = OH R2 = CI-h R6 = Rg= OCH3 R3= O-rutinose ~ = Rs= R7= H(80) R] = ~ = Rg= OH R3= CH3 R6 = OCH3 Rs= R7= H R2=O-glucopyranose(81) R] = OH R2= CH3 ~ = Rs= H R6 = R7= Rg= OCH3

R3=O-~-D-glucopyranose(82) R] = ~ = Rs= R7= H R2= CH3~ = Rg= OCH3

R3=O-~-D-galactopyranose

(83) R 1 = Rs= Rg= OH R2 = CH3 ~ = R6 = R7= H R3= O-~-D-galactopyranose

(84) R] = Rs= Rg= OH R2 = CH3R6 = OCH3 ~ = R7= HR3=O-~-D-galactopyranosyl(1-74)-O-~-D-mannopyranose

(85) R 1= ~ = Rg= OH R3= CH3 R6 = OCH3 Rs= R7= HR2=O-~-D- glucopyranose

(86) R] =~ = Rs= R7= H R2 = CH3R6 = Rg= OCH3 R3= O-~:'D-glucopyranose

(87) R1 = OH R2 =~ = Rs= H R6 = R7 = Rg= OCH3 R3=O-~-D-glucopyranose

(88) R 1= R6 = OH R3= CH3 R2= ~ = Rs= R7= H Rg=O-sophorose(89) R 1 = R7= Rg= OH R2 = CH3 ~ = OCH3 Rs= R6 = H

R3=O-~- galactopyranose(90)R] =~ = OH R2= CH3 R6 = R7= Rg= OCH3 Rs= H

R3=O-~-D-glucopyranose

(91) R1 = O-glucose R2 =~ = Rs= R7= H R3= CH3 ~ = OCH3 Rg=OH(92) R] = OH R2 = R3= R4 = Rs= R7= H R6 = CH3 Rg= O-gentiobiose(93) R 1 = O-~-D-galactose R2 = CH3 R3= OH~ = Rs= R7= H

R6 =Rg=OCH3

Chapter 1 21

OH 0 OH

R

o

(94) R= H

o(95) R= OCH3

OHOH 0

0

(96)

0

R6

Rs

0

0

R6'

Rs'

R4' 0

(97) R] = R7= R3'=~' = OH R3= R]' = CH3R -D·-R -R -R'-R'-D-'-R'-H2 - 1.~ - 5 - 6 - 2 - 5 - 1.'{) - 7-

(98) R] = R7= R]' = R3' = ~'= R3= OH R2 =R2' = CH3

Rs= R.<;' = OCH3 R4 = R.<; = R7= Rs' =R7' =H(99) R] = R7=~' = OH R2 = R2' = Rs= R.<;' = CH3

R3 = R 1' = OCH3 ~=R6=R3' =Rs' =R7' =H(100) R 1= R3= R 1' = R3' = OH R2 = R2' = CH3

Rs = R7= ~'= R6' = OCH3 ~ =R.<; =Rs' = R/ = H(101) R 1= R7= R3' =R4' = OH R3 = R 1' = CH3

R2 = R4 = Rs = R6 = R3' = Rs' = R6' = R7' = H

Chapter 1

(105)

(102) X=O R=OH(103) X=H2 R=OH(104) X = 0 R = glucose

OR OR 0

on

(106)

22

OH

OH

Chapter 1

R'

OH OH 0

R

OH

23

(107) R = OCH3

(108) R= CH3

(109) R = CH3

R'=CH3

R'=OCH3

R'=H

(110)

Chapter 1 24

2. Biosynthesis starting fro~ shikimic acid.

The pathway is believed to take place as in Chart 2:· This has been

proved in Rubia tinctorum when C14 labelled shikimic acid was

specifically incorporated into alizarin and purpurin.

Chart 2

Glutamate ~deamination

eOOH0/ +TPP

eOOHJeoo:oqeooH

~ ~HO + ITPP HO

OH

2-Ketoglutaric acid TPP-Succinic acid Shikimic acidsemi aldehyde complex

HO«~OHeoOH eOOH

--~ I "'(. ~ 07''''eOOHHO ....;<~.. -.. --- --- ":::". I

OH TPP OH 0

Complex Succinyl benzoic acid

o OH

oAlizarin

Cyclisation

HO~/ eOOHHO

Mevalonic acid

OH

~COOH

'YOH

2-carboxy-l,4-naphthoquinoI

+OH

eOOH

OH

o OH

Purpurin-3-carboxylicacid

Chapter 1 25

Almost all anthraquinones, their glycosides and bianthraquinones,

reported from Cassia are 9,10- anthraquinones. Four 1,4-anthraquinones,

sengulone (107), isosengulone (108) 5, 1O-dihydroxy-2-methyl-9­

(physcion -Tyl) 1,4-anthraquinone (109) and presengulone (110) have

been isolated from C.multiglandulosa4,5 C.didymobotrya6 and

C.sophera7. Two 1,2 dihydro anthraquinones, roxburghinol (94) and 1,2­

dihydro-l ,3-dihydroxy-6,8-dimethoxy-2-methylanthraquinone (95) have

been reported from C.roxburghi8 and C.javanica. 9 1,8-dihydroxy

anthraquinones are the most commonly occuring anthraquinones in

Cassia species.

Anthraquinones and their glycosides are identified by colour

reactions, UV, IR, NMR and mass spectra and their stereochemistry

determined by CD cotton curves. 10

Preliminary information of hydroxyl substituents In

anthraquinones is obtained from the following colour reactions. Presence

of p- hydroxyl group is shown by solubility in sodium carbonate. Blue

green colour with alcoholic FeCl3 indicates presence of at least one free

phenolic hydroxyl group. 11 Vicinal hydroxyl groups can be ruled out if it

does not respond to this test. 13 Pink colour with methanolic magnesium

acetate shows presence of 1,3-dihydroxy system. Formation of a

complex with copper sulphate indicates presence of a chelated hydroxyl

function ie a hydroxyl a to the carbonyl.12

Anthraquinones having only one a- hydroxyl group show peaks at

222,260,373 and 450 nm in the UV spectrum in methanol. 14 Substituted

anthraquinones bearing three a-hydroxyls show characteristic absorption

bands in EtOH as solvent. (210, 265, 305, 482, 518 nm)9 Ortho di-

Chapter 1 26

hydroxyl groups are distinguished by a maximum absorption at 282 nm

and a bathochromic shift of 37 nm on adding H3B03 - NaOAc. 15

The presence of phenolic hydroxyl (3320 cm- I), chelated carboxyl

(1625 cm- I), non chelated carboxyl (1672 cm-l), and ~- methyl group

(1450 cm-I) can be ascertained from IR spectrum.8,11

Chelated hydroxyls can be detected using NMR by characteristic

singlet peaks at 8 12.05 and 8 12.26. Meta coupled aromatic protons are

identified by doublets at 87.32 and 86.60 with J 2.5 Hz. Other

characteristic peaks are methyl (8 2.45) and methoxyl (8 3.92).16 The

position of substituents can be confirmed by NOE experiments.4

Glycosides are identified by hydrolysis into aglycone and sugar.

Complete hydrolysis using emulsin indicates that the aglycone is linked

to the sugar by ~ linkage. 18 Complete hydrolysis with diastase indicates

a linkage. 19 The number of moles of periodate consumed during

periodate oxidation proves whether the sugar is in pyranose form or

not,20 The inter sugar linkages can be identified by IH NMR. II They can

be confirmed by I3C NMR.21

2. Anthrones

All anthrones (9, 1OH-anthracenones), their dimers (dianthrones)

and their glycosides so far isolated from Cassia are listed in Table 2.

Sennosides A (123) and B (124) have been proved to be the most active

constituents of Senna pods and leaves which have long been used as

laxatives and purgatives.22 Didyronic acid (116)was reported for the first

time from Cassia didymobotrya. Biogenetically anthrones are precursors

of anthraquinones. Studies on the biosynthesis of anthrones is available

in literature.The formation of the naturally occuring diastereomers,

Chapter 1 27

aloins A and B are investigated in Aloe arborescens using 14C labelled

compounds.23 ,24 Investigation into the conversion of anthrones to

anthraquinones in plants has also been reported. 25 No such study is

reported in plants of Cassia genus.

Anthrones are identified by UV, IR, IH and I3C NMR, appropriate

2D-NMR (COSY, NOESY, HMQC, HMBC) techniques, mass and

elemental analysis.

UV spectrum with EtOH Amax nm 225, 255, 293 and 354 and IR

spectrum with KBr Vmax em-I 1640, 1620, 1585, 1480, 1285, 1220, 1160

and 780 are characteristic of anthrones.26 A chelated carbonyl group

would give an absorption at 1637 em-I.

The proton NMR of anthrones was found to be similar to those of

anthraquinones. H-2 and H-4 of 1,3 substituted A ring would not show

any significant difference in chemical shifts if C-l 0 is not substituted. 28

Anthrones with no substituents at C-IO give a characteristic two proton

singlet at 8 4.21-4.39 due to the methylene group in IH NMR.27,16 In

anthrones where there is one substituent at C-I0, cross peaks between

methine protons at H-I0 (8 4.85 d) and ex hydrogen of the substituent are

seen in IH_IH COSY spectrum.242 The positions of the substituents are

confirmed by NOE experiments.27 I3C NMR spectra of naturally

occuring anthrones have been studied by Tamano. M and Koketsu. J.29

The~ of anthrones is obtained by high resolution EIMS.27

TABLE 2

Anthrones from Cassia

()::r~

'"0.....(]).....

SI.no Compound Molecular formula Source Part M.poC Reference

111. Chrysophanic acid -9-anthrone (111) CisH lOO6 Cassia tora Seeds, 200 231Cpodocarpa Flowers 232Csiamea Leaves 235

112. Emodin anthrone (112) C1sH120 4 Crogeoni Leaflets - 168Cnomane Seeds 170Ctorosa " 236

113. Chrysophanol anthrone (113) ClsHl203 Csiamea Leaves - 124114. Physcion-9-anthrone (114) Cl6H I 104 Ctorosa Seeds,root - 225,61

Cnor.zane Seeds 238,239115. 1,8-dihydroxy-3-methyl-9-anthrone (115) C1sH120 3 Cpodocarpa Flowers - 232116. Didyronic acid (116) CisHlOO7 C didymobotrya Pods >300 28117. Aloin(barbaloin) (117) C2lH2209 C.fistula Fruit 146-8 233118. Sennidin C (118) C30H2009 Csenna Leaves - 224,158

167119. Physcion chrysophanol dianthrone (119) C31H2207 C occidentalis Seeds - 137

120. Chrysof'hanol dianthrone (120) C30H2206 Csiamea Leaves - 124tv00

tv\0

Chapter 1

(111) R1 = OH R2 = COOH(112) R1 = OH R2 = CH3(113) R1= H R2 = CH3(114) R1= CH3 R2 = OCH3(115) R1= H R2 = CH3

OH 0 OH

30

HO

HO COOH

OH

(116)

OH

(117)

OH 0 OH

OH 0 OH

(118) R1 = COOH R2 = CH20H R3=~ = H(119) R1 =OCH3 R2 =H R3=~=CH3

(120) R1 = R2 = CH3 R3=~ = H(121) R) = R2 = OCH3 R3=~ = CH3(122) R) = COOH R2 = CH3 R3= OCH3 ~ = H

Chapter 1 31

(123) R1 = Rz= 0- glucopyranose R3= OR &. = COOR 10-10' = R-R(124) R1 = R2 = 0- glucopyranose R3 = OR &. = COOH 10-10' = R-S(125) R1 =Rz = OH R3= O-glucopyranose &. = CH20H

Oxanthrones

Oxanthrones are 10-hydroxy-9, 1O-anthracenones which are

intermediates in the biogenetic transformation of anthrones to

anthraquinones. The inter relationship between anthraquinone

derivatives is given in Chart 3.30

Oxanthrones and their derivatives are synthesised from

anthrones,31 amino anthracene32 etc. by oxidation. 10-propionyl

oxanthrone is synthesised from the corresponding anthrone by the anodic

oxidation of the active methylene group at C-I 0 in presence of excess of

carboxylic acid. 33 A large amount of literature is available on the

reactions of oxanthrones,34,35and their role as intermediates In the

synthesis of tetracycline36,37and anthraquinones.38They act as catalysts in

alkali pulping ofwood.39

Though a large number of oxanthrones are synthetically prepared

only twelve naturally occuring oxanthrones have been isolated from

Chapter 1 32

plant sources. Three oxanthrones have been isolated from the genus

Cassia and they are listed in Table 3a. Since in our study four 'new

oxanthrones are isolated from Cassia kleini, (Chapters II and III), the

remaining nine oxanthrones from literature are also listed in Table 3b.

Chart 3

o

oAnthraquinone

OH

o

4H

Anthrone

oxanthrone

"'"...

OH

Anthranol

Inter relationship between anthraquinone and its derivatives.

Chapter 1

TABLE 3a

Oxanthrones from Cassia

33

SI. Compound Molecular Source Part M.P.oC Referenceno. formula

126. Cassialoin Cz1HnOg Cassia Heart 302,147(lO-hydroxy- garretiana wood 24410-C-D-glucosylchrysophanol-9-anthrone)(126)

127. 10-hydroxy- C3I I-bOg C. didymobotrya Pods 182-4 610-physcion -7'-ylchrysophanol(127)

128. Alarone (128) ClsHIOO7 C.alata Stem 303

Chapter 1 34

OH 0 OH

OH

(126)

(127)

OH 0 OH

HO OCHOHO H

(128)

TABLE 3b

Naturally Occuring Oxanthrones

SJ.no. Compound Molecular formula Source Part M.P.oC Reference

129. 10-hydroxy aloin B -6"-O-acetate CZ3H24011 Aloe claviflora Leaves - 240(129)

130. 10-hydroxy aloin B (130) CZIH2Z01O " Leaves 136-8° 240,241A.littoralis 43A.vera 243Rhamnus purshiana 304

131. 10- hydroxy aloin A (131) CZIH22010 Aloe vera Leaves - 243Rhamnus purshiana Bark 304

132. Littora1oin (132) CZgH3Z013 Aloe littoraloin Leaves - 43133. Deacetyllittora1oin (133) CZ6H30012 " Leaves - 43134. lO-isopentenyl emodin anthran-lO-ol CzoHzoOs Psorospermum Root 190-2° 40

(134) tenuifolium Bark135. Isofo1iosone (135) CZ4HzoOg Kinophofia Stem - 42

foliosa136. Foliosone (136) CZ4HzoOg " Stem - 42137. Rheinoside A,B (137) CZ7H30016 Aloe 305

n::;­po

"0.-+(l)....

VJV>

Chapter 1 36

(129) R1= CH20H R2 = H R3 = glucosyl -6"-O-acetate(130) R1 = CH20H R2 = H R3 = ~-D-glucopyranose (R)(131) R1= CH20H R2 = H R3 = ~-D-glucopyranose (S)(132) R1 = CH20COCH(CH3)CH(OH)CH3 R2 = H

R3 = 6"-acetyl glucosyl(133) R1= H R2 = H R3 = ~-D-glucopyranose

(134) R1 = OH R2 = H R3 = -CH2CH=C(CH3)

ox

(135) X=H(136) X= CH3

COOHHO OR

(137) R = ~-D-glucopyranose

Chapter 1 37

Oxanthrones are identified by their UV, IR, and NMR spectra.

Spectral assignments are mainly based on analogies of chemical shifts

with those of anthrones and anthraquinones.

Oxanthrones and anthrones would show the presence of

chromophore in UV less extended than in anthraquinones (Amax 430nm)

The Amax of oxanthrones which has only one carbonyl group.is

comparable with those ofxanthones or benzophenones.(Amax 360 nm) and

those having two carbonyl groups ego aiarone303 (128) would show an

absorption at 440-460 nm.

The IR spectra would show the presence of only one carbonyl

compared to the two in anthraquinones. If chelated it would show a Vmax

at 1620 cm- I and if non chelated at 1670 cm-'.40

Nuclear magnetic resonance spectra of oxanthronestHNMR

The IH NMR of oxanthrones are characterised by the absence of

the two proton singlet at <5 4.21 due to the active methylene group at C­

10 in anthrones. If the C-10 is substituted by a saturated alkyl chain the

alkyl methylene would show peaks at <5 0.80 which suggests a link with

an Sp3 carbon. In 10-ethyl-1 0-hydroxy-9-anthrone methylene proton

signals were observed at <5 0.80.41 The saturated chain can freely rotate

and the fixed proton a, ~ or y to the ring are often found above the

nucleus, which explains their resonance at an elevated field~

Chemical shifts of the aromatic protons and that of substituents on

the aromatic nucleus are the same as that of anthrones. Chelated

hydroxyls at 1,8 positions give singlets at <5 11.5-12.5 and phenolic

Chapter 1 38

hydroxyls at 8 4-10. As an example, the hydroxyl resonances of

isofoliosone42 (135) are given below.

1

12.31

8

12.25

2'

11.96

4'

11.19

6'

4.8

Chemical shifts of other substituents on the aromatic nucleus are

methyl at 8 2.46s methoxyl at 8 3.88s and hydroxy methylene at 84.63d

for a -CH20H group. Protons of the aromatic nucleus give peaks in the

region of 8 6.5-7.9. Depending on the substitution pattern of the ring,

ABC pattern multiplet or meta or ortho coupling doublets are observed.

Chemical shifts and the coupling constants for aromatic protons of

representative oxanthrones are tabulated in Table 4.

Table 4

1 H NMR Chemical shifts of aromatic protons for fourrepresentative oxanthrones

Sl:no. Compound Proton no. Chemical shift Reference1 10-hydroxy aloin 2H 86.87d

(130) (J= 1.5)4H 87.40d

(J=1.5)5H 87.32dd 43

(J=7.8,1.0)6H 87.62t

(J=7.8)7H 86.93dd

(J=7.8,1.0)

2 isofoliosone 2H 86.68 br s(135) 4H 86.90 br s

5H 87.08 br d 426H 87.41 t7H 86.85 br d

Chapter 1 39

Table 4 (contd.)

Sl:no. Compound Proton no. Chemical shift Reference

3 foliosone 2H 06.66 br s(136) 4H 06.86 br s

5H 07.05 brd 426H 07.41 t7H 06.84 br d

10- 2H 06.28 d4 isopentenyl emodin (J=2)

anthran-10-ol 4H 07.0 d(134) (J=2)

5H o7.25d 40(J= 1.5)

6H 07.2 d(J=1.5)

7H 06.65 d(J= 1.5)

BC NMR spectra of oxanthrones have been studied in detail. 29

Assignments of 13C NMR are mainly based on analogies of chemical

shifts with those of anthrones and 1,8-dihydroxy-9, 10-anthraquinones.

Oxanthrones show a quaternary carbon resonance at 0 78.7 for C-10

indicating genation at this position and hence the presence of oxanthrone

moiety.42 The 13C NMR of a few representative oxanthrones (aglycones)

are given in Table 5.

Chapter 1

Table 5

13 C NMR Chemical shifts for three representative

oxanthrones

Carbon no: 1 2 3

1 163.9 162.1 162.32· 121.1 115.7 114.53 149.8 149.4 152.94 119.9 115.9 115.45 118.1 118.4 118.16 137.4 136.1 136.17 117.8 117.8 117.78 163.5 162.5 162.59 191.1 194.0 194.210 78.7 76.9 76.711 147.9 145.9 146.512 112.9 117.2 117.213 115.4 116.6 115.614 148.1 146.5 148.815 65.6 64.2

1. isofoliosone42 2. r I' 43 3. 10-hydroxy aloin B43Ittara om

40

Mass spectra

The fragmentation of the side chain at C-10 occurs giving rise to

the oxonium ion (a) as is shown in Chart 4.40 The oxonium ion degrades

to give the anthraquinone. The ElMS of oxanthrones give the~ of their

corresponding anthraquinones as the base peak.The anthraquinones, then

fragment further by a-cleavage.

Chapter 1 41

Chart 4

OR

OR 0 OR OR OR

-CsHg

01-1 OH

(a)

l-HOR

o

Mass spectral fragmentation of oxanthrones to anthraquinones.

Chapter 1 42

3. Flavonoids

Species of Cassia are rich sources of flavonoids which are of great

taxonomic interest. Flavones, isoflavones, flavonones, flavan-3,4-diols,

anthocyanidins, dimers of anthocyanins and their glycosides isolated

from Cassia are listed in Table 6.

Flavones with substituents in A, Band C rings are of common

occurence. Quercetin (140) and kaempferol (143) are reported from ten

different species of Cassia. Apigenin (142) and Luteolin (145) too are

common flavones. Proanthocyanidins containing flavan-3-01 units with

2R and 2S configuration are found in Cfistula, Cjavanica44 and

C.abbreviata.45 The ratio of 2R:2S units can be determined by applying

chiral resolution high-performance liquid chromatography.(HPLC)44

Flavanoid glycosides are of mono, di and triglycosidic nature. They are

identified by mild acid hydrolysis and their interglycosidic linkage by

13C NMR. Flavanoids are identified by their UV, IR, NMR ( IH, 13C) and

2D NMR techniques.

Chrysoeriol-7-0-(2"-O-~-D-mannopyranosyl)-~-D­

allopyranoside (172) not reported before from any plant source IS

reported for the first time from C. alata. 17

TABLE 6

Flavonoids from Cassia

(')go

'"0<i:".....

Sl.no Compound Molecular formula Source Part M.poC Reference

138. Kaempferol-3-diglucoside (138) C27H30016 Cassia tora Leaves 225-6 245139. Kaempferol-3-glucoside (139) C21H21011 Cnodosa Leaves - 246

Cspectabilis Flowers 160Cjavanica Leaves 126

140. Quercetin C1sHJOO7 Cglauca Flowers,pods 313-4 247,165,172(3,3',4',5,7-pentahydroxy flavone) (140) Csiberiana Leaves 105

Cmarginata Flowers 258C obtusifolia Leaves 248Claevigata Flowers 249Cjavanica Leaves 153Cmontana Heartwood 250Chirsuta Flowers 251Ccorymbosa Leaves,fruits 162,163

14l. Diosmetin (5,7,3'-trihydroxy, 4'- C I6HI20 6 C marilandica Leaves 253-5 136methoxy flavone) (141) Ctorosa Leaves 252

142. Apigenin(5,7,4'-trihydroxy flavone) CISHIOOS Cjaegii Leaves 347-8 141(142) Cabsus Seeds 106

Csiamea Leaves 87C didymobotrya - 152

.j::>.w

TABLE 6 (contd.) ()::r-p;>

"0......

Sl.no(1)

Compound Molecular formula Source Part M.poC Reference...,......

163. 3,5,3',4'-tetrahydroxy-7-methylflavone-3- C2SH3Z01S C. occidentalis Pods - 264O-(2"-rhamnosyl glucoside) (163)

164. 5,7,4'-trihydroxy-3,6,3'-trimethoxy- C30H36017 " " 264-flavone-7-0- (2"-rhamnosylglucoside)(164)

165. 4'-hydroxy-7,3'-dimethoxy flavone-5-0-13- CZ3H24011 c.spectabilis Seeds 207 265D(+) glucopyranoside (165)

166. Kaempferol-3-0-rutinoside (166) CZ7H3001S c.montana Heartwood - 250167. 5,7-dihydroxy-3',4'-methylenedioxy C16H lOO6 C. marginata seeds - 14

flavone (167)168. Torosaflavone A (apigenin-6-C-{3-D- CZIHzoOs c.torosa Leaves 171-2 266

olioside) (168)169. Torosaflavone B (diosmetin-6-C-I3-D- C2zH220 9 " " 240-1 266

olioside) (169)170. Kaempfero1-3-0-sophoroside (170) CZ7H300 16 C.alata Leaves - 268171. 7,4'-dihydroxy flavone-5-0-I3-D- CZIHzoOIO C. auriculata Roots - 268

galactopyranoside (171)172. Chrysoerio1 -7-0(2"-0-P-D- CzsH320 16 C.alata Seeds 164 17

mannopyranosyl) p-D-allopyranoside(172)

173. Rhamnetin -3-0-(2"-0-P-D- CzsH32017 " II 279 17

mannopyranosy1)13-D-allopyranoside (173)174. Quercetin-7,3'-dimethy] ether-3-0- CZ3Hzs0 12 C. tomentosa Leaves - 270

galactoside (174)._-~-_._._---- ....

0\

nTABLE 6 (contd.)

::r"'Pl

'"0.....CD...,

Sl.no Compound Molecular formula Source Part M.poC Reference

175. Kaempferol-3- O-galactorhamnoside C 27H3001S Ctomentosa Leaves - 270(175)

176. Kaempferol-3-0-I3-D-glucosyl-6-0-a-L- C27H30016 Cjavanica Leaves - 126rhamnopyranose (176)

177. Luteolin-7-O-glucoside (177) C2lH2oOl1 Ctorosa Leaves - 252Cnomane Aerial parts 257

178. Torosaflavone - B C2gH320 14 Ctorosa Leaves - 252-3' -0-I3-D-g1ucopyranoside (178)

179. Tamarixetin-3 -rutinoside-7- C34H42020 Citalica Aerial parts - 2rhamnoside(179)

180. Demethyl torosaflavone D (180) C1gHl20g Cnomane Aerial parts 270 257,267181. Penduletin(4',5-dihydroxy-3,6,7- C1gHl60 7 Ccorymbosa Leaves,fruits 216-7 162

trimethoxy flavone) (181)182. Rhamnetin -3-0-(6'-0-a-L-rhamno C2gH32016 Csiamea Stem bark - 272

pyranosyl)-I3-D-galactopyranose (182)183. Isorhamnetin-5-glucoside (183) C22H220 12 Cspectabilis Flowers - 160184. 5,7-dihydroxy-6-methoxy flavone-4' -0- C2gH32016 C marginata Roots - 273

neohesperidoside (184)185. Isorhamnetin (185) Cl6Hl207 C didymobotrya Whole plant 305 28186. 4'-methoxy kaempferol-3-0-a-L-rharnno C27H30014 Cbiflora Leaves - 274

pyranosyl-7-O-I3-D-xylopyranoside (186)187. Isorhamnetin-3-0-I3-g1ucoside (187) C22H22012 Cangustifolia Leaves - 260

188. Quercetagetin (188) ClsHIOOg C corymbosa Fruits 318-20 163189. Rhamnetin-3-0-gentiobiosic!e{l891 _ ~2gI:!32Q17 Cfistula Roots - 275 ..,.

--.l

()

TABLE 6 (contd.)::r~

"0.....(1l...,

Sl.no Compound Molecular formula Source Part M.poC Reference

190. Centaureidin (190) C1gH l60 g C didymobotrya Aerial parts - 9519l. 5,7-dihydroxy-4'-methoxy flavanol-3-0-~- C22H220 I I Cglauca Pods - 172

D-galactopyranoside (191)192. Diosmetin-7-glucoside (192) C22H220 11 C marilandica Leaves - 136193. Quercetin-3',4',7-trimethyl ether-3-0-a-L- C24H26011 Cjavanica Flowers 190 54

rhamnopyranoside (193)194. Jaceidin-7-rhamnoside (194) C24H26012 C occidentalis Leaves 200 276195. 5-hydroxy-3',4',5',6,7-pentamethoxy flavone- C26H320 12 Crenigera Stem bark 230 256

5-0-a-L-rhamnopyranoside (195)196. Kaempferol-3-arabinoside (196) C2oH1gOlO C.fistula - - 277197. Apigenin-7-galactoside (197) C21 H200 10 Csiamea Leaves - 135198. Rharnnetin (198) C16H120 7 Cgarretiana Heartwood 294 107199. Luteolin-7-O-~-D-glucopyranosyl-(1-74)-O- C26H2g0 1S Cglauca Seeds - 278

a-L-arabinopyranoside (199) Cmimosoides Seeds ,roots 166

200. Rharnnocitrin C16H120 6 Cgarretiana Heartwood 221-2 107(kaempferol methyl ether) (200)

20l. Hyperin(quercetin-3-a-D-galactoside) (201) C21H200 12 C tomentosa Leaves 237-8 270

202. Rutin(quercetin rutinoside) (202) C27H300 16 Cmontana Heartwood >190 250Chirsuta Flowers 251Crugosa - 279

203. 3,5,8,3',4',5'-hexahydroxy flavone (203) C1sHlOOg Ctora Stem bark - 280Leaves 281

204. 5,7,3',4'-tetrahydroxy -6,8-dimethoxy C22H220 13 C.fistula Stem bark 285 72flavone-3-O-a-arabinopyranoside (204)

.j:>.00

()g

TABLE 6 (contd.)'"0...

(1)..,

Sl.no Compound Molecular formula Source Part M.poC Reference

205. 5,7,4'-trihydroxy-6,8,3'-trimethoxy C30H36018 Cfistula Stem bark 210 72flavone-3-0-a-L-rhamnosyl(l.-72)-O-P-D-glucopyranoside (205)

206. 2,3',6'-trihydroxy-4'-methoxy flavone-7-0- C28H32016 Csiamea Leaves - 282neohesperidoside (206)

207. Nodosin (2'-hydroxygenistein-6-C-a-L- C27H30017 Cnodosa Flowers - 283rhamnosyl- (l.-72)-glucopyranoside (207)

208. 8-C-glucosyl genistein (208) C21H20011 " " 283-209. 2' ,4',5,7-tetrahydroxy-8-C- C21H200 12 Csiamea Leaves - 284

glucosylisoflavone (209)210. Cassiglucin (210) C28H340 17 Cmultijuga Seeds - 28521l. 3,5,6',4',5'-pentahydroxy -7-methoxy C22H24013 Csophera Leaves - 286

flavanone-8-C-L-rhamnopyranoside (211). ,

212. 7,3',4'-trihydroxy flavonone (212) ClsH120 S Cnomane Aerial parts 270 257213. 5-hydroxy-4'-methoxy flavonone-7-a-L- C21 H2409 Crenigera Stem bark - 188

rhamnopyranoside (213)214. Matteucinol-7-rhamnoside (214) C24H2809 C occidentalis Leaves 170 276215. Goratensidine(4',5,7-trihydroxy flavan-3,4- ClsH l40 6 Cgoratensis Leaves - 287

diol) (215) Cmarginata Trunk bark 288216. Fistucacidin(5,4'-dihydroxy flavan-3,4- ClsHl40S Cfistula Stem bark 245-7 289,116,

diol) (216) Sapwood 290217. 6-pentenyl pelargonidin (217) C20H220S Cmarginata Flowers >320 291218. Catechin(3,3',4',5,7-pentahydroxy flavonol) ClsH1406 C marginata Leaves 96 96

l218) . Cjistula Sapwood 157-l:>.\Q

(J

TABLE 6 (contd.)::::;I'J-0

,..;-(1)...,

Sl.no Compound Molecular formula Source Part M.poC Reference

218. Catechin(3,3',4',5,7-pentahydroxy flavonol) ClsH1406 Cgrandis Aerial parts 96 95(218)

219. 7,3',4',-trihydroxy flavan-3,4-diol (219) ClsH140 6 C marginata Leaves - 96220. Epicatechin (220) ClsH140 6 Csieberiana Roots - 292221. Epiafzelechin (221) ClsH140 S Croxburghi Pods 242 92

Cabbreviata Bark 45Cjavanica Wood 89Csiberiana Root bark 293C.jistuZa Sapwood 157

222. 4'-0-methyl entgallocatechin (222) C16H1607 C trachypus Roots 138-40 223223. Afzelechin (223) ClsH140 S Cabbreviata Bark - 45224. Epigallocatechin (224) C1sH140 7 Csiberiana Roots - 292225. Gallocatechin (225) ClsH1407 " " - 292226. Leucopelargonidin (226) ClsH140 6 " " - 292227 Leucocyanidin-3-0-a-L - C21H240 11 Cjavanica Root bark - 294

rhamnopyranoside (227)228. Leucopeonidin-3-0-a-L- CnH260 11 Cjavanica Root bark - 294

rhamnopyranoside (228)229. Leucocyanidin-7,4'-0-dimethyl-3-0-~-D- C23H2S0 12 CZaevigata Stem - 295

glucopyranoside (229)230. Leucocyanidin-7,4'-0-dimethyl-3-0- C29H3S0 16 CZaevigata Stem - 295

rutinoside (230)231. Leucopelargonidin-3-0-L- C21H2S0 11 Ctora Roots - 186

rharnnopyranoside (231)Vl0

()

TABLE 6 (contd.)::r"'Pol

"0(t..,

Sl.no Compound Molecular formula Source Part M.poC Reference

232. Leucocyanidin-4'-O-methyl ether-3-0-J3- C22H260 12 Cjavanica Flowers 240 54D-galactopyranoside (232)

233. Peonidin-3-0-a (4)rhamnopyranoside C22H230 10 Cjavanica Flowers - 296(233)

234. Pelargonidin-5-0-J3-D-galactose (234) C21 H21 O IO Cauriculata Heartwood - 297235. 3',6-dihydroxy-4-methoxy chalcone (235) C16H 1404 Cjavanica Root bark - 298236. Demethyltorosaflavone C (236) C21 H 14Og Cnomane Aerial parts 280 257,267237. 3',4',7-trihydroxy flavan-(4a-78)- C30H26010 Cnomane Dried fruits - 299

catechin (237)238. Guibourtinidol-(4a-78)-afzelechin (238) C30H2609 Cabbreviata Bark - 45239. Guibourtinidol-(4a-78)-catechin (239) C30H26010 Cabbreviata " 45-240. Fisetinidol-(4a-78")-gallocatechin (240) C30H26012 Cauriculata Stem bark - 192241. Fisetinidol-(4a-78")-epigallocatechin C30H26012 C auriculata Stem bark - 192

(241)242. 3',4',7-trihydroxy flavan-(4J3-78)- C30H260 10 Cnomane Dried fruits - 299

catechin (242)243. Guibourtinidol-(4a-78)-epicatechin (243) C30H26010 C abbreviata Bark - 45244. Ent-guibourtinidol-(4J3-78)-epicatechin C30H26010- " " 45-

(244)245. Auricacidin (245) C30H220 12 C auriculata Flowers - 300

VI

Chapter 1 52

(138) R 1= R3= R6 = OH Rz = Rs= R7= H ~ = O-diglucose(139) R1= R3= ~ = OH Rz= Rs= R7= H ~ = O-glucose(140) R1= R3= ~ = Rs= R6 = OH Rz= R7= H(141) R1=R3=Rs=OH Rz=~=R7=H ~=OCH3

(142) R1=R3= ~= OH Rz=~=Rs=R7=H(143) Rl=R3=~=~=OH Rz=Rs=R7=H(144) R1= R3= R6 = R7= OH Rz= ~= OCH3 Rs= H(145) R 1= R3= Rs= R6 = OH Rz= ~= R7= H(146) R1= R3= Rs=~ = OR Rz= R7= H ~ = O-glucopyranose(147) R1= R3= R6 = OH Rz= Rs= R7= H Rt = O-arabinopyranose(148) R1 = R3= R6 = OH Rz= Rs= R7= H Rt = O-glucopyranose(149) R1= R3= R6 = R7= OH Rz= Rs= H Rt = O-glucose(150) R 1= R7= OH R3= R6 = OCH3 Rz= Rs= H ~ = O-galactopyranose(151) R1=OH Rz=Rs=H R3=~=R7=OCH3

Rt=O-~-D(+) galactosy1-0-~-D(+)galactopyranose(152) R1 = R3= R6 = OH Rz= Rs= R7= H ~=O-~-glucopyranose

(153) R1= R3= Rs= R6 = OH Rz= R7= H ~ = O-~-D-galactopyranose

(154) R1= Rt= R7= OH Rz= Rs= H R3= ~= OCH3(155) R1= R7= OH Rz= Rs= H R3= ~ = OCH3 ~=O-neohesperidose

(156) R1= R6 = R7= OH Rz= Rs= H R3= Rt=O-rhamnopyranose(157) R1= Rs=~ = OH Rz= R7= H R3= OCH3

~ =O-3-galactosyl(l-74)galactopyranosde(158) R 1= Rs= R6 = OH Rz= R7= H R3=OCH3

~=0-galactosyl-(l-76)-galactose

(159) R1 = Rs= R6 = OH Rz= R7= H R3= OCH3 Rt=O-~-D-glucose

(160) R1 = R3= OH Rz= R4 = Rs= H R7= CH3 R6=0-L-rhamnopyranose(161) Rl=R3=~=Rs=R7=H R6 =OCH3 Rz =O-arabinopyranose(162) R1= OH Rz= Rs= H R3= ~ = R7= OCH3 ~=O-arabinopyranose

(163) R1= ~= R7= OH Rz= Rs= H R3= CH3Rt=0-2"- rhamnosylglucose

Chapter 1 53

(164) R]=R6 =OH Rz=~=R7=OCH3 Rs=HR3=0-2"-rhamnosyl glucose

(165) R] = R3 = R6 = OH Rz= Rs= R7= H ~ = O-galactorhamnose(166) R] = R3 =~ = OH Rz= Rs= R7= H

~ = 0-P-D-glucosyl-6-0-a-L-rhamnopyranose(167) R] = R3= OH Rz=~ = Rs = H ~ = R7= -O-CHz-O-(168) R]=R3=~=OH Rz=C-P-D-oliose ~=R5=R7=H

(169) R] = R3= R7= OH ~ = Rs= H Rz= C-P-D-oliose ~=OCH3

(170) R] = R3 =~ = OH Rz= Rs= R7= H ~ = O-sophorose(171) R] = O-p-D-galactopyranose Rz=~ = Rs= R7= H R3=~ = OH(172) R]=R6 =OH Rz=R4 =Rs=H R7=OCH3

R3= 0-(2'-0-p-D-mannopyranosyl)p-D-allopyranose(173) R] = R6 = R7= OH Rz= Rs= H R3= OCH3

~ = 0-(2"-0-p-D-mannopyranosyl)-p-D-allopyranose(174) R] = R6 = OH Rz= R7= H R3= Rs= OCH3 ~ = O-galactose(175) R] = O-glucopyranose Rz=~ = Rs= H ~ = OH

R3=R7=OCH3(176) R 1= R3= R6 = OH Rz= Rs= R7= H R4 = O-rutinose(177) R] = Rs= R6 = OH Rz=~ = R7= H R3= O-glucose(178) R] = R3= R6 = OH ~ = Rs= R7= H Rz= P-D-glucose(179) R] = R7= OH R6 = OCH3 Rz= Rs= H R3= O-rutinose

~ = O-rhamnose '(180) R] = R3= R6 = R7= OH Rz= -CH=CH-COOH ~ = Rs= H(181) R]=~=OH Rz=R3=~=OCH3 Rs=R7=H(182) R] = R6 = R7= OH Rz= Rs= H R3= OCH3

~ = (O-a-L-rhamnopyranosyl)-p-D-galactopyranose(183) R 1= O-glucose Rz= Rs= H R3=~ =~ = OH R7= OCH3(184) R 1= R3= OH Rz= OCH3 R4 = Rs= R7= H R6 = O-neohesperidose(185) R 1= R3= R6 = OH· Rz=~ = Rs= H R7= OCH3(186) R 1= ~ = OH Rz= Rs= R7= H R3= 0- a-L-rhamnopyranose

~ = O-P-D-xylopyranose(187) R 1= R3= R6 = OH Rz= Rs= H ~ = O-p-glucose R7= OCH3(188) R1= Rz= R3= R4 = R6 = R7=,OH Rs= H(189) R] = Rs= R6 = OH Rz= R7= H R3 = OCH3

~=O-gentiobiose

(190) R1= R3= R7= OH Rz= R4 = R6 = OCI-I3 Rs= H(191) R1= R3 = OH Rz= Rs= R7= H ~ = O-galactopyranose ~ = OCH3(192) R1= R7= OH Rz= R4 = Rs= H R3= O-glucose R6 = OCH3(193) R 1= OH Rz= R7= H R3= Rs= R6 = OCH3 ~ = O-rhamnopyranose(194) R 1= R6 = OH R3= O-rhamnose Rz= ~ = R7= OCH3 Rs= H

Chapter 1 54

(195) R j = O-a-L-rhamnopyranose R2 =R3 = Rs= ~ = R7 = OCH3 ~ = H(196) R j = R3 = R6 = OH R2 = Rs= R7 = H ~ = O-arabinose(197) R j = R6 = OH R3 = O-galactose R2 =~ = Rs= R7 = H(198) R j = ~= Rs= R6 = OH R2 = R7 = H R3 = OCH3(199) R 1= Rs= R6 = OH R2 = R4 = R7 = H

R3 = O-glucopyranosyl-(1-74)- a-L-arabinopyranose(200) R j = R3 =~ = OH ~ = OCH3 R2 = Rs= R7 = H(201) R j = R3 =~ = R7 = OH R2 = Rs= H ~ = O-galactose(202) R j = R3 = Rs=~ = OH R2 = R7 = H ~ = O-rutinose

R9

(203) R j =~ = Rs= R7 = Rg = R9= OH R2 = R3 =~ = RIO = H(204) R j = R3 = R9= Rg = OH R2 =~ = OCH3 ~ = R7 = RIO = H

Rs= O-a-arabinopyranose(205) R j = R3 = Rg = OH R2 =~ = R9= OCH3 ~ = R7 = RIO = H

Rs= O-a-L-rhamnosyl- (1-72)- O-P-D-glucopyranoside(206) R j =R2=~=Rs=R7=H Rg = OCH3 ~=R9=RIO= OH

R3 = O-neohesperidose

OH

(207) R j = a-L-rhamnosyl-(1-72)-glucopyranoseR2 =H R3 =OH

(208) R j = H R2 = glucose R3 = H(209) R j = H R2 = glucose R3 = OR

Chapter 1

(210) R)=R3=R9=OH R2=~=~=R7=Rg=H R lO =OCH3Rs= O-P-D-glucopyranosyl-(1-76)-P-D-glucopyranose

(211) R) = Rs= ~= R7= Rg= OH R3= OCH3 R2= R9= R lO = H~ = rhamnopyranose

(212) R) = R2= ~= Rs= R6 = R7= RIO = H R3= Rg= R9= OH(213) R) = OH R2= ~=Rs= ~=R7=R9= RIO=H Rg= OCH3

R3= rhamnopyranose(214) R) = OH R2= Rt= CH3 Rs= R6 = R7= R9= RIO = H

Rg= OCH3 R3= O-rhamnose

Rs

(215) R) =R3=~=Rs=R7= OH R2=~=Rg=H

(216) R2=R3=~=Rg=H R) = R7=Rs= ~= OH(217) R) = R3=~ = Rs= R7= OH R2= (CH3-CH2)CH=CH-CH3

~=Rg=H

(218) R) = R3= Rs = R6 = R7= OH R2= ~= Rg= H(219) R) = R2= R6 = H R3=~ = Rs= R7= Rg= OH(220) R) = R3= Rs= R6 = R7= OH R2= ~ = Rg= H(221) R)=R3=Rs=R7=OH R2=R4 =R6 =Rg=H(222) R) = R3= Rs= R6 = Rg= OH R2= ~= H R7= OCH3(223) R 1= R3= Rs= R7= OH R2= ~ = R6 = Rg= H

55

Chapter 1

HO

OH

(224)

OH

OH

OH HO

OH

(225)

56

OH

/< ~ OH

OH OH

(226) R1= R2 =~ = OH R3 = H(227) R1= R3 =~= OH R2 = O-a-Lrhamnopyranose(228) R1=~= OH R3 = OCH3 R2 = O-a-L-rhamnopyranose(229) R1=~= OCH3 R2 = O-P-D-glucopyranose R3 = OH(230) R1 = ~= OCH3 R2 = O-rutinose R3 = OH(231) R1 = ~ = OH R2 = O-rhamnopyranose R3 = H(232) R1 = R3 = OR R2 = O-p-D-galactopyranose ~= OCR3

HO

OH

(233) R1= OR R2 = O-a -L-rhamnopyranose R3 =OCR3

(234) R1= O-p-D-galactose R2 = OR R3 = R

Chapter 1

o

57

HO

(235)

OH

HO

OH

o(236)

HO

OH

(237) R1= R1' = R R2 = R2' = OR(238) R1 = R1' = OR R2 = R2' = R(239) R, = R1'= OR R2= R R2' = OR

Chapter 1

HO

HO

OH

(240)

OH

OH

(241)

OH

58

HO

OH

(242)

OH

Chapter 1

HO

OH

(243)

59

H0Yy0l""'..( ) OH

~OHHO 1,,,,,,< ( OH

"""OH OH

OH

(244)

HO

01-1

(245)

OH

Chapter 1 60

4. Triterpenes

Triterpenes and sterols isolated from Cassia are listed out in Table

7. The triterpenes have one of the following skeleton types lupane,

oleanane or friedelane. Trihydroxy isohopane (273) is reported from one

species, C.hirsuta.46 Lupeol, (246) betulin, (247) a and P amyrins

(253,254)are reported from several species of Cassia.

The most commonly occurring phytosterols are p-sitosterol, (259)

stigmasterol, (261) and their glycosides. p-sitosterol is reported from

nineteen species. Other sterols isolated from some of the species are

cholesterol, (262) fucosterol, (263) isofucosterol, (264) campesterol,

(266) and their glycosides.

5. Alkaloids

Alkaloids comprise a small group of secondary metabolites from

Cassia. Majority of the alkaloids belongs to the piperidine class. Three

isoquinolone alkaloids siaminine A, Band siamine47; and a new

chromone alkaloid cassidinine48 are isolated from C.siamea. N1,N8_

bibenzoyl spermidine is the first example of a simple benzoyl derivative

from a natural source. 16 c.spectabilis, c.carnaval, C.siamea and

C.leptophylla are species which yielded the most number of alkaliods.

TABLE 7

Triterpenes and sterols from Cassia

n::r'P:>'0......

CD....

Sl.no Compound Molecular formula Source Part M.P.oC Reference

246. Lupeo1 (246) C30HsoO Cassia siamea Root bark 212 132,306" Flowers 307

Cjistula Stem bark 308Csiberiana Root bark 293Cabbreviata Whole plant 142

247. Betulin (247) C30Hso02 Csiamea Trunk bark 248 222

" Flowers 48C holosericae Aerial parts 309Crenigera Bark 310

248. Lupenone (248) C3oRtSO Csiamea Trunk bark 170 311249. Betulic acid (249) C30RtS03 Cgarrettiana Heartwood 316-8 107

C obtusifolia Roots 60250. Lup-20(29)-ene -1 ~,3~ -diol (250) C30Hso02 Csiamea Stem bark - 31225I. Lup-20(29)-ene -3~-octanoate (251) C3sH660 C roxburghi Fruits - 161252. 01eanolic-3-galactosyl(1 ~4) C42H6S0 13 Claevigata Flowers >300 249

galactopyranoside (252)253. a-amyrin (253) C30HsoO Cjavanica Leaves 186 153

Cholosericae Aerial parts 309Crenigera Bark 310,313C tomentosa Leaves 270

0\

()

TABLE 7 (contd.)::r"I'l-0.....

(1).....~

SI.no Compound Molecular formula Source Part M.P.oC Reference

253. a-amyrin (253) C30HsoO Citalica Leaves 314,110Croxburghi Fruits 161

254. ~-amyrin (254) C30HsoO Cjavanica Leaves 197-8 153C holosericae Aerial parts 309Crenigera Leaves 310

" Bark 313C tomentosa Leaves 270

255. 19a,24-dihydro urs-12-ene,28-oic acid- C33HS20 g Csiamea Stem bark 13030-~-D-xylopyranoside (255)

256. Ursolic acid (256) C30~g03 Csiamea Leaves 291 282257. Oleanolic acid (257) C30~g03 Csiamea Trunk bark 306-8 306258. Freidelin (258) C30HSOO C obtusifolia Leaves 262-3 285

Csiamea Flowers 48259. ~-sitosterol (259) C29HSOO Ctora Roots 136 186

" Stembark 280Cauriculata Flowers 254C auriculata Leaves 122Cjavanica Heartwood 315

" Flowers 296Csiamea Flowers,bark 306,307C obtusifolia Leaves,seeds 248,104Cmarginata Flowers 255Csiberiana Rootbark 293Cjistula Flowers 316

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Chapter 1

(246) R] = H R2 = OH R3 = CH3

(247) R] = H R2 = OH R3 = CH20H(248) R1= H R2 = 0 R3 = CH3

(249) R] = H R2 = OH R3 = COOH(250) R] = R2 = OH R3 = CH3

(251) R] = H R2 = OC(O)CgH]6 R3 = CH3

,,,,

(252)R] = O-galactosyl(1-74)galactopyranoseR2 = COOH R3 = H ~ = Rs= CH3

(253) R] = OH R2 = R3 = CH3 ~ = H Rs= CH3

(254) R] = OH R2 = R3 = H ~ = Rs= CH3

(255) R1= R3 = Rs= H R2 = COOH~ = O-xylopyranose

(256) R] = OH R2 = COOH R3 =Rs= CH3 ~=H

(257) R] = OH R2 = COOH R3 =H ~=Rs=CH3

65

~(262) R1= OH R2 =

Chapter 1

(261) R1 = OH

66

(258)

(259) R1=OH R2 =~(260) R1= O-glucopyranose R2 =~R2=~~(263) R1= OH R2 = (264) R1= OH R2 =

(265) R1= O-glucose R2 =~ (266) R1= OH R2 =

(267) R1~ O-glucose R2 =~

Chapter 1

R

67

(268) R= 0 (269) R= OH

HO

(270)

HO

(271)

(272)

Chapter 1

HO

(273)

68

6. Aliphatic compounds.

This category includes aliphatic hydrocarbons, acids, alcohols,

esters and ketones isolated from Cassia. Aliphatic hydrocarbons are

isolated from the wax obtained from the plants. The composition of this

wax varies with the environmental history and with the age of the plant.

Homologous series of n-alkanes (C I6-C3S) have been isolated from

c.s,iamea, C.sophera, C.fistula, and C.occidentalis.49 Widely distributed

aliphatic compounds in this genus are hexacosanol (C26), octacosanol

(C28) and triacontanol (C30). All straight chain saturated and unsaturated

acids reported from Cassia have even number of carbon atoms except

pentacosanoic acid.

7. Polysaccharides

Monosaccharides, polysaccharides and galactomannans are

isolated from different species of Cassia. The monosaccharides isolated

are rhamnoseso, glucose, galactose and xylose. 51 One disaccharide

sucrose 271 and a trisaccharide raffinose 51 are isolated from C. grandis

and C. tara respectively. Polysaccharides are isolated from a few

species.52 Galactomannan is widely distributed in Cassia genus and is

isolated from the seeds of several species of Cassia. Galactomannan is

Chapter 1 69

composed of galactose and mannose but their molar ratio and their

interlinkage vary from plant to plant.52,53,55 The structure of

galactomannans and polysaccharides are investigated using chemical

methods55,80 and spectral data.56

8. Miscellaneous compounds.

The compounds discussed under miscellaneous group are divided

into the following classes.

1. Naphthopyrones and y - pyrones

2. Xanthones.

3. Tetrahydroanthracenes.

4. Chromones.

5. Aromatic compounds.

(1) Naphthopyrones and y- pyrones

Naphthopyrones isolated from Cassia can be further subdivided

into a-naphthopyrones, y-naphthopyrones and angular y-

naphthopyrones.

The a-naphthopyrones reported from Cassia are toralactone, its

derivatives and glycosides isolated from C tora,57 C obtusifolia,59,60 and

Ctorosa. 61 The y-naphthopyrones from Cassia are rubrofusarin,

quinquangulin62 and their glycosides.58,63 Four new angular

naphthopyrones; 10- demethyl flavasperone and its deivatives which

show antimicrobial activity are reported from C pudibunda.64

Three y-pyrones chelidonic acid, monomethyl chelidonate and

dimethyl chelidonate are isolated from C spectabilis. 65 ,66 Potassium

Chapter 1 70

chelidonate which is concerned with the circardian rythm in nyctinastic

plants is isolated from C.mimosoides. 67,68

(2) Xanthones

There are only five reports of xanthones from Cassia. The first

report is in C. occidentalis from which cassiollin is isolated. 69 Pinselin

and 1,7-dihydroxy-3-methylxanthone are isolated from C.occidentalis.70

The other xanthones isolated are cassiaxanthone 71 and 1,8-dihydroxy­

3,7-dimethoxy xanthone 4 -O-glycoside. 72

(3) Tetrahydroanthracenes

Tetrahydroanthracenes have been isolated from a wide variety of

sources including plants and fungi. 79 Torosachrysone,74 trachrysone,75

germitorosone, germichrysone73,78 their derivatives and glycosides are

isolated from different species of Cassia.

Seven bitetrahydroanthracenes are isolated from Cassia.

Phlegmacin, torosaol land 2 from C. torosa,77,79 singueanol land 2 from

C.singueana73 and occidentalol 1 and 2 from C. occidentalis. 81

(4) Chromones

A few bioactive chromones are reported from Cassia. 5­

acetylmethyl-7-hydroxy-2-methyl chromone isolated from C.siamea82 is

the first example of a chromone with an acetonyl side chain in the 5

position meta to the hydroxyl group. 5-acetonyl-2-methylchromone-7-0­

~-D-glucopyranoside and 5-acetonyl-6-glucosyl-7-hydroxy-2-methyl

chromone isolated from C. multijuga83,84 has not been reported earlier

from any plant source. c.spectabilis 85 also yields chromones.

Chapter 1 71

Barakol, a dioxaphenalene isolated from Csiamea86,87 can be

chemically converted into 5-acetyl methyl-7-hydroxy-2-methyl

chromone showing that both substances must be derived from the same

polyketide chain. It is the first reported example of a naturally occurring

compound containing both a chromone hemiacetal and a dioxaphenalene

system.

(5) Aromatic compounds

Compounds included under this group are stilbenes, stilbenoids,

cinnamic acid, cinnamaldehyde, benzaldehyde, phloroacetophenone and

their derivatives and simple aromatic compounds.

Three stilbenes; piceatanol,88,89,90 roxburghin91 ,92 and cis-3,3',5,5'­

tetrahydroxy-4-methoxystilbene63 and stilbenoids; cassigarol A, B, C

and D,93,154 which are piceatanol dimers are isolated from Cassia genus.

Cinnamic acid,52 trans-3-methoxy-4,5-methylene dioxy cinnamaldehyde,

and myrysticin95 are reported from Cgrandis and coreopsin96 from

Cmarginata. The neolignan eupamatenoid-7 isolated from

Clindheimerriana97 is the third report from a natural source.

Syringaresinol-4-0-glucoside9l! is the first example of a lignoid reported

from the genus Cassia. Two dihydro naphthalenes, 6,8-dihydroxy-7­

acetyl-I-keto-3-methoxy-4,4-dimethyl-1 ,4-dihydronaphthalene and its

dimer are isolated from Csemicordata. 99 Derivatives of naphthalene and

h · 1 'd kn . h' . 100101 M . 'd 102tell' g ycoSI es are own to occur m t IS specIes.' argmosl e

and cassiosidel03 are phloroacetophenones reported from Cassia. 102,103

Other aromatic compounds are m-cresol,

methoxyacetophenone,104 catechol,105 terephthalicacid,92

benzoicacidl06 and protocatechuic acid. l07,108

2-hydroxy-4­

2,5-dihydroxy

Chapter 1 72

Biological activity studies

Cassia leaves and pods have long been used as laxatives and

purgatives.8o,229 The anthraquinone derivatives including oxanthrones are

responsible for the purgative action shown by plants in Cassia genus.

Sennosides A and B have been proved to be the most active constituents

of Cassia.22 I,8-dihydroxy anthraquinone glycosides are favourably

absorbed by the intestine and the glucose moiety protects the active

principle against degradation.3

I-[(~-D-glucopyranosyl-(1~3)-O-~-D-glucopyranosyl-(1 ~6)-O­

~-glucopyranosyl)oxy]-8-hydroxy-3-methyl-9, la-anthraquinone, and its

derivatives are partly responsible for the antihepatotoxic activity of

C 21.tora. Cassiaside, rubrafusarin- 6-~-gentiobiosides and 6-[(a-

apiofuranosyl - (1~6) -~-D-glucopyranosyl)oxy ]-rubrofusarin are found

to have significant hepato protective effects against galactosamine

damage.58

Anthraquinones isolated from Cpudibunda showed significant

antimicrobial activity. Chrysophanol dimethyl ether was found to be

effective against Candida krusei.63 I,5-dihydroxy-3-methoxy-7-methyl

anthraquinone isolated from C italica was found to be bacteriostatic for

Bacillus anthracis, Corynebacterium pseudodiphthericum and

Pseudomonas aeruginosa but is bactericidal for Pseudomonas

pseudomalliae. It is also used to treat melioidosis, an infectious disease

of rodents transmitted to man. It is found non toxic in human clinical

trials. lIO Spectaline and spectalinine, show cytotoxicity in Vero monkey

and chinese hamster ovary cell cytotoxicity assays. III Antitumour

activity of polysaccharide fraction from Cangustifolia was tested against

solid Sarcoma-I80 in mice and it exhibited significant activity with an

Chapter 1 73

inhibition of 51 %.80 7-hydroxy-5-acetylmethyl-2-methyl chromone

shows considerable antibiotic activity against gram negative organisms.82

Potassuim lespedezate and isolespedezate isolated from

C.mimosoides is responsible for the leaf opening of the plant 68