Biosynthesis of antimalarial lignans from Holostylis reniformis.
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.
Messiano
Gisele B
GB
Instituto de Química, São Paulo State University, UNESP, C.P. 355, 14801-970 Araraquara, SP, Brazil.
da Silva
Tito
T
Nascimento
Isabele R
IR
Lopes
Lucia M X
LM
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
D000962:Antimalarials; D017705:Lignans