title: Bioactive constituents of the stem bark of Beilschmiedia zenkeri.
abstract: Phytochemical investigation of the stem bark of Beilschmiedia zenkeri led to the isolation of four new methoxylated flavonoid derivatives, (2S,4R)-5,6,7-trimethoxyflavan-4-ol (1), (2S,4R)-4,5,6,7-tetramethoxyflavan (2), beilschmieflavonoid A (3), and beilschmieflavonoid B (4), together with seven known compounds. The structures of 1-4 were established by spectroscopic methods, and their relative configurations confirmed by X-ray crystallographic and CD analysis. The isolated compounds were evaluated in vitro for their antibacterial activity against three strains of bacteria, Pseudomonas agarici, Bacillus subtilis, and Streptococcus minor, and for their antiplasmodial activity against Plasmodium falciparum, chloroquine-resistant strain W2.
authors.affiliation: Department of Chemistry, Higher Teachers' Training College, University of Yaoundé 1, P.O. Box 47, Yaoundé, Cameroon.
authors.forename: Bruno Ndjakou
authors.initials: BN
authors.lastname: Lenta
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Tantangmo
authors.forename: Krishna Prasad
authors.initials: KP
authors.lastname: Devkota
authors.forename: Jean Duplex
authors.initials: JD
authors.lastname: Wansi
authors.forename: Jean Rodolphe
authors.initials: JR
authors.lastname: Chouna
authors.forename: Rene Cosme Fongang
authors.initials: RC
authors.lastname: Soh
authors.forename: Beate
authors.initials: B
authors.lastname: Neumann
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Stammler
authors.forename: Etienne
authors.initials: E
authors.lastname: Tsamo
authors.forename: Norbert
authors.initials: N
authors.lastname: Sewald
mesh_terms: D001412:Bacillus subtilis / Q000187:drug effects; D002163:Cameroon; D002738:Chloroquine / Q000494:pharmacology; D004351:Drug Resistance / Q000187:drug effects; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D019770:Lauraceae / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D021261:Parasitic Sensitivity Tests; D024301:Plant Bark / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D010963:Plasmodium falciparum / Q000187:drug effects; D011549:Pseudomonas / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
chemical_list: D005419:Flavonoids; D002738:Chloroquine