Synthesis of a Range of Polyhydroxy 8-Aryl Flavones

Flavonoids from Podocarpus macrophyllus and their cardioprotective activities

One new 8-aryl flavone, podocarflavone A (1), together with 15 previously reported flavonoids were isolated from the twigs and leaves of Podocarpus macrophyllus. Their structures were established on the basis of extensive spectroscopic analysis and by the comparison with spectroscopic data reported in the literature. Antioxidant capacities of the isolated substances were determined using the 1,1-diphenyl-2-picrylhydrazyl, ferrous ions, and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical in vitro assays, and their cytoprotective activities were also tested on H2O2-induced apoptosis in H9c2 cardiomyocytes. The results showed that those flavonoids exhibited significant cardioprotective effects by decreasing the H2O2-induced death of H9c2 cell, and the levels of lactate dehydrogenase and creatine kinase, and by inhibiting the elevated intracellular concentration of reactive oxygen species.

Application of the Suzuki-Miyaura reaction in the synthesis of flavonoids

The application of the Suzuki-Miyaura reaction in the synthesis of flavonoids, an important class of natural products, is reviewed. This reaction has not only been employed to provide access to flavonoid nuclei, but has also been applied to the synthesis of dimeric flavonoids and in the synthesis of libraries of flavonoid derivatives for biological activity studies. The classes of flavonoids that are discussed are the chalcones, flavones, isoflavones, neoflavones, biflavones and derivatives of flavonoids obtained by C-C bond formation via the Suzuki-Miyaura reaction.