EVALUATION OF THE CHANGES ON PHENOLIC COMPOUNDS PROFILE BY ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY - TANDEM MASS SPECTROMETER (UPLC-MS/MS) DURING THE RIPENING OF FRUTA-DO-LOBO (Solanum lycocarpum ST. HILL)

Fruta-do-lobo (Solanum lycocarpum St. Hill) is a native fruit found in the Brazilian Cerrado and it has been used in popular medicine as a hypoglycemic and hypocholesterolemic agent. Fruits of Solanum genus are characterized by their high levels of alkaloids and most studies focus only on the biological activities related to this class of compounds. However, recent studies have demonstrated the importance of the phenolic compounds present in fruits of this genus. These compounds contribute to the quality, nutritional value, aroma and flavor in fruits. Considering that these compounds are transformed during maturation, the objective of this study was to evaluate the influence of the maturation stage on the phenolic compounds of the three fractions of the fruta-do-lobo (peel, pulp, and seed). Fruit maturation was confirmed by the increase in total titratable acidity (0.2±0.02 – 0.82±0.27 % citric acid/100 g of pulp) and total soluble solids (2.5±0.02 – 17.5±0.02 %) and by pH values decrease (5.23±0.03 – 5.05±0.32). Phenolic compounds were identified by UPLC-MS/MS. In general, there was a predominance of 5-O-Caffeoylquinic acid (chlorogenic acid) in all parts of the green fruit, comprising about 80 % of all phenolic detected. With the ripeness, this compound reduces its levels and predominate the p-coumaroylquinic acid for peel and pulp (about 20 %) and 1-O-sinapoyl-glucoside (15 %) for seeds. We also observed an increase in the relative abundance of chlorogenic acid dimers and trimers with maturation. This behavior has already been reported in leaves of plants of the same family, which showed that chlorogenic acid may be linked to a greater initial protection of the vegetal material against sunlight. With the ripening of the fruits, these compounds are being relocated to the plant, as they participate in its lignification process. In addition, reaching ripeness, most edible fruits have a lower content of phenolics in the pulp and a higher content of color-related phenolics (anthocyanins) in the skin. This is because the biological process of seed ripening is over and the protection from herbivores, in the form of the unpleasant taste of unripe fruit, is no longer needed. The focus of color-related phenolics is subsequently transferred from protection to the attraction of seed carriers. This is the first time that the phenolic compound profile has been reported in the literature. Our results show that the stage of ripeness influence on phenolic compound composition. These data provide support for future research aimed at exploring the application of these compounds with respect to their biological activity.