Evaluation of the Phenolics and in vitro Antioxidant Activity of Different Botanical Herbals Used for Tea Infusions in Brazil

Background: The consumption of herbal teas has gained much attention due to its health-promoting benefits, including antioxidant, neuroprotective, antimicrobial, antitumor, and anti-inflammatory effects. These biological activities are associated in part to the antioxidant activity of chemical compounds present in teas, especially flavonoids and phenolic acids. Objective: The aim of this study was to evaluate a total of 17 different botanical herbal infusions consumed in Brazil in terms of their phenolic antioxidants. Methods: The analysis performed were total phenolic compounds, total flavonoids, total flavonols, tannin content and in vitro antioxidant activity (DPPH, ABTS, CUPRAC, FRAP, and ORAC assays). Data were processed using univariate, bivariate and multivariate analysis (hierarchical cluster analysis). Results: The use of Hierarchical Cluster Analysis (HCA) suggested an unsupervised classification relationship based on level of functionality of the herbal teas. Higher levels of total phenolics, total flavonoids and antioxidant activity were found in Anemopaegma mirandum while higher values of tannin content and total flavonols were found in Peumus boldus. All antioxidant activity assays showed significant correlations among each other (r > 0.84, p < 0.001), and with total phenolic and flavonoids (r > 0.83, p < 0.001). Using HCA, three clusters were suggested and cluster 1 showed the highest functionality. Conclusion: The herbal infusions evaluated can be a good resource of bioactive compounds to consume and supplementing food products. Nevertheless, future studies should focus on the evaluation of these herbal teas using in vivo systems to understand the mechanisms of action when these different herbal infusions are used as beverages.