A LC-MS method, which GSH was used as substrate, was employed to reveal the compounds with NQO1 induction activity from Angelica keiskei. Some compounds, proposed as isobavachalcone, xanthoangelol and 4-hydroxyderricin, have NQO1 induction activity. To make the actual structures and bioactivities of these compounds clear, 23 compounds, including above mentioned compounds and two new compounds 4-hydroxy-3,5,5-trimethyl-4-(1,2,3-trihydroxybutyl)cyclohex-2-enone (18) and (Z)-2-(3-hydroxypent-1-ynyl)-3-(non-1-enyl)oxiran-2-ol (23), were isolated from the 95% ethanol extract of A. keiskei. The bioassay results suggested the compounds had notable NQO1 induction activity. The radical scavenging and alpha-glucosidase inhibition activities of the isolated compounds were also tested. Compounds (E)-1-(2,4-dihydroxy-3-(3-methylbut-2-enyl)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (1), (E)-1-(3-((E)-3,7-dimet hylocta-2,6-dienyl)-2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (2), 1-(3-hydroxy-10, 13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[alpha]phenanthren-17-yl)et hanone (17), 4-hydroxy-3,5,5-trimethyl-4-(1,2,3-trihydroxybutyl)cyclohex-2-enone (18) could scavenge DPPH radical by more than 20%. Compounds (E)-1-(2,4-dihydroxy-3-(3-methylbut-2-enyl)phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (1), (E)-1-(3-((E)-3,7-dimethylocta-2,6-dienyl)-2,4-dihydroxyphe nyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (2), (E)-1-(2-hydroxy-4-methoxy-3-(3-methylbut-2-enyl) phenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one (3), 7-hydroxy-6-(3-methylbut-2-enyl)-2H-chromen-2-one (5), 10-hydroxy-8,8-dimethyl-2-oxo-9,10-dihydropyrano[6,5-H]chromen-9-yl)-3-methylbut-2-eno ate (9), 2-(4-hydroxyphenyl)-7-methoxy-8-(3-methylbut-2-enyl)-2,3-dihydrochromen-4-one (16), (10S, 15R,Z)-10,15-dihydroxyheptadeca-8,16-dien-11,13-diynyl acetate (20), (3R,8S,Z)-heptadeca-1,9-dien-4,6-diyne-3,8-diol (21) exhibited excellent a-glucosidase inhibition activity. (C) 2011 Elsevier Ltd. All rights reserved.