Sazonalidade e composição química do óleo essencial de acessos de Croton grewioides Baill

Abstract

Croton grewioides Baill., commonly known as "canelinha" or "alecrim-de-caboclo", is a native plant of the Brazilian Caatinga, widely recognized for its bioactive properties, such as antioxidant, antimicrobial, and anti-inflammatory activities, associated with its essential oils. This study aimed to evaluate the influence of seasonality on the chemical composition and essential oil content of 12 C. grewioides accessions from the germplasm bank of medicinal and aromatic plants from the Experimental Farm of the Federal University of Sergipe. Leaves were collected during the dry and rainy seasons in 2021 and 2022, and the essential oil was extracted by hydrodistillation using a Clevenger apparatus. Chemical analysis was conducted using gas chromatography-mass spectrometry (GC-MS), with compound identification performed by comparing mass spectra and retention indices with different databases. The data were subjected to analysis of variance (ANOVA) in a split-split plot design over time, principal component analysis (PCA), and Euclidean distance clustering to identify significant variations in chemical profiles. The results revealed the presence of nine major compounds, with 55.56% being sesquiterpenes and 44.44% phenylpropanoids. Among the predominant compounds, eugenol, methyl eugenol, and methyl chavicol stood out, showing significant variations due to seasonal conditions and the accessions evaluated. The sesquiterpenes spathulenol and bicyclogermacrene were found in all accessions, regardless of the season, with average percentages ranging respectively from 1.35% to 2.18% and 2.63% to 5.67% in the rainy season, and from 1.04% to 2.00% and 1.69% to 4.69% in the dry season. The interaction between accessions and seasons highlighted the complexity of C. grewioides' metabolic responses to environmental changes. PCA analyses explained between 59.91% and 68.88% of the data variance, and Euclidean distance-based dendrograms grouped the accessions into two to four chemical clusters per season. The results of this study reinforce the potential of C. grewioides as a source of bioactive compounds with pharmaceutical, cosmetic, and agricultural applications. However, seasonal variations in chemical composition underscore the need for continuous studies to optimize the management and use of this species. The detailed chemical characterization provides important insights for valuing C. grewioides as a strategic genetic resource, particularly within the context of Caatinga biodiversity.