Kicel Agnieszka, Olszewska Monika Anna
Nat Prod Commun. 2015 Mar;10(3):483-6.
This study was designed to evaluate the flavonoid, saponin (TSC) and phenolic (TPC) contents and in vitro antioxidant activity of the crude (CME) and dry extracts and fractions of Medicago lupulina L. aerial parts. A validated RP-HPLC method led to quantitation of flavonols (kaempferol, quercetin and myricetin) and flavones (apigenin and luteolin) in the hydrolyzed extract. TSC and TPC were assayed spectrophotometrically at 560 and 760 nm, respectively. The antioxidant activity of the CME and the dry fractions were followed in vitro by DPPH free radical and ferric reducing antioxidant power (FRAP) methods. The flavonoid content of CME was 1.27 mg/g dw. The prevailing flavonoids were luteolin and myricetin, at concentrations of 0.37 and 0.36 mg/g dw, respectively. TSC and TPC were detected in CME at the level of 90.4 mg ESE/g dw, and 12.9 mg GAE/g dw, respectively. In the DPPH and FRAP tests, the CME exhibited antioxidant capacity with TEAA and FRAP values of 45.4 μmol Trolox®/g dw and 0.2 mmol Fe2+/g dw, respectively. The diethyl ether dry fraction was the most valuable one, showing the highest antioxidant activity (TEAA = 726.1 μmol Trolox®/g dw, FRAP = 2349.4 μmol Fe2+/g dw) that was in accordance with its high TPC (162.4 mg/g dw).
本研究旨在评估天蓝苜蓿地上部分的粗提物（CME）、干提取物及其馏分中的黄酮类、皂苷（TSC）和酚类（TPC）含量以及体外抗氧化活性。一种经过验证的反相高效液相色谱法可对水解提取物中的黄酮醇（山奈酚、槲皮素和杨梅素）和黄酮（芹菜素和木犀草素）进行定量分析。TSC和TPC分别在560和760 nm处通过分光光度法进行测定。通过DPPH自由基法和铁还原抗氧化能力（FRAP）法对CME和干馏分的体外抗氧化活性进行跟踪检测。CME的黄酮类含量为1.27 mg/g干重。主要的黄酮类化合物是木犀草素和杨梅素，浓度分别为0.37和0.36 mg/g干重。在CME中检测到的TSC和TPC水平分别为90.4 mg ESE/g干重和12.9 mg GAE/g干重。在DPPH和FRAP测试中，CME表现出抗氧化能力，TEAA和FRAP值分别为45.4 μmol Trolox®/g干重和0.2 mmol Fe2+/g干重。二乙醚干馏分是最有价值的一个，表现出最高的抗氧化活性（TEAA = 726.1 μmol Trolox®/g干重，FRAP = 2349.4 μmol Fe2+/g干重），这与其高TPC（162.4 mg/g干重）一致。
