ABSTRACT
The toxicity and safety associated with the use of medicinal plants remains a major concern. In this study, the antidiabetic properties of the dichloromethane (DCM) fraction of C. volubile leaves were investigated in vitro. Its cytotoxic effect and mechanism of toxicity were also investigated in Human Embryonic Kidney (HEK293) cells. The fraction was subjected to in vitro antioxidant assays using the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging and Ferric reducing antioxidant power (FRAP) protocols. Its enzyme-inhibitory properties were investigated on α-glucosidase and α-amylase activities. Gas Chromatography Mass Spectroscopy (GCMS) and Fourier Transform Infrared (FTIR) spectroscopic analysis were used to identify its phytoconstituents. Cytotoxicity was determined via MTT assay. The treated cells were assayed for reduced glutathione (GSH), non-protein thiol, nitric oxide and malondialdehyde (MDA) levels, as well as Superoxide Dismutase (SOD), catalase, myeloperoxidase and ATPase activities. Cell apoptosis and/or morphological changes were determined using the acridine orange and ethidium bromide (AO/EB) dual staining method. The fraction showed significant (pâ¯<â¯0.05) antioxidant and enzyme-inhibitory activity. It showed significant (pâ¯<â¯0.05) cytotoxic effect against HEK293 cells with concomitant depletion of antioxidative and elevation of proinflammatory biomarkers. Morphological changes were examined in the cells with an apoptotic index of 0.84. 1,1-Dodecanediol, diacetate was identified as the most predominant compound, while aromatics and amines as the most functional groups present in the fraction. These results suggest the antidiabetic and cytotoxic effects of C. volubile leaves. The toxicity can be attributed to induced oxidative stress and proinflammation with concomitant depletion of ATP leading to apoptosis of the cells.