A Systematic Review: Polyphenol Contents in Stressed-Olive Trees and Its Fruit Oil

Olive oil includes high amounts of phenols and polyphenols. Through health benefits to humans, the antioxidant role of polyphenols that contain more than two phenolic hydroxyl groups has been well proven. Of those polyphenols, oleuropein, hydroxytyrosol, catechin, chlorogenic acids, hesperidin, nobiletin, and isoflavones are major compounds. Along with the present study, (1) the uses and biological roles of polyphenols have not been limited to their physiological roles to human health; their physiological roles for plant and aromatic values for plant are also evaluated; (2) possible roles of major components in response to environmental stressors are discussed; (3) bibliometric analysis of studies concerned with polyphenols in olive fruit oil has been done to evaluate the research trends concerned with polyphenol in olive fruit oil, considering the main theme of the studies. The study is concluded with highlights, limitation, and future outlooks