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Year : 2016  |  Volume : 7  |  Issue : 1  |  Page : 29-32  

Insignificant effect of ethanol extract of Dipterocarpus turbinatus (Dipterocarpaceae) bark on selected parameter in alloxan-induced diabetic rats

1 Department of Pharmacognosy, Creative Educational Society's College of Pharmacy, Kurnool, Andhra Pradesh, India
2 Department of Pharmacology, NET College of Pharmacy, Raichur, Karnataka, India
3 Department of Pharmacognosy, Prime College of Pharmacy, Palakkad, Kerala, India

Date of Web Publication19-Feb-2016

Correspondence Address:
Diptanu Biswas
Department of Pharmacognosy, Creative Educational Society's College Pharmacy, NH-7, Chinnatekur, Kurnool - 518 218, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0976-9234.177059

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Objective: The present investigation was designed to find out the antidiabetic potency of ethanol extract of the bark of Dipterocarpus turbinatus by alloxan monohydrate-induced diabetic rats. Materials and Methods: The bark powder of D. turbinatus was extracted with different solvents (according to the polarity of the solvent). Preliminary phytochemical evaluation of the plants showed different chemical entities including alkaloids, steroids, flavonoids, terpenoids, and tannins. Ethanol extracts (200 mg/kg and 400 mg/kg body weight) were used for antidiabetic study. Oral administration of ethanol extract of the stem bark of D. turbinatus in alloxan monohydrate (150 mg/kg) induces diabetic rats for 14 days. Results and Discussion: Various parameters such as blood glucose level, body weight, and various biochemical parameters (plasma cholesterol, serum creatinine, and urea) were measured by the spectrophotometric method. There was no significant reduction seen in the blood glucose as compared with the diabetic control from the 200 mg/kg dose (P < 0005), and no positive effect could be shown on biochemical parameters as compared with the diabetic control group in both concentrations (200 mg/kg and 400 mg/kg). Conclusion: On the basis of this investigation, we may partially conclude that D. turbinatus is not a potent antidiabetic agent.

Keywords: Alloxan, antidiabetic, blood glucose, Dipterocarpus turbinatus, flavonoids

How to cite this article:
Biswas D, Gouda ST, Gowrishankar NL. Insignificant effect of ethanol extract of Dipterocarpus turbinatus (Dipterocarpaceae) bark on selected parameter in alloxan-induced diabetic rats. J Pharm Negative Results 2016;7:29-32

How to cite this URL:
Biswas D, Gouda ST, Gowrishankar NL. Insignificant effect of ethanol extract of Dipterocarpus turbinatus (Dipterocarpaceae) bark on selected parameter in alloxan-induced diabetic rats. J Pharm Negative Results [serial online] 2016 [cited 2020 Aug 14];7:29-32. Available from:

   Introduction Top

Diabetes mellitus is the most common metabolic disease worldwide. It is a chronic condition, characterized by hyperglycemia, occurring due to impaired insulin secretions. [1] Most of the antidiabetic agents on the market are synthetic in origin and thus cost more and show toxicity. A variety of plants are used in the management and treatment of diabetes mellitus in various indigenous systems of medicine. Pharmacological studies on antidiabetic herbal remedies are in progress and may lead to find out a new anti diabetic entity from natural source. It may help to reduce the side effects and costs of synthetic antidiabetic agents. [2]   Indigenous tribal peoples are one of the important parts of the ecosystem, living in harmony with nature and maintaining a close link between humans and the environment. [3] Northeast India is one of the biodiversity hotspots (Indo-Burma and Himalayan) on the world map, one of the richest reservoirs of natural sources of medicine, and Tripura is India's third smallest hilly state in the northeastern part of the country. [4] Dipterocarpus turbinatus is widely distributed across Tripura. Dipterocarpus turbinatus has been traditionally used as an anti diarrheal, astringent, to treat wounds, ulcer, burns and obesity. [5],[6],[7] In Ayurveda it is named Asanadi gana and is one of the ingredients out of 23 plants used in the treatment of diabetes. The tribal people of Tripura use Dipterocarpus turbinatus plant and plant-derived product for various purposes. [8] The present study was designed to determine the antidiabetic potency of ethanol extract of D. turbinatus in alloxan (150 mg/kg)-induced diabetic rats. Drug extract was introduced in two different doses (200 mg/kg and 400 mg/kg) in 2% acacia solution for 14 days. Various parameters such as body weight, blood glucose level, and various biochemical parameters were evaluated. In this study, biochemical parameters showed insignificant results. Phytochemical investigation was done to learn about the presence of various chemical entities in these drugs.

   Materials And Methods Top

Plant materials

Bark of Diptercarpus turbinatus was collected from the forest around Gangachara village, Tripura and identified by the Forest Department of Tripura in the month of June 2012. Plant materials were identified and authenticated by Prof. P. Jayaraman, M.Sc., Ph.D, Director of the Plant Anatomy Research Centre, Tambaram, Chennai, TN, India. Voucher specimens (no. PARC/2012/1277) were deposited for further reference. Plant materials were dried under shade and made into coarse powder by pulverization in our college laboratory.

Preparation of extracts and phytochemical study

About 250 g of pulverized powder of the bark defatted with petroleum ether and extracted with chloroform, and ethanol (70%) by soxhlet apparatus respectively for 18 h in Soxhlet apparatus in a successive manner. The extract was dried at 55°C in a rotary vacuum evaporator ( Equitron), dried in a water bath at 60°C till solid mass was obtained (18%), and kept in a desiccator to eliminate moisture. [9]  Extracts were stored bellow 10°C. Various phytoconstituents present in the various extracts were detected by  respective chemical tests. [10],[11] The ethanol extract was selected for antidiabetic activity.

Screening of antidiabetic potency of ethanol extract of D. turbinatus

0Experimental animals

Wistar albino rats of either sex were procured from the National Institute of Nutrition, Hyderabad, and used throughout the experiments. After randomization into various groups and before initiation of the experiment, the rats were acclimatized for a period of 7 days. Standard environmental conditions such as temperature (26 ± 2°C), relative humidity (45-55%), and a 12-h dark/light cycle were maintained in quarantine. All the animals were fed with a synthetic diet (from Suresh Agency, Hyderabad) and water was allowed ad libitum under strict, hygienic conditions. The entire animals were utilized for studies according to the protocol approved by the institutional Animal Ethics Committee (approval ID no. IAE/SKIPS/2012/MAY08/1/12/RAT-96/MICE-36).

Induction of diabetes

Alloxan evokes a sudden rise in insulin secretion in the pancreas or absence of glucose, which appears just after alloxan treatment. [12],[13] In alloxan-induced diabetic rats, insulin release occurs for a short duration, followed by the complete suppression of the islet response to glucose even when high concentrations of glucose were used; [14],[15] this causes insulin-dependent diabetes. Alloxan monohydrate was procured from Loba Chemie, Mumbai, MH. The animals were fasted for 18 h and were injected with alloxan monohydrate dissolved in sterile normal saline at a dose of 150 mg/kg body weight intraperitoneally (IP). [16],[17]

Experimental design

The rats were divided into five groups, each group containing six animals: [18]

Group I:

Normal control, received normal saline mix with acacia 2% solution

Group II:

Group II: Diabetic control received 150mg/kg alloxan monohydrates in saline (2 % solution, IP)

Group III:

Test group I, received 150 mg/kg alloxan monohydrates in saline (2% solution, IP); 48 h later received ethanol extract of D. turbinatus 200 mg/kg [per os (PO)] dissolved in 2% acacia in normal saline for 14 days

Group IV:

Test group II, received 150 mg/kg alloxan monohydrates in saline (2% solution, IP); 48 h later received ethanol extract of D. turbinatus 400 mg/kg (PO) dissolved in 2% acacia in normal saline for 14 days

Group V:

Received 150 mg/kg alloxan monohydrate in saline (2% solution IP), and metformin HCl 150 mg/kg (PO) for 14 days.

Hematological and biochemical analysis

For the hematological and biochemical analysis, blood samples were collected by retroorbital puncture. [19] Blood samples were centrifuged at 4000 rpm by  Remi research centrifuge R24, (Mumbai India) for 15 min. The plasma was collected and the fasting blood glucose level was determined by colorimetric assay according to the  Span Diagnostics kit instruction manual. Some plasma was used for the estimation of plasma cholesterol, serum creatinine, and urea by spectrophotometric assay using the  Mispa Excel Chemistry analyzer, (mispa biosystem, Agappe diagnostic Ltd, Kerala, India) according to the Span Diagnostics kit instruction manual.

Oral glucose tolerance test (OGTT) on alloxan-induced diabetic and normal rats

After 2 weeks, animals with blood glucose levels 450 mg/dL were selected for study prior to the OGTT. Rats were fasted for 16 h just after the treatment was administered with distilled water, standard metformin HCl 150 mg/kg, and 200 mg/kg and 400 mg/kg of the test drug. After 30 min, glucose (3 gm/kg) was orally administrated to each rat through a feeding tube. Blood samples were collected from the retroorbital puncture at 30 min (just before the administration of the distilled water fraction of ethanol extract of D. turbinatus and metformin HCl in the respective groups),   At 0 min, 30 min, 60 min, 120 min, and 180 min after glucose loading for the assay of glucose.

Body weight

Body weight was determined for the various groups of treated animals.

Statistical analysis

Data were expressed as mean ± standard error of mean (SEM). Differences were considered significant at  *** P < 0.001 or P < **01 or P < 05 when comparing the test group with the diabetic control group. For numerical results, one-way analysis of variance (ANOVA) with Tukey's test was done. Posttest comparisons were performed using  Graph Pad Prism insert Version 5.01. All graphs were prepared using GraphPad Prism software.

   Results Top

Antidiabetic study

Serum urea, serum cholesterol, and serum creatinine levels were determined for the ethanol extract of D. turbinatus (at 200 mg/kg and 400 mg/kg). There was no significant reduction of blood urea, serum creatinine, and serum cholesterol levels after 14 days of treatment. The results are shown in [Table 1].
Table 1: Effects of D.turbinatus on biochemical Parameters in Alloxan monohydrate induced diabetic rats

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Effect of ethanol extract D.turbinatus bark extract on fasting blood glucose level

Ethanol extract of D. turbinatus was subjected to antidiabetic activity in rats where alloxan monohydrate was used as a diabetogenic agent. A marked rise in the fasting blood glucose level observed in diabetic control compared to normal control rats. Ethanol extracts of D. turbinatus (at 200 mg/kg) did not exhibit a dose-dependent manner. However, with 400 mg/kg there was a significant effect in the reduction of blood glucose level on the 7 th and 14 th days compared to the diabetic control. The antihypoglycemic activity of ethanol extract was found to be less effective than the reference standard metformin HCl at a dose of 150 mg/kg. Metformin HCl produces a significant reduction in blood glucose levels compared to the diabetic control. The results are shown in [Table 2].
Table 2: Effects of D.turbinatus sample on blood glucose level in Alloxan induced diabetic rats

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Effect of D. turbinatus bark extract on body weight in diabetic rats.

The body weight was slightly increased in the normal control rats compared to initial body weight, whereas in the diabetic control rats there was significant decrease in the body weight. On ethanol extracts of D. turbinatus 200 mg/kg and 400 mg/kg treatment, there was loss of body weight. However, with metformin HCl (150 mg/kg), increase in body weight was significant when compared to the final weight of the normal control group.

   Discussion Top

In recent times, many traditionally used, medicinally important plants were tested for their antidiabetic potency by various investigations in experimental animals. Bioflavonoids are well-known for their multidirectional biological activities, including their antidiabetic efficacy. [20],[21] Dietary flavonoids exert their antidiabetic effect by targeting various cellular signaling pathways in the pancreas. [22] Flavonoids exert their effect by influencing β-cell mass and function as well as energy metabolism and insulin sensitivity in peripheral tissue. [23] Apart from streptozotocin, alloxan is one of the substances generally used for the induction of diabetes mellitus. Alloxan has a destructive effect on the β-cells of pancreas and causes a massive reduction in the insulin released by the destruction of β-cells of the  Islets of Langerhans More Details, thereby inducing hyperglycemia. [23] Diabetes was induced by alloxan monohydrate, metformin HCl was used as a reference standard, and ethanol extracts of D. turbinatus (200 mg/kg and 400 mg/kg) were used for study. The results from the study [Table 1] also indicate that D. turbinatus is unable to reduce the levels of serum urea, serum creatinine, and serum cholesterol significantly. On the glucose tolerance test with the lower dose it was unable to reduce blood glucose levels [Table 2] significantly on the 7 th and 14 th days of treatment. However, with higher doses on the 7 th and 14 th days, it reduced blood glucose levels significantly compare to the diabetic control. This result shows that the ethanol extract (70%) of D. turbinatus stem bark has less beneficial effect on blood glucose levels and shows insignificant results in other biochemical parameters. As D. turbinatus ethanol extract showed the presence of flavonoids, we were tempted to explore its antidiabetic potency using alloxan-induced diabetic rats. Though it contains flavonoids, other chemical entities present along with flavonoids may inhibit their antidiabetic activity.

   Conclusion Top

The effect of ethanol extract of Dipterocarpus turbinatus bark was insignificant on diabetic animals. The extract was also unable to show significant reduction in blood glucose levels in the lower dose compared to the standard metformin HCl (150 mg/kg); with the higher dose it showed a significant effect. However, it did not show any significantly positive response for other biochemical parameters. From this study, we can conclude that ethanol extract of the bark of D. turbinatus is not a potent antidiabetic agent. Further research is needed to confirm the reasons why.

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Conflicts of interest

There are no conflicts of interest.

   References Top

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  [Table 1], [Table 2]


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