Antioxidant and Hepatoprotective Activity of Phenyl Glycosides Isolated From Heliciopsis lobata

Abstract

A new macrocyclic glycoside named helilobatoside A (1) and 5 known phenyl glycosides as 3,5-dimethoxy-4-hydroxyphenyl-1- O-β-d-glucopyranoside (2), tachioside (3), isotachioside (4), 1-(4-hydroxy-3-methoxyphenyl)-1-propanone-3- O-β-d-glucopyranoside (5), and 1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone-3- O-β-d-glucopyranoside (6), were isolated from the wood of Heliciopsis lobata (Merr.) Sleumer. Their chemical structures were elucidated using a combination of high-resolution electrospray ionization mass spectrometry, 1-dimensional (1D) and 2D nuclear magnetic resonance (NMR) spectral data as well as by comparison with data in the previous literature. This is the first time the 13C NMR data of compounds 5 and 6 were reported and also were assigned by heteronuclear single quantum correlation and heteronuclear multiple bond correlation spectra. Compounds 2-6 were first isolated from Heliciopsis genus. The isolated compounds were evaluated for their antioxidant and hepatoprotective activities in vitro. Compound 2 showed potential as an antioxidant in a 2,2-diphenyl-1-picryl-hydrazyl-hydrate assay (half-maximal inhibitory concentration [IC50] = 6.07 ± 0.17 µg/mL) and in thio-barbituric acid reactive substances assay (IC50 = 89.55 ± 8.26 µg/mL). This compound could also reduce the toxic effects of carbon tetrachloride on HepG2 survival and significantly protect the viability of cells up to 52.25 ± 4.36% at the 100 µg/mL treatment ( P < 0.05). Thus, with obtained results, the hepatoprotective activity of compound 2 could be related to radical scavenging and limited the lipid peroxidative activities.