Antioxidant Properties and Structure-Antioxidant Activity Relationship of Allium Species Leaves

Allium is a genus that is widely consumed and used as traditional medicine in several countries. This genus has two major species, namely cultivated species and wild species. Cultivated species consist of A. cepa L., A. sativum L., A. fistulosum L. and A. schoenoprasum L. and wild species consist of A. ursinum L., A. flavum L., A. scorodoprasum L., A. vineale L. and A. atroviolaceum Boiss. Several studies report that the Allium species contain secondary metabolites such as polyphenols, flavonoids and tannins and have bioactivity such as antioxidants, antibacterial, antifungal, anti-inflammatory, pancreatic alpha-amylase, glucoamylase enzyme inhibitors and antiplatelets. This review summarizes some information regarding the types of Allium species (ethnobotany and ethnopharmacology), the content of compounds of Allium species leaves with various isolation methods, bioactivities, antioxidant properties and the structure-antioxidant activity relationship (SAR) of Allium compounds.