Two novel antioxidant ortho-benzoyloxyphenyl acetic acid derivatives from the fruit of Vaccinium uliginosum

Two new ortho-benzoyloxyphenyl acetic acid derivatives, vacciuligins A (1) and B (2), were isolated, along with five known compounds, quercetin 3-O-alpha-arabinopyranoside (3), syringetin 3-O-ss-glucopyranoside (4), syringetin 3-O-ss-galactopyranoside (5), protocatechuic acid (6), and syringic acid (7) from the methanol extract of the fruit of Vaccinium uliginosum L., and their chemical structures were determined from spectroscopic data. Compounds 1-3 displayed almost identical antioxidative activity as that of a-tocopherol, and 4-7 were identified as stronger antioxidants than a-tocopherol by the ferric thiocyanate method. Moreover, 1, 3, 6, and 7 exhibited stronger radical-scavenging effect than that of a-tocopherol. In addition, twelve anthocyanins in the methanol extract were identified by high performance liquid chromatographic analysis.