Novos constituintes químicos das cascas do caule de Tabebuia heptaphylla

Abstract

A new triterpene, 3β,6β,21β-trihydroxyolean-12-ene and a new iridoid, 8α-methyl-8β-hydroxy-6β-(3′,4′-dimethoxy) benzoyloxy-1α,3α-dimethoxy-octahydro-cyclopenta[c]pyran were isolated from the trunk bark of a specimen of Tabebuia heptaphylla (Bignoniaceae) collected in the "Pantanal" of Mato Grosso do Sul, Brazil. Twelve known compounds were also obtained in this work, comprising four iridoids, 6-O-p-hydroxybenzoylajugol, 6-O-p-methoxybenzoylajugol, 6-O-3″,4″-dimethoxybenzoylajugol, 8α-methyl-8β-hydroxy- 6β-(4′-hydroxy)benzoyloxy-1α,3α-dimethoxy-octahydro- cyclopenta[c]pyran, a cyclopentene dialdehyde, 2-formyl-5-(3′,4′- dimethoxybenzoyloxy)-3-methyl-2-cyclopentene-1-acetaldehyde, a phenylethanoid glycoside, verbascoside and three benzoic acid derivatives, p-hydroxybenzoic, pmethoxybenzoic and 3,4-dimethoxybenzoic acids, in addition to squalene, sitostenone and sitosterol. The antioxidant properties of the isolated compounds were also evaluated in this work.