Optimization of extraction process of clove total polyphenols by ultrasonic assisted extraction with constant temperature ( UAECT) and its inhibition of fluorescence on low density lipoprotein ( LDL) in the process of oxidation modification

Oxidation of low density lipoprotein has been a major cause of atherosclerosis.In order to explore the extracting effect on total polyphenols from clove based on ultrasonic assisted extraction with constant temperature ( UAECT) , and its inhibition effect on fluorescence during the process of oxidation of ( low density lipoprotein) LDL, the extrcation technology of total polyphenols from cloves were firstly optimized, then the inhibition effect on fluorescence during oxidation of LDL was analysized.The results showed that the optimal parameters of the extracting technology were as follows: ultrasound power was270 W, ultrasound frequency was 80 k Hz, ultrasound time was 30 min, ultrasound temperature was 50 ℃, solid-liquid ratio was1∶ 30, and ethanol concentration was 60%. Under this optimal extracting technology, the total polyphenol content was ( 0.301 ±0.0043) g/g.The total polyphenols from clove by the optimal extracting technology significantly inhibited fluorescence of Trp from quenching, inhibited the generation of fluorescent products and lipofuscin from generating, and inhibited the variation of three-dimensional fluorescence. And the inhibition effects were proportional to the concentrations, it showed positive does-effect relationship. This study laid the foundation for the subsequent research and development of functional foods of total polyphenols from clove for inhibiting oxidation of LDL.