Análise metabolômica não-direcionada de pimentas (Capsicum spp.) por CG-EM

Abstract

The genus Capsicum belongs to the Solanaceae family and comprises more than 30 species, their fruits are popularly known as pepper and were used by native people as spices, food preservatives, and medicines. With the purpose of studying and conserving the biodiversity of species of Capsicum, Embrapa Clima Temperado (Pelotas, RS) maintains an Active Germplasm Bank (AGB), which requires agronomic, morphological, genetic, metabolic, and technological potential characterizations, thus enabling the knowledge of the individuals, supporting the selection for different applications. The knowledge of the total of compounds present in peppers can be obtained by metabolomic analysis strategy. Therefore the objective was to characterize the metabolic profile of 61 accessions of peppers from Embrapa Clima temperado Capsicum AGB including C. baccatum, C. annuum, C. chinense, and C. frutescens by Gas Chromatography and Mass Spectrometry in two extracts (polar fraction A and B). It was observed wide variety of compounds such as amino acids, simple sugars, organic acids, capsaicinoids, steroids, and esters. The amino acid content varied between 3.7 and 13.4mg g -¹ dry weight (dw) and Lasparagine predominated in 75% of the accessions. Total sugar content ranged between 45.0 and 189.8mg g -¹ dw, the most abundant was fructose representing on average 59%. In most accessions citric acid predominated reaching concentrations of up to 11.3mg g -¹ dw. Total organic acid content was quantified between 2.4 and 15.2mg g -¹ . Capsaicin represented 59% of total capsaicinoids evaluated while dihydrocapsaicin represented 30%. Capsaicinoids were not identified for accessions P27 and P179 (C. baccatum), P135 (C. chinense) and P46 (C. annuum). Hydrocarbons and esters were present in concentrations between 0.2–14.6mg g -¹ dw and 0.5–57.9mg g -¹ dw respectively. Principal component analysis (PCA) of polar fraction A did not show the formation of clusters by species. Separated from the main group (outliers) were P116 (C. chinense), P46 and P76 (C. annuum), mainly due to the higher concentration of sucrose and fructose present in these access ions. PCA of polar fraction B, indicated the separation of P221 (C. annuum) and P200 (C. chinense), due to the high content dihydrocapsaicin of these accessions. The characterization of the metabolic profile by GC-MS allowed simultaneous identification and quantification of compounds 90. These results extend and complement the metabolic database of the AGB of Capsicum spp..