Abstract
Sigesbeckia orientalis, more commonly referred to as Herba Sigesbeckiae or Xi Xian Cao in traditional Chinese
medicine and hy thiêm in traditional Vietnamese medicine, is used in China and Vietnam
to treat inflammatory diseases such as arthritis, rheumatism, and joint pain. In initial
investigations, the dichloromethane extract from the aerial parts of S. orientalis showed distinct inhibitory effects on the release of interleukin-8 in human neutrophils.
Therefore, the purpose of the present study was the phytochemical investigation of
the bioactive dichloromethane extract and the in vitro analysis of the effects of the isolated compounds on interleukin-8, interleukin-1β, tumor necrosis factor-α, and monocyte chemoattractant protein 1 release, and surface expression of adhesion
molecules (CD11a, CD11b, and CD62L) in lipopolysaccharide-stimulated human neutrophils
to identify the active principle(s). The separation of the bioactive
dichloromethane extract using various chromatographic techniques led to the isolation
of nine compounds. Their chemical structures were elucidated from nuclear magnetic
resonance and mass spectrometry data. One diterpene, 17(13 → 14)-abeo-ent-3S*,13S*,16-trihydroxystrob-8(15)-ene, was identified as a new natural product. Three germacranolide
sesquiterpene lactones inhibited interleukin-8 production with IC50 values between 1.6 and 6.3 µM, respectively, and tumor necrosis factor-α production with IC50 values between 0.9 and 3.3 µM, respectively. Furthermore, they significantly inhibited
interleukin-1β and monocyte chemoattractant protein 1 production and diminished the effects of lipopolysaccharide
on the surface expression of the adhesion molecules CD11a, CD11b, and CD62L. These
findings support the traditional use of S. orientalis in the treatment of inflammatory diseases.
Key words
Sigesbeckia orientalis
- Asteraceae - inflammation - neutrophils - diterpenoids - sesquiterpene lactones
