A new flavone C-glycoside, isovitexin 6″-O-E-p-coumarate (1) and two known flavonoid glycosides—quercetin 3-O-β-D-glucuronopyranoside (2) and isoorientin (3)—were isolated from an ethanol extract of aerial parts of Clematis rehderiana. Their structures were determined by spectroscopic methods. The antioxidant effects of the two flavone C-glycosides were evaluated by both the MTT and DPPH assays. Compound 1 showed potent activities against H2O2-induced impairment in PC12 cells within the concentration range tested, whereas compound 3 scavenged DPPH radical strongly, with an IC50 value of 13.5 μM.

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A novel norditerpene was isolated from the flower of Eupatorium adenophorum, named (4aR,7R,8S,8aR)-1,2,4a, 5,6,7,8,8a-octahydro-8-[3-methylenebut-4-alyl]-4,4a,7,8-tetramethylnaphthalen-2(1H)-one (1). Its structure was established by extensive NMR experiments. Based on the diversity of the side chains, a possible biodegradation pathway for the compound from the clerodane skeletone is proposed.