Antioxidant compounds of Achyrocline satureioides inhibit Western equine encephalitis virus

SABINI MC; MENIS CANDELA F; CARIDDI LN; ESCOBAR FM; CONTIGIANI M; COMINI L; ZANON S; SABINI LI

Congreso; III Reunión Conjunta de Sociedades de Biología de la República Argentina; 2015

Alphavirus (Togaviridae family) are highly virulent pathogens that cause encephalitis in humans and horses, affecting different regions of America. One of its members is the Western Equine Encephalitis (WEEV) virus. There are no effective antivirals to deal with its infection. Achyrocline satureioides (Asteraceae family) has many medicinal properties. Phytochemical analysis of extract of A. satureioides revealed the presence of luteolin (L), quercetin (Q), chlorogenic acid (CLA) and caffeic acid (CA). The aim of this study was to evaluate the in vitro antiviral action of the compounds (C) of A. satureioides against WEEV. The aqueous extract was obtained from the aerial parts of the plant and analyzed by HPLC-mass. Cytotoxicity was assessed by Neutral Red Uptake (RN) and MTT reduction in Vero cells. Then, the antiviral activity of C during the whole viral replication cycle was evaluated by plaque reduction assay. Further, the action stage in the replication cycle was determined. Finally, the selectivity index (SI) was calculated. Cytotoxicity studies revealed low toxicity of all C. The studies of antiviral ability indicated that WEEV was inhibited 100% by L (15 μg/mL) and 55% by CA (10 μg/mL), Q and CLA were not active against WEEV. Both compounds exert their action in post-viral adsorption and penetration stage. Selectivity indices of L were: 146 (RN) and 99 (MTT). L and CA showed strong inhibitory action against WEEV and may be useful for the treatment of infections caused by alphaviruses.