|Year : 2015 | Volume
| Issue : 1 | Page : 91-95
Anti-diabetic activity of methanolic extract of Alpinia galanga Linn. aerial parts in streptozotocin induced diabetic rats
Ramesh Kumar Verma1, Garima Mishra1, Pradeep Singh1, Keshri K Jha1, Ratan L Khosa2
1 Department of Pharmaceutical Chemistry, Teerthanker Mahaveer College of Pharmacy, Teerthanker Mahaveer University, Moradabad, India
2 Department of Pharmaceutical Science, Bharat Institute of Technology, Meerut, Uttar Pradesh, India
|Date of Web Publication||4-Nov-2015|
Department of Pharmaceutical Chemistry, Teerthanker Mahaveer College of Pharmacy, Teerthanker Mahaveer University, Moradabad - 244 001, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Alpinia galanga Linn. belongs to the family Zingiberaceae has been used as a traditional medicine in China for relieving stomach ache, treating cold, invigorating the circulatory systems, diabetes, and reducing swelling. Aim: To evaluate the antidiabetic activity of methanolic extract of A. galanga aerial parts on streptozotocin (STZ) induced diabetic rats. Materials and Methods: Diabetes was induced by single intraperitoneal injection of STZ at a dose of 60 mg/kg bodyweight. Test drug methanolic extract of A. galanga (200 and 400 mg/kg b.w.) and glibenclamide (10 mg/kg b.w.) as standard drug was administered orally for 21 consecutive days in STZ-induced diabetic rats. Fasting blood glucose level, serum lipid profiles, as well as initial and final changes in body weight were assessed along with histopathology. All the parameters were statistically analyzed by using one-way ANOVA followed by Bonferroni t-test. Results: Experimental findings showed significant dose dependent antidiabetic potential of methanolic extract in terms of reduction of fasting blood glucose level and various biochemical parameters in diabetic rats when compared with that of the diabetic control group, which might be due to the stimulatory effect of methanolic extracts on the regenerating β-cells and also on the surviving β-cells. Conclusion: Methanolic extract of aerial parts of A. galanga was effective in controlling blood glucose level and improve lipid profile in euglycemic as well as diabetic rats.
Keywords: Alpinia galanga, antidiabetic activity, methanolic extract, streptozotocin
|How to cite this article:|
Verma RK, Mishra G, Singh P, Jha KK, Khosa RL. Anti-diabetic activity of methanolic extract of Alpinia galanga Linn. aerial parts in streptozotocin induced diabetic rats. AYU 2015;36:91-5
|How to cite this URL:|
Verma RK, Mishra G, Singh P, Jha KK, Khosa RL. Anti-diabetic activity of methanolic extract of Alpinia galanga Linn. aerial parts in streptozotocin induced diabetic rats. AYU [serial online] 2015 [cited 2020 Oct 21];36:91-5. Available from: https://www.ayujournal.org/text.asp?2015/36/1/91/169006
| Introduction|| |
Diabetes mellitus (DM) is a disease characterized by disturbed metabolism and abnormally high blood sugar levels resulting from the body's inability to produce or properly use insulin. Instances of diabetes have increased and it is expected that there will be over 472 million people with diabetes worldwide by the year 2030. India has more than 40 million diabetic people that represent nearly 20% of total diabetic population worldwide. DM occurs in several forms. Approximately 10% of diabetes patients have type 1 DM, an autoimmune disease that destroys insulin-producing β-cells in the pancreas leading to a decrease in the concentration of insulin in the body, and the remainder have type 2 (noninsulin-dependent DM). Type 2 DM is a metabolic disorder characterized by a progressive decline in insulin action. Beside these common types, other forms of diabetes are gestational diabetes, feline diabetes, and juvenile diabetes. The β-cells normally compensate for insulin resistance by secreting greater amount of insulin in order to maintain glucose homeostasis. In type 2 DM, this β-cell function becomes impaired due to insulin resistance leading to deterioration in glucose homeostasis and a subsequent development of impaired glucose tolerance (glucose resistance in the body which leads to high blood sugar level)., Insulin and oral hypoglycemic agents are the most widely used drugs for lowering blood sugar in diabetes, but these drugs also have various side effects such as hypoglycemia, weight gain (sulfonylurea), and lactic acidosis (biguanides), and all of these drugs can cause liver and renal damage. More than 800 plants are used as traditional remedies for the treatment of diabetes throughout the world. Herbal drugs enjoy the advantages of being comparatively less toxic than synthetic drugs, more harmony with the biological system and affordable to all classes of people. However, a scientific proof of the antidiabetic activity of medicinal plants and phytopharmaceuticals with fewer side-effects is still lacking.
Alpinia galanga Linn. is used in traditional medicine, is also known as greater galangal in English and Kulanjan in Hindi. The plant is widely used in Southern India. Throughout southern India, the rhizome of A. galanga is used as Rasna for rheumatism, intermittent fever, dyspepsia, and respiratory disorders. The hypoglycemic activity of this plant extract was already reported on alloxan induce diabetic rabbit. The current study attempts to evaluate the antidiabetic activity of the A. galanga methanolic extract on streptozotocin (STZ) induced diabetic rats.
| Materials and Methods|| |
Drugs and chemicals
Streptozotocin from Sigma (Sigma, USA), Gluco-one (Glucose determination Diagnostic kit) from Dr. Morpen, glibenclamide tablets (Daonil) from Aventis Pharma Limited, Goa, India, and analytical grade solvents were obtained from Rankem (Rankem, Pvt. Ltd, New Delhi).
Fresh aerial parts of A. galanga were collected from the Manoj Nursery, Lucknow and dried in the shade and made into a coarse powder with the use of mixer grinder. The plant species was identified and authenticated at Birbal Sahni Institute of Palaeobotany (BSIP), Lucknow, India. A voucher specimen no. 13316 was submitted in BSIP, Lucknow and also in Department of Pharmacognosy, Teerthanker Mahaveer College of pharmacy, Moradabad, India.
Preparation of extract
Dried aerial parts (100 g) were defatted with petroleum ether (60–80°C) and then extracted with methanol by soxhlation. The extraction was carried out for around 50–60 cycles with each solvent. All the extracts were evaporated to dryness using rotary evaporator and collected in the form of semi-solid mass. The percentage yield of the methanolic extract was found to be 13.18%.
The preliminary phytochemical screening of petroleum ether and methanolic extract was performed in order to determine the presence of various phytoconstituents such as alkaloid, carbohydrate, flavonoid, proteins, amino acids, phenols, tannins, glycosides, and steroids.,,
Male Wistar albino rats weighing between 120 and 160 g and swiss albino mice (25 g ± 5 g) were obtained from animal house, Teerthanker Mahaveer University, Moradabad for this experiment. The experimental protocol was approved by the Institutional Animal Ethics Committee (1205/C/08/CPCSEA/21.04.08). Animals were housed in polypropylene cages for one week before starting of study and allowed food and water ad libitum. The standard environmental conditions of temperature 27°C ± 2°C with humidity of 50–60% RH and light/dark cycle of 12 h/day, were maintained throughout the period. The animals were allowed to acclimatize to laboratory conditions for 48 h before the start of the experiment. Animals were provided with standard rodent pellet diet and the food was withdrawn 18–24 h before the experiment was conducted.
Acute toxicity study
Acute oral toxicity study was performed as per OECD-423 guidelines (acute toxic class method). Albino mice (n = 6) of either sex selected by random sampling technique were kept fasting for overnight providing only water, after that the extract of A. galanga was administered orally at the dose level of 5 mg/kg body weight and observed for 14 days. If mortality was observed in 2–3 animals, then the dose administered was assigned as toxic dose. If mortality was observed in one animal, then the same dose was repeated again to confirm the toxic dose. If mortality was not observed, the procedure was repeated for further higher doses such as 50, 100, 200, 400, 800, and 1600 mg/kg body weight.
Induction of diabetes mellitus
Diabetes was induced experimentally in rats by single intraperitoneal injection of a freshly prepared solution of STZ at a dose of 60 mg/kg bodyweight. After 72 h, blood was collected from the tail vein under ether anesthesia with aseptic procedure and blood glucose levels were determined using Gluco-one (Glucose determination Diagnostic kit) from Dr. Morpen. Animals were considered to be diabetic if the blood glucose values were above 250 mg/dL and STZ-induced diabetic rats were stabilized in diabetic condition over a period of 7 days.
The rats used for the study were classified into five groups (n = 6). Group I served as normal control and received normal saline (5 ml/kg b.w. p.o.); Group II was treated as diabetic control; Group III was treated with glibenclamide (10 mg/kg b.w. p.o.) and Group IV and V received methanolic extracts at dose level of 200 and 400 mg/kg, and were administered orally for 21 days. At the end of the experimental period, the animals were fasted overnight and blood was collected for various biochemical estimations.
Fasting blood glucose was measured at different time intervals to check the hyperglycemic state. At the end of 21 days study period, blood samples were collected under fasting conditions. The serum obtained after centrifugation was used for the determination of glucose levels. The measurement of serum total cholesterol, triglycerides and serum high density lipoprotein (HDL) and low density lipoprotein (LDL) was determined by using commercial kits (Erba limited, India).
At the end of study, the rats were sacrificed and pancreas was collected. The tissue was fixed in 10% formalin immediately after removal from the animal to avoid decomposition. Embedding in paraffin was carried out by removal of water using alcohol dehydration and infiltration of xylene or chloroform as a solvent for wax.
Thin sections of the tissue (7 µm) were cut using a microtome and these were stained with hematoxylin and eosin., The tissue sections were subjected to rehydration by exposure of them to decreasing concentrations of alcohol from 100% to 30% and then staining with hematoxylin, which has an aqueous base. The sections were dehydrated using increasing concentrations of alcohol and then stained with eosin. They were then treated with diphenyl xylene and examined under the microscope.
The values were expressed as mean ± standard error of the mean. The results were analyzed for statistical significance using one-way ANOVA followed by Bonferroni t-test. Levels of P < 0.05, P < 0.01, and P < 0.001 were considered as significant.
| Results|| |
The preliminary phytochemical investigation revealed the presence of carbohydrate, steroids, alkaloids, glycosides, and phenolic compounds.
The result of acute toxicity study exhibited that methanolic extract of aerial parts of A. galanga has no mortality up to 7 days after treatment at various doses of 50, 100, 200, 400, 800, and 1600 mg/kg.
The hypoglycemic effects of the methanolic extract of A. galanga aerial parts on fasting blood glucose levels of diabetic rats for both low- and high-dose studies as shown in [Table 1]. Methanolic extract of A. galanga aerial parts administered in 200 mg/kg and 400 mg/kg doses levels to STZ treated diabetic rats showed a significant reduction in blood glucose levels which are related to the duration of treatment. The maximum reduction in blood glucose was observed after 4th day at dose 400 mg/kg body weight and after 15th day at dose 200 mg/kg body weight. At the end of study, the extract at dose 200 and 400 mg/kg of body weight showed a significant reduction in blood sugar level in comparison with that of diabetic control group. Body weight of rats increases normally when the test/standard doses were given to the rats in comparison to the control rats. The diabetic control group decreases in body weight was observed from the starting day to until the end of the study [Table 2].
|Table 1: Effect of methanolic extracts of aerial parts of Alpinia galanga on fasting blood glucose level in diabetic rats|
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|Table 2: Effect of Alpinia galanga methanolic extracts (aerial parts) on body weight of streptozotocin induced diabetic rats|
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Oral administration of methanol extract of aerial parts of A. galanga resulted in a significant reduction of serum triglyceride and total cholesterol and lipid levels LDL and increases HDL in rats; in comparison to the diabetic rats [Table 3].
|Table 3: Effect of methanolic extract of aerial parts of Alpinia galanga on lipid profile in STZ-induced model|
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Histopathological results are shown in [Figure 1]-5 at ×100. The control group revealed no any histological alteration of Islets of Langerhans More Details. In diabetic control group, the islets showed necrosis and severe damage due to STZ. In the standard group, the sections showed mild to moderate necrosis and degeneration of islets. Further, the methnolic extract of A. galanga (200 mg/kg and 400 mg/kg) prevented the degeneration of islets of Langerhans in pancreas and maintain the normal cellular size of the islets in a dose dependent manner.
|Figure 1: Transverse Section of pancreas (a) Normal control group animal showing no necrosis or destruction of tissue, (b) Diabetic control group animal showing more necrosis or destruction of tissue, (c) Standard group animal showing no necrosis or destruction of tissue, (d) 200 mg/kg (low dose) test drug group animal showing necrosis or destruction of tissue, (e) 400 mg/kg (high dose) test drug group animal showing very less necrosis or destruction of tissue|
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| Discussion|| |
The present investigation was aimed to evaluate the hypoglycemic effects of methanolic extracts of aerial parts of A. galanga on STZ-induced diabetes-mediated metabolic alterations in rats. The observed effect on fasting blood glucose level in experimental rats might be due to the stimulatory effect of methanolic extracts of aerial parts of A. galanga on the regenerating β-cells and also on the surviving β-cells in diabetic rats. It has been reported that STZ administration produces partial destruction of pancreatic β-cells with permanent diabetes condition. The present study showed increase in plasma triglycerides, total cholesterol and LDL cholesterol with a decrease in HDL cholesterol., Potential of the extract to decrease cholesterol and triglyceride levels could be helpful in improving lipid metabolism in diabetics, which in turn will help to prevent  diabetic complications. LDL-cholesterol being involved in the transport of cholesterol from the liver to peripheral tissues is the key factor in atherogenesis. Potential of the extract to reduce LDL-cholesterol thereby indicates its possible involvement in prevention of DM induced cardiovascular complications. The stimulatory activity of extract was compared with the effect of glibenclamide. Histopathological studies of untreated diabetic rats showed almost complete destruction of cells due to the STZ. Diabetic rats which were treated with methanolic extract of aerial parts showed almost normal cells at high dose while low dose given some damages of cells due to STZ. It seems that the extract either protected the cells from the toxic effect of STZ or the cells recovered after the initial injury. In the treated group, cytoplasmic granulation in the cells is visible, though not as in the normal case. The results of preliminary phytochemical studies showed the presence of alkaloids, triterpenes, steroids, polyphenols and carbohydrates in methanolic extract of aerial parts of A. galanga. Among them polyphenolics are the most reported phytoconstituents showing a wide range of pharmacological effects including antidiabetic activity., The presence of polyphenols or other phytoconstituents may be responsible for the promising antidiabetic activity of methanolic extract of aerial parts of A. galanga.
| Conclusion|| |
Alpinia galanga has potential as hypoglycemic agent and exhibited significant improvement in blood glucose level, various parameters like body weight and lipid profile as well as protection of pancreatic islets of Langerhans and so might be valuable in diabetes treatment. The plant may be further explored for its phytochemical profile to recognize the active constituents responsible for its antidiabetic activity.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]
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