Research Article Identification of nonvolatile phenolic acids and flavonoids with antioxidant activity in Micromeria barbata extract by RF-HPLC

An effective RF-HPLC method was performed for the determination and purification of nonvolatile mixture of phenolic acid and flavonoids contents in Micromeria barbata ethanolic extract. The HPLC was done on Ascentis RF-Amide at 25°C using a mixture of diluted orthophosphoric aqueous acid (0.085%) (A)- acetonitrile (B). A gradient elution was conducted starting at 85% and ending with 15% of A after 60 minutes. Identification of phenolic acids and flavonoids was done by comparing their retention times to those of stock standard compounds. Aluminum chloride and FolinCiocalteau spectrophotometry analysis was used for quantification. It was found that the ethanolic extract inhibits the DPPH radical with an IC50 (26.74μg/ml) which was significantly less than that of BHT (91.40 μg/ml).