Characterization and bioactivities of coffee husks extract encapsulated with polyvinylpyrrolidone.

Coffee processing generates large amounts of residues of which a portion still has bioactive properties due to their richness in phenolic compounds. This study aimed to obtain a coffee husks extract (CHE) and to encapsulate it (ECHE) with polyvinylpyrrolidone using a one-step procedure of solid dispersion. The extraction and encapsulation yields were 9.1% and 92%, respectively. Thermal analyses revealed that the encapsulation increased the thermal stability of CHE and dynamic light scattering analyses showed a bimodal distribution of size with 81% of the ECHE particles measuring approximately 711 nm. Trigonelline and caffeine were the main alkaloids and quercetin the main phenolic compound in CHE, and the encapsulation tripled quercetin extraction. The total phenolics content and the antioxidant activity of ECHE, assayed with three different procedures, were higher than those of CHE. The antioxidant activity and the bioaccessibility of the phenolic compounds of ECHE were also higher than those of CHE following simulated gastrointestinal digestion (SGID). Both CHE and ECHE were not toxic against Alliumcepa cells and showed similar capacities for inhibiting the pancreatic α-amylase in vitro. After SGID, however, ECHE became a 1.9-times stronger inhibitor of the α-amylase activity in vitro (IC50 = 8.5 mg/mL) when compared to CHE. Kinetic analysis revealed a non-competitive mechanism of inhibition and in silico docking simulation suggests that quercetin could be contributing significantly to the inhibitory action of both ECHE and CHE. In addition, ECHE (400 mg/kg) was able to delay by 50% the increases of blood glucose in vivo after oral administration of starch to rats. This finding shows that ECHE may be a candidate ingredient in dietary supplements used as an adjuvant for the treatment of diabetes.

Cytotoxicity of erythrosine (E-127), brilliant blue (E-133) and red 40 (E-129) food dyes in a plant test system - doi: 10.4025/actascibiolsci.v35i4.18419

The objective of this work was to evaluate the cytotoxic effect of the food dyes erythrosine, brilliant blue and red 40 on the cell cycle of Allium cepa L. Each dye was evaluated at doses of 0.4 and 4.0 ml, at exposure times of 24 and 48 hours, in onion root tip cells. Cells and the presence of chromosomal aberrations were analyzed throughout the whole cell cycle, totaling 5,000 cells for each group of bulbs. The mitotic index was calculated and the statistical analysis was conducted through the Chi-square test (p 0.05). From the obtained results, it was verified that the food additives erythrosine and brilliant blue were not cytotoxic to the cells of the test system. However, the red 40 dye, at the two evaluated doses and the two exposure times used in this bioassay have promoted a significant reduction in cell division and induced the emergence of anaphasic and telophasic bridge aberrations and micronucleated cells. Additional cytotoxicity studies should be conducted to add information to these and other previously obtained results in order to evaluate, with property, the action of these three dyes on a cellular level.