Reações biomiméticas com metaloporfirinas de metabólitos secundários das folhas de Passiflora edulis var. flavicarpa Degener

Abstract

Orientin and isoorientin are C-glycosidic flavonoids and markers of the species Passiflora edulis var. flavicarpa Degener and other plant species, which are reported in the literature for their various pharmacological properties. To evaluate and characterize the in vitro metabolism of these flavonoids, phase I biotransformation reactions using Salen complexes were simulated. Thus, through the techniques of classical column chromatography and HPLC, orientin and isoorientin were isolated from the hydroethanolic extract of the leaves P. edulis. These flavonoids were subjected to reactions with m-CPBA and PhIO as oxidants and catalyzed by the Jacobsen catalyst (Mn (Salen)), an efficient and easily synthesized and purified catalyst, and with the synthesized catalyst [Mn (3MeOSalen) Cl], not reported yet in biomimetic studies, which was characterized by spectroscopic and electrochemical techniques, highlighting its oxidation potential, higher than the potential of the Jacobsen catalyst. By HPLC-DAD quantification, the reaction of isoorientin with mCPBA in the ratio 1:20:20 (catalyst: oxidant: flavonoid) showed higher consumption of the substrate for both catalysts when compared to others oxidants, while the reaction of the orientin with PhIO in the proportion 1:10:10 showed higher substrate consumption also for both catalysts. The best condition was optimized showing that the orientin and isoorientin isomers exhibits distinct reactivity. The reaction’s products were characterized by HPLC-MS and HPLC-MS/MS, 3 for orientin and 5 for isoorientin, where the [Mn (3MeOSalen) Cl] catalyst formed a larger number of compounds, and with the addition of two oxygen, whereas the Jacobsen’s catalyst formed compounds with the addition of only one oxygen atom. The products characterized were not found in the literature, however the formation of epoxides, which are compounds highly reactive, is highlighted. Thus, this study can serve as a basis for subsequent pharmacological and toxicological studies that confirm the presence of these compounds as phase I metabolites and ensure the safety of the use of plant products that have isoorientin and orientin as markers.