Six new phenylpropanoids from Kaempferia galanga L . and their anti-inflammatory activity

Kaempferia galanga L. is an aromatic medicinal plant belonging to the Zingiberaceae family. Its rhizome has been widely used as traditional Chinese medicine and a flavor spice for a long time. In this study, six previously undescribed phenylpropanoids, including four [2 +2]- cycloaddition-derived cyclobutane natural products ( 1- 4 ), and two phenylpropanoids ( 5- 6 ) were isolated from the rhizomes of K. galanga L. Their structures were elucidated by spectroscopic methods, single-crystal X-ray diffraction, NMR calculation, and ECD spectra calculation. These cyclobutane derivatives were isolated from K. galanga for the first time. Furthermore, compounds 1-6 were evaluated for the potential inhibitory activities on NO production and NF- kappa B nuclear translocation in LPStriggered RAW 264.7 macrophages. The results showed that the isolated compounds have a moderate antiinflammatory activity measured on their potency to inhibit NO production and the expression of iNOS and COX-2. Additionally, compound 2 effectively suppressed NF- kappa B nuclear translocation at a concentration of 40 mu M.