Neolignans from Myristica fragrans seeds, revision of their absolute configurations, reduction products and biological activities

Chromatographic purification of the CH₂Cl₂ extract of Myristica fragrans seeds provided 19 known compounds, four dihydrofuran neolignans, licarines A, B and maceneolignans A, B were among the isolates. Prior to hydrogenation, in order to obtain their di- and tetrahydrogenated products, the absolute configuration of these compounds was thoroughly investigated based on their optical rotations and ECD spectra. This report provides evidences concerning the disagreement between the use of an aromatic quadrant rule and time-dependent density function theory calculation for the prediction of the absolute configurations at C-7 and C-8 in these dihydrobenzofuran neolignans. The absolute configurations of licarines A, B and maceneolignans A, B were subsequently redefined. The antimicrobial and cytotoxic activities of the isolates and reduction products of licarines A, B and maceneolignans A, B were also investigated.