Natural Antioxidants of the Underutilized and Neglected Plant Species of Asia and South America

Background: Plants have played an essential role in the search for new compounds for the most diverse therapeutic purposes. Recently, more attention has been paid to natural antioxidants because of the possible insecurity of synthetic antioxidants Objective: The review is aimed at summarizing the most important and common natural antioxidants and their resources from medicinal plants. Methods: The research was performed using databases of PubMed, Google Scholar, Science Direct, Taylor and Francis, etc., to search for all collected scientific publications. Results: The most important medicinal plants with antioxidant activities in Iran are Artemisia, berberry fruit, borage, calendula, coriander, cumin, green tea, hawthorn, jujube, pomegranate, rose, rosemary, black zira, tea, and thyme. Important traditional medicinal plants with antioxidant activities in China are Asparagus, bindii, blueberries, camellia, Chinese bayberry, Chinese bitter melon, Chinese cabbage, Chinese cherry, Chinese jujube, Chinese olive, pomegranate, Chinese rose tea, Chinese toon, Chinese watermelon, black tea, knotweed, Chinese quince, Chinese rhubarb, sumac, wolfberry, dendrobium, drumstick tree, Fiscus species, ginger, ginkgo, goji berry, grape, Jerusalem thorn, kiwifruit seed oil, and liquorice root. Anacardium occidentale L., Ananas comosus (L.) Merril, Baccharis trimera (Less) DC., Carapa guianensis Aubl., Casearia sylvestris Sw., Cordia verbenacea DC., Croton lechleri Müll. Arg., and Eugenia uniflora L. are the main medicinal plants with antioxidant activities in Brazil. Conclusion: Antioxidants are those molecules that are involved in the scavenging of these reactive species causing oxidative stress and are defined as those substances which could prevent the oxidation of the substrate at low concentrations. The main derived exogenous natural antioxidants are derived from medicinal plants, fruits, foods, flowers, and traditional herbal medicines in different parts of the world.