Studies On The Chemical Constituents And Biological Activities From Two Medicinal Plants Of Polygala

The Polygala genus (Polygalaceae), with about 500 species distribute worldwide, has about 42 species and 8 varietas in China. The root of P. tenuifolia Willd. and P. sibirica L. are recorded as a tonic, sedative, expectorant and resuscitating agents in the Chinese Pharmacopeia (2005). Other plants of Polygala genus were also widely used in folk of southern China. In order to determinate the relationship between the chemical constituents and bioactivities, as well as develop a method for the quality control of Polygala genus, the herbs of P. hongkongensis Hemsl. and P. japonica Houtt were subjected to phytochemical and pharmacological studies. 59 compounds have been isolated by various chromatographic methods and their structures were determined by spectroscopic methods. Among them, there are 8 new compounds. Some isolates exhibited various biological activities including protective effect of nerve cells, anti-tumor and antioxidate acivites. More and more interests have been focused on the family Polygala. The analytical methods based on HPLC technology were also established.Fifty-eight compounds were isolated from the 70% methanol extracts of the whole plant of P. hongkongensis by various column chromatographies. On the basis of spectral analysis, fifty structures of them were elucidated. There are 17 xanthones, 13 flavonoids, 3 megastigmane glycosides, 3 oligosaccharide esters and 14 other types of compounds. They are: mangiferin, 7-O-methylmangiferin, polyhkgenoside B, polygalaxanthoneⅢ, polygalaxanthoneⅤ, polyhkgenoside A, 1, 3-dihydroxy- 4, 7-dime thoxyxanthone, 1, 7-dihydroxy-2, 3-methylene-dioxyxanthone, polyhkgenoxanthone A, 1, 7-dihydroxy-3,4-dimethoxyxanthone, 1, 4, 7-trihydroxy-3-metho xyxanthone, 1, 7-dihydroxy-3, 4, 8-trimethoxyxanthone, euxanthone, 1, 3, 6-trihydroxy-xanthone, 1-methoxy-7-hydroxy-2, 3-methylenedioxy xanthone, polyhkgenoxanthone B, 1, 3,7-trihy-droxy-4, 8-dimethoxyxanthone, isorhamnetin, quercetin, kaempferol, isoquercitrin, kaempferol-3-O-β-D-glucopyranoside, rutin, kaempferol-3-O-β-D-rutioside, formenonetin, 7-hydroxy-2′, 3′, 4′-trimethoxy-isoflavan, isomucro nulatol, santal, epimedin C, formenonetin-3-hydroxy -7-O-β-D-glucopyranoside, 7Z-roseoside, 7Z-trifostigmanoside I, trifostigrnanosideⅡ, 3, 6′-di-O-sinapoyl-sucrose, glomeratose D, tenuifoliside A, liriodendrin, syringaresinol-4′-O-β-D-monoglucoside, cis-syringin, hongkongpolygaline, hongkongpolygenin, p-hydroxyacetophenone, p-hydroxy-trans-cinnamic acid, o-hydroxy benzoic acid, methyl 2, 5-dihydroxybenzoate, p-hydroxybenzoic acid, 3, 4-dihydroxybenzoic acid,β-sitosterol, daucosterol, stigmasterol, of which 8 were new, 18 isolated from Polygala for the first time and 24 were first isolated from this plant. Twelve compounds were isolated from the 70% methanol extracts of the whole plant of P. japonica, and nine of them were identified as polygalasaponinⅫ, polygalasaponinⅩⅢ, polygalasaponinⅡ, polygalasaponinⅨ, tenuifolin, plygalasaponinⅩⅩⅥ, polygalasaponinⅩⅩⅤ, bayogenin-3-O-glucoside, polygalacerebroside.A facile method based on high-performance liquid chromatography (HPLC) was developed for the simultaneous quantitative determination of 3, 6′-di-O-sinapoyl-sucrose in the of polygala genus. The fingerprints of Polygala genus were also established by HPLC technologies. This methods could be applied for the related Polygala genus medicinal plants to evaluate and control the quality, identify the species of Polygala genus, as well as clarify the relative between different species.The extracts and pure compounds isolated from P. hongkongensis and P. japonica were screened with the pharmacological models of protective effect of nerve cells, anti-oxidation and cytotoxicity in vitro. In protective effect of nerve cells activity assay, The EtOAc part and compounds polygalasaponinⅩⅩⅤ, bayogenin-3-O-glucoside, showed potent activity. In the anti-oxidation activity assay, the n-BuOH extract exert antioxidant effect. The flavonoids isorhamnetin, quercetin, kaempferol, isoquercitrin, kaempferol-3-O-β-D-glucopyranoside, rutin, kaempferol-3-O-β-D-rutioside and xanthones mangiferin, 7-O-methyhnangiferin with three over hydroxyl substitutes showed the potent anti-oxidation activities. It was suggested that the anti-oxidation activities of flavonoids and xanthones maybe relative with the hydroxyl substitutes. In the cytotoxicity activity assay, xanthones 1, 7-dihydroxy-2, 3-methylenedioxyxanthone, 1, 7-dihydroxy-3, 4-dimethoxyxanthone, 1, 7-dihy- droxy-3, 4, 8-trimethoxyxanthone, Polyhkgenoxanthone B and 1, 3, 7-trihydroxy-4, 8-dimethoxy- xanthone had the inhibitory on the tumor cell lines, of which 1, 7-dihydroxy-2, 3-methylene- dioxyxanthone and polyhkgenoxanthone B showed higher activity against hepatocellular carcinoma.In addition, advances in the research of chemical constituents and pharmacological activities of medical plant from Polygala genus were reviewed with 199 references.