Seven New Phenylhexanoids with Antioxidant Activity from Saxifraga umbellulata var. pectinata .

Seven new phenylhexanoids, ()-(+)-3,4-dihydroxy-11-methoxyphenylhex-9-one (), () 3,4-dihydroxy-phenylhex-10-en-9-one (), ()-4-hydroxyphenylhex-10-en-9-one (), ()-(-)-3,4,11-trihydroxyphenylhex-9-one 11---d-glucopyranoside (), ()-(-)-4,11-dihydroxyphenylhex-9-one 11---d-glucopyranoside (), phenylhex-4,9,11-triol 11---d-glucopyranoside (), and 9--acetyl-phenylhex-4,9,11-triol 11---d-glucopyranoside (), were isolated and identified from Tibetan medicine var. . The antioxidant activities of these compounds were evaluated using the DPPH and ABTS radical scavenging experiments. In the ABTS experiment, compounds (IC 13.99 ± 2.53 μM) and (IC 13.11 ± 0.94 μM) exhibited significantly better antioxidant activity than L-ascorbic acid (IC 23.51 ± 0.44 μM).