Electrochemical, bioactive mechanism of interaction and analytical studies of anthocyanins and related compounds

Polyphenols are natural molecules containing one or more hydroxylated rings. They can be divided into different subclasses viz., phenylethanol derivatives, phenolic acids, flavones and flavonols, catechins, procyanidins and anthocyanins. Anthocyanins are glycosylated polyhydroxy and polymethoxy derivatives of flavylium salts, which are a group of naturally occurring phenolic compounds responsible for the brilliant red, orange and blue colors of most fruits and flowers. They have shown antioxidative, antimutagenic, antidiabetic, and anticarcinogenic acitivities in vitro. Electrochemical techniques viz., cyclic voltammetry, square wave voltammetry, differential pulse voltammetry and amperometry have been employed for the characterization of the antioxidative properties of anthocyanins from various sources and for their assay in fruit juices and plant extracts. The binding ability of anthocyanins to DNA and protein has attracted attention of researchers, recently as anthocyanins are proven to be bioactive. Such investigations are being studied by employing different analytical/spectroscopic techniques. The present review also reports the assay of anthocyanins in various natural sources by analytical methods viz., spectrophotometry, voltammetry, HPLC, LC-MS, MS/MS, MALDI-TOF-MS and others.