A comparative study on in-vitro antioxidant, anticancer and antimicrobial activity of the methanol extracts of the roots of four species of Aristolochia L. from southern Western Ghats of India

‘Green medicine’, the drugs derived from plants attained a wide spread interest, as believed to be safe and dependable, compared with costly synthetic drugs that have adverse effects. The present study is an attempt to evaluate the antioxidant, anticancer (cytotoxic) and antimicrobial effects of the methanol extract of the roots of four ethnomedicinally important Aristolochia species from southern Western Ghats. Antioxidant activity was evaluated by three separate methods: DPPH free radical scavenging, reducing power assay, NBT superoxide radical scavenging assay. Out of four Aristolochia species tested, A. bracteolata, A. tagala and A. krisagathra recorded significant antioxidant activity. Anticancer activity of the extracts was tested against Breast cancer cell lines (MDAM B-231), Cervical cancer cell lines (HeLa), Lung cancer cell lines (A 549) and Colon cancer cell lines (HTL 116) using MTT method. Methanol extract of A. krisagathra recorded significant activity and best activity was recorded against HeLa and MDAM B-231 with IC50 value of 25 µg/ml. Antimicrobial activities was recorded by minimum inhibitory concentration and agar disc diffusion method. The maximum antimicrobial activity was found in the methanol extract of A. indica, which inhibited all the ten tested bacteria in relatively low concentration below 125µg/ml, except Salmonella typhi and Staphylococcus simulans. The extract of the A. tagala also recorded relatively good antibacterial activity which inhibited all of the tested bacteria. To the contrary, the extracts of the candidate species showed poor antifungal activity. The results of the present study showed that Aristolochia species demonstrated a strong antioxidant, anticancer and antibacterial activity and deserve detailed pharmacological studies.