Figure 5.

(a) General structure of the flavonoid framework with the four main types of flavonoids; (b) other flavonoid-related frameworks; (c) particular plant compounds and (d) marine compounds used in cosmeceutics (see Table 1). (a) The second line includes the four main types of flavonoids: flavonols, flavones, flavanones, and flavanols. (b) Flavonoid-related structure of the isoflavonoid framework (ring B is bound to position 3) and chalcone; (c) two important plant compounds, epigallocatechin-3-gallate (EGCG) found in green tea and resveratrol found in grape vine; (d) marine topsentin from a sponge and palythine from coral.