ANTIVIRAL ACTIVITY OF FRUIT EXTRACTS

Inactivation of poliovirus with strawberry extract was time and concentration dependent and could be prevented or reduced but not reversed with serum or gelatin. Strawberry extract inactivated several enteric viruses and herpes simplex virus, and extracts of several fruits inactivated poliovirus; the degree of activity varied with the virus type and the and the fruit species showing a minimum 2 log reduction with undiluted fruit extracts, adjusted to pH 7.0. Step-wise ultrafiltration of strawbery extract indicated that activity was found in fractions of MW <500, 500-2000, 10,000-30,000 and > 300,000. Several compounds of plant origin were antiviral; tannic acid was especially potent. Treatment of HEp-2 [human oval carcinoma] cells with strawberry extract or tannic acid reduced subsequent infection with virus, almost a log; inhibition was prevented and reversed completely with serum or gelatin. The antiviral components of various fruits and plants may act both on viruses and host cells to prevent infection.