Prospecção da erva baleeira (Varronia curassavica Jacq.) em fragmentos da Mata Atlântica nos estados do Rio de Janeiro e Espírito Santo, em busca por genótipos com maior teor de β-cariofileno e α-humuleno e propriedades biológicas

Abstract

The wild sage (Varronia curassavica, Boraginaceae) is a native species that has medicinal properties and, therefore, of interest to the pharmaceutical industry. In this context, the present study aimed to study the chemical diversity of the essential oil of 36 Varronia curassavica plants, collected in coastal regions of Rio de Janeiro and Espírito Santo, in restinga vegetation. The plant material was stabilized by reducing the moisture content to around 15% and then the essential oil was extracted by hydrodistillation and subjected to chromatographic analysis (GC-FID and GC-MS). After chemical characterization of essential oils, data were organized and subjected to descriptive and multivariate statistical analysis (ACP and AAH). The toxicity of the essential oils extracted against the insect pest Callosobruchus maculatus, the phytopathogenic fungus Pestalotia sp. and the epimastigote form of the protozoan Trypanosoma cruzi. The essential oil was also evaluated for its insecticidal and fungicidal toxic activity. It was possible to observe variations in the essential oil content ranging from 0.34 to 4.20%, where the highest essential oil contents were observed in EB24 plants (4.20%) corresponding to the individual collected in the state of Rio de Janeiro, followed by of the individual EB41 (3.93%), collected in the state of Espírito Santo. A total of 177 substances were identified, in which the substances with the highest frequencies and highest concentrations were also highlighted, they are: α-Humulene, Caryophyllene Oxide, Germacrene D, (2E,6Z)- Farnesol, Shyobunol and 2,3- dihydro-Farnesol. The analysis of hierarchical clusters discriminated the formation of 5 distinct groups: group 1 ((2E, 6Z)-Farnesol), group 2 (Shyobunol and Germacrene D-4-ol), group 3 (α-Santalene), group 4 (β -caryophyllene, Elemol and (2Z, 6E)-Farnesol) and group 5 (β-caryophyllene; 1,10-di-epi-Cubenol and 2,3-dihydro-Farnesol). On the other hand, when applying the criteria of dominance among the majority compounds (proposed by the research group), we observed only four different chemotypes (qt) among the 36 individuals studied: Shyobunol, Germacrene D

(30.9; 17.3%); Shyobunol, Cubebol, Germacrene D (23.5; 12.3; 11.7%); Shyobunol, α- Santalene, Germacrene D (15; 14; 11.7%) and Shyobunol (31.7%). The essential oils

tested did not show relevant toxic activity against the species C. maculatus and Pestalotia sp., on the other hand, two chemotypes were toxic against the epimastigote form of T. cruzi. These results point to a great intraspecific chemical diversity among the plants studied in situ, indicating that there are genotypes with potential to be explored from an agronomic and biological point of view against T. cruzi.