Chemical constituents from Piper marginatum Jacq. (Piperaceae)—antifungal activities and kinetic resolution of (RS)-marginatumol by Candida antarctica lipase (Novozym 435)

The leaves of Piper marginatum contain the antifungal compounds 3,4-methylenedioxypropiophenone 1, 2-methoxy-4,5-methylenedioxypropiophenone 2, 1-(3,4-methylenedioxyphenyl)propan-1-ol 3 (marginatumol), 5,4′-dihydroxy-7-methoxyflavanone 4 and 5,7-dihydroxy-4′-methoxyflavanone 5. The absolute configuration of natural marginatumol was determined as (+)-(R)-3 (ee 48%) by comparison of its optical properties with the chiral forms obtained by kinetic resolution of racemic 3 using Candida antarctica lipase (Novozym 435).

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(−)-(S)-1-(3,4-Methylenedioxyphenyl)propan-1-ol (marginatol)C10H12O3Ee = 99%[α]D25=-34.1 (c 3.26, CHCl3)Absolute configuration: (S)

(+)-(R)-1-(3,4-Methylenedioxyphenyl)propan-1-ol (marginatol)C10H12O3Ee = 99%[α]D25=+31.6 (c 3.20, CHCl3)Absolute configuration: (R)

(+)-(R)-1-(3,4-Methylenedioxyphenyl)propyl acetateC12H14O4Ee = 99%[α]D25=+101.3 (c 3.10, CHCl3)Absolute configuration: (R)