Anthocyanin

Anthocyanins (from Greek, anthos meaning flower and kyanos means blue) is an important pigment in plants that determines the color orange, dark red, pink, violet and blue on the plant. This pigment is phenolic compounds that can dissolve in water and are included in the group of flavonoids. Generally anthocyanin abundant in epidermal tissue, but also present in palisade and spongy mesophyll tissues of leaves, pods, and roots (Oren-Shamir 2009). The basic structure of anthocyanin is anthocyanidins. Anthocyanidins or aglycone consists of aromatic rings (A) that binds to the heterocyclic ring (C) that contains oxygen and bound by carbon-carbon bonds in the third aromatic ring (B). When anthocyanidins found in the form of glycosides, it is called anthocyanin. Anthocyanin is very unstable and susceptible to damage. Stability is affected by several factors such as pH, temperature, chemical structure, light, solvents, enzymes, flavonoids, protein and metal ions (Castañeda-Ovando et al. 2009). Figure 3: Structure of anthocyanin (Castañeda-Ovando et al. 2009) Anthocyanins are synthesized in the shikimic biosynthetic pathway and use phenylalanine as a precursor (Fig. 4). Enzymes that work is PAL (phenylalanineammonialyase), CHS (Chalcone synthase), CHI (Chalcone isomerase), F3H (flavonone 3-hydroxylase), F3'H (flavonoid 30-hydroxylase), DFR (dihydroflavonol reductase), LDOX (anthocyanidin synthase), GST (glutathione-S-transferase) (Guo et al.2001) Anthocyanins in plants serves as a veil to ultraviolet B light and protect chloroplasts against high light intensity. Anthocyanins may also act as a means of transport for the monosaccharides and as an osmotic regulator during periods of drought and low temperature. In general, anthocyanin antioxidants are believed to increase the response of plants to survival in biotic or abiotic stress. In addition, anthocyanins also plays an important role in the reproduction of plants that attract pollinators that can help in the pollination of flowers (Mori et al. 2007). Anthocyanins are considered as an important component in human nutrition as a higher antioxidant than vitamins C and E. These compounds can capture free radicals by donating a hydrogen atom phenolic. Anthocyanins can be transported in the human body and show the antitumor activity, anticancer, antiviral, anti-inflammatory, inhibiting platelet aggregation, lowering blood capillary wall permeability and boost immunity (Stintzing and Carle 2004).