Evaluation of immunomodulatory activity of trans-anethole and estragole, and protective effect against cyclophosphamide-induced suppression of immunity in Swiss albino mice

Summary. The positional isomers trans -anethole and estragole are present in essential oils extracted from many aromatic plants used in traditional medicine, and have largely been used as flavoring agents in the food industry. There are many studies describing the biological activities of these essential oils; however, few studies have been performed to determine the biological effects of these substances as neat compounds. Furthermore, their immunomodulatory activity remains elusive. In this paper, we evaluated the immunogenic activity of both trans -anethole and estragole as pure substances. In this regard, a series of experiments was conducted to determine the effect of the test compounds on cell- and humoral-mediated immune responses in mice. Our data showed that trans -anethole and estragole promote some changes in the immune system by reducing the delayed-type hypersensitivity response, and increasing the number of leucocytes in peripheral blood in mice. Also, we observed that trans -anethole improved the humoral response. Finally, these compounds promoted a protective effect against cyclophosphamide-induced suppression of immunity. In conclusion, we propose that the immunological effects exerted by trans -anethole and estragole are promising and merit further investigations. Industrial relevance. According to recent studies, essential oils containing trans -anethole or estragole, as the major natural products, exert a wide variety of biological activities. These two compounds have a wide variety of applications in the food, pharmaceutical, and cosmetic industry and, consequently, the study of their biological activities has promising commercial use. In this study, we conducted a series of experiments with the purpose of evaluating the potential immunogenic activity exerted by trans -anethole, and estragole, on cell- and humoral-mediated immune response, using an in vivo murine model. The screening of the biological activity of these phenylpropenes may be useful to develop new plant-based products with immunomodulatory properties, which are unlikely to produce the undesirable side-effects of current chemotherapeutic agents. Keywords. Immunomodulatory activity; trans -anethole; estragole