Caracterização ecogeográfica, morfo-agronômica, molecular e fitoquímica de acessos de Lippia origanoides Kunth. ocorrentes no estado da Bahia

Abstract

There is an increasing economic interest in the aromatic species Lippia origanoides Kunth. due to its biologic activities. The presence of essential oils in its leaves, flowers, stem allow the use of this plant, in which nine chemotypes are recognized. This phytochemical variation can be a result of environmental factors around the plant, and despite all the interest about the plant, the knowledge about environmental characteristics in which L. origanoides naturally occurs is insufficient. Thus, the aim of this work was to characterize environments where L. origanoides, collected in the states of Bahia and Pernambuco, naturally occurs, investigate if there are variations in the chemical composition of essential oils and evaluate possible interactions among environmental factors and phytochemical variation. In total, 19 sites were collected, from which 18 were in Bahia and 01 in Pernambuco, obtaining geographic coordinates, leaves and soil samples. Based on the geographic coordinates obtained, the environmental characterization of each site was carried out using vector files provided by the IBGE, obtaining data of mean annual temperature, annual average rainfall, soil class, biome, vegetation and climate. Soil samples were analyzed for determining concentrations of elements P, K, Ca, Mg, Al, Na and values concerning pH (in water), Ca:Mg ratio, potential acidity (H+Al), sum of bases (SB), ion exchange capacity (CTC), base saturation (V) and organic matter (MO). Leaf samples were dried and posteriorly used in the extraction of essential oil by hydrodistillation and chemical composition analysis by GC/FID and GC/MS techniques. The results showed that the specie occurs predominantly in Caatinga, anthropic areas and Tropical Central Brazil climate zones. Additionally, it occurs in soils with distinct nutritional levels. The study allowed to identify chemotypes rich in carvacrol, thymol and E-nerolidol, already known for L. origanoides, besides genotypes with essential oils with high percentages of camphor, elemenol, E-caryophyllene, linalool and linalool acetate, indicating the occurrence of new chemotypes in this specie. The chemical diversity of this species seems to be influenced by either concentration of Al and V values in the soil and genetic diversity.