Chemical structures of the studied compounds.

Abstract

<p><b>1:</b> xanthone V₁, <b>2:</b> 2-acetylfuro-1,4-naphthoquinone; <b>3:</b> physcion; <b>4:</b> bisvismiaquinone; <b>5:</b> vismiaquinone; <b>6:</b> 1,8-dihydroxy-3-geranyloxy-6-methylanthraquinone.</p