title: Biosynthesis of antimalarial lignans from Holostylis reniformis.
abstract: Holostylis reniformis biosynthesizes 8-8' linked lignans without 9,9'-oxygenation. To elucidate the biosynthetic pathways to these lignans, the reputed precursors [U-(14)C]phenylalanine, [9-(3)H(1)]coniferyl alcohol, and [9-(3)H(1)]isoeugenol were administered to roots of the plant, which led to the incorporation of (3)H and (14)C into ten 2,7' linked-lignans (aryltetralone lignans) and two 7,7'-epoxylignans (furan lignans). These administration experiments demonstrated that the lignans were propenylphenol-derived and that H. reniformis can exhibit regioselective control over radical-radical coupling (via isoeugenol radicals). Regiospecific control over propenylphenol-derived lignan biosynthesis was observed, together with diastereoselective control of C2-C7' bond formation for the aryltetralone lignans (7'R). These experiments provide evidence that isoeugenol is a biosynthetic intermediate to the aryltetralone and furan lignans.
authors.affiliation: Instituto de Química, São Paulo State University, UNESP, C.P. 355, 14801-970 Araraquara, SP, Brazil.
authors.forename: Gisele B
authors.initials: GB
authors.lastname: Messiano
authors.forename: Tito
authors.initials: T
authors.lastname: da Silva
authors.forename: Isabele R
authors.initials: IR
authors.lastname: Nascimento
authors.forename: Lucia M X
authors.initials: LM
authors.lastname: Lopes
mesh_terms: D000962:Antimalarials / Q000378:metabolism*; D029065:Aristolochiaceae / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D017705:Lignans / Q000096:biosynthesis*; D009682:Magnetic Resonance Spectroscopy; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000962:Antimalarials; D017705:Lignans