ANTIDIABETIC PROPERTIES OF Tarchonanthus camphoratus IN FRUCTOSE-INDUCED DIABETIC WISTAR RATS

Abstract

Tarchonantus camphoratus (TC) has been used traditionally to manage several diseases such as diabetes mellitus (DM) including in Kenya but its anti-diabetic efficacy has not been scientifically evaluated. Therefore, this study aimed at evaluating the antidiabetic properties of Tarchonantus camphoratus crude leaf extract in fructose-induced diabetic Wistar rats. DM in rats was induced using high fructose (25% w/v) in drinking water in experimental groups for 12 weeks. Rats were divided after the DM induction into five groups (n=7 per group) as follows: Group I, normal control; Group II, diabetic untreated; Group III diabetic treated with metformin (100 mg/kg.bw/day), Groups IV and V; diabetic treated with 300 (low dose –LD) and 600 (high dose – HD) mg/kg.bw/day of TC extract respectively. Oral treatments were administered daily for 21 days. Changes in fasting body weights and blood glucose levels were monitored weekly. At the end of the treatment period, oral glucose tolerance test, skeletal muscle tissue weights and serum lipid profile parameters were analysed. For renal function, serum creatinine and urea were analysed while for liver function, serum alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), total proteins (TP), C-reactive protein (CRP) and albumin (ALB) were analysed. The skeletal muscle triglyceride (TG) mass was also analysed. Phytochemicals in the TC crude leaf extract were qualitatively analysed using standard procedures. Statistical analysis was done by Tukey’s test and one-way analysis of variance (ANOVA). Values with p < 0.05 were considered to be statistically significant. After 12 weeks, DM was successfully induced in the diabetic untreated group with rats having significantly higher body weights compared to all other groups (p ˂ 0.05). As compared to the untreated controls, there was a significant amelioration in fasting hyperglycemia in HD and LD groups (33.9% and 27.30% respectively). There was also increased glucose tolerance observed in both treatment groups. Further, TC extract significantly improved fructose-induced hypertriglyceridemia in the treatment groups compared with DM groups. The serum levels of ALP, ALT, and CRP were significantly reduced while TP and ALB were elevated in the extract-treated diabetic rats compared with unaltered DM rats. DM group also exhibited significantly higher skeletal muscle TG mass when compared to normal control and diabetic treatment groups. The observed hypoglycaemic and hypolipidemic activities in the diabetic treatment groups could be associated with the phytochemicals present in TC extract. TC crude leaf extract therefore possesses potential for alternative medicine for DM treatment and management.