Quantification of Phenolic Compounds by HPLC-DAD and In vitro Antioxidant Activity of Root Extract of Echinops kebericho Mesfin (Asteraceae)

Abstract

Echinops kebericho Mesfin is wild endemic medicinal herb to Ethiopia and the root is used traditionally for the treatment infectious and non-infectious diseases. This study was designed to identify and quantify the phenolic compounds and in vitro antioxidant activity of the root extracts. Seven phenolic acids, six flavanols, and two aliphatic organic acids were analyzed by high performance liquid chromatography-diode array detector (HPLC-DAD), among which hydroxycinnamic acid (413.14 ± 6.60 µg/g), quercetin-3-O-galactoside (7.07 ± 0.34 µg/g) and succinnic acid (702.95 ± 42.54 µg/g) were the major components. The methanol extract exhibited the highest total phenolics (29.14 ± 0.38 milligram gallic acid equivalent gram of dried extract), total flavonoid content (1.08 ± 0.03 milligram of quercitin equivalent/gram of dried extract), and antioxidant activities followed by ethanol and water extracts. Antioxidant capacity were 99.96 ± 7.53µg/mL and 246.88 ± 15.60µg/mL as determined by the DPPH (IC50), ferric reducing power (IC50) assays, respectively. Total phenolic content (TPC) and total flavonoid content (TFC) were strongly correlated with DPPH (R 2 = 0.93, R 2 = 0.91) and ferric reducing power (R 2 = 0.98, R 2 = 0.71), respectively. The study revealed that crude root extract of E. kebericho can be used as natural antioxidants as well as for preventing oxidative stress mediated human disorders.