Diabetes can be controlled either by non-pharmacological (diet and exercise) or pharmacological (insulin and oral hypoglycemic agents) methods. However, the main side effects are weight gain and hypoglycemia with sulfonylureas, gastrointestinal disturbances with metformin, liver dysfunction with thiazolidinediones, hypersensitivity reactions with meglitinides and flatulence, diarrhea and abdominal bloating with a-glucosidase inhibitors³. Hence, the search for new therapeutic agents with hypoglycemic actions continues. Recently, the practice of herbalism has become main stream throughout the world.

Nature has been a source of medicinal agents for thousands of years and an impressive number of modern drugs have been isolated from natural sources, many based on their use in traditional medicine. Higher plants, as sources of medicinal compounds, have continued to play a dominant role in the maintenance of human health since ancient times⁴.

The herb Hibiscus rosasinensis Linn ( Malvaceae ) is a glabrous shrub widely cultivated in the tropics as an ornamental plant and has several forms with varying colours of flowers. H. rosa sinensis (Malvaceae) has been reported to possess antilipidemic, antioxidant⁵, analgesic activity⁶, anti-inflammatory activity⁷, antiulcer activity⁸, neuroprotective effect⁹. In the absence of systemic literature, the present study was aimed to evaluate the antidiabetic, antioxidant and antidyslipidemic activity of ethanolic extract of Hibiscus rosasinensis in alloxan induced diabetic rats.

MATERIALS AND METHODS:

PLANT MATERIAL

Hibiscus rosasinensis leaves were collected from Vellore District. The plants were identified and authenticated by a taxonomist and a voucher specimen has been deposited at the Department of Botany, University of Madras, Chennai.

PREPARATION OF PLANT EXTRACT

Hibiscus rosasinensis leaves were dried at room temperature and powdered in an electrical grinder, which was then stored in an airtight container at 5° C until further use. The powdered root was delipidated with petroleum ether (60-80°C) for overnight. It was then filtered and soxhalation was performed with 95% Ethanol. Ethanol was evaporated in a rotary evaporator at 40 – 50° C under reduced pressure (Yield 24g).

PRELIMINARY PHYTOCHEMICAL SCREENING

The ethanolic extract of Hibiscus rosasinensis leaves were subjected to preliminary phytochemical screening of various plant constituents^{10, 11}.

EXPERIMENTAL ANIMALS

Male albino Wistar rats (150-180 g) were purchased from Tanuvas, Madavaram, Chennai. The rats were housed in polypropylene cages lined with husk and kept in Animal house, Department of Biochemistry. It was renewed every 24 hours. The rats were fed with commercial pelleted rats chow (VRK Nutritional Solutions, Maharashtra, India) and had free access to water. The experimental rats were maintained in a controlled environment (12:12 hours light/dark cycle) and temperature (30 ± 2° C). The experiments were designed and conducted in accordance with the ethical norms approved by Ministry of Social Justices and Empowerment, Government of India and Institutional Animal Ethics Committee Guidelines for the investigation of experimental pain in conscious rats. The rats were acclimatized for one week before starting the experiments.

INDUCTION OF DIABETES MELLITUS

Diabetes was induced by single intraperitonial injection of alloxan monohydrate dissolved in sterile normal saline at a dose 120 mg/Kg, after 18 hours fasting to induce hyperglycemia. After 1 hour alloxan administration, the animals were fed on standard pellets and water ad libitum. Rats were supplied with 5% glucose solution for 48 hours after alloxan injection in order to prevent severe hypoglycaemia. After 1 week time for the development and aggravation of diabetes, the rats with moderate diabetes having persistant glycosuria and hyperglycemia (Blood Glucose range of above 250 mg/dL) were considered as diabetic rats and used for the experiment. The treatment was started on the eighth day after alloxan injection and this was considered as first day of treatment.

EXPERIMENTAL DESIGN

The rats were grouped into 4 groups, comprising of 6 rats in each group as follows:

Group I: Control Rats (Water and food ad libitum).

Group II: Alloxan induced diabetic Rats.

Group III: Diabetic rats treated with Hibiscus rosasinensis leaves extract (250 mg/ Kg body weight/ day) in aqueous solution orally for 30 days.

Group IV: Diabetic rats treated with gliclazide (5mg/Kg body weight/ day) in aqueous solution orally for 30 days.

During the experimental period, body weight and blood glucose levels of all the rats were determined at regular intervals. At the end of the experimental period, the rats were fasted over night, anaesthetized, and sacrificed by cervical decapitation. The blood was collected with or without anticoagulant for plasma or serum separation respectively.

The liver and pancreatic tissues were dissected out and washed in ice-cold saline, which is then used for further experimental studies.

PREPARATION OF TISSUE HOMOGENATE

The liver and pancreatic tissues were excised, rinsed in ice- cold saline. Known amount of the tissues were homogenized in Tris–HCl buffer (100 mM, pH 7.4) at 4°C, in a Potter–Elvehjem homogenizer with a Teflon pestle at 600 rpm for 3 min. The homogenate was then centrifuged at 12,000×g for 30 min at 4°C. The supernatant was collected as tissue homogenate, which was used to assay various parameters.

Biochemical Estimations

Blood glucose level was estimated by the method of glucose oxidase/ peroxidase as described by Trinde¹²and urea by Natelson et al.¹³.Plasma was separated and used for insulin assay using ELISA kit for rats. Levels of hemoglobin and glycosylated hemoglobin were estimated according to methods of Drabkin and Austin¹⁴ and Nayak and Pattabiraman¹⁵, respectively. Plasma was used for protein assay¹⁶and serum for determination of creatinine¹⁷ and uric acid¹⁸. Aspartate transaminase (AST), Alanine transaminase(ALT) and Alkaline phosphatase (ALP) were assayed by the method of King et al.^{19, 20}. For the estimation of glycogen, the extraction was carried out by the method of Morales et al. (1973)²¹. The pancreatic tissue homogenate was then centrifuged at 5000g to remove cellular debris and supernatant was used for the determination of lipid peroxides and enzymatic antioxidants.

Lipid peroxides were determined using thiobarbituric acid reactive substances by the method of Ohkawa et al.²² Levels of vitamin C, vitamin E, ceruloplasmin and glutathione (GSH) were determined by the methods of Omaye et al,²³ Desai²⁴, Ravin²⁵, Sedlak and Lindsay²⁶, respectively. Enzymatic antioxidants such as superoxide dismutase²⁷, catalase²⁸, glutathione peroxidase²⁹ in pancreatic supernatant.

ORAL GLUCOSE TOLERANCE TEST (OGTT)

Prior to an OGTT, all the rats were fasted for 16 h and the fasted rats were divided into four groups of six animals each. Group I served as control and Group II served as Alloxan induced diabetic rat, received distilled water. Group III and Group IV received ethanolic extract of Hibiscus rosasinensis leaves extract at an oral dose of 250 mg/Kg and the standard drug gliclazide 5 mg/Kg respectively. All the groups were loaded with 50% glucose (2 g/ Kg) with a feeding syringe 30 minutes after drug administration. Blood samples were collected from the tail vein by tail milking at -30 just prior to drug administration and at 30, 60, 90 and 120 min. after glucose loading. The level of blood glucose was measured using glucometer.

Lipid profile

Plasma was used for the estimation of lipid profile. Cholesterol content was estimated by the method of Parekh and Jung³⁰. Triglyceride was estimated by the method of Rice³¹. HDL Cholesterol fraction was separated by the precipitation techniques of Burstein and Scholnick³² and the cholesterol content was determined.

RESULTS:

Table 1 shows the qualitative analysis of phytochemical in the ethanolic extract of Hibiscus rosa sinensis leaves. The phytochemical screening of the Hibiscus rosa sinensis leaves extract revealed the presence of alkaloids, flavanoids, tannins, carbohydrates, phenols, saponins and glycosides.

Table 1 Phytochemical screening of H. rosasinensis leaves extract

PHYTOCONSTITUENTS	INFERENCE
Alkaloids	+
Flavonoids	+
Carbohydrates	+
Glycosides	-
Saponins	+
Tannins	+
Phytosterol	+
Triterpenoids	+
Anthraquinones	+
Phenols	+

The results presented in table 2, shows the changes of body weight in control and experimental group of rats. Diabetic rats exhibited reduction in body weight; However, oral administration of the leaves extract to diabetic rats showed a significant improvement in body weight. Similar observation was also noted in the diabetic rats treated with gliclazide.

Table 2 Effect of H. rosasinensis leaves extract on changes in body weight of experimental groups of rats after 30 days treatment.

Groups	Body weight (g)
Groups	Initial	Final
Control	167.10 ± 3.68	218.70 ± 5.19
Diabetic	170.32 ± 2.94	145.15 ± 7.33*
Diabetic + H. rosasinensis extract	160.25 ± 3.10	178.55 ± 4.95^@
Diabetic + gliclazide	163.32 ± 4.08	185.14 ± 6.32^@

Values are given as mean ± SD for groups of six rats in each. Values are statistically significant at p < 0.05. Statistical significance was compared within the groups as follows: *compared with control, ^@compared with diabetic rats.

Table3 shows the changes in the levels of blood glucose, after oral administration of glucose (2g/ kg) in control and experimental rats. The data of OGTT revealed that the blood glucose value in control rats reach peak at 60 minutes after the oral glucose load and gradually return backs to normal levels after 120 minutes. In diabetic control rats, the peak increases in blood glucose concentration was observed after 60 minutes and stayed high over the next 60 minutes. Treatment with Hibiscus rosa sinensis leaves extract showed definite lower peak blood glucose values, 60 minutes after glucose load also gives lower values almost at the end of 120 minutes.

Table 3 Effect of H. rosasinensis leaves extract on the blood glucose level (mg/dl) in the experimental groups of rats receiving an oral glucose load.

Groups	Fasting	30 min	60 min	90 min	120 min
Control	91.25 ± 5.28	148.21 ± 8.94	178.96 ± 15.57	130.49 ± 13.10	100.10 ± 10.05
Diabetic	264.80 ± 17.56*	315.73 ± 25.16*	399.48 ± 25.51*	355.17 ± 25.80*	320.93 ± 22.40*
Diabetic + H. rosasinensis extract	155.71 ± 11.64^@	182.28 ± 17.24^@	255.81 ± 22.74^@	200.07 ± 20.72^@	148.91 ± 15.69^@
Diabetic + gliclazide	138.24 ± 9.29^@	170.64 ± 15.74^@	225.75 ± 18.28^@	175.84 ± 13.68^@	130.87 ± 11.50^@

Table 4 Effect of H. rosasinensis leaves extract on the levels of blood glucose, plasma insulin, hemoglobin, glycosylated hemoglobin, and urine sugar in the experimental groups of rats.

Groups	Glucose (mg/dl)	Insulin (µU/ml)	Hemoglobin (g/dl)	Glycosylated hemoglobin (%)	Urine sugar
Control	95.59 ± 9.25	14.98 ± 2.68	13.85 ± 2.35	6.25 ± 1.60	Nil
Diabetic	298.70 ± 21.46*	5.70 ± 1.02*	10.11 ± 1.95*	12.28 ± 2.69*	+++
Diabetic + H. rosasinensis extract	145.32 ± 12.54^@	10.11 ± 2.14^@	11.74 ± 2.59^@	8.02 ± 1.90^@	Nil
Diabetic + gliclazide	120.12 ± 15.27^@	12.12 ± 1.95^@	13.36 ± 2.04^@	7.78 ± 2.04^@	Nil

Table 6 Effect of H. rosasinensis leaves extract on the levels of protein, urea, creatinine and uric acid in plasma of experimental groups of rats.

Groups	Protein (g/dl)	Urea (mg/dl)	Creatinine (mg/dl)	Uric acid (mg/dl)
Control	8.02 ± 1.05	23.91 ± 2.05	1.05 ± 0.09	2.37 ± 0.92
Diabetic	5.36 ± 0.82*	48.62 ± 4.28*	2.11 ± 0.12*	5.15 ± 1.08*
Diabetic + H. rosasinensis extract	6.85 ± 0.88^@	30.19 ± 3.12^@	1.21 ± 0.11^@	3.11 ± 0.86^@
Diabetic + gliclazide	7.14 ± 0.87^@	30.52 ± 2.58^@	1.15 ± 0.10^@	2.56 ± 1.02^@

Table 7 Effect of H. rosasinensis leaves extract on the activity of AST, ALT and ALP in the serum of experimental groups of rats.

Groups	AST	ALT	ALP
Control	64.32 ± 6.44	17.26 ± 2.49	84.51 ± 10.16
Diabetic	110.79 ± 14.78*	45.18 ± 4.81*	151.36 ± 18.24*
Diabetic + H. rosasinensis extract	90.17 ± 10.29^@	23.82 ± 3.96^@	98.75 ± 11.28^@
Diabetic + gliclazide	80.52 ± 8.21^@	20.71 ± 2.98^@	100.64 ± 12.81^@

Table 8 Effect of H. rosasinensis leaves extract on the level of TBARS in plasma, pancreas and liver of experimental groups of rats.

Groups	TBARS
Groups	Plasma	Pancreas	Liver
Control	4.07 ± 0.69	40.24 ± 4.75	1.70 ± 0.26
Diabetic	8.02 ± 1.61*	77.26 ± 9.44*	4.37 ± 0.69*
Diabetic + H. rosasinensis extract	5.19 ± 1.16^@	57.29 ± 6.81^@	2.49 ± 0.30^@
Diabetic + gliclazide	5.04 ± 1.02^@	54.99 ± 7.43^@	2.65 ± 0.34^@

Units: mM/100 g in tissues; nM/ml in plasma. Values are given as mean ± SD for groups of six rats in each. Values are statistically significant at p < 0.05. Statistical significance was compared within the groups as follows: *compared with control, ^@compared with diabetic rats.

Table 9 Effect of H. rosasinensis leaves extract on the activity of SOD, Catalase and GPx, and the level of GSH in pancreas of experimental groups of rats.

Groups	SOD	Catalase	GPx	GSH
Control	5.16 ± 1.25	14.42 ± 2.09	6.17 ± 1.02	25.10 ± 2.75
Diabetic	1.29 ± 0.41*	5.53 ± 1.40*	3.19 ± 0.32*	11.49 ± 1.63*
Diabetic + H. rosasinensis extract	3.61 ± 0.92^@	11.25 ± 1.87^@	4.80 ± 0.65^@	19.85 ± 2.17^@
Diabetic + gliclazide	3.79 ± 0.86^@	12.02 ± 1.98^@	5.35 ± 0.92^@	21.10 ± 2.84^@

Table 10 Effect of H. rosasinensis leaves extract on the activity of SOD, Catalase and GPx, and the level of GSH in liver of experimental groups of rats.

Groups	SOD	Catalase	GPx	GSH
Control	16.05 ± 2.47	70.91 ± 8.31	11.26 ± 1.09	37.29 ± 5.74
Diabetic	5.07 ± 0.62*	31.29 ± 3.54*	3.64 ± 0.55*	21.39 ± 2.91*
Diabetic + H. rosasinensis extract	10.85 ± 1.14^@	62.92 ± 5.30^@	8.05 ± 0.89^@	31.57 ± 4.28^@
Diabetic + gliclazide	12.12 ± 1.41^@	65.75 ± 5.79^@	9.06 ± 1.10^@	33.61 ± 4.60^@

Table 11 Effect of H. rosasinensis leaves extract on the levels of vitamin C, vitamin E, ceruloplasmin and GSH in plasma of experimental groups of rats.

Groups	Vitamin C	Vitamin E	Ceruloplasmin	GSH
Control	1.48 ± 0.15	0.68 ± 0.09	12.28 ± 1.62	30.74 ± 3.89
Diabetic	0.49 ± 0.09*	0.31 ± 0.04*	5.05 ± 0.89*	14.99 ± 2.35*
Diabetic + H. rosasinensis extract	0.95 ± 0.12^@	0.54 ± 0.07^@	9.94 ± 1.46^@	22.86 ± 2.77^@
Diabetic + gliclazide	1.01 ± 0.14^@	0.58 ± 0.05^@	10.40 ± 1.88^@	25.15 ± 3.16^@

Units: mg/dl. Values are given as mean ± SD for groups of six rats in each. Values are statistically significant at p < 0.05. Statistical significance was compared within the groups as follows: *compared with control, ^@compared with diabetic rats.

Table 12 Effect of H. rosasinensis leaves extract on the levels of total cholesterol, triglycerides, LDL-cholesterol and HDL-cholesterol in the plasma of experimental groups of rats.

Groups	Total cholesterol	Triglycerides	LDL	HDL
Control	85.71 ± 10.54	60.39 ± 9.56	50.11 ± 5.52	28.69 ± 2.08
Diabetic	165.12 ± 18.75*	151.87 ± 15.57*	124.35 ± 9.31*	14.44 ± 1.42*
Diabetic + H. rosasinensis extract	105.57 ± 15.78^@	88.14 ± 10.15^@	72.69 ± 7.32^@	20.13 ± 1.88^@
Diabetic + gliclazide	94.28 ± 14.52^@	81.46 ± 8.49^@	60.87 ± 6.59^@	23. 41 ± 1.94^@

DISCUSSION:

The phytochemical analysis of Hibiscus rosasinensis leaves extract has a positive response for the presence of alkaloids, flavonoids, tannins, saponins, steroids, and terpenoids. Phytochemicals are naturally occurring biologically active chemical compounds in plants. Phytochemicals are known to have protective and disease preventing properties particularly free radical mediated diseases such as diabetes, cancer etc. Certain phytochemicals are almost structurally identical to insulin and act as an ‘insulin mimic” that helps in the remedy of diabetes. Most plants with antidiabetic properties have been found to contain secondary metabolites such as glycosides, alkaloids and flavonoids³³. It has been shown that many plants efficient antioxidant properties owing to their phenolic constituents. It has been reported that Hibiscus rosasinensis leaves contain bioactive compouds such as anthocyanins, and flavonoids alkaloids and vitamins. Hence, compounds which can scavenge the excess of free radicals formed or that inhibit their production are of wide therapeutic value. The presence of biologically active ingredients in the extract may account for the pharmacological activity.

Decrease in the body weight due to derangement of metabolic pathways is a common feature in diabetes³⁴ and this might be due to the excessive break down of tissue proteins and lipids because of insulin deficiency in alloxan induced toxicity. Diabetic rats treated with Hibiscus rosasinensis leaves extract at the concentration of 250mg/kg body weight/rat/day for 30 days showed a significant improvement in the body weight when compared to alloxan induced diabetic rats,which can be attributed to the improvement in insulin secretion and glycemic control.

The glucose tolerance test was devised to measure the metabolic response of an individual after a glucose load. In alloxan induced diabetic rats, the blood glucose level has increased to its peak at 60 mins and remained high over the next 60 mins. Hibiscus rosasinensis extract treated diabetic rats showed an increase at 60 mins and then the reduction in peak was observed at 120 mins which finally exhibited the near normal range of control rats. Thus, the observed effect might be due to the improved glycemic control.

Blood glucose is an index for the diagnosis of diabetes mellitus. Insulin deficiency ultimately results in increased production of glucose by the liver, and decreased utilization of glucose in peripheral tissues³⁵. The elevated blood glucose level observed in the diabetic rats was significantly decreased in H. rosasinensis treated group of rats suggesting hypoglycemic nature of H. rosasinensis leaves. The elevation in the plasma insulin in the leaves extract treated diabetic rats could be because of the insulinotrophic substances present in the Hibiscus rosasinensis leaves extract. Urine sugar which was present in the diabetic groups of rats was found to be absent in the rats treated with extract indicating the improved glucose homeostasis.

The decreased level of total hemoglobin (Hb) in the diabetic rats is mainly due to the increased formation of glycosylated hemoglobin (HbA_1c). The increase in the glycosylated hemoglobin is directly proportional to the fasting blood glucose level³⁶. A significant elevation was observed in the levels of glycosylated hemoglobin while there was a decrease in the levels of total hemoglobin in alloxan induced diabetic rats when compared to the control group of rats. Oral administration of Hibiscus rosasinensis leaves extract has brought back the levels of Hb andHbA_1c to near normal values indicating improved glycemic control.

Glycogen is the primary intracellular storage form of glucose and its levels in various tissues are a direct reflection of insulin activity because insulin promotes glycogen deposition by stimulating glycogen synthase and inhibiting glycogen phosphorylase³⁷. Liver is an important organ that plays a vital role in glycolysis and gluconeogenesis pathways. The observed decrease in glycogen content in our study is due to increased glycogen phosphorylase and decreased glycogen synthase activity which is the key regulatory enzyme in glycogen metabolism. Alteration in the activity of these enzymes may be due to hyperglycemic state in diabetes mellitus. A significant decrease in the liver and muscle glycogen were observed in the diabetic rats compared to the normal rats. Oral administration of Hibiscus rosasinensis leaves extract as well as standard drug, to the diabetic rats showed an increase in the glycogen content of the liver skeletal muscle. This might be due to the decreased glycogen phosphorylase activity and increased glycogen synthase activity. Also, the restoration of glycogen content indicates the improved glucose homeostasis.

The levels of urea, uric acid and creatinine were measured, as DM also causes renal damage due to abnormal glucose regulation, including elevated glucose and glycosylated protein tissue levels, haemodynamic changes within the kidney tissue and increased oxidative stress³⁸. Alloxan induced diabetic rats exhibited significantly higher plasma urea, uric and creatinine levels compared to the DM group. However, the H. rosasinensis leaves extract lowered these plasma values to a control range. A significant elevation in serum creatinine and urea levels indicates an impaired renal function of diabetic animals. H. rosasinensis leaves supplement lowered the plasma urea, uric acid and creatinine levels by enhancing the renal function.

Aspartate transaminase (AST) and Alanine transaminase (ALT) are the enzymes which are associated with the conversion of aminoacids to ketoacids and are used as marker enzymes to assess tissue damage³⁹. The elevation of serum enzyme activity represents the state of diabetes. Oral administration of Hibiscus rosasinensis extract for 30 days resulted in the near normalization of the activities of AST, ALT, and ALP indicating the non toxic nature of the extract indicating he non toxic nature of the extract.

Diabetes is usually accompanied by increased production of free radicals or impaired antioxidant defenses⁴⁰. Excessively high levels of free radicals cause damage to cellular proteins, membrane lipids and nucleic acids and eventually cell death. Glucose oxidation is believed to be the main source of free radicals. In its enediol form, glucose is oxidized in a transition metal dependent reaction to an enediol radical anion that is converted into reactive ketoaldehydes and to superoxide anion radicals. The superoxide anion radicals undergo dismutation to hydrogen peroxidase, which if not degraded by catalase or glutathione peroxidase and in the presence of transition metals, can lead to production of extremely reactive hydroxyl radicals⁴¹. Hydroperoxidases have toxic on cells both directly and through degradation to highly toxic hydroxical radicals. They may also react with the transition metals like iron or copper to form stable aldehydes such as melondialdehydes that will damage cell membranes.

Antioxidant vitamins:

Antioxidants (AO) have gone through a gradual transition from “Miracle Molecules” to “Marvelous Molecules” to “Physiological Molecules”⁴². Numerous studies have been demonstrated that the oxidative stress is mediated mainly by hyperglycemia-induced generation of free radicals that contributes to the development and progression of diabetes and its complications⁴³. It is known that free radical cause auto-oxidation of unsaturated lipids in food⁴⁴. On the other hand, antioxidants are believed to intercept the free radical chain of oxidation and donate hydrogen from the phenolic hydroxyl groups, thereby forming a stable end product, which does not initiate or propagate further oxidation of lipid. The enzymatic antioxidants such as SOD, catalase, Glutathione peroxidase were found to be decreased in the diabetic rats indicating hyperglycemia mediated oxidative stress.

Vitamin C and vitamin E, often referred as “antioxidant vitamins “that have been suggested that have been suggested to limit oxidative damage in humans and lower the risk of certain chronic disease such as diabetes mellitus. Vitaminc C cooperates with Vitamin E to regenerate α-tocopherol from α-tocopherol radicals in membrances and lipoproteins⁴⁵ and also raises intracellular glutathione levels thus playing an important role in protein thiol group protection against oxidation⁴⁶. The reduced concentration of vitamin C in blood may arise due to the excessive oxidation and lack of regeneration from their radical form to reduce form⁴⁷. Vitamin C has been reported to contribute up to 24% of the total peroxy radical trapping antioxidant activity.

Reduced glutathione (GSH) plays an important role in the detoxxfication of xenobiotic compounds. GSH plays a crucial role in cell defense against ROS. The decreased in GSH level may be associated with reactive oxygen species (ROS) generation by mechanisms creating oxidative stress in chronic hyperglycemia⁴⁸. Furthermore the depletion in GSH level may be related to the apparent increased in lipid peroxidation in the tissues of rats. Recent studies have revealed lowered antioxidant enhanced peroxidative status diabetic condition particularly in the liver and kidney⁴⁹. In the present study, altered levels of enzymatic and non enzymatic antioxidants were improved upon treatment with the leaves extract indicating the antioxidant potential of the extract.

The plasma lipid level is raised during diabetes, and also a risk factor for coronary heart disease. The lowering of plasma lipid levels through dietary and drug therapy appears to be associated with a decrease in the risk of vascular disease⁵⁰. Hypercholesterolemia is directly proportional to the severity of diabetes. During diabetic conditions lipogenesis is decreased while lipolysis is increased in the hepatic tissue. The increased level of cholesterol in tissues is due to the decreased level of high density lipoprotein (HDL) cholesterol. In the present study, a marked prevention in the alteration of lipid profile by a treatment with Hibiscus rosasinensis leaves extract to diabetic animals was observed. The altered lipid profile was normalized by Hibiscus rosasinensis leaves extract indicating the hypolipidemic potential of the extract.

CONCLUSION:

The results of the present study clearly indicate that the ethanolic extract of Hibiscus rosasinensis leaves possess hypoglycemic, hypolipidemic and antioxidant potential. The observed pharmacological action might be due to the synergistic actions of the phyto-constituents present in the extract.

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Received on 02.01.2013

Modified on 20.01.2013

Accepted on 02.06.2013

Research Journal of Pharmacognosy and Phytochemistry. 5(6): November –December 2013, 306-314

Groups	Glycogen (mg glucose/g tissue)
Groups	Liver	Skeletal muscle
Control	40.53 ± 3.50	7.90 ± 0.79
Diabetic	18.60 ± 2.17*	3.85 ± 0.41*
Diabetic + H. rosasinensis extract	32.78 ± 3.96^@	5.34 ± 0.63^@
Diabetic + gliclazide	30.77 ± 2.95^@	5.83 ± 0.62^@

Alkaloids

Glycosides