Anti-inflammatory oleanane triterpenoids with mono-, di-, and tri-palmitoyl chains from the stamen of Nelumbo nucifera Gaertn

Ten undescribed compounds were isolated from the stamen of Nelumbo nucifera Gaertn., including seven oleanane triterpenoid glycosides with 1 - 3 palmitoyl chains ( 1 -7 ), an oleanane triterpenoid aglycon ( 8 ), and two degraded cycloartane triterpenoids ( 9 and 10 ). In addition, seven known oleanane triterpenoids ( 11 -17 ) were isolated. Among these compounds, 9 was an artificial and 14 was novel and natural product. The antiinflammatory activity of the 10 undescribed compounds was evaluated by analyzing their inhibitory effects on the release of NO in LPS-induced RAW264.7 macrophages. Nelmnucifergenin A ( 8 ) and nelmnucifergenin B ( 9 ) showed the maximum inhibitory effects with IC 50 values of 16.79 and 20.78 mu M, respectively. Additionally, they inhibited the production of TNF- alpha and IL -6 and down-regulated the key inflammation-related enzymes (iNOS and COX -2).