Polyphenol Components And Functional Evaluation Of Quercus Variabilis Acorn Nutlet

Quercus Variabilis acorn as wildlife resources is rich in yield.It contains a lot of polyphenols which has the unique biological activities.Research interest in this area has increased remarkably in the last decade.In order to make full use of the resources of acorns,this paper conducted a preliminary study about the extraction of polyphenol from the Quercus Variabilis acorns nutlet,and separation and purification by Sephadex LH-20,and the quantitative analysis by qualitative tests,spectrum analysis and HPLC-ESI-MS,as well as the anti-oxidative and anti-microbial activities.The main results were shown as follows:(1)The acorns were smashed and screened through mesh size of 80,with the conditions of ultrasonic-assisted extraction were as follows:ethanol concentration of 50%,liquid-solid ratio of 29:1(v/m),extraction time of 30 min,supersonic ware power of 200 W,the extraction rate of polyphenols was the highest,reaching 73.17±0.56 g/kg.(2)Separation of crude extracts by Sephadex LH-20 column chromatography yielded a total of five fractions(F1,F2,F3,F4,F5).Based on the results of characteristic color reactions and,we confirmed that the fractions were all polyphenols.The UV-vis spectrum analysis proved F1,F2,F3,F4,F5 fractions contained benzoyl structure and F4 fraction was in accordance with characteristic ultraviolet absorption of flavonoid constituent.The IR spectrum analysis proved that all fractions had structure of hydroxyl group,aromatic rings and C-O-C,and F1 contained phenolic hydroxyl group,F2,F3,F4 and F5 contained carbonyl group.Then we used HPLC-ESIMS to preliminary deduct that the fraction F1 contained quininic acid,caffeic acid derivatives,gibberellin A7,and two unknown compounds which molecular weights were 226,259,F3 and F5 contained sinapinic acid,F3 and F4 contained the unknow compounds which molecular weights were 224,741,respectively.(3)The sequence of DPPH free radical scavenging ability was F5>F4>Vc>F2>F3>Fall>F1.The sequence of hydroxyl radical scavenging ability was Vc>Fall>F5>F4>F1>F2>F3.The sequence of ABTS radical scavenging ability was F5>F2>Vc>F3>F4>F1>Fall.The sequence of total reducing power was F4>Vc>F2>F3>F5>Fall>F1.Using the inhibitory zone diameter as evaluation index,the antibacterial effect to four bacteria such as E.coli,Bacillus subtilis,staphylococcus aureus,salmonella of acorn nutlet polyphenols was measured,the results showed that acorn nutlet polyphenols had inhibitory effect on four bacterias.The antibacterial effect of F5 fraction was stronger than other fractions,the acorns nutlet polyphenols were enhanced after seperation.