Computer-Assisted Structure Elucidation of Black Chokeberry (<i>Aronia melanocarpa</i>) Fruit Juice Isolates with a New Fused Pentacyclic Flavonoid Skeleton

Abstract

Melanodiol 4″-<i>O</i>-protocatechuate (<b>1</b>) and melanodiol (<b>2</b>) represent novel flavonoid derivatives isolated from a botanical dietary supplement ingredient, dried black chokeberry (<i>Aronia melanocarpa</i>) fruit juice. These noncrystalline compounds possess an unprecedented fused pentacyclic core with two contiguous hemiketals. Due to having significant hydrogen deficiency indices, their structures were determined using computer-assisted structure elucidation software. The in vitro hydroxyl radical-scavenging and quinone reductase-inducing activity of each compound are reported, and a plausible biogenetic scheme is proposed