RESUMO
BACKGROUND: Minthostachys verticillata (Griseb.) Epling is a South American traditional medicinal herb used as digestive, anti-spasmodic, anti-inflammatory and bronchial dilator agent among other uses. Its anti-microbial activity against staphylococcal strains and its anti-viral properties against HVS-1 and strain RC/79 of PrV have been demonstrated. OBJECTIVE: To determine the immunomodulating ability of M. verticillata decoction and essential oil. As a complementary study, the main constituents of the essential oil were identified. MATERIALS AND METHODS: Lymphocyte-proliferating activity of both vegetal derivatives was tested and compared with cellular expansion induced by PHA, Pokeweed, CGB in cytomorphological study. A non-stimulate culture was used as control reference. The score of lymphocyte clusters and colonies was performed using the method described by Lange. Among proliferated cells, LT CD8+ subpopulation was characterized by direct immunofluorescence. The in vitro degranulant ability of the vegetal fractions was tested on basophils from allergic and non-allergic individuals sensitized to environmental fungi. Essential oil components of M. verticillata were identified by gas chromatography technique. RESULTS: M. verticillata derivatives reached higher proliferation levels compared to non-stimulated cultures, showed mitogenic activity and induced cluster and colony formation similar to PHA, Pokeweed and CGB. Cells that proliferated after stimulation with derivatives showed 40% of LT CD8+. Tested concentrations of decoction and essential oil did not reach minimum degranulation indexes over basophils, from both allergic and non-allergic individuals. Gas chromatography analysis revealed the presence of pulegone and menthone as the main constituents. CONCLUSIONS: M. verticillata derivatives were mitogenic over LT, inducing significant cluster and colony formation. There was no evidence of degranulating ability over basophils at the concentrations tested. We assume that the derivatives from M. verticillata would induce Th1 deviation in cellular cultures from allergic patients, which would diminish hypersensitivity reactions. Some of the compounds of the essential oil revealed by gas chromatography analysis may be responsible of the biological activity of these products.