A New Monoterpene from the Leaves of a Radiation Mutant Cultivar of Perilla frutescens var. crispa with Inhibitory Activity on LPS-Induced NO Production

Abstract

The leaves of <i>Perilla frutescens</i> var. <i>crispa</i> (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 <i>P. frutescens</i> var. <i>crispa</i> in our research group resulted in the development of a new perilla cultivar, <i>P. frutescens</i> var. <i>crispa</i> (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 [(2<i>E</i>)-1-(3-furanyl)-4-hydroxy-4-methyl-2-penten-1-one; <b>1</b>]. Compound <b>1</b> exhibited inhibitory activity on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 cells with an IC₅₀ value of 14.4 μM. 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.