Abstract
Drug discovery based on medicinal plants remains an important source of bioactive compounds, many of which have been the basis for new chemical structures for the pharmaceutical and food industries. According to the World Health Organization, about 80% of the worldwide population still depends on plant drugs, and several medicines have been obtained from medicinal plants. Unfortunately, the potential benefits of these plants have led to unscientific exploration of natural resources, a fact that is being globally observed. The aim of this study was to evaluate eleven aromatic medicinal plants and compare them to Azorean Camellia sinensis green tea in terms of antioxidant activity, total phenolics, and flavonoid content, and also to evaluate the possibility of their valorization as a nutraceutical material. The results revealed that Camellia sinensis presented higher values for free radical scavenging activity (FRSA, EC50 = 3.43 µg/mL), ferric reducing antioxidant power (FRAP, EC50 = 5.12 µg/mL), and total phenolic content (TPC, 294.43 mg acid gallic equivalents per g of dry extract (DE)). However, the aromatic medicinal plants also presented significant results in terms of FRSA and FRAP, particularly Aloysia citrodora, Mentha pulegium, and Stevia rebaudiana. For ferric ion chelating (FIC), the highest value was found in Cymbopogon citratus (80.60%). Mentha pulegium and Aloysia citrodora had significant values for TPC (199.15 and 187.15 mg GAE/g DE, respectively), but were lower than the values of Camellia sinensis. For flavonoid content (TFC), the highest value was shown in Achyrocline satureioides (265.75 mg rutin equivalents per g DE). This study revealed the importance of some aromatic medicinal plants in terms of bioactivities, and that their combination with green tea is a perfect blend for added value with beneficial nutraceutical effects for human health.