Antioxidant lignans from petroleum ether extract of Schisandra chinensis
The fruit of Schisandra chinensis, a woody liana, has been used for centuries in traditional Chinese medicine. The fruit is prescribed for the treatment of viral and chemically induced hepatitis in China. Extracts of Schisandra chinensis have demonstrated hepatoprotective and cardioprotective activities, which can be potentially connected with ability to reduce oxidative stress .
The aim of our study was to characterise compounds, which correspond for antioxidant activity of Schisandra chinensis. The petroleum ether extract of seeds of Schisandra chinensis showed scavenging activity against the free stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) . The petroleum ether extract was extracted with methanol and the methanolic extract was further chromatographed on silica gel column with petroleum ether, benzene, diethyl ether and ethanol as a mobile phase. The most active fractions eluted with benzene were further fractioned on silica gel column and Sephadex LH-20 column and by semi-preparative RP-HPLC. Bioassay guided fractionation led to the isolation of dibenzylbutane lignan meso-dihydroguaiaretic acid and dibenzo[a,c]cyclooctadiene lignans schisanhenol and gomisin J. All active lignans containing one or two phenolic hydroxyls belong to minor lignan constituents of Schisandra. Together with the active lignans, nine dibenzo[a,c]cyclooctadiene lignans were isolated, namely, schizandrin, deoxyschizandrin, γ-schizandrin, gomisin A, gomisin N, tigloylgomisin H, angeloylgomisin H, tigloylgomisin P and wuweizisu C. The lignans were identified by spectroscopic methods (1H and 13C NMR, MS).
Acknowledgements: This work was supported by Grant Agency of Czech Republic (No. 522/07/0995).
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