Involucrasin C, Anti‐Inflammatory 2,3‐Dihydro‐1H‐Indene Derivative from Chinese Dai Ethnic Medicine Shuteria involucrata

(±)-Involucrasin C (1), a pair of new 2,3-dihydro-1H-indene enantiomers, along with an enantiomeric analog (2), were isolated from Shuteria involucrata. Their structures were established by the basis of comprehensive spectroscopic data analysis and X-ray crystallographic diffraction. Both 1 and 2 significantly inhibited the secretion of pro-inflammatory cytokines IL-6, TNF-α, and IL-1β, suggesting that these two natural 2,3-dihydro-1H-indene derivatives may be active components of S. involucrata and may block inflammation in the initial stage.