Flavonol monoglycosides isolated from the antiviral fractions of Persea americana (Lauraceae) leaf infusion

An infusion of Persea americana leaves (Lauraceae) strongly inhibited herpe s simplex virus type 1 (HSV-1), Aujeszky's disease virus (ADV) and adeno vi rus type 3 (AD3) in cell cultures. Its fractionation, guided by anti-HSV-1 and ADV assays, allowed the isolation and identification of two new flavono l monoglycosides, kaempferol and quercetin 3-O-alpha-D-arabinopyranosides, along with the known kaempferol 3-O-alpha-L-rhamnopyranoside (afzelin), que rcetin 3-O-alpha-L-rhamnopyranoside (quercitrin), quercetin 3-O-beta-glucop yranoside and quercetin, The known quercetin 3-O-beta-galactopyranoside was identified in a mixture. Afzelin and quercetin 3-O-alpha-D-arabinopyranoside showed higher activity against acyclovir-resistant HSV-I, Chlorogenic add significantly inhibited the HSV-1 replication without any cytotoxicity. However, all the substances tested were less active than the infusion or fractions. The same substance s did not affect ADV replication. Chemical structures were elucidated by the analysis of UV, H-1 and C-13 NMR data, mainly by APT, homo and heteronuclear COSY experiments. The configur ation of the D-arabinose unit, not usual in natural plant products, was est ablished on the basis of the optical rotation of the free sugar obtained af ter acid hydrolysis, (C) 1998 John Wiley & Sons, Ltd.