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 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 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.

Preparative Separation of Three Monoterpenes from Perilla frutescens var. crispa Using Centrifugal Partition Chromatography

“…crispa (cv. Antisperill) mainly comprised three major compounds, namely 9-hydroxy isoegomaketone ( 1 ), isoegomaketone ( 2 ), and peril ketone ( 3 ), as indicted by their HPLC profile (Figure 2), obtained using the established method described in our previous reports [9, 21]. For successfully separating target compounds using CPC, a search for an optimum two-phase solvent system with a suitable partition coefficient ( K ) is required.…”

“…The preparative separation of compounds 1 and 2 using CCS was first reported in this study, although compound 3 has already been separated by high speed countercurrent chromatography [19]. Compound 1 was isolated as a new compound in our previous study [9], and compound 2 has been reported to be isolated only from Perilla species [7, 22] and its synthesis has been studied [23], but a large-scale isolation of 2 using CCS has not been reported before. Therefore, although the simultaneous separation of 1 and 2 was not possible in this study, the optimized conditions are developed for the rapid and large-scale purification of 1 and 2 respectively.…”

“…The ethanol or supercritical carbon dioxide (SC-CO 2 ) extract of P. frutescens var. crispa and its constituents including monoterpenes, flavonoids, and phenolic acids, exhibit diverse biological effects, such as antioxidant [2, 3], anti-inflammatory [4–9], and antitumor [10, 11] effects. A new cultivar of this plant, namely, P. frutescens var.…”

“…crispa [7]. In our previous studies on quantitative analyses of the components of this new cultivars [8, 9], the SC-CO 2 extract of this new cultivar possesses higher content of monoterpenes, 9-hydroxy isoegomaketone ( 1 ; 1.33 ± 0.07 mg/g, dry w/w), isoegomaketone ( 2 ; 2.76 ± 0.05 mg/g, dry w/w), and perilla ketone ( 3 ; 6.96 ± 0.17 mg/g, dry w/w), compared with their contents of the SC-CO 2 extract of the original cultivar (Figure 1). In addition, in our previous biological evaluations on these monoterpenes, compounds 1 and 2 inhibited nitric oxide (NO) production in lipopolysaccharide- (LPS-) stimulated macrophages [4, 11].…”

“…crispa (cv. Antisperill) using column chromatography [9], there was a problem that this extract contained a large amount of chlorophylls, resulting in the time-consuming separation steps and a low yield of pure compounds. In addition, although several previous studies have demonstrated the separation of phenolic acids [16, 17], flavonoids [16], anthocyanins [18], and a monoterpene, perilla ketone [19] from Perilla species, there has no report on the separation and purification of 1 and 2 from Perilla species using CCS.…”