Biochemical Systematics and Ecology 35 (2007) 42e44www.elsevier.com/locate/biochemsyseco

Quassinoids and a coumarin from Castela macrophylla(Simaroubaceae)

Helen Jacobs a,*, Denise S. Simpson a, William F. Reynolds b

a Department of Chemistry, University of the West Indies, Mona, Kingston 7, Jamaicab Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Canada M5S 3H6

Received 1 April 2006; accepted 23 August 2006

Keywords: Castela; Simaroubaceae; Quassinoids; Coumarin

1. Subject and source

Approximately 15 species of the genus Castela Turpin (Simaroubaceae) are known, and all occur in the tropical andwarm Americas (Mabberley, 1997). Castela macrophylla Urb. is the only Castela species found in Jamaica, and it isendemic to the island (Adams, 1972). Aerial parts of this plant were collected at Hellshire Hills, St. Catherine, Ja-maica, in June 2003. A voucher specimen (UWI-Mona 34,982) is preserved in the Herbarium at the University ofthe West Indies, Mona, Jamaica.

2. Previous work

Castela Turpin (Simaroubaceae) has been reported to accumulate mainly quassinoids, most of which are of the C20

skeletal type (Grieco et al., 1999a; Kubo et al., 1993; Chaudhuri and Kubo, 1992; Kubo and Chaudhuri, 1993; Griecoet al., 1995, 1994). Compounds of other structural classes reported from this genus include a sterol (Kubo et al., 1992),pregnane derivatives (Grieco et al., 1994, 1999b), and a novel b-glycoside (Grieco et al., 1999b).

In a previous study of C. macrophylla, a mixture of a- and b-amyrin acetates and b-tocopheryl acetate was obtainedfrom an acetylated fraction of the hexane extract of the branches (Harding, 1999), but no quassinoids were detected.This seemingly anomalous phytochemical profile prompted a re-investigation of the plant, the results of which aredescribed in this report.

3. Present study

In this report we describe the isolation of three C20 quassinoids, (�)-glaucarubolone (1), (�)-holacanthone (2) and(�)-glaucarubolone-15-O-b-D-glucopyranoside (3) from the aerial parts of C. macrophylla. The coumarin scopoletin

* Corresponding author. Tel.: þ1 876 512 3025; fax: þ1 876 977 1835.

E-mail address: helen.jacobs@uwimona.edu.jm (H. Jacobs).

0305-1978/$ - see front matter � 2006 Elsevier Ltd. All rights reserved.

doi:10.1016/j.bse.2006.08.005

43H. Jacobs et al. / Biochemical Systematics and Ecology 35 (2007) 42e44

and the trisubstituted derivative of benzoic acid, methyl vanillate were also obtained. The compounds were identifiedon the basis of spectroscopic data (1H and 13C NMR, HRMS, IR, UV) and the assignments corroborated by compar-ison with literature values of these and physical data.

O O

OHO

H

OHHO

HOH

H

O

H

OHOOH

O

O O

OHO

H

OHHO

H

H

O

HOH

HO

O O

O

HO

H

OHHO

HO

H

O

H O

1 32

The leaves, twigs, and thorns of C. macrophylla were air-dried and chopped. The chopped material (4.1 kg) waspercolated successively with hexane (1� 16 L), Me2CO (2� 16 L) and MeOH (3� 16 L). Evaporation of the solventfrom the acetone extract yielded a dark green gum (37 g). The gum (37 g) was subjected to flash column chromatog-raphy on silica gel (230 g) with gradient elution using Me2COehexane (5e100%). Fifty-one fractions of volume500 mL were collected.

The residue from the 60% Me2COehexane fractions (2.5 g) was chromatographed on silica gel (157 g) withEtOAceCH2Cl2 mixtures of increasing polarity (0e100%) and 64 fractions of volume 250 mL were taken. The res-idue from the 40% EtOAceCH2Cl2 fractions (494 mg) was recrystallized from CH2Cl2ehexane to give a pale yellowsolid (242 mg). This solid (242 mg) was triturated with cold MeOH to yield (�)-holacanthone (2) (200 mg) (Handaet al., 1983). The 80% EtOAceCH2Cl2 fractions were evaporated and the residue (201 mg) column chromatographedon silica gel (31 g) with 3% MeOHeCH2Cl2 and the eluent collected in 71 fractions. Fractions 39e66 were combined,evaporated and the residue recrystallized from CH2Cl2ehexane to give white crystals of (�)-glaucarubolone (1)(68 mg) (Handa et al., 1983; Grieco et al., 1993).

The residue from the 20% Me2COehexane fractions (2.4 g) was chromatographed on silica gel (80 g) usingCH2Cl2 as eluent. Fifty-six fractions of volume 50 mL each were collected. The residue from fractions 23e44(126 mg) was recrystallized from EtOAcehexane to give scopoletin (92 mg) (Chatterjee et al., 1974; Basak and Chak-raborty, 1970; Pouchert and Behnke, 1993).

Evaporation of the solvent from the MeOH extract gave a dark brown gum (111 g) which was stirred with 20%MeOHeCH2Cl2 (750 mL) for 22 h. The resulting suspension was filtered through a pad of silica gel (59 g) andthe silica gel thoroughly washed with 20% MeOHeCH2Cl2 (4� 200 mL). The filtrate and washings were com-bined and evaporated to give a dark green gum (34 g) which was subjected to flash chromatography on silica gel(261 g) with mixtures of MeOHeCH2Cl2 (3e100%); 36 fractions of volume 250 mL were taken. The residue offractions 14e20 (912 mg) was column chromatographed on silica gel (88 g) using 2e5% MeOHeCH2Cl2; 67fractions of 50 mL were collected. Fractions 36e38 were combined and the solvent evaporated to give glaucar-ubolone-15-O-b-D-glucopyranoside (3) (750 mg) (Bhatnagar et al., 1984).

The residue of the 3% MeOHeCH2Cl2 fractions (6.8 g) was column chromatographed on silica gel (101 g) using5e10% Me2COehexane and 106 fractions (50 mL each) collected. Fractions 23e32 were combined and the residue(129 mg) treated with decolorizing carbon to give a yellow semi-solid (127 mg). This semi-solid (127 mg) was col-umn chromatographed on silica gel (25 g) using 60% CH2Cl2ehexane and gave 72 fractions. Fractions 38e42 werecombined and the solvent evaporated to yield methyl vanillate (7 mg) (Pouchert and Behnke, 1993).

4. Chemotaxonomic and ecological significance

Quassinoids are found only in simaroubaceous genera and are considered taxonomic markers of this family (Dreyer,1983; Fernando et al., 1995). They have been thoroughly studied because of their wide spectrum of pharmacologicalactivities. The isolation of the C20 quassinoids (�)-glaucarubolone, (�)-holacanthone and (�)-glaucarubolone-15-O-b-D-glucopyranoside (1e3) is consistent with the chemical profile of the other Castela species studied. (�)-Glau-carubolone (1) has been reported to display moderate antifeedant activity against the tobacco budworm, Heliothisvirescens (Lidert et al., 1987) while (�)-holacanthone (2) has been reported to possess in vitro activity against

44 H. Jacobs et al. / Biochemical Systematics and Ecology 35 (2007) 42e44

Plasmodium falciparum (O’Neill et al., 1988). (�)-Glaucarubolone-15-O-b-D-glucopyranoside (3) completely inhibitsthe growth of Plasmopara viticola (Hoffman et al., 1992).

Acknowledgements

Financial support from the University of the West Indies Board for Graduate Studies and Research and the NaturalSciences and Engineering Research Council of Canada is gratefully acknowledged. We thank Mr. Patrick Lewis andMr. Edwin Duffus for assistance with plant collection and identification.

References

Adams, C.D., 1972. Flowering Plants of Jamaica. University Press, Glasgow.

Basak, S.P., Chakraborty, D.P., 1970. J. Indian Chem. Soc. 47, 722.

Bhatnagar, S., Polonsky, J., Prange, T., Pascard, C., 1984. Tetrahedron Lett. 25, 299.

Chatterjee, A., Banerjee, B., Ganguly, S.N., Sircar, S.M., 1974. Phytochemistry 13, 2012.

Chaudhuri, S.K., Kubo, I., 1992. Phytochemistry 31, 3961.

Dreyer, D.L., 1983. In: Waterman, P., Grundon, M. (Eds.), Chemistry and Chemical Taxonomy of the Rutales. Academic Press, London, 215 pp.

Fernando, E.S., Gadek, P.A., Quinn, C.J., 1995. Am. J. Bot. 82, 92.

Grieco, P.A., Collins, J.L., Moher, E.D., Fleck, T.J., Gross, R.S., 1993. J. Am. Chem. Soc. 115, 6078.

Grieco, P.A., Moher, E.D., Seya, M., Huffman, J.C., Grieco, H.J., 1994. Phytochemistry 37, 1451.

Grieco, P.A., Vander Roest, J.M., Pineiro-Nunez, M.M., Campaigne, E., Carmack, M., 1995. Phytochemistry 38, 1463.

Grieco, P.A., Haddad, J., Pineiro-Nunez, M.M., Huffman, J.C., 1999a. Phytochemistry 50, 637.

Grieco, P.A., Haddad, J., Pineiro-Nunez, M.M., Huffman, J.C., 1999b. Phytochemistry 51, 575.

Handa, S.S., Kinghorn, A.D., Cordell, G.A., Farnsworth, N.R., 1983. J. Nat. Prod. 46, 359.

Harding, W.W., 1999. PhD thesis, University of the West Indies, Mona, Jamaica.

Hoffman, J.J., Jolad, S.D.F., Hutter, L.K., McLaughlin, S.P., 1992. J. Agric. Food Chem. 40, 1056.

Kubo, I., Murai, Y., Chaudhuri, S.K., 1992. Phytochemistry 31, 3262.

Kubo, I., Chaudhuri, S.K., 1993. Phytochemistry 32, 215.

Kubo, I., Murai, Y., Chaudhuri, S.K., 1993. Phytochemistry 33, 461.

Lidert, Z., Wing, W., Polonsky, J., Imakura, Y., Okano, M., Tani, S., Lin, Y.-M., Kiyokawa, H., Lee, K.-H., 1987. J. Nat. Prod. 50, 442.

Mabberley, D.J., 1997. The Plant Book. Cambridge University Press, UK, 269 pp.

O’Neill, M.J., Bray, D.H., Boardman, P., Wright, C.W., Phillipson, J.D., Warhurst, D.C., Gupta, M.P., Correya, M., Solis, P., 1988. J. Ethnophar-

macol. 22, 183.

Pouchert, C.L., Behnke, J. (Eds.), 1993. Aldrich Library of 13C and 1H FT NMR Spectra, first ed. Library of Congress, USA.