[The chemical constituents of Polygala hongkongensis Hemsl]

Polygala hongkongensis Polycalaceae is mostly distributed in southern China, such as Guangdong, Jiangxi, Fujian and Sichuan provinces. And its herbs is used as a remedy of heat-clearing and detoxicating, removing food retention, promoting blood flow and expelling phlegm to arrest coughing in the folk medicine. Previous phytochemical investigations on Polygala plants have reported that the main chemical constituents are sapaonins, xanthones and oligosaccharide esters. To the best of our knowledge, there is no chemical report on the Polygala hongkongensis Hemsl. yet. In order to search and make use of natural resources from Polygala and to find the bioactive compounds and new compounds, we carried out studies on chemical constituents of this plant. The herbs of P. hongkongensis were extracted with 70% MeOH. The extract was combined and evaporated in vacuum to residue, which was suspended in water and successively partitioned with EtOAc and n-BuOH. Part of the n-BuOH extract was isolated and purified by various column chromatographs such as a macroporous resin, silica gel, Sephadex LH-20 column and semipreparative HPLC. The structures of isolated and purified compounds were determined by spectral analysis such as UV, IR, HRESI-MS, ESI-MS, 1H NMR, 13C NMR, HMQC, HMBC, H-H COSY, NOESY and physico-chemical property. Six compounds were identified as polyhongkonggaline (1), 3, 6'-di-O-sinapoyl-sucrose (2), tenuifoliside A (3), glomeratose D (4), cis-syringin (5), syringaresinol-4'-O-beta-D-monoglucoside (6). Compounds 1 is new compound, and 2-6 were isolated from this plant for the first time. Farther studies on the chemical constituents and pharmacological activities of P. hongkongensis will be carried out.