Antidiabetic effect of methanolic extract of <i>Piliostigma reticulatum</i> leaf in streptozotocin-induced diabetic rats

Abstract

Piliostigma reticulatum (Caesalpiniaceae) is a plant whose leaves are used ethnomedically for the treatment of bacterial infections, wound, injury, diarrhea and dysenteries. The study aims at evaluating the antioxidant and antidiabetic effect of the methanol extract of Piliostigma reticulatum leaf on streptozotocin-induced diabetic rats. The powdered leaves were extracted with 70% methanol to afford MeOH extract. The acute toxicity study and phytochemical screening were carried out on the extract followed by the determination of antioxidant property of the extract using DPPH assay. Antidiabetic activity of the extract at the doses of 250mg/kg, 500mg/kg and 1000mg/kg was evaluated on streptozotocin-induced diabetic rats by oral administration. The acute toxicity study showed LD₅₀ of 5000mg/kg while the phytochemical screening revealed the presence of flavonoids, saponins and alkaloids majorly. The three doses exhibited significant reduction in blood glucose levels but was more pronounced in 250mg/kg on 4^th day when compared with glibenclamide, a well-known antidiabetic drug. The MeOH extract demonstrated significant antioxidant activity at IC₅₀ value of 1.96μg/mL compared to standards used ascorbic acid, gallic acid and rutin (IC₅₀ 11.8, 47.4 & 75.4μg/mL, respectively). This study showed that methanolic extract of Piliostigma reticulatum leaf possesses antidiabetic and antioxidant activities. Therefore, it can be employed as a natural source of antidiabetic agents.

Keywords: Diabetes mellitus, Antioxidant, Streptozotocin, Antidiabetic activity, Piliostigma reticulatum