Antiviral Activity of Seaweed Extracts against Feline Calicivirus

Norovirus, which causes gastroenteritis in humans, is an important food-borne pathogen worldwide. In an effort to discover an antiviral substance against norovirus, extracts from several seaweeds were evaluated for antiviral activity against feline calicivirus (FCV), which was used as a surrogate. The methanolic extract of Undaria pinnatifida exhibited the most significant antiviral activity and virucidal efficacy against FCV. The concentrations of the extract that reduced viral replication by 50% (EC50) and resulted in the death of 50% of the host cells (CC50) were 0.05 mg/mL and 1.02 mg/mL, respectively. The selectivity index, calculated from the ratio of the CC50 and EC50 was 20.4. No FCV infection of host cells occurred following a 1-h incubation in the presence of 12.50 mg/mL U. pinnatifida extract, indicating that the virus was completely inactivated by the extract treatment. The results obtained in this study will contribute to the development of a natural antiviral substance that will prevent food-borne disease caused by norovirus. KCI Citation Count: 3