Amino acid
Amino acids are organic compounds containing amine (-NH) and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid. The key elements of an amino acid are carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), although other elements are found in the side chains of certain amino acids. About 500 naturally occurring amino acids are known (though only 20 appear in the genetic code) and can be classified in many ways. They can be classified according to the core structural functional groups' locations as alpha- (α-), beta- (β-), gamma- (γ-) or delta- (δ-) amino acids; other categories relate to polarity, pH level, and side chain group type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid residues form the second-largest component (water is the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis.
Antioxidant effect of polyphenols and natural phenols
The main source of polyphenols is dietary, since they are found in a wide array of phytochemical-bearing foods. For example, honey; most legumes; fruits such as apples, blackberries, blueberries, cantaloupe, pomegranate, cherries, cranberries, grapes, pears, plums, raspberries, aronia berries, and strawberries; and vegetables such as broccoli, cabbage, celery, onion and parsley are rich in polyphenols. Red wine, chocolate, black tea, white tea, green tea, olive oil and many grains are sources. Ingestion of polyphenols occurs by consuming a wide array of plant foods.