Isolation of anti-inflammatory compounds from Sambucus ebulus leaves through in vitro activity-guided fractionation

Abstract

The in vitro anti-inflammatory effects of subextracts (n-hexane, chloroform, ethyl acetate, n-butanol, remaining water) of the methanol extract of the leaves of Sambucus ebulus L. (Adoxaceae) were investigated for their inhibitory activities on the activation of Nuclear factor kappa B (NF-κB) on lipopolysaccharide induced Raw 264.7 cells. The n-hexane, chloroform and ethyl acetate subextracts inhibited NF-κB activation at 50, 100 and 100 µg/mL concentrations, respectively. Two flavonoid mixtures [quercetin-3-O-β-D- glucopyranoside, quercetin-3-O-β-D-galactopyranoside], two flavonoids [isorhamnetin-3-O- β-D-glucopyranoside (1), isorhamnetin-3-O-rutinoside (2)] were isolated from ethyl acetate subextract. 10-O-acetylpatrinoside (3) and a new iridoid [Sambulin B (4)] was obtained from chloroform and n-hexane subextracts respectively. Structures were elucidated by NMR and MS. The compounds exerted inhibitions between 30 – 80% on NF-κB. Flavonoids were applied to cells at 25, 50, 75 and 100 µg/mL concentrations. Sambulin B was applied at 6,25, 12,5, 25 and Sambulin A applied at 12,5, 25 and 50 µg/mL concentrations.