Enhanced accumulation of caffeic acid, rosmarinic acid and luteolin-glucoside in red perilla cultivated under red diode laser and blue LED illumination followed by UV-A irradiation

Red perilla (Perilla frutescens var. purpurea cv. Akajiso) is a plant rich in polyphenols such as rosmarinic acid and luteolin with great potential as a functional food material. The present study examines whether growth under controlled artificial illumination could be used for cultivation of red perilla to enhance rosmarinic acid and luteolin content. Red perilla plants were cultivated for 7 weeks in a greenhouse or in a closed environment under a regime of artificial light comprising 80% red laser diode (680 nm) and 20% blue LED (460 nm) at 360 μmol/m2/s for 14-h light period, followed by a 2-h illumination with ultraviolet A (365 nm). HPLC analysis of polyphenols revealed that the content of caffeic acid and rosmarinic acid was 7.9 and 6.6 times higher respectively, in plants grown under artificial light than in greenhouse grown plants. The content of luteolin-7-O-glucoside was 20 times higher in the light treated plants compared to the greenhouse grown ones. Our results indicate that artificial illumination is effective for inducing the accumulation of rosmarinic acid and luteolin with functional food properties in red perilla.