Penchinones A–D, two pairs of cis-trans isomers with rearranged neolignane carbon skeletons from Penthorum chinense†
Penchinones A–D (1–4), two pairs of novel cis-trans lignan isomers with rearranged neolignane carbon skeletons, together with six known flavonoids (5–10), were isolated from the ethyl acetate-soluble portion of a hepatoprotective water decoction of Penthorum chinense. Their structures were determined by extensive spectroscopic data analysis, ECD calculation, and single-crystal X-ray diffraction. Penchinones C and D (3 and 4) featured an unprecedented 7,3′-neolignane carbon skeleton. Penchinone A (1) exhibited protective activity against acetaminophen-induced damage to the HL7702 hepatocyte and selective cytotoxicity against the human cancer ovarian cell line, Hey, in vitro.