Phytochemical analysis and bioactivities of Argemone mexicana Linn. leaves

Summary The aim of the study was to evaluate the in vitro antimicrobial, antioxidant, cytotoxic and thrombolytic activities of n-hexane, ethyl acetate and methanol extracts of Argemone mexicana leaves. Phytochemicals were also identified to establish the possible causes of the pharmacological activities. The leaves extracts were screened for major phytochemicals using established procedures. Antimicrobial and cytotoxic studies of the leaves extracts were conducted using disc diffusion and brine shrimp lethality bioassay methods, respectively while an in vitro thrombolytic model was used to assess the clot lysis effect of the extracts using streptokinase as positive control. Antioxidant activity was evaluated by free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) assay as well as total phenolic content. The results showed that the leaves extracts were a rich source of phytochemicals. Extracts showed partial antimicrobial activity (zone of inhibition was ranges between 9 to 13 mm) against the tested microorganisms at the 1000 µg/disc compared to the standard, ciprofloxacin. Ethyl acetate and methanol extracts of the leaves showed higher antioxidant property compared to n-hexane extract. Median inhibitory concentration, IC 50 , of ethyl acetate extract was 39.91 µg/ml for DPPH free radical which was much lower than standard ascorbic acid (IC50: 76.11 µg/ml). Although the extracts were not cytotoxic, n-hexane and ethyl acetate extracts showed significant clot lysis activity (p<0.001) with reference to negative control and % clot lysis of the extracts was around 13. The present findings suggest that the plant widely available in Bangladesh could be a prominent source of medicinally important natural compounds.