Demonstrating the relationship between the phytochemical profile of different teas with relative antioxidant and anti-inflammatory capacities

Abstract

Background: Indigenous or traditional aqueous plant extracts are commonly used by nearly 80% of the world’s population for primary health needs. Accordingly, teas such as Camellia sinensis and herbal teas were characterized for their phytochemical content and potential to offer specific bioactivities that could benefit human health by mitigating oxidative stress and inflammation. Methods: In the present study, we compared the phytochemical profiles, antioxidant, and anti-inflammatory activities of four Camellia sinensis teas, including white, green, oolong, black, and two herbal teas. These two herbal teas, Rooibos and Yerba mate, are produced and consumed by different populations worldwide. We also studied the impact of the Rooibos tea on the production of inflammatory mediators, including nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and different cytokines in Raw 264.7 cells, both with or without interferon γ (IFN-γ) and lipopolysaccharide (LPS) stimulation. Results: White tea had the highest total phenolic content (TPC) and antioxidant activity among the six teas that were examined. In contrast, Rooibos tea had the lowest TPC, antioxidant, and anti-inflammatory activities. Yerba mate tea exhibited the greatest potential to inhibit NO production in IFN-γ and LPS-induced Raw 264.7 cells. The anti-inflammatory activity of teas was discovered to be correlated with antioxidant activity and phytochemical composition. Among the six teas examined, only Rooibos tea was found to induce NO in unstimulated Raw 264.7 cells. Under basal conditions, Rooibos tea induced interleukin-1α (IL-1α), IL-1β, IL-6, IL-10, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-α), iNOS, and COX-2 production. However, Rooibos tea also demonstrated a dose-dependent inhibition of IL-6, IL-10, iNOS, and COX-2 expression in stimulated Raw 264.7 cells. Although a high concentration of Rooibos tea was effective in inhibiting induced IL-1α, G-CSF, and GM-CSF, lower concentrations also up-regulated the expression of these cytokines. No inhibitory effects of Rooibos tea examined were discovered with the mitigation of IL-1β and TNF-α. Conclusion: Rooibos tea possesses dual functions on inflammation, either by promoting an inflammatory response to cytokine induction or alternatively inhibiting inflammation during tissue injury or a pathogen infection via a mechanism involving the inhibition of pro-inflammatory cytokines and mediators such as iNOS and COX-2. The potential of Rooibos tea to induce NO production is also noteworthy in mitigating disease states including hypertension and cardiovascular diseases.