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鈥?b>27). The structures of the isolated compounds were identified by analysis of their physical and spectroscopic data ([伪]
D, NMR, IR, UV, and MS). Altogether, 17 compounds (
1鈥?b>4,
9,
15鈥?b>17, and
19鈥?b>27) showed significant antioxidant activity in the hydroxyl radical-scavenging assay, with hyperin (
24, ED
50 = 0.17 渭M) being the most potent. The new compound (
1, ED
50 = 0.44 渭M) also exhibited potent antioxidant activity in this assay. Three constituents of black chokeberry fruits doubled quinone reductase activity at concentrations <20 渭M, namely, protocatechuic acid [
9, concentration required to double quinone reductase activity (CD) = 4.3 渭M], neochlorogenic acid methyl ester (
22, CD = 6.7 渭M), and quercetin (
23, CD = 3.1 渭M).
Keywords:
Aronia melanocarpa; black chokeberry; Rosaceae; ethyl 2-[(3,4-dihydroxybenzoyloxy)-4,6-dihydroxyphenyl] acetate; antioxidant constituents; hydroxyl radical-scavenging activity; quinone reductase-inducing activity