Diabetes and medicinal plants

About author:
Amir Khan*, Fouzia Ishaq
^*Dept. of Biotechnology & Biochemistry
Sardar Bhagwan Singh Post Graduate Institute of Biomedical Sciences & Research, Dehradun, India
*e-mail: amiramu@gmail.com

Introduction:
Diabetes mellitus (DM) is a common and very prevalent disease affecting the citizens of both developed and developing countries. It is estimated that 25% of the world population is affected by this disease. Diabetes mellitus is caused by the abnormality of carbohydrate metabolism which is linked to low blood insulin level or insensitivity of target organs to insulin. Despite considerable progress in the treatment of diabetes by oral hypoglycemic agents, search for newer drugs continues because the existing synthetic drugs have several limitations. The herbal drugs with anti-diabetic activity are yet to be commercially formulated as modern medicines, even though they have been acclaimed for their therapeutic properties in the traditional systems of medicine. The plants provide a potential source of hypoglycemic drugs because many plants and plant derived compounds have been used in the treatment of diabetes. Ayurveda and other traditional medicinal system for the treatment of diabetes describe a number of plants used as herbal drugs. Hence, they play an important role as alternative medicine due to less side effects and low cost. The active principles present in medicinal plants have been reported to possess pancreatic beta cells re-generating, insulin releasing and fighting the problem of insulin resistance.  Insulin and oral hypoglycemic agents like sulphonylureas and biguanides are still the major players in the management but there is quest for the development of more effective anti-diabetic agents.
Key words: Diabetes mellitus, blood insulin, medicinal plants, herbal drugs
Description:
medicinal plants with anti-diabetic and related beneficial properties
Acacia arabica (Lam) Wild. (Mimosaceae): It is found all over India. The plant extract acts as an antidiabetic agent by acting as secretagouge to release insulin. It induces hypoglycemia in control rats but not inalloxanized animals. Powdered seeds of A. arabica when administered (2, 3 and 4 g/kg body weight) to normal rabbits, induces hypoglycemic effect by initiating release of insulin from pancreatic beta cells.
Allium sativum L. (garlic): (Liliaceae) It is a perennial herb cultivated throughout India. Oral administration of the garlic extract significantly decreases serum glucose, total cholesterol, triglycerides, urea, uric acid, creatinine, AST and ALT levels, while increases serum insulin in diabetic rats but not in normal rats when compared with antidiabetic drug glibenclamide. The antidiabetic effect of the extract was more effective than glibenclamide. It is concluded that the plant must be considered as excellent candidate for future studies on diabetes mellitus .
Aloe vera (L) Burm.(Asphodelaceae): It grows in arid climates and is widely distributed in Africa, India and other arid areas. Aloe vera gel at 200 mg/kg 1possessessignificant antidiabetic, cardioprotective activity,  reduces the increased TBARS, maintains the Superoxide dismutase and Catalase activity up to the normal level and increases reduced glutathione by four times in diabetic rats The leaf pulp extract showed hypoglycemic activity on IDDM and NIDDM rats, the effectiveness being enhanced for type II diabetes in comparison with glibenclamide
Andrographis paniculata Burm. (Acanthaceae): It is a herbaceous plant native to India, Sri Lanka and widely cultivated in southern Asia. Oral administration of andrographis significantly increases the activity of SOD andCatalase. Also decreases blood glucose levels due to its antioxidant properties . The ethanolic extract of A.paniculata possesses antidiabetic property and may be attributed at least in part to increase glucose metabolism. Itshypotriglyceridemic effect is also beneficial in the diabetic state.
Helicteres isora L., As.(Sterculiaceae): Distributed widely in forests throughout India. The hot water extract of fruit of H. isora exhibits significant antioxidant activity and moderate antidiabetic activity, at 200 mg/mL dose it shows glucose uptake activity and found to be active comparable with insulin and metformin . The ethanolic extract has insulin-sensitizing and hypolipidemic activity and has the potential for use in the treatment of type- 2 diabetes.
Syzigium cumini (L) Skeels.(Myrtaceae): Commonly known as ‘Jamun’, is widely used in Indian folk medicine for the treatment of diabetes mellitus. Oral administration of 2.5 and 5.0 g/kg body weight of the aqueous extract of the seed for 6 weeks results in significant reduction in blood glucose and an increase in total haemoglobin, but in the case of 7.5 g/kg body weight the effect is not significant. The aqueous extract also decreases free radical formation which clearly shows the antioxidant property. Thus the study shows that Jamun seed extract (JSEt) has hypoglycemic action.
Conclusion: Diabetes is a serious metabolic disorder. Differences in social structure, psychic stress, obesity, hormonal imbalance and heredity are optimizing the growth of pandemic. At present, the treatment of diabetes mainly involves a sustained reduction in hyperglycemia by the use of biguanides, thiazolidinediones, sulphonylureas, D-phenylalanine derivatives, meglitinides and α-glucosidase inhibitors in addition to insulin. However, due to unwanted side effects the efficacies of these compounds are debatable and there is a demand for new compounds for the treatment of diabetes. Hence, plants have been suggested as a rich, as yet unexplored source of potentially useful antidiabetic drugs. However, only a few have been subjected to detailed scientific investigation due to a lack of mechanism-based available in vitro assays. These efforts may provide treatment for all and justify the role of novel traditional medicinal plants having anti-diabetic potentials.