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

An infusion of Persea americana leaves (Lauraceae) strongly inhibited herpes simplex virus type 1 (HSV-1), Aujeszky's disease virus (ADV) and adenovirus type 3 (AD3) in cell cultures. Its fractionation, guided by anti-HSV-1 and ADV assays, allowed the isolation and identification of two new flavonol monoglycosides, kaempferol and quercetin 3-O-α-D-arabinopyranosides, along with the known kaempferol 3-O-α-L-rhamnopyranoside (afzelin), quercetin 3-O-α-L-rhamnopyranoside (quercitrin), quercetin 3-O-β-glucopyranoside and quercetin. The known quercetin 3-O-β-galactopyranoside was identified in a mixture.

Afzelin and quercetin 3-O-α-D-arabinopyranoside showed higher activity against acyclovir-resistant HSV-1. Chlorogenic acid significantly inhibited the HSV-1 replication without any cytotoxicity. However, all the substances tested were less active than the infusion or fractions. The same substances did not affect ADV replication.

Chemical structures were elucidated by the analysis of UV, ¹H and ¹³C NMR data, mainly by APT, homo and heteronuclear COSY experiments. The configuration of the D-arabinose unit, not usual in natural plant products, was established on the basis of the optical rotation of the free sugar obtained after acid hydrolysis. Copyright © 1998 John Wiley & Sons, Ltd.