Two new lignan glycosides from the fruits of Pyrus ussuriensis

Two new lignan glycosides, ussuriensislignan A (1) and ussuriensislignan B (2), together with seventeen known compounds (3-19), were isolated from the fruits of Pyrus ussuriensis. Their structures were determined by various spectroscopic methods. This is the first report of the isolation of lignans (compounds 1-3) from the genus Pyrus, and compounds 3-6, 12-16 were reported from Pyrus for the first time.

Antioxidant and quinone reductase-inducing constituents of black chokeberry (Aronia melanocarpa) fruits

Using in vitro hydroxyl radical-scavenging and quinone reductase-inducing assays, bioactivity-guided fractionation of an ethyl acetate-soluble extract of the fruits of the botanical dietary supplement, black chokeberry (Aronia melanocarpa), led to the isolation of 27 compounds, including a new depside, ethyl 2-[(3,4-dihydroxybenzoyloxy)-4,6-dihydroxyphenyl] acetate (1), along with 26 known compounds (2-27). The structures of the isolated compounds were identified by analysis of their physical and spectroscopic data ([α](D), NMR, IR, UV, and MS). Altogether, 17 compounds (1-4, 9, 15-17, and 19-27) showed significant antioxidant activity in the hydroxyl radical-scavenging assay, with hyperin (24, ED(50) = 0.17 μM) being the most potent. The new compound (1, ED(50) = 0.44 μM) also exhibited potent antioxidant activity in this assay. Three constituents of black chokeberry fruits doubled quinone reductase activity at concentrations <20 μM, namely, protocatechuic acid [9, concentration required to double quinone reductase activity (CD) = 4.3 μM], neochlorogenic acid methyl ester (22, CD = 6.7 μM), and quercetin (23, CD = 3.1 μM).