Color-Stabilizing Effects and Mechanisms of Schisandra Lignans on the Anthocyanins Enriched with Petunidin-3-O-glucoside

This study systematically explored the copigmentation effects of lignan extracts, lignan eluent fractions, and individual lignans from Schisandra sphenathera and Schisandra chinensis fruits on the anthocyanins enriched with petunidin-3-O-glucoside. The results showed that two ethanol extracts contained higher levels of lignans and were more effective in copigmentation reactions than their water counterparts. The isolation of ethanol extracts on macroporous resin rendered a large proportion of lignans enriched in 95% EtOH eluent fractions, one of which from S. sphenathera exhibited the strongest ability to stabilize the color. Meanwhile, correlational analyses suggested that six lignans, namely, schisandrol A, schisandrol B, schisantherin A, schisantherin B, schisandrin A, and schisandrin B, were the major active copigments that thermodynamically stabilize the target anthocyanins, with schisandrin B being the best one. Moreover, the structure-function relationships of these compounds revealed that the biaryl backbone was essential for copigmentation, which can be enhanced by the aromatic methylenedioxy groups.