**2.1 Distribution of Flavonoid subclasses in the plant kingdom**

According to study, flavonoids may be found in angiosperms, gymnosperms, and pteridophytes. Due to the wealth of information available on flavonoids in many species, flavonoid subclasses (such as anthocyanins, chalcones, flavones, flavonols, and proanthocyanidins) are present in each subgroup of plants can be identified. Flavone and flavanone are present in all plant groups, with the exception of hornworts. Plant families that produce flavonoid subclasses have evolved and diversified as well. For instance, the angiosperms have the most varied flavonoid aglycones. The liverworts *Radula variabilis* and *Radula spp.* contain prenyldihydrochalcone, whereas more than 1000 prenylflavonoids have been found in legumes. These results indicate that either the two plant groups independently evolved the ability to make prenylflavonoids or that many species lost this capacity over evolution. Flavonoid molecules show that plants have genes for the manufacture of flavonoids. Therefore, analytical approaches for identifying flavonoids are necessary to comprehend the evolution of flavonoid metabolism in the plant kingdom [16] (**Figure 2**).
