Estudo piloto do própolis do Vale do Jequitinhonha: uma avaliação por metabolômica global

Abstract

Propolis is a complex bee product whose chemical composition varies according to the botanical and environmental diversity of its region of origin. This study aimed to investigate the chemical profile of propolis samples collected from different localities in the Vale do Jequitinhonha region, Minas Gerais, Brazil. A metabolomics approach based on liquid chromatography coupled to mass spectrometry (LC MS), complemented by visible molecular absorption spectrophotometry, was used to explore variations related to geographic origin and possible influences of local flora. A total of 54 propolis samples extracted with 70% ethanol were analyzed, with data acquired in both positive and negative ionization modes. Initial data processing was performed using Compound Discoverer 3.3 for compound detection, grouping, retention time alignment, background removal, and annotation. The data were then exported, filtered, and organized into a matrix of relative intensities for analysis in MetaboAnalyst 5.0. Exploratory and comparative analyses showed that the geographic subdivision into Alto and Baixo Jequitinhonha was not sufficient to explain the observed diversity. Complementary classification by microrregions (Diamantina, Capelinha, Araçuaí, and Almenara) provided better discrimination, but only samples from Felício dos Santos and Diamantina showed specific grouping. Exploratory classification based on extract color and visible absorption spectra (400–800 nm) was more effective in discriminating chemical profiles, revealing characteristic bands of green propolis (630–750 nm) and red propolis (450 600 nm) in samples from different areas of the valley. Classical markers such as vestitol, neovestitol, and formononetin (red propolis), as well as Artepillin C, caffeoylquinic acids, and aromadendrin (green propolis), were detected, along with other metabolites such as galangin, rutin, quercetin, chrysin, medicarpin, calycosin, and isoliquiritigenin, with distinct distribution patterns among groups. Some detected compounds belonged to classes such as flavonoids, phenolic acids, terpenes, alkaloids, and lipid derivatives, many of which are associated with the flora of the Cerrado, predominant in the studied region. Some samples showed atypical profiles compared to what would be expected based on their color, suggesting the influence of multiple botanical sources, mixed resin collection, or variation in local flora. The results indicate that local botanical factors, more than geographic location itself, determine the chemical profile of propolis from Vale do Jequitinhonha. In addition to contributing to the chemical characterization of a scarcely studied type of propolis, this work highlights methodological challenges of applying conventional untargeted metabolomics workflows. The study emphasizes the importance of complementary biological evaluations, comparisons with other Brazilian propolis types, and investigation of metabolites from local flora to expand knowledge and add value to the propolis produced in the region.