Quantification of major phenolic and flavonoid markers in forage crop Lolium multiflorum using HPLC-DAD

ABSTRACT

ABSTRACT The objective of this study was to perform preliminary screening of phytochemical compounds and quantification of major phenolics and flavonoid markers in Italian ryegrass extract using HPLC-DAD. Previously, LC-MS analysis has identified different phenolic acids, including caffeic acid, ferulic acid, p-coumaric acid, chlorogenic acid, dihydroxy benzoic acid, propyl gallate, catechin, and six flavonoids including rutin hydroxide, luteolin, kaemferol, vitexin, narcissoside, and myricetin from Italian ryegrass extract. In the present study, Italian ryegrass silage powder was extracted with ethanol water for 20 min at 90 °C. The extract targeted optimum yield of phenolic acids and flavonoids. Crude phenolic acid and flavonoids were then purified by solid phase extraction method. Purified fractions were then injected into HPLC with a diode-array detector. Quantified concentrations of isolated phenolic acids and flavonoids ranged from 125 to 220 µg/g dry weight. Limits of detection and limits of quantification for all standards (unknown compounds) ranged from 0.38 to 1.71 and 0.48 to 5.19 µg/g dry weight, respectively. Obtained values were compared with previous literatures, indicating that our HPLC-DAD quantification method showed more sensitivity. This method showed better speed, accuracy, and effectiveness compared to previous reports. Furthermore, this study could be very useful for developing phenolic acids and flavonoids from compositions in Italian ryegrass silage feed for pharmaceutical applications and ruminant animals in livestock industries.