Chemical constituents of the Lagerstroemia indica L. bark

A phytochemical investigation of the ethyl acetate fraction of Lagerstroemia indica L. bark was conducted using various chromatographic techniques, including silica gel column chromatography, MCI column chromatography, Sephadex LH-20 column chromatography, and semi-preparative liquid chromatography. The structures of the isolated compounds were elucidated through modern spectroscopic methods, such as NMR, HR-ESI-MS, UV and IR spectroscopy. As a result total of ten compounds were isolated and identified, including a new phenylpropanoid derivative, lagerindicinol A (1), six norisoprenoids sarmentol F (2), (6R,7E,9R)-9-hydroxy-4,7-megastigmadien-3-one (3), 3-hydroxy-β-damascone (4), megastigman-5-ene-3β,9R-diol (5), (3S,5R,6S,7E,9R)-7-megastigmene-3,6,9-triol (6), boscialin (7), as well as three lignans matairesinol (8), arctigenin (9) and (7S,8R)-dihydrodehydrodiconiferyl alcohol (10). The anti-inflammatory activity of some isolated compounds was evaluated, and the results revealed that these compounds did not exhibit inhibitory effects on LDH release at a concentration of 10 μmol/L. Among the isolated, compounds 1−7, 9, and 10 were reported from L. indica for the first time. The present study expands the phytochemical diversity of Lagerstroemia species and provides a scientific basis for the further development and utilization of L. indica bark.