Anti-Arthritic Activities of Supercritical Carbon Dioxide Extract Derived from Radiation Mutant Perilla Frutescens Var. Crispa in Collagen Antibody-Induced Arthritis.

We investigated the anti-arthritic effects of the radiation mutant Perilla frutescens var. crispa leaf extract (SFE-M) and wild type leaf extract (SFE-W), both prepared by supercritical carbon dioxide (SC-CO2) extraction, on collagen antibody-induced arthritis (CAIA) in Balb/c mice. Animals were randomly divided into four groups: control, CAIA, CAIA + SFE-M (100 mg/kg/day), and CAIA + SFE-W (100 mg/kg/day). The mice were subjected to the respective treatments via oral gavage once daily for 4 days. Mice treated with SFE-M developed less severe arthritis than the CAIA mice. They showed significantly improved arthritic score, paw volume, and paw thickness compared to the CAIA mice from days 3 through 7. Furthermore, histopathological analysis of ankle for inflammation showed that SFE-M treatment reduced inflammatory cell infiltration and edema formation. Similarly, the neutrophil-to-lymphocyte ratio (NLR) in the whole blood was 37% lower in mice treated with SFE-M compared with the CAIA mice. However, treatment with SFE-W did not result in any significant difference compared with the CAIA group. In conclusion, SFE-M treatment delays the onset of arthritis and alleviates its clinical manifestations in CAIA mice.

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

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.

A possible role of an anthocyanin filter in low-intensity light stress-induced flowering in Perilla frutescens var. crispa.

The red-leaved form of Perilla frutescens var. crispa was induced to flower by low-intensity light stress. The leaves of this form are normally red, but turned green under low-intensity light due to anthocyanin depletion in the epidermis. Flowering did not occur when plants were grown under light passed through a red-colored cellophane paper, which has an absorption spectrum similar to that of anthocyanins. High-concentration anthocyanins may play the role of a red-colored optical filter under normal light conditions, and this filter effect may be lost under low-intensity light, causing a change in the wavelength characteristics of the light with which the mesophyll cells are irradiated. This change may induce a photobiological effect leading to flowering. The gene expression and enzyme activity of phenylalanine ammonia-lyase (PAL), the key enzyme for anthocyanin biosynthesis, decreased under low-intensity light. L-2-aminooxy-3-phenylpropionic acid (AOPP), which is widely used as a PAL inhibitor, inhibited low-intensity light stress-induced flowering and increased PAL activity and anthocyanin content. The inhibition of flowering by AOPP in P. frutescens may be through different mechanisms than PAL inhibition.

Controllable spectrum artificial sunlight source system using LEDs with 32 different peak wavelengths of 385-910 nm.

This study developed a lighting system that produces an approximate spectral irradiance (SI) of ground level sunlight in the wavelength range of 385-910 nm (GLS385₋910) using 547 light-emitting diodes (LEDs) with 32 different peak wavelengths. The produced SI can be modified over an arbitrary wavelength band. The SI at the light outlet reached up to 1/2 of the GLS385₋910 of a sunny April day, although the produced SI deviated from the GLS385₋910 at some wavelengths. For subsequent experiments, the reference SI was defined as 1/4 GLS385₋910 of a sunny April day. The SI produced from the lighting system was adjusted to approximate the reference SI. The ratios of the produced SI and the reference SI were within 0.72-1.28. As an application of the lighting system for biological studies, the transmitted SI of a green leaf of perilla (Perilla frutescens L.) was investigated. The curve shape of the transmitted SI, which had characteristically low transmission percentages of blue and red light, reflected the characteristics of the absorption spectra of chlorophylls. The lighting system is therefore potentially beneficial for use in diagnosing physiological conditions of plant leaves, although its application is not limited to plant physiological studies.

Obligatory short-day plant, Perilla frutescens var. crispa can flower in response to low-intensity light stress under long-day conditions.

An obligatory short-day plant, Perilla frutescens var. crispa was induced to flower under long-day conditions when grown under low-intensity light (30 micromol m(-2) s(-1)). Plant size was smaller under lower light intensity, indicating that the low-intensity light acted as a stress factor. The phenomenon is categorized as stress-induced flowering. Low-intensity light treatment for 4 weeks induced 100% flowering. The plants responded to low-intensity light immediately after the cotyledons expanded, and the flowering response decreased with increasing plant age. The induced plants produced fertile seeds, and the progeny developed normally. The plants that flowered under low-intensity light had greener leaves. This greening was because of the decrease in anthocyanin content, and there was a negative correlation between the anthocyanin content and percent flowering. Treatment with L-2-aminooxy-3-phenylpropionic acid, an inhibitor of phenylalanine ammonia-lyase (PAL), did not induce flowering under non-inductive light conditions and inhibited flowering under inductive low-intensity light conditions. The metabolic pathway regulated by PAL may be involved in the flowering induced by low-intensity light.