49 International Journal of Natural Products Research 2011; 1 (4):49-54

ISSN: 2249-0353

Original Article Lipid lowering and hypoglycaemic potential of dried Dalbergia latifolia Roxb. bark extract in

Sprague-Dawley rats induced with high fat diets.

Mohammad Khalid*1, H.H. Siddiqui

1

1Faculty of Pharmacy Dasauli Kursi road, Integral University, Lucknow, India. 226026.

*Email: m_khalid07@yahoo.co.in

Received 14 October 2011; accepted 31 October 2011

Abstract

The present study was designed to investigate the hypolipidemic and hypoglycaemic activity of Dalbergia latifolia with regard to protection of LDL oxidation and disturbances of carbohydrates, fats and protein metabolism in-vivo study in rats made

hypercholesterolemic by continuous feeding of high fat diet. It contains dalbinol a new 12a-hydroxyrotenoid, sisafolin

coumarin from seeds, β- sitosterol, also contain dalbergichromene, lupeol, latifolin, and dalbergin from bark. Administering the

dried Dalbergia latifolia bark extracts (DL-extract) at doses of 100, 200 and 400 mg/kg daily together with continuous high fat

diet feeding to hypercholesterolemic rats for 8 weeks significantly decreased serum cholesterol level by 139.84±1.67 and

152.22± 3.93, respectively (p < 0.01 and 0.05); serum triglycerides level by 64.79±3.41 and 67.82±2.26 respectively (p < 0.01

and 0.05); serum low density lipoprotein (LDL) level by 51.58 ± 3.24 and 53.83 ± 1.38, respectively (p < 0.01 and 0.05); blood

glucose level 90.02 ± 0.98 and 92.31±1.63 (p < 0.01 and 0.05) whereas oral administration of 100 mg/kg daily it was showed

no significant (p > 0.05) on serum cholesterol, triglyceride, LDL and blood glucose levels.

© 2011 Universal Research Publications. All rights reserved

Key words: Dalbergia latifolia bark, cholesterol, low density lipoprotein, hypolipidemic, β- sitosterol.

Introduction

Hyperlipidemia and reduced high-density lipoproteins (HDL-

C) ocures a several risk factors that may be life style, geneti,

metabolism or other conditions that enfluence plasma

lipoprotein metabolism [1]. Atherosclerosis is one of the

major risk factors for coronary heart disease and it is widely

recognized that the oxidative modification of human low

density lipoprotein may play an important role [2]. Excess

LDL in the artery wall due to hypercholesterolemia can

undergo oxidative modifications. The oxidative modification

hypothesis of atherosclerosis predicts that low-density lipoprotein oxidation is an early event in atherosclerosis and

that Ox-LDL contributes to atherogenesis. Diabetes mellitus

is chronic metabolic disorder, mainly characterized by

disruptions in carbohydrates, proteins and fat metabolism

caused by the complete or relative insufficiency of insulin

secretion and/or insulin action [3]. Herbal remedies are

apparently efficient, produce least or no side effects in

clinical experience and are comparatively of low costs as

compared to oral synthetic antidiabetic agents [4].

Dalbergia latifolia (Roxb) Family-Fabaceae, a large glabrous

tree a single stem with characteristic smells [5]. The bark is

grey, thin with irregular short cracks, exfoliating in fibrous

longitudinal flakes [6]. It is distributed in Bihar, Bundelkhand

and Central India [7]. It contain dalbinol a new 12a-

hydroxyrotenoid [8], sisafolin coumarin from seeds, β-

sitosterol, also contain dalbergichromene, lupeol, latifolin,

and dalbergin from bark of the tree [9], heartwood contains

latinone, neoflavonoid dalcriodon [10] and Latinone, a substituted phenanthrene-1,4-quinone was isolated from

Dalbergia latifolia [11]. Ethanomedicinally, the stem bark

contain tannin is used for treatment of leprosy and worm [7].

Many species of Dalbergia are important timber trees, valued

for their decorative and often fragrant wood, rich in aromatic

oils [12, 13]. Traditionally various species are reported to be

used as aphrodisiac, abortifacient, expectorant, anthelmentic,

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50 International Journal of Natural Products Research 2011; 1 (4):49-54

antipyretic, appetizer, allays thirst, vomiting, burning

sensation, cures skin diseases, ulcers, diseases of the blood,

reduces obesity, used in leucoderma, dyspepsia, dysentery,

for diseases of the eye and nose, syphilis, stomach troubles,

leprosy, leucoderma, scabies and ringworm [14].

Materials and methods

Chemicals

Diethyl ether, trichloroacetic acid, Disodium ethylene

diamine tetra acetate, Total cholesterol (TC), triglyceride

(TG), high density lipoprotein (HDL), low density lipoprotein

(LDL), glucose, Aspartate aminotransferase (AST), alanine

aminotransferase (ALT), Blood urea nitrogen (BUN) and

creatinine test kits were purchased from clinical chemistry

division of span diagnostic Ltd. India.

Collection and preparation of plant extract

Dalbergia latifolia bark (DLB) was collected in the month of June from area old Delhi market and identified from the

Jamia Hamdard University New Delhi India (reference

voucher No: 001783). Barks were air dried at room

temperature for 3 weeks to get consistent weight. Two

hundred grams of crude powder of barks were shaken with

hydro alcoholic for 24 hrs on an orbital shaker at room

temperature. The extract was resuspended in the respective

solvent [15].

Animals

The female Sprague-Dawley rats (SD rats) were purchase from the Central Drug Research Institute Lucknow (India).

They were housed for 1 week under a 12/12 h light/dark

cycle in a temperature and humidity-controlled room and

freely fed standard laboratory chow with water ad libitum.

The standard laboratory chow contained. All studied were

performed as per CPCSEA guideline, India (Reg.

No.1213/ac/08/CPCSEA/IU).

In vivo hypolipidemic effects of the dried DL-extracts

Thirty-six female Sprague-Dawley rats weighing 125–135 g

were used in this study. The experimental protocol for animal experiments was approved by the Animal Ethic Committee,

Faculty of Pharmacy, Integral University Lucknow. Six rats

per cage were housed in cages in an animal room at the

Faculty of Pharmacy, Integral University. Rats were fed with

commercial pellet diet (National Institute of Nutrition,

Hyderabad, India) and tap water ad libitum. DL-extracts at a

dose of 100, 200, 400 mg/kg and 5 mg/kg standard

(Atorvastatin) drugs daily administered orally using animal

feeding needles at the same time of day for a total 60 days.

Briefly animals were divided into normal control (Group-I)

administered laboratory diet, control obese group induced

with high fat diet [HFD (National Institute of Nutrition, Hyderabad, India)] (group-II), standard drug plus HFD rats

(group-III) and DL-extract (100 and 200 and 400 mg/kg) plus

HFD rats (group-IV, V and VI). At the end of study, rats

were anesthetized with diethyl ether, and blood was collected

by tail vein into glass tubes with Na2EDTA.

Observation and examination method

In-vivo estimation of lipid profile

Rats were anaesthesias with diethyl ether the blood sample

was collected from tail vein at the end of the experiment. The

serum level of TC, HDL, LDL and VLDL were estimating

[16, 17] by methods and TG was estimated by [18] method.

In-vivo effects on serum glucose, blood urea nitrogen and

creatinin of DL-extract At the end of experiments rats were anesthetized with diethyl

ether and blood was collected by tail vein into append drop

tubes and estimation of Blood urea nitrogen and serum

creatine were commercially available span diagnostic kits [19] and glucose was estimated by [20] method.

In-vivo effects on AST and ALT levels of DL-extract

At the end of experiments rats were anesthetized with diethyl

ether and blood was collected by tail vein into append drop

tubes and estimation of AST and ALT were perform

according to the [21] method.

Results and discussion

In-vivo hypolipidemic effects of DL-extract

In the period of induction of hypercholesterolemia through feeding high fat diet in rats, serum cholesterol level increased

over the time period in all groups due to the growth of rats.

The 8 weeks of the induction period, rats in the high fat diet

group exhibited significantly increased serum cholesterol

level, as compared with rats in normal control group

(163.04±2.65 mg/dl p < 0.01) group-I. The administering 5

mg/kg of atorvastatin, used as a positive control, in

hypercholesterolemic rats significantly decreased the levels

of cholesterol (117.22±4.39), HDL (72.87±3.46), LDL

(50.64±3.97), VLDL (9.96±0.79) and TG (64.09±3.29) in

group-III. The administering 200 and 400 mg/kg daily of DL-extract in hypercholesterolemic rats significantly (p<0.01 and

0.05) decreased serum cholesterol level 159.41±1.76 and

152.22±3.93 respectively after 8 weeks of treatment in group

IV-V (Figure 1 & 2). On the other hand, treatment in group

VI with DL-extract 100 mg/kg did not showed significant (p

> 0.05) hypercholesterolemic (159.41±1.76) and

hypotriglyceridemic (71.75±2.16) effect as compared with

hypercholesterolemic rats. Recently, a number of clinical

studies suggest that the increased risk of coronary heart

disease is associated with a high serum concentration of TC,

LDL-C and triglyceride. The abnormally high concentration

of serum lipids is mainly due to the increase in the mobilization of free fatty acids from the peripheral depots

51 International Journal of Natural Products Research 2011; 1 (4):49-54

Figure 1. Effects of DL-extract on serum TC, HDL, LDL

and VLDL levels

Figure 2. Effects of DL-extract on serum triglyceride level

Figure 3. Effects of DL-extract on serum glucose, blood

urea nitrogen and creatinin level.

Figure 4. Effects of DL-extract on serum AST and ALT

levels

52 International Journal of Natural Products Research 2011; 1 (4):49-54

[22]. On the other hand, low serum concentration of HDL-C

is also responsible for coronary heart disease [23]. Recently,

a number of clinical studies suggest dyslipidemia as one of

the major risk factors for coronary disease and preclinical

observations demonstrate that hypercholesterolemia promotes

accumulation of oxidative modified low density lipoprotein (Ox-LDL) in the arterial wall, promoting endothelial cell

(EC) dysfunction and the development of atherosclerosis [24,

25]. In the present study, atorvastatin was used as a positive

control because it is a potent hypolipidemic drug with known

mechanism of action and effects including inhibition of

HMG-CoA reductase, the rate-limiting step in cholesterol

biosynthesis, and resultant increases in LDL-receptors. In

addition, it possesses an inhibitory effect on the inhibition of

LDL oxidation [26, 27]. The treatment of

hypercholesterolemic rats with 200 and 400 mg/kg of DL-

extract along with high fat diet loading for 8 weeks

significantly decreased serum cholesterol, HDL, LDL, VLDL and triglycerides levels but not at 100 mg/kg. Since

phytoconstituent β-sitosterol compound have been reported to

possess hypocholesterolemic effect in-vivo, it may be

speculated that the hypolipidemic effects of DL-extract are

attributed to these compounds. β-sitosterol, a plant sterol

which is structurally similar to cholesterol except for the

substitution of an ethyl group at C24 of its side chain, has

been suggested to reduce cholesterol by lowering the

concentration of LDL cholesterol [28]. The cholesterol level

decreased significantly in liver and plasma without any side

effects in rats fed with the mixture of 0.25% β-sitosterol in diet for days [29]. Thus, a result of the decrease in bile acids

content, cholesterol biosynthesis in rat hepatocytes was

enhanced. Treatment with the DL-extracts (200 and 400

mg/kg) daily result, significantly (p < 0.05) reduced in serum

HDL level but 100 mg/kg did reduced. Hypercholesterolemia

is one of the risk factors of atherosclerosis, in which Ox-LDL

plays a crucial role. In addition, changes of lipid composition

in LDL may also influence the oxidation process. Reduction

of cholesterol and triglycerides contents in LDL may have the

beneficial effect of a decrease in LDL oxidation [30]. The

increased susceptibility of LDL oxidation may be due to changes of triglycerides and cholesterol compositions in rat

LDL particles after induction of hypercholesterolemia.

In-vivo effects on serum glucose, blood urea nitrogen and

creatinin of DL-extract

Glucose, blood urea nitrogen (BUN) and serum creatinin was

found to be significantly increased (101.60±3.16, 48.39±2.17

and 2.06±0.17) when compare with normal control group.

Treatment of 5mg/kg/day atorvastatin showed significantly

decrease (p<0.01) in glucose, BUN and creatinin

(85.93±2.37, 35.28±1.48 and 1.03±0.17 mg/dl) levels in

group III. On treatment of DL-extract 200mg/kg and 400mg/kg daily showed significantly decrease (p<0.01 and

p<0.05) in serum glucose, BUN and creatinin (90.02 ± 0.98,

41.92 ± 1.74 and 1.37 ± 0.04; 92.31±1.63 and 44.63±2.13,

1.46±0.02) in groups V and VI (Figure 3). When

administration of 100mg/kg daily administered, observed non

significant of glucose, BUN and creatinine (98.67 ± 1.43,

49.52±1.74 and 1.76 ± 0.02) in groups IV and compare with obese control group-II. The hypoglycaemia is characterized

by a reduction in insulin-mediated glucose disposal in type-2

diabetes patients [31]. In HFD group more food intake blood

glucose level high as compare to the normal group. The

administration of DL-extract (200 and 400 mg/kg/day) have

been significantly decreased (p<0.01 and p<0.05) the glucose

in circulating blood. The serum creatinine and blood urea

nitrogen levels were impaired due to abnormal regulation,

including elevated glycosylated protein tissue levels and

homodynamic changes within the kidney tissue, and

increased oxidative stress [32]. The HFD induced SD rats

exhibited significantly higher serum creatinine and blood urea nitrogen levels compared to the control normal group.

However, the DL-extract supplement (200 and 400 mg/kg)

daily significantly (p<0.01 and p<0.05) reduced the serum

level of creatinine and blood urea nitrogen in HFD groups V

and VI. Thus, it would appear that the DL-extract supplement

lowered the serum creatinine and blood urea nitrogen levels

by enhancing the renal function that is generally impaired in

diabetes.

In-vivo effects on serum AST and ALT levels of DL-extract

The significantly increase (p<0.01) in the serum AST and ALT levels when compare to normal control group.

Treatment of 5mg/kg/day atorvastatin showed significantly

decrease (p<0.01) in AST and ALT (87.36±3.54 and

32.51±3.98 U/ml) levels in group III. On treatment of DL-

extract (200 and 400 mg/kg) daily showed significantly

decrease (p<0.01 and p<0.05) in serum AST and ALT

(104.79±0.93, 54.17±0.90 and 108.13 ± 1.34, 58.28 ±0.78) in

groups V and VI (Figure 4). When administration of

100mg/kg daily administered, observed non significant of

serum AST and ALT (118.21±0.74 and 65.26±1.34) in

groups IV when compare with obese control group-II. The enzymes AST and ALT are present with higher

concentrations in the liver under normal conditions whereas

during hepatic necrosis or membrane damage, these enzymes

will be released into the systemic circulation, as indicated by

elevated serum enzyme levels [33]. AST is an enzyme that is

present in high quantities in the cytoplasm and mitochondria

of liver, also present in the heart, skeletal muscle, kidney.

ALT is a hepatospecific enzyme that is principally found in

the cytoplasm [34]. These results indicated that DL-extract

have liver protective effect as they significantly reduced

(p<0.01 and p<0.05) the level of both the enzymes on

administration of DL-extract (200 and 400 mg/kg) daily in HFD groups V and VI.

53 International Journal of Natural Products Research 2011; 1 (4):49-54

Conclusion

Thus to conclude, the study showed that administration of

DL-extract at dose level 200mg/kg daily is effective as

hypolipidemic and hypoglycaemic activity. The active

ingredient present in plant may recover the disorders in lipid metabolism noted in hyperlipidemic state and further work

would be necessary to evaluate the active constituents

responsible for the activity and mechanisms of these effects.

Acknowledgement

Authors are very thankful to Honb’le Vice Chancellor,

Integral University, Lucknow for providing research facilities

in university premises for research.

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Source of support: Nil; Conflict of interest: None declared