Abstract:
Based on centrifugal partition chromatography(CPC) and thin-layer chromatography(TLC), preparative high performance liquid chromatography(Pre-HPLC) and so on, the total polyphenol extract(TPF) of olive oil was extracted from extra virgin olive oil, and then TPF was used as raw material to separate and prepare 2-(4-hydroxyphenyl) ethyl(
E)-4-formyl-3-(2-oxoethyl)hex-4-enoate(oleocanthal, OLEO) and 2-(3, 4-dihydroxyphenyl)ethyl(
Z)-4-formyl-3-(2-oxoethyl)hex-4-enoate(oleacein, OLEA) monomer compounds. Their structures were characterized by
1H NMR and their antioxidant activities were also investigated. The results showed that 14 fractions were obtained during the process of CPC with the solvent system of
n-hexane/ethyl acetate/ethanol/water volume ratio of 3∶2∶3∶2 from 9 g extract in 20 mL of methanol. After purification, 422.3 mg OLEO and 163.0 mg OLEA with the purity of ≥95% were obtained, respectively; the antioxidant activities of OLEO and OLEA at different concentrations(0-1 g/L) were evaluated by their free radical scavenging capacity on ABTS
+·, DPPH· and total antioxidant capacity(T-AOC), it indicated that OLEA had stronger antioxidant activity than OLEO, and the 50% inhibition concentration(IC
50) values of OLEO and OLEA for DPPH· were 0.029 and 1.85×10
-11 g/L, respectively, the scavenging capacties of OLEO and OLEA against ABTS
+· were 0.765 5 and 0.894 2 mmol/L(calculated by the concentration of Trolox); and their total antioxidant capacities reached 0.157 1 and 0.646 2 mmol/L(calculated by the concentration of FeSO
4), respectively.