Anti-inflammatory diarylheptanoids and phenolics from the rhizomes of kencur (Kaempferia galanga L.)

Kencur (Kaempferia galanga L.) is an aromatic plant of the Zingiberaceae family. It is widely cultured as a crops and its rhizome has been widely used as a flavor spice existing in various cooking. In this study, three new diarylheptanoids (1-3), one new phenolic glycoside (4), together with thirteen known phenolics were isolated from the rhizomes of kencur. Their chemical structures were elucidated based on IR, 1D and 2D NMR, HR-ESI-MS spectroscopic analysis and electronic circular dichroism (ECD) methods. Diarylheptanoids were evaluated for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a macrophage RAW 264.7 cell line. Except for compound 7, most of diarylheptanoids exhibited pronounced inhibitory activities compared with indomethacin. The results demonstrated that the diarylheptanoids may be partially responsible for the anti-inflammatory activity of kencur, which suggested that it could be served as an anti-inflammatory agent for healthy or medicinal products.