The Antidiabetic Efficacy of Combined Extracts from Two Continental Plants: Azadirachta indica (A. Juss) (Neem) and Vernonia amygdalina (Del.) (African Bitter Leaf)

Abstract

Polyherbal therapy is said to be a current pharmacological principle having the advantage of producing maximum therapeutic efficacy with minimum side effects. We assessed the antidiabetic efficacy and hence the impact on biochemical indices of toxicity by a combination of extracts from neem and bitterleaf. Thirty rats, 25 diabetic and 5 non-diabetic rats, were used for the study. The diabetic rats were divided equally into five groups and respectively treated: saline (diabetic control), extracts from neem and bitterleaf combined, neem only, bitterleaf only and chlorpropamide for a 24 day period. After oral administration of the first dose of extract (400 mg kg 1 b.w.) and chlorpropamide (4.286 mg kg 1 b.w.), blood glucose was monitored in vivo at various time intervals for 9 h, thereafter daily administration continued for 24 days. Whereas single dose treatment with neem only showed peak reduction (28.56%) an hour after, treatments with combined extracts, bitterleaf and chlorpropamide had their peak reductions all at the 7th hour (24.78, 47.31 and 60.51%, respectively). Percentage reductions in blood glucose relative to their initial values at the end of treatment were 71.05, 44.95, 88.63 and 75.83 for combined extract, neem, bitterleaf and chlorpropamide respectively. The decrease in blood glucose for the groups treated with combined extracts and bitterleaf only compared well (p<0.01) with chlorpropamide and non diabetic control, but not with neem alone. Determination of markers of hepatotoxicity in serum including GPT and GOT activities, total protein, albumin and urea indicated that, of the four treatments, neem provides the best protection against hepatic dysfunction. In the group treated with combined extracts these alternate selective advantages of neem and bitterleaf were expressed as a positive synergy, hence more beneficial than individual treatments.

Toxicity profile of ethanolic extract of Azadirachta indica stem bark in male Wistar rats

“…Medicinal plants have formed the basis of health care throughout the world since the earliest days of humanity and are still widely used with considerable importance in international trade [1,2] . In certain African countries, however, up to 90% of the population still relies exclusively on plants as a source of medicines [3] .…”

Protective Effect of Ethanolic Extract of Gongronema Latifolium Leaves in Alloxan-Induced Diabetic Rats

“…Hence plant materials are continuously scrutinized and explored for their beneficial effect. The phytochemicals identified from traditional medicinal plants are presenting an exciting opportunity for the development of new types of therapeutics, with accelerated global efforts to harness and harvest those medicinal plants that bear a substantial amount of potential phytochemicals showing multiple beneficial effects in combating diabetes and diabetes-related complications [7,8]. Treatment by herbal medicines may have some advantages over treatment by single purified chemicals; as herbal medicine are the mixtures of more therapeutic or preventive components, and so might have more activity than single products alone.…”

Hypoglycaemic and Hypolipidemic Effects of Polyherbal Formulation in Streptozotocin-Induced Diabetic Rats.

“…There is an increased focus on plants in the search for appropriate hypoglycaemic and anti-hyperglycaemic agents for diabetic conditions (Ebong et al, 2008). Not all plants prepared and administered locally have been tested and proven scientifically to justify their traditional uses and potencies.…”