Citrus fruits essential oils are rich in various compounds, including polymethoxylated flavones. Tangerine essential oil contains the largest amount of the polymethoxylated flavone tangeretin, while oranges contain almost equal amounts of nobiletin, tetra-0-methylscutellarein, heptamethoxyflavone, and tangeretin. Lemon and grapefruit are poorer in the amount of polymethoxylated flavones, although they contain more hydroxylated polyphenols. Therefore, their antioxidant activity is higher than that of orange and tangerine essential oils.