ANTIDIABETIC ACTIVITY AND SAFETY OF Maerua decumbens METHANOLIC ROOT EXTRACT IN WISTAR RATS

Abstract

Diabetes mellitus (DM) is increasingly affecting many people worldwide. Use of conventional antidiabetic drugs is expensive and is also associated with undesirable side effects that necessitates the need to find alternative drugs which are affordable and with minimal side effects. Despite the wide use of herbal medicines as an alternative especially in developing countries, there is inadequate scientific evidence on their antidiabetic activity and safety. For instance, there is no scientific evidence on the antidiabetic claims of Maerua decumbens roots and also its safety. Therefore, this study aimed at evaluating oral toxicity and antidiabetic activity of M. decumbens methanolic root extract in Wistar albino rats. Qualitative phytochemical analysis of the extract was also assessed. In acute toxicity study, extract (2000 mg/kg b.wt) was orally administered once to female rats and monitored for 14 days. In sub-acute toxicity study, the extract was administered daily at 400 and 800 mg/kg to rats of both sexes for 28 days. Weekly b.wt were determined and at the end of the treatment period, rats were sacrificed, organ weights (liver, kidney, heart and spleen) recorded, serum indices of liver and kidney function, hematological parameters, liver and kidney histology were performed. In antidiabetic study, streptozotocin (50 mg/kg) induced diabetic rats were treated with M. decumbens extract (100 and 400 mg/kg) and metformin (100 mg/kg) for 21 days and fasting b.wt and blood glucose (FBG), liver malondialdehyde (MDA) levels, and histology of liver and pancreas were investigated. Statistical analyses were done using Student t-test and Analysis of Variance (p<0.05). Phytochemical screening showed presence of alkaloids, glycosides, flavonoids, saponins, steroids, tannins and terpenoids. In toxicity studies, extract-treated rats showed no signs of toxicity or mortality and b.wt versus the normal control. The relative organ weights showed marginal differences while serum indices of liver and kidney function showed normal levels except significant decreases in total protein and urea levels in extract-treated rats versus normal control. There was no notable change in the White Blood Cells’ differential count, while Red Blood Cells’ indices showed significant alterations but their values remained within published normal reference ranges for the species. In antidiabetic study, extract-treated diabetic rats showed a marginal increase in b.wt, significant decreases in FBG and MDA, and cytoprotection of liver and pancreas versus untreated-diabetic rats. Therefore, M. decumbens root extract administered orally in rats is safe coupled with antidiabetic activity that provides great potential for its use as medicine for DM.