Chemodiversity and trypanocidal activity of the essential oils of tropical black sage

Abstract

Tropical black sage (Varronia curassavica Jacq.) is a species native to ecosystems subject to strong anthropic action, and thus is at risk of genetic erosion. However, little is known about this important genetic resource, with possible uses in the aromas, fragrances and pharmaceutical sectors. The objective of this work was to prospect and study native specimens of tropical black sage regarding the concentration, chemical profile and trypanocidal activity of the essential oils (EOs). For this purpose, we collected in situ 47 specimens. The EOs were obtained by distillation from leaves, quantified, and analyzed by GC-FID and GC-MS. The resulting data were submitted to descriptive statistical and multivariate analyses. The concentration of EOs ranged from 0.3 to 4.2% based on dry leaves. The EOs had average contents of 33.4 and 44.9% of oxygenated and non-oxygenated sesquiterpenes, respectively. The concentration of the substance α-humulene varied from 0.3 to 11.1%, with frequency of 100%. Cluster analysis indicated the formation of 10 groups with 50% similarity among the EOs samples. The sample with the best trypanocidal activity was ESB45, with IC50% of 74.6 µg/mL and 100% inhibition of the viability of the epimastigote form of Trypanosoma cruzi at the concentration of 300 µg/mL. Tropical black sage is a source of oxygenated sesquiterpenes, an important chemical class for synthesis and development of medicines. For this reason, efforts are necessary to preserve the genetic information about the species.