**5. Flavonoids**

Flavonoids are pigments synthesized by plants and there are many different subclasses, each comprising many different compounds, such as isoflavones (biochanin A, daidzin, daidzein, formononetin, glycitein, genistein); flavononols (astilbin, genistin, taxifolin, engeletin); anthocyanidins (cyanidin, malvidin, delphinidin, apigenin, peonidin, pelargonidin, petunidin); chalcones (okanin, butein); flavonols (isorhamnetin, quercetin, kaempferol, myricetin); flavanols (positive-catechin, negative-epicatechin, positive-gallocatechin, negative-epigallocatechin, negative-epicatechin gallate); flavones (apigenin, luteolin, chrysin, rutin); flavanones (eriodictyol, isosakuranetin, hesperidin, naringin, naringenin, taxifolin) [41].
