Epigallocatechin gallate (EGCG) is a type of catechin, which is a class of polyphenolic compounds known as flavonoids. EGCG is one of the most abundant and biologically active catechins found in green tea, particularly in high-quality, unoxidized green tea leaves. It is considered a major bioactive compound in green tea and has gained attention for its potential health benefits and antioxidant properties.