Three novel sesquiterpene polyol esters from the root bark of <i>Celastrus angulatus</i> Maxim and their nitric oxide inhibitory activity

Three new sesquiterpene polyol ester compounds angulatin V [1<i>β</i>,15-diacetoxy-2<i>β</i>-(α-methyl)-butanoyloxy-4α,6α-dihydroxy-8α-isobutanoyloxy-9<i>β</i>-benzoxy-<i>β</i>-dihydroagarofuran], angulatin W [1<i>β</i>,2<i>β</i>-diacetoxy-4α,6α-dihydroxy-8-carbonyl-9<i>β</i>-benzoxy-15-isobutanoyloxy-<i>β</i>-dihydroagarofuran], angulatin X [1<i>β</i>,2<i>β,</i>8α-triacetoxy-4α, 6α-dihydroxy-9<i>β</i>-benzoxy-15-nicotinyl-<i>β</i>-dihydroagarofuran] (<b>1-3</b>), together with one known compound Putterine B (<b>4</b>), were isolated from the root bark of <i>Celastrus angulatus</i> Maxim. The structures of compounds <b>1-3</b> were elucidated by NMR, HRESIMS, IR data, and comparison with the literature data. The anti-inflammatory activity of all compounds was evaluated by measuring nitric oxide production in RAW264.7 macrophages. Compounds <b>1-4</b> showed no significant nitric oxide inhibitory activity at 2.5 and 5 μM concentrations.