Sedative effects of inhaled Perilla frutescens essential oils on mice

Perilla frutescens is an ingredient for cooking and for Japanese traditional medicine formulations. Essential oils extracted from P. frutescens are classified according to their composition, which are genetically regulated. Here, we extracted five types of essential oil from P. frutescens and studied their sedative activities. We grew P. frutescens strains that give oils of type PK, PA, PP, EK, and C, and extracted the essential oils by hydrodistillation. We then measured the spontaneous locomotor activity of mice who had inhaled the oils in an open field test. All types of essential oil except the PK type decreased the spontaneous locomotor activity of mice. The effective doses were 4.0 × 10⁻³ to 4.0 × 10⁻² mg/cage (PA type), 4.0 × 10⁻⁴ mg/cage (PP type), 4.0 × 10⁻⁵ mg/cage (EK type), and 4.0 × 10⁻⁵ to 4.0 × 10⁻³ mg/cage (C type). Our results show that the essential oils of type PA, PP, EK, and C have a sedative effect.