Inhibitory effects of orobol 7-O- d-glucoside from banaba (Lagerstroemia speciosa L.) on human rhinoviruses replication

The anti-human rhinovirus (HRV) activity of orobol 7-O- d-glucoside (O7G) from Lagerstroemia speciosa L. (Lythraceae) was evaluated in Hela cells. We tested anti-HRV activity of O7G using a cytopathic effect (CPE) reduction method, which exhibited broad-spectrum anti-HRVs activity with a 50% inhibitory concentration (IC₅₀) ranging from 0·58 to 8·80 μg ml⁻¹. The 50% cytotoxicity concentration (CC₅₀) of O7G is more than 100 μg ml⁻¹, and the derived therapeutic indices are more than 12. Ribavirin didn't possess antiviral activity against HRV15, HRV3 and HRV5, but exhibited weak antiviral activity against HRV2 and HRV3, and showed strong anti-HRV6 and -14 activities. These results suggest that O7G is a novel drug class with broad spectrum antiviral activity against HRV species A (HRV1B, HRV2, HRV15 and HRV40) and species B (HRV3, HRV6 and HRV14), as well as pleconaril-resistant virus (HRV5). Therefore, these findings provide important information for the utilization of Q7G promising broad spectrum for human rhinovirus treatment.