Abstract

The present communication dealt with cytotoxic and free radical scavenging potential of tertiary and quaternary alkaloid extracts of Tribulus terrestris fruits. Tertiary and quaternary alkaloid extracts were found to be cytotoxic to leukemic cells (Jurkat E6-1) with LC50 values of 100 and 42 µg/ml, respectively. Compared to the control, reactive oxygen species and reactive nitrogen species were significantly reduced in the cells treated with lower concentrations of tertiary and quaternary alkaloid extracts. Cells treated with tertiary alkaloid extract demonstrated significantly elevated levels of peroxidise, catalase and superoxide dismutase-like activities, whereas cells treated with quaternary alkaloid extracts showed insignificant elevations of the tested enzyme activities, compared to the control cells. The antioxidant activity of tertiary alkaloid (100 µg/ml) extract was 46.78 and 14.92 µg/ml of ascorbic acid equivalent as estimated in ferric reducing antioxidant potential and total antioxidant assays. Quaternary alkaloid extract displayed an IC50 value of 159 µg/ml in the nitric oxide mitigation assay. Cells treated with quaternary alkaloid extracts showed 1.4-fold increase in superoxide dismutase-like activity compared to the control cells. These results suggest that tertiary and quaternary alkaloid extracts possessed cytotoxic and free radical scavenging potential against leukemic cells.