Anti-inflammatory Triterpenes from Euonymus alatus Leaves and Twigs on Lipopolysaccharide-activated RAW264.7 Macrophage Cells

As a part of ongoing phytochemical research on Euonymus alatus leaves and twigs, we have isolated one new reissantane-type triterpene (1), together with eight known triterpenes, isoarborinol (2), ffiedelin (3), abruslactone A (4), 3 beta,22 alpha-dihydroxyolean-12-en-29-oic acid (5), 3 alpha,22 alpha-dihydroxyolean-12-en-29-oic acid (6), 3 alpha,22 beta-dihydroxyolean-12-en-29-oic acid (7), 22 alpha-hydroxy-3-oxoolean-12-en-29-oic acid (8), demethylregelin (9). The structure of 1 has been elucidated as 24,24-dimethyl-reissant-7(8),25-dien-3 alpha-ol, by extensive 1D and 2D spectroscopic methods including H-1-NMR, C-13-NMR., H-1-H-1 COSY, HSQC, 1-11/ffiC and NOESY. Anti-inflammatory activities of the isolated compounds were determined as potential regulating excessive inflammatory responses in RAW264.7 macrophage cells. Particularly, abruslactone A (4) and demethylregelin (9) showed the most potent activity, which effectively reduced the expression of iNOS protein and subsequent nitric oxide production induced by lipopolysaccharide in RAW264.7 cells.