ABSTRACT
Objective To evaluate the inhibitory effect of polysaccharides from Selaginella tamariscina on Enterovirus 71 (EV71) replication in vitro. Methods For detecting the cytotoxicity, series of doses of polysaccharides from Selaginella tamariscina were added in RD cells, cell survival rates were evaluated by observing the cytopathic effect (CPE) and using cell counting Kit-8 (CCK8) assay, then the half toxic concentration(CC50) of the drugs were calculated. For studying the antiviral activity, the cellular model was established by infecting RD cells with EV71. Several groups were set in the experiments: normal control group, virus-infected group, positive drug treated EV71 -infected group(ribavirin 3. 2 mg/L) and series of doses of polysaccharides treated EV71 -infected groups. The CPE inhibitions were determined by using CCK8 assay and the half inhibitory concentrations of drugs(IC50) were calculated. The inhibitiory effect of polysaccharides on EV71 RNA were determined by using real-time RT-PCR methods for detecting the virus RNA levels in cell cultures. Results The CC50 of 30% and 50% alcohol precipitated polysaccharides from Selaginella tamariscina on RD cells were 396 and 142 mg/L, respectively; the IC50 calculated according to the CPE inhibitory rates were respectively 40. 8 and 26. 2 mg/L. Additionally, these two polysaccharides significantly reduced viral RNA copies in EV71-infected RD cells. Conclusion Selaginella tamariscina together with its 30% and 50% alcohol precipitated polysaccharides can be developed as potential new anti - E V 71 drugs.