Anti-poliovirus activity of medicinal plants selected from the Nigerian ethno-medicine

Abstract

This study was carried out to validate acclaimed anti-poliovirus effect of crude methanol extracts from 14 medicinal plants used by traditional healers in Southwest Nigeria. Plant samples were powdered and extracted by cold maceration into absolute methanol and maximum non toxic concentration (MNTC) of each plant extract to rhabdomyosarcoma (RD) cells was determined in tissue culture. Using serial twofold dilution of the MNTC (specific for each extract), ability of extract to inhibit viral-induced cell death (CPE) in tissue culture was evaluated three days post-infection by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assays. 50% inhibitory concentration (IC₅₀) and 50% cytotoxic concentration (CC₅₀) was determined by statistical analysis. Selective index was calculated as ratio of CC₅₀ to IC₅₀. Out of the 14 plant extracts evaluated for anti-poliovirus activity, Senna siamea (Lamk.) Irwin et Barneby (bark extract) and Zephyranthes candida Lindl (whole plant) demonstrated significant in vitro activity with IC₅₀ of 0.0019 and 0.121 μg/mL, respectively. Bioassay-guided fractionation of extracts indicated that activities were retained in chloroform fraction of Z. candida, and also in hexane and chloroform fractions of S. siamea, but none of the polar fractions were active. These results support the traditional use of S. siamea and Z. candida as antiviral agents and suggest that they could provide a possible source for anti-poliovirus drug discovery and development.

Keywords: Anti-poliovirus activity, traditional medicine, MTT colorimetric assay

African Journal of Biotechnology Vol. 12(24), pp. 3878-3883