Two new β -dihydroagarofuran sesquiterpene polyesters from the seeds of Celastrus angulatus Maxim and their nitric oxide inhibitory activity

Two new β-dihydroagarofuran sesquiterpene polyesters, angu-latinpip I (1β,15-biacetoxy-8α-butanoyloxy-9β-benzoyloxy-β-dihy-dro---agarofu-ran) (1) and angulatinpip II (1β,9α,15-triacetoxy-8α-benzoyloxy-β-dihydroagarofuran) (2), together with two known compounds 1β,6α-biacetoxy-9α-benzoyloxy-β-dihydroagarofuran (3) and angulatueoid F (4), were isolated from the seeds of Celastrus angulatus Maxim. The structures of the new compounds were elucidated by means of extensive spectrometric analyses (IR, HRESI MS, 1D and 2D NMR). The anti-inflammatory activity of all compounds was evaluated by measuring nitric oxide production in RAW264.7 macrophages. Compounds 1-4 all exhibited a certain degree of inhibitory effect on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages. Compounds 2 and 3 demonstrated inhibitory activities, with their half-maximal inhibitory concentration (IC₅₀) values determined to be 8.93 μM and 42.52 μM, respectively. Moreover, their inhibitory effects showed a dose-dependent relationship.