393
19.3 Distributions of Polyphenols
Polyphenols are widely distributed in nature. The main dietary sources of polyphenols are from vegetables, fruits and beverages. Flavones and flavonols are polyphenols ubiquitous in plants and thus the most common within the flavonoid group of
polyphenols (Bravo 1998). Catechins and epicatechin are monomeric flavan-3-ols
and gallocatechin, Catechin derivative are majorly found in tea leaves and cocoa
beans. They are the most abundant flavonoids in diet, which also include their oxidized products. They are common in dry legumes, cereals, wine, fruit juice, coffee,
tea and chocolate.
Condense tannins are found as constituents of woody plants. Anthocyanidins are
components of purple, blue and red pigments, which are distributed in some fruits,
flower petals and vegetables. These anthocyanidins may also be present in plants as
anthocyanins when glycosylated (Bravo 1998). Anthocyanins are water-soluble and
are important pigments in plants where they impact colour ranging from vivid red
to blue color (Khoo et al. 2017). Table 19.1 shows specific plant sources of polyphenol and the various classes of polyphenol found in them.
Fig. 19.2 Classifications of major polyphenols
19 Polyphenols: Classifications, Biosynthesis and Bioactivities
19.3 Distributions of Polyphenols
Polyphenols are widely distributed in nature. The main dietary sources of polyphenols are from vegetables, fruits and beverages. Flavones and flavonols are polyphenols ubiquitous in plants and thus the most common within the flavonoid group of
polyphenols (Bravo 1998). Catechins and epicatechin are monomeric flavan-3-ols
and gallocatechin, Catechin derivative are majorly found in tea leaves and cocoa
beans. They are the most abundant flavonoids in diet, which also include their oxidized products. They are common in dry legumes, cereals, wine, fruit juice, coffee,
tea and chocolate.
Condense tannins are found as constituents of woody plants. Anthocyanidins are
components of purple, blue and red pigments, which are distributed in some fruits,
flower petals and vegetables. These anthocyanidins may also be present in plants as
anthocyanins when glycosylated (Bravo 1998). Anthocyanins are water-soluble and
are important pigments in plants where they impact colour ranging from vivid red
to blue color (Khoo et al. 2017). Table 19.1 shows specific plant sources of polyphenol and the various classes of polyphenol found in them.
Fig. 19.2 Classifications of major polyphenols
19 Polyphenols: Classifications, Biosynthesis and Bioactivities