Terpenes and Phenolic Compounds from Agastache rugosa and Their Inhibitory Effect on the Release of β-Hexosaminidase in RBL-2H3 Cells

Agastache rugosa (Fisch. et Meyer) O. Kuntze., commonly known as Korean mint, is a perennial herb in the family Labiatae which is distributed in Korea, China, Japan and Russia. The herb has been used for the treatment of summer flu, summer cold, headache, stomachache, nausea, vomiting, and dyspepsia in Chinese and Korean traditional medicines. Previous studies on A. rugosa, have investigated several biological activities including antioxidative, antibacterial, antiviral, antifungal, and anticancer activities. In continuation of our search for anti-allergic compound from natural products, we have found that the hexane extract of A. rugosa has anti-allergic activity. The dried aerial part of A. rugosa was extracted with hexane. The anti-allergic activity of the hexane extract was comparatively higher than that of second-generation H₁-antihistamine ketotifen as positive control. Twelve terpenes and phenolic compounds were isolated from the hexane extract. The structures of isolated compounds were identified as linalool, trans-isopulegone, linalyl acetate, β-caryophyllene, eugenol, estragole, cis-jasmone, phytol, l-menthone, methyl eugenol, and trans-carveol by comparison of their spectral data with literature values. The anti-allergic activity of isolated compounds was evaluated in an in vitro assay on β-hexosaminidase release inhibition using RBL-2H3 cells stimulated by DNP-BSA.