Antimicrobial, antioxidant and anticancer activities of Strychnos lucida R. Br.

Abstract

Backgroud: Strychnos lucida check for this species in other resources R. Br. (Loganiaceae), a well-known indigenous medicine in Timor Leste, has been used for the treatment of ailments such as malaria, diarrhoea, fever, hypertension, cancer, diabetes mellitus and skin infections. Its pharmacological activity has never been reported. The aim of this study was to determine the biological activities of S. lucida, including antimicrobial, antioxidant and anticancer activities. Materials and methods: The stem, stem bark, twig and leaves of S. lucida were extracted by non-polar (hexane) and polar (ethyl acetate and methanol) solvents. Antimicrobial activity of the plant extracts against 29 microorganisms was evaluated using the agar dilution method and antioxidant properties were determined using DPPH and SOD assays. Anticancer activity was investigated against HepG2, HuCCA-1, A549 and MOLT-3 cell lines using the MTT and XTT assays. Results: It was found that the hexane and ethyl acetate extracts of S. lucida selectively inhibited the growth of Gram positive bacteria (Bacillus subtilis check for this species in other resources ATCC 6633, Bacillus cereus check for this species in other resources and Streptococcus pyogenes check for this species in other resources) with MICs range of 32-128 μg/mL. Antioxidant activities, radical and superoxide scavenging properties, were observed for ethyl acetate and methanol extracts of S. lucida. Particularly, the ethyl acetate extracts selectively showed inhibitory activity against MOLT-3 cells. Notably, the plant extracts showed the relationship between antimicrobial, antioxidant and anticancer activities. Conclusion: The findings support the medicinal usage of S. lucida.