Discovery, Preliminary Structure-Activity Relationship, and Evaluation of Oleanane-Type Saponins from Pulsatilla chinensis for the Treatment of Ulcerative Colitis.

To discover ulcerative colitis (UC) treatment agents, 28 oleanane-type triterpenoid saponins ( 1 - 28 ) including three new saponins, pulsatillosides P-R ( 1 - 3 ), were isolated from Pulsatilla chinensis . The isolated saponins could observably ameliorate UC by improving the intestinal epithelial cell barrier and intestinal flora in vivo . The structure-activity relationship indicated that the oligosaccharide chain at C-28 was essential for their anti-UC activities; the methyl group at the C-23 site of triterpene saponins showed important effects on anti-UC efficacy; the chain length of oligosaccharides at position C-28 had little effect on their anti-UC activities. In vivo investigation of representative saponins 1 and 13 further confirmed that 23-methyl-3,28-bisdesmosidic oleanane-type saponins inhibited the TNFα-NFκB-MLCK axis to improve the intestinal epithelial cell barrier of the colon in UC mice. These findings revealed the potential of 23-methyl-3,28-bisdesmosidic oleanane-type saponins from P. chinensis as promising candidates for the treatment of UC.