Quantificação de compostos fenólicos, poder antioxidante e teor de açúcares em produtos comerciais a base de Camellia sinensis L / Quantification of phenolic compounds, antioxidant power sugar content in commercial products based on Camellia sinensis L

Objetivo: Analisar e comparar quantitativamente compostos fenólicos, capacidade antioxidante e açúcares presentes em infusões e extratos solúveis de Camellia sinensis L. Método: O estudo apresenta delineamento inteiramente casualizado, utilizando amostras por conveniência. Foram adquiridas três amostras aleatórias de cada tipo de chá. As análises de compostos fenólicos totais e flavonoides foram determinadas pelo método colorimétrico de Folin-Ciocalteu e cloreto de alumínio, respectivamente, taninos totais por complexação com caseína e os condensados pelo método do butanol-HCl. A capacidade antioxidante, pela metodologia do ferricianeto e sequestro de radicais livres pelo radical 2,2-difenil-1-picril-hidrazil, e os açúcares redutores e não redutores, através do reagente ácido 3-5-dinitrossalicílico. Resultado: Os extratos infusos apresentaram quantidades significativamente maiores de compostos fenólicos totais e flavonoides em comparação ao solúvel. Esse comportamento foi o mesmo para os taninos e atividade antioxidante. As infusões obtiveram maior poder redutor e capacidade de redução do radical livre. Os extratos solúveis foram destaque, com maior presença de açúcares. Esses resultados foram confirmados pela literatura e não houve trabalhos realizados com extratos solúveis e metodologias semelhantes ao realizado aqui para comparação. Conclusão: As infusões estudadas no presente trabalho foram mais ricas em compostos bioativos e antioxidantes, favorecendo seus benefícios para a população, tendo os extratos solúveis maior presença de açúcares adicionais. (AU)

Objective: To analyze and quantitatively compare phenolic compounds, antioxidant capacity and sugars present in infusions and soluble extracts of Camellia sinensis L, Methods: The study presents a completely randomized design, using samples for convenience, Three random samples of each type of tea, The analyzes of total phenolic compounds and flavonoids were determined by the Folin-Ciocalteu colorimetric method and aluminum chloride, respectively, total tannins by complexation with casein and condensates by the butanol-HCl method, The antioxidant capacity, by ferricyanide methodology and free radical scavenging by the radical 2,2-diphenyl-1- picryl-hydrazil, and reducing and non-reducing sugars, through the reagent 3-5 dinitrosalicylic acid, Result:: The infused extracts showed significantly higher amounts of total phenolic compounds and flavonoids compared to the soluble, This behavior was the same for tannins and antioxidant activity, The infusions obtained greater reducing power and capacity to reduce free radicals, Soluble extracts were highlighted, with a greater presence of sugars, These results were confirmed by the literature and there were no studies carried out with soluble extracts and methodologies similar to that performed here for comparison, Conclusion: The infusions studied in the present study were richer in bioactive and antioxidant compounds, favoring their benefits for the population, with soluble extracts having a greater presence of additional sugars. (AU)

Changes in oxidative stress markers and cardiometabolic risk factors among Roux-en-Y gastric bypass patients after 3- and 12-months postsurgery follow-up.

BACKGROUND: Evidence shows potential reduction in oxidative stress after Roux-en-Y gastric bypass. However, this outcome can vary, with postsurgery time, type of markers significantly altered, and possible relation with cardiometabolic risk markers, thus indicating the need for more studies. OBJECTIVE: To evaluate changes in oxidative stress and its relation with cardiometabolic risk markers in Roux-en-Y gastric bypass patients after 3 and 12 months postsurgery. SETTING: Federal University of Viçosa, Brazil. METHODS: All data were collected before surgery and after 3 and 12 months postsurgery. Biochemical data were collected, and insulin resistance was determined by homeostasis model assessment of insulin resistance, triglyceride/glucose index, and triglycerides/high-density lipoprotein cholesterol. Additionally, catalase, superoxide dismutase, ferric-reducing antioxidant power, nitric oxide, carbonylated protein, and malondialdehyde were analyzed. RESULTS: After 3 months postsurgery, excess weight loss was 46%. It increased to 82% after 12 months. We observed a significant reduction in levels of serum insulin, triglycerides, homeostasis model assessment of insulin resistance, triglyceride/glucose index, and triglycerides/high-density lipoprotein cholesterol indices and nitric oxide, throughout the entire study period. Also, reduced levels of total cholesterol, low-density lipoprotein, serum glucose, malondialdehyde, and superoxide dismutase were observed at 3 and 12 months postsurgery compared with baseline. On the other hand, reduction in ferric-reducing antioxidant power occurred only at 3 months postsurgery. We also observed that nitric oxide was positively correlated with triglycerides, percent excess weight loss, total cholesterol/high-density lipoprotein cholesterol, and triglyceride/glucose index. CONCLUSION: Roux-en-Y gastric bypass is able to reduce oxidative stress, insulin resistance, and improve lipid profile after 3 and 12 months postsurgery. Furthermore, changes in oxidative stress and cardiometabolic risk markers are correlated.