title: Norbergenin derivatives from Diospyros crassiflora (Ebenaceae).
abstract: From the ethyl acetate extract of the stems of Diospyros crassiflora Hiern, three new norbergenin derivatives, 4,11-di-O-galloylnorbergenin (1), 3-O-galloylnorbergenin (2), and 4-O-(4'-hydroxy-3'-methoxybenzoyl)-norbergenin (3), were isolated along with ten known compounds (4-13). Their structures were established by mean of spectroscopic techniques namely 1- and 2-D NMR experiments, mass spectrometry and comparison with reported data. Isolates 1-9 were evaluated for their ability to protect PC12 cells against hydrogen peroxide induced injury. Compounds with a galloyl group in their structure were found to prevent toxicity induced by H2O2 in PC12 cells.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Douala, P.O. Box: 24157, Douala, Cameroon. mvotcarine@yahoo.fr
authors.forename: Carine Mvot
authors.initials: CM
authors.lastname: Akak
authors.affiliation: Department of Organic Chemistry, Faculty of Science, University of Yaounde 1, P.O. Box: 812, Yaounde, Cameroon.
authors.forename: Augustin Ephrem
authors.initials: AE
authors.lastname: Nkengfack
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, PR China.
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Tu
mesh_terms: D000818:Animals; D001578:Benzopyrans / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D029788:Diospyros / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D016716:PC12 Cells; D051381:Rats; D013329:Structure-Activity Relationship
chemical_list: D001578:Benzopyrans; C063922:norbergenin