Determination of antioxidant activity and phenolic compounds of Muntingia calabura Linn, peel by HPLC-DAD and UPLC-ESI-MS/MS

摘要

Antioxidant activity in Muntingia calabura Linn, peel was evaluated by DPPH radical, ORAC, ABTS cation radical, FRAP assays and total phenolic contents by different extraction conditions. In addition, a method for determination of phenolic compounds in calabura peel samples harvested in Brazil using methanol:water and magnetic stirring as the extraction method, HPLC-DAD and UPLC-ESI-MS/MS analysis were developed. Calabura peel showed antioxidant activity for all extraction conditions and assays evaluated, the most polar solvents being more effective. The developed HPLC-DAD method allowed the accurate determination of phenolic compounds, with recoveries in the range of 72-107% and precision values ≤4%, with exception for chlorogenic acid. Gallic acid was determined at the highest concentration levels, followed by myricetin, ferulic acid and vanillic acid. However, all the five proposed phenolic compounds were identified in calabura peel samples by UPLC-ESI-MS/MS. Thus, calabura peel, an uncommon edible fruit part, can be appointed as a rich source of phenolic compounds.