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DOI: 10.1055/s-0029-1234387
Activity guided isolation of antioxidants from the stem bark of Diospyros sanza-minika A. Chevalier
Many species of Diospyros (Ebenaceae) are used in African and Chinese traditional medicinal systems for the prevention of gastric ulcers, inflammatory disorders and hepatotoxicity [1]. Recent studies show that some of these species possesses antitumor, antidiabetic and antioxidant effects [2]. The methanol extract from the stem bark of Diospyros sanza-minika showed radical scavenging activity against DPPH with IC50 values of 1.33mg/mL. This extract was exhausted with hexane, dichloromethane and ethyl acetate. The strongest active fraction (ethyl acetate, 1.18mg/mL) was subjected to activity-guided purification to give norbergenin (1) and 4-O-galloylnorbergenin (2). These compounds were isolated for the first time from Diospyros sanza-minika. Norbergenin and 4-O-galloylnorbergenin, the main components of the plant, showed DPPH scavenging activities with IC50 values of 1.12 and 0.61mg/mL, respectively, which were comparable to that of quercetin (0.74mg/mL).
Acknowledgments: Jean Gustave Tangmouo wishes to acknowledge AUF for „Bourse post-doctorat“ in University of Geneva, Switzerland.
References: [1] Mallavadhani, U.V. et al. (1998) Phytochemistry 49:901–951.
[2] Chen, X.N. et al. (2008)J. Food Sci. 73:C24–28.