title: Triterpene saponins of Maesa lanceolata stem wood.
abstract: Phytochemical analysis of aqueous MeOH extract of Maesa lanceolata stem wood has led to the isolation of four new triterpene saponins characterized as 16α,21β-diacetoxy-22α-angeloyl-28-hydroxyolean-12-ene 3-O-[α-rhamnopyranosyl-(1″″ → 6‴)-β-glucopyranosyl-(1‴ → 3')][β-glucopyranosyl-(1″ → 2')]-β-glucuronopyranoside (1), 16α-acetoxy-21β-hydroxy-22α-angeloyl-13β,28-oxydoolean-28α-ol 3-O-[α-rhamnopyranosyl-(1″″ → 6‴)-β-glucopyranosyl-(1‴ → 4')][β-glucopyranosyl-(1″ → 2')]-α-arabinopyranoside (2), 16α-acetoxy-21β,22α-diangeloyl-13β,28-epoxyoleanane 3-O-[α-rhamnopyranosyl-(1″″ → 6‴)-β-glucopyranosyl-(1‴ → 4')][β-glucopyranosyl-(1″ → 2')]-β-xylopyranoside (3), and 16α,22α-diacetoxy-13β,28-oxydoolean-28α-ol 3-O-[β-glucopyranosyl-(1″ → 2')][β-glucopyranosyl-(1‴ → 3')]-β-glucuronopyranoside (4), together with the known compounds β-acetylamyrin, physcion, emodin, chrysophanol, ursolic acid, 16α-hydroxy-12-oleanene 3-O-glucoside, β-amyrin, sitosterol 3-O-β-glucoside, stigmasterol, and 3β,28-dihydroxyolean-12-ene. Their structural elucidation was accomplished by homo- and heteronuclear 2D NMR technique as well as comparison with data from known compounds. The in vitro antibacterial activity of the aqueous MeOH extract was also investigated and zones of inhibition ranging from 32 ± 1.1 to 14 ± 0.2 mm were observed. Among the isolates, compound 1 was the most active with an minimum inhibitory concentration value of 25 μg/ml against Staphylococcus aureus.
authors.affiliation: Chemistry Department, Maseno University, PO Box 333-40105, Maseno, Kenya. kamanguro@yahoo.com
authors.forename: Lawrence Onyango A
authors.initials: LO
authors.lastname: Manguro
authors.forename: Peter
authors.initials: P
authors.lastname: Lemmen
authors.forename: Pang
authors.initials: P
authors.lastname: Hao
authors.forename: Keng-Chong
authors.initials: KC
authors.lastname: Wong
mesh_terms: D013293:Enterococcus faecalis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D007630:Kenya; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D029623:Primulaceae / Q000737:chemistry*; D012485:Salmonella typhi / Q000187:drug effects; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000187:drug effects; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D014734:Vibrio cholerae / Q000187:drug effects; D014934:Wood / Q000737:chemistry; D000097245:Ursolic Acid
chemical_list: D012503:Saponins; D014315:Triterpenes; D000097245:Ursolic Acid