In Vivo Antidiabetic Effects And Safety Of Five Medicinal Plants Traditionally Used To Manage Diabetes Mellitus In Embu County, Kenya

ABSTRACT

Diabetes mellitus is a glucose metabolism disorder that has become an issue of public health concern in Kenya today. Conventional drugs used in management of the disease are unaffordable to the general populace and are associated with many undesirable side effects. Locally made herbal extracts are cheap and readily available but proper scientific study has not been conducteed on most medicinal plants to validateK their efficacy and safety. M. indica, E. schlechterianum (Loes.) Loes. L. bussei (Harms), A. mossambicensis (Oliv.) Wild and A. adscensionsis L. have been used for a long time in management of diabetes mellitus and many other ailments. The efficacy and safety of these extracts on long term use has not been evaluated. The aim of this study is to determine the hypoglycemic activity and safety of their aqueous extracts. In vivo hypoglycemic activity was assayed by orally and intraperitoneally administering the aqueous extracts in alloxan induced diabetic Swiss albino mice. The study plan involved dividing the diabetic animals into four groups which were orally and intraperitoneally administered with the plants extracts doses at 50, 100, 200 and 300 mg/kg body weight, 1 IU/kg of insulin and 4.6mg of glibenclamide (200 mg/kg body weight) were used as the standard drug. The results obtained on administration of the extracts were compared with those of the standard drug, the normal, positive and the negative control groups which also consisted of five mice each. Blood glucose levels in all the groups for both routes of administration were measured at the start of the experiment and after 1, 2, 3, 4, 6 and 24 hours from the time of administration of the drugs. Toxicity studies involved administration of the extracts to Swiss albino mice at 450, 670 and 1000 mg/kg body weight daily for 28 days. The animals were then exsanguinated and blood drawn from the heart. Haematological and blood biochemistry parameters were determined. Intraperitoneal and oral administration of the five extracts at the said dosages daily for 28 days caused a significant decrease in weekly body weight gain and an increase in the relative percent organ to body weights of the brain, liver, kidney, heart, lungs, spleen and the testes for both oral and intraperitoneal routes. Also, there were notable changes in the level of RBC, WBC, Hb, PCV, PLT, and MCV, MCHC, neutrophils, lymphocytes, eosinophils, basophils, monocytes and biochemical parameters: AST, ALT, GGT, CK, α-AMY, LDH, TBIL, D-BIL, I-BIL, TG, TC, LDL-C, HDL-C UA, urea and creatinine. Quantitative phytochemical analysis of extracts revealed presence of tannins, flavonoids, saponins, alkaloids and phenols. TXRF analysis showed presence of Fe, Ni, V, Cr, Mn, K, Hg, Cu, Rb, Se, Br, Ti, Zn, As, Pb and Ca at varied levels. All the five plant extracts showed strong hypoglycemic activity due to presence of phytochemicals and minerals that have been found to exhibit strong hypoglycemic and antioxidant properties. The study confirmed the ethno pharmacological use of the five plants and also established their efficacy and safety at the tested doses. Data obtained can be used as a guide on their proper use in management of diabetes mellitus. Future studies and should be considered but in higher animals like apes before commencement of preclinical trials. Organic solvent extraction in vivo studies should be considered so as to compare their efficacy with the aqueous extracts.