Chapter 15 - Citrus Polymethoxyflavones: Biofunctional Molecules of Therapeutic Interest

Abstract

Abstract Polymethoxyflavones (PMFs) are group of flavonoids exist almost exclusively in the genus citrus, especially in the peels. The natural occurrence, chemical structures, in addition to various medicinal effects reported for these compounds have attracted the attention of many researchers who consider PMFs as a molecular target. PMFs have shown many biological activities such as anticancer, antiinflammatory, antiallergic, antimutagenic, antiatherosclerosis, hypoglycemic, antioxidant, and neuroprotective effects. The chemical structure of the members of this group is similar yet different and plays an important role in their biological properties. Several techniques have been recently developed for extraction, isolation, and identification of PMFs. Multidimensional preparative liquid chromatographic system coupled with a photodiode array detector, and a single quadrupole mass spectrometer was developed for purification, nanoliquid chromatography system coupled with an electron ionization mass spectrometer was developed for characterization while high-performance liquid chromatography coupled with electrochemistry detection was developed for simultaneous determination of PMFs. A series of PMFs were synthesized through dehydrogenation, O-methylation, glycoside hydrolysis, dimethyldioxirane oxidation, and regioselective demethylation, starting from abundant and inexpensive natural sources. New synthetic route for PMFs was developed such as CuBr-catalyzed and microwave-assisted aromatic nucleophilic substitution of bromide by methoxy group. PMFs alone or in combination with other drugs represent promising candidates to develop new therapies or improve the existing ones. This chapter looks at the structures of PMFs in relation with its pharmacological properties, recent development in their extraction, isolation, identification, analytical, and synthetic methods.