The Effect of the Oil of<i>Agastache rugosa</i>O. Kuntze and Three of Its Components on Human Cancer Cell Lines

Abstract

Abstract The reduction of tumor cell proliferation and antimutaginicity of the essential oil from Agastache rugosa O. Kuntze and its major components such as methyl chavicol (82.8%), limonene (3.9%) and anisaldehyde (2.6%) were investigated by using four human carcinoma cell lines. Both the oil and its three major components were shown to possess low cytotoxicity on normal human liver cells, WRL68 by only inhibiting less than 12% of normal cell growth. Its inhibition percentage was much less than those from other medicinal herb extracts. The oil had relatively strong antimutaginicity when screened against a genetically engineered Chinese Hamster Ovary (CHO AS-52) cell line, and the results of antimutaginicity were shown to be closely related to the effect of inhibiting cancer cell growth. In general, the oil had better inhibition effect on cancer cells than individual components: 63% for crude oil vs. 49% for anisaldehyde at 1 g/L of the treatment. It was found that the oil could effectively inhibit the growth of human lung cancer cell up to 82 %, having 0.09 of IC50. The proliferation of other human cancer cell lines have also been retarded in the range of 40—80% by addition of the oil. This was well matched with the result of antimutaginicity as follows: 75% for the oil and 38–63% for individual oil components at 1 g/L, respectively. The functions of antimutaginicity and inhibiting cancer cell growth of the components were also confirmed by the kinetic analysis of human immune cell growth. The growth of both B and T cell lines was enhanced up to about 200% by adding the oil, but the oil components could not improve the human T cells. The results of a kinetic analysis using a microphysiometer revealed that the oil could affect human B cell growth rapidly within 10 min of the treatment showing up to 180% enhancement of the growth. While the individual components only reacted after 20 min. This may be interpreted that the oil (mixture of components) can have a synergistic effect on the growth of human T cells and better inhibition of cancer cell growth. These results also imply that the oil could selectively inhibit the proliferation of human cancer cells (>1.5 of the selectivity) better than the individual oil components, possibly due to the synergistic effect of the three major components and/or the combined effects by other unknown minor components in the oil.