the leaves of perilla frutescens var. crispa (lamiaceae)-known as 'jureum-soyeop' or 'cha-jo-ki' in korean, 'zi su ye' in chinese, and 'shiso' in japan-has been used as a medicinal herb. recent gamma irradiated mutation breeding on p. frutescens var. crispa in our research group resulted in the development of a new perilla cultivar, p. frutescens var. crispa (cv. antisperill; pfca), which has a higher content of isoegomaketone. the leaves of pfca were extracted by supercritical carbon dioxide (sc-co2) extraction, and phytochemical investigation on this extract led to the isolation and identification of a new compound, 9-hydroxy-isoegomaketone [(2e)-1-(3-furanyl)-4-hydroxy-4-methyl-2-penten-1-one; 1]. compound 1 exhibited inhibitory activity on nitric oxide (no) production in lipopolysaccharide (lps)-activated raw264.7 cells with an ic50 value of 14.4 m. the compounds in the sc-co2 extracts of the radiation mutant cultivar and the original plant were quantified by high-performance liquid chromatography with diode array detection.