title: Novel antimicrobial diterpenoids from Turraeanthus africanus.
abstract: The dichloromethane-methanol (1/1) extract of the stem bark of Turraeanthus africanus (Meliaceae) showed remarkable antimicrobial activity against Cryptococcus neoformans, Staphylococcus aureus and methicillin-resistant S. aureus. Phytochemical investigation of this extract afforded six new diterpenoid derivatives, (+)-16-acetoxy-12,15-epoxylabda-8(17),12,14-triene ( 3), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin A, 4), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-isopropoxy- ent-labda-8(17),13(16)-diene (turraeanin B, 5), [16( E),12 S,15 R]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin C, 6), [16( E),12 R,15 S]-16-acetoxy-12,15-epoxy-15-methoxy- ent-labda-8(17),13(16)-diene (turraeanin D, 7) and (12 S,13 S,15 R)-12,15-epoxy-15-methoxy- ent-labd-8(17)-en-16-al (turraeanin E, 9) together with the known compounds, 15,16-epoxy- ent-labda-8(17),13(16),14-triene ( 1), (+)-pumiloxide ( 2), ent-labda-8(17),12 ( E)-diene-15,16-dial ( 8) and 16-acetoxy-12( R),15-epoxy-15beta-hydroxylabda-8(17),13 (16)-diene ( 10). Compound 10 was obtained as its acetoxy derivative ( 10a) and compound 11 was the product of hydrolysis of 6. Antimicrobial activity of the isolates was assayed and compounds 8, 9, 10a and 11 exhibited significant activities.
authors.affiliation: Department of Organic Chemistry, University of Yaounde, Yaounde, Cameroon.
authors.forename: Simplice Joel
authors.initials: SJ
authors.lastname: Tatsimo
authors.forename: Pierre
authors.initials: P
authors.lastname: Tane
authors.forename: Pullela V
authors.initials: PV
authors.lastname: Srinivas
authors.forename: Beibam L
authors.initials: BL
authors.lastname: Sondengam
authors.forename: Jacob
authors.initials: J
authors.lastname: Melissa
authors.forename: Christopher O
authors.initials: CO
authors.lastname: Okunji
authors.forename: Brian M
authors.initials: BM
authors.lastname: Schuster
authors.forename: Maurice M
authors.initials: MM
authors.lastname: Iwu
authors.forename: Ikhlas A
authors.initials: IA
authors.lastname: Khan
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects; D003455:Cryptococcus neoformans / Q000187:drug effects; D004224:Diterpenes / Q000737:chemistry* / Q000494:pharmacology*; D029582:Meliaceae / Q000737:chemistry*; D016106:Methicillin Resistance; D015394:Molecular Structure; D008517:Phytotherapy; D024301:Plant Bark / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000998:Antiviral Agents; D004224:Diterpenes