In Vivo Hypoglycemic Activity And Safety Of Selected Medicinal Plants Used In The Management Of Diabetes Mellitus In Elgeiyo-Marakwet County, Kenya

ABSTRACT 

Diabetes Mellitus is a group of metabolic disorders sharing a common underlying feature of hyperglycemia with disturbances of carbohydrate, protein and fat metabolism. The disease may present with characteristic symptoms such as polydipsia, polyuria, polyphagia, blurring of vision, and weight loss and in its most severe forms, ketoacidosis or a non-ketotic hyperosmolar state may develop and lead to stupor, coma and, in absence of effective treatment, death. Hyperglycemia may be as a result of defects in insulin secretion, insulin action or both. The use of conventional antidiabetic drugs may have adverse effects including hematological, cutaneous and gastrointestinal reactions, hypoglycemic coma, flatulent, diarrhea and impairment of liver and kidney functions. Some do not lower blood sugar when used alone and require combination therapy. The aim of this study was to determine the antidiabetic activity and safety in a rat model of five plants, Maerua subcordata (Gilg) De Wolf, Chasmanthera dependens Hochst, Pappea capensis Spreng, Syzigium cordatum and Mayrtenus undata (Thumb) traditionally used to manage diabetes mellitus (DM). The plant parts were collected, dried, crashed into fine powder, extracted using distilled water at 60oC and lyophilized using a Freeze Dryer, packaged in air tight containers and stored at -20oC ready for use. The extracts were orally and intraperitoneally screened in alloxan induced diabetic mice for their hypoglycemic activity at doses of 25, 48.4, 93.5, 180.9 and 350 mg/kg body weight. Diabetes in mice was induced using 186.9 mg/kg body weight of alloxan monohydrate. Negative controls included normal and diabetic mice orally and intraperitoneally administered with physiological saline while positive controls included diabetic rats administered with glibenclamide as oral and insulin as intraperitoneal reference drug. The safety of the extracts was studied in mice orally and intraperitoneally administered with 450, 670, and 1000 mg/kg body weight daily for 28 days by recording the changes in body and organ weight, hematological and biochemical parameters and histopathology. Mineral composition of the extracts was estimated using total reflection X-ray fluorescence system (TRXF) and atomic absorption spectroscopy while the types and quantities of phytochemicals present were assessed using standard procedures. Results revealed hypoglycemic activity in three out of the five studied plants at the five different doses when given either orally or intraperitoneally. Results revealed significant difference between the control and experimental mice on total white blood cell and differential white blood cell count, RBC, PCV, Hb, MCV in mice models treated with Maerua subcordata and Mayrtenus undata, α-AMYL in those treated with Syzigium cordatum and Pappea capensis and TC and LDL-C in Chasmanthera dependens extract treated mice. There was significant loss of body weight and loss or gain of organ weights. At tissue level, there was accumulation of inflammatory cells in mice treated with P. capensis and in mice treated with high doses of Mayrtenus undata and Chasmanthera dependens. Phytochemicals present included saponins, flavonoids, alkaloids, tannins and total phenols. All the analyzed trace elements were within the recommended daily allowance RDA) except for Manganese in P. capensis. In conclusion, the studied plants exhibited safe hypoglycemic activity which was contributed by the phytochemicals and mineral elements present in these plants extracts. The study recommends continued use of the three studied plant extracts at low doses. Similar studies should be carried out using higher animals including man.