Flavonoids are secondary polyphenolic metabolites occurring commonly in many fungi and plants. To the family of flavonoids belong several classes of compounds including anthoxanthins, in turn subdivided into two subgroups: flavones and flavonols; flavanones; flavanonols; flavans, in turn subdivided into three subgroups: flavan-3-ols, flavan-4-ols and flavan-3,4-diols; antocyanidins and isoflavonoids. The chemical structure of flavonoids is a 15-carbon skeleton which consist of two phenyl rings named A and B linked via a heterocyclic 4H-pyrane ring named C. Examples of known flavonoids are: Apigenin 1 and Quercetin 2 (antoxanthins: flavone and flavonol respectively); Naringenin 3 (flavanone); Taxifolin 4 (flavanonol); Catechin 5, Apiforol 6 and Leucocyanidin 7 (flavans: flavan-3-ol, flavan-4-ol and flavan-3,4-diol respectively); Malvidin 8 (anthocianidin) and Genistenin 9 (isoflavon). Flavonoids are also antiangiogenic agents through the regulation of the expression of VEGF, MMPs, EGFR and the inhibition of NFkB, PI3-K/AkT, ERK 1/2 signal pathways. This class of natural compounds is able to interfere in all the phases of cancer progression by modulating different enzymes and receptors involved in proliferation, differentiation, apoptosis, angiogenesis, metastasis and reverse multidrug resistance process.

References

1.Raffa D, et al. Eur J Med Chem. 2017;142:213–228.