In vitro screening of antiviral activity of lyophilized extracts of azhadirachta indica and quercus lusitanica on dengue 1 & 3 Serotypes

Dengue fever has become a global concern and can lead to a severe life threatening illness. The development of dengue vaccines is complicated by the antibody dependent enhancement effect. Thus the development of a plant based antiviral preparation promises a more potential alternative in combating dengue disease. The present study investigated the antiviral effects of standardized lyophilized aqueous, aqueous-ethanolic and ethanolic extracts of Azhadirachta indica and Quercus lusitanica on Dengue 1 & 3 strains in Vero cell line and compared with known antiviral drug Ribavirin. The antiviral activity of lyophilized aqueous extract of Azhadirachta indica showed better activity for Dengue 1 & 3 at a Maximum nontoxic dose concentration of 500µg/ml and the ethanolic extracts are partially inhibited at the concentration of 500µg/ml to dengue 1 but not in dengue 3. Whereas the aqueous-ethanolic extract of neem and three extracts of Quercus lusitanica did not show any inhibition on dengue 1 & 3. The antiviral activity of Ribavirin exhibited 15.6µg/ml & 7.5µg/ml for dengue 1 & 3 respectively. These data suggest that the lyophilized aqueous extracts of Azhadirachta indica possess the ability of inhibiting the activity of Dengue 1 & 3 by in vitro assays. This plant is worth to be further investigated and might be advantageous as an alternative drug for dengue treatment.