Anthocyanin composition of wild Colombian fruits and antioxidant capacity measurement by electron paramagnetic resonance spectroscopy.

The qualitative and quantitative anthocyanin composition of four wild tropical fruits from Colombia was studied. Compounds of "mora pequena" (Rubus megalococcus Focke.), "uva de arbol" (Myrciaria aft cauliflora O. Berg), coral, and motilon (Hyeronima macrocarpa Mull. Arg.) fruits were separately extracted with methanol acetic acid (95:5, v/v). The anthocyanin-rich extracts (AREs) were obtained by selective adsorption on Amberlite XAD-7. Each extract was analyzed by HPLC-PDA and HPLC-HRESI-MSn with LCMS-IT-TOF equipment in order to characterize the anthocyanin pigments and the coinjection in HPLC using standards allowed identifying the major constituents in each extract. The antioxidant activity was measured by electron paramagnetic resonance (EPR) and UV-vis spectroscopy, using ABTS and DPPH free radicals. The ARE of motilon (H. macrocarpa Mull. Arg) exhibited the highest radical scavenging activity in comparison to the other extracts. A second-order kinetic model was followed in all of the cases. These results suggested that the studied fruits are promising not only as source of natural pigments but also as antioxidant materials for food industry.