title: Antibacterial triterpenes from Syzygium guineense (Myrtaceae).
abstract: Antibacterial bioassay-guided fractionation of Syzygium guineense leaf extracts afforded 10 triterpenes, namely betulinic acid 1, oleanolic acid 2, a mixture of 2-hydroxyoleanolic acid 3a, 2-hydroxyursolic acid 3b, arjunolic acid 4a, asiatic acid 4b, a mixture of terminolic acid 5a, 6-hydroxyasiatic acid 5b, and a mixture of arjunolic acid 28-beta-glucopyranosyl ester 6a and the asiatic acid 28-beta-glucopyranosyl ester 6b. Isolated compounds were submitted to an antibacterial assay system against gram-positive and -negative bacteria and human pathogen bacteria. Compounds 4a and 4b showed the most significant antibacterial activity against Escherichia coli, Bacillus subtilis and Shigella sonnei. The fraction 5a-5b was the least active, whereas compounds 1, 2 and the mixtures of 3a-3b and 6a-6b were inactive in the assays.
authors.affiliation: Université of Neuchâtel, Institut de Chimie, av. Bellevaux 51, CH-2000 Neuchâtel, Switzerland.
authors.forename: J D
authors.initials: JD
authors.lastname: Djoukeng
authors.forename: E
authors.initials: E
authors.lastname: Abou-Mansour
authors.forename: R
authors.initials: R
authors.lastname: Tabacchi
authors.forename: A L
authors.initials: AL
authors.lastname: Tapondjou
authors.forename: H
authors.initials: H
authors.lastname: Bouda
authors.forename: D
authors.initials: D
authors.lastname: Lontsi
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000494:pharmacology*; D027842:Syzygium / Q000737:chemistry*; D014315:Triterpenes / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D014315:Triterpenes