Anti-allergic effect of Perilla frutescens and its active constituents.

The leaves of Perilla frutescens Britton (Labiatae) are one of the most popular garnishes in Japan, used as an antidote for fi sh and crab meat allergy or as a food colorant. The present study was conducted to evaluate its anti-allergic effect and to identify its active constituents using mice ear-passive cutaneous anaphylaxis (PCA)-reaction. 48 h after the cutaneous injection of anti-ovalbumin serum into the ears of mice, ovalbumin and evansblue dye were intravenously injected. Perilla was extracted with boiling water, and intraperitoneally injected 15 min before ovalbumin-treatment. Thirty min after ovalbumin-treatment, the ears were removed and the colorant in the ear was colorimetrically quantitated. Perilla extract significantly suppressed the PCA-reaction, which was brought about by rosmarinic acid with a partial contribution from some macromolecular compounds. The anti-allergic titer of rosmarinic acid was more effective than tranilast, which is a modern anti-allergic drug. Perilla and rosmarinic acid are potentially promising agents for the treatment of allergic diseases.