Constituintes químicos e atividade antioxidante de Sida galheirensiS Ulbr. (Malvaceae)

Abstract

The phytochemical investigation of Sida galheirensis led to the isolation of 5,4′-dihydroxy-3,7,3′-trimethoxyflavone, 173- ethoxyphaeoforbide, a rare natural product, 6,7-dimethoxycoumarin, ortho-hydroxybenzoic acid, sitosterol-3-O-β-D-glucopyranoside, stigmasterol-3-O-β-D-glucopyranoside, 5,7,4′-trihydroxyflavone, 5,7,3′,4′-tetrahydroxyflavone, kaempferol-3-O-β-D-(6″-E- p-coumaroyl) glucopyranoside and luteolin 7-O-β-D-glucopyranoside. Their structures were assigned based on spectroscopic analyses, including two-dimensional NMR techniques. Antioxidant activities of hexane, CHCl 3, EtOAc, BuOH and EtOH extracts of Sida galheirensis were measured using the 1,2-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay. This is also the first work reporting the chemical investigation of Sida galheirensis.