Studies On The Extraction, Separation, Identification And Biological Activity Of Polyphenol From Lotus Root

In this paper lotus root Nelumbo nucifera cv. 'Daomao jie' was used to investigated the composition, quantity of the polyphenol and biological activity, including the determination, extraction, separation, purification, identification, antimicrobial action and antioxidant action.The optimum conditions of the determination of the total phenol in the joint of lotus root were investigated. The results showed that the reaction conditions were volume fraction 1:1 (in volume ratio), volume 3 ml, temperature 25℃, operation time 30 min, there was linear over the range of 2-10 μ g/ml, the rate of recovery of the total phenol content ranged from 89.5% to 96.5%, the variation coefficient was 2.14%. It was a kind of correct and accurate method to determinate the total phenol content in the joint of lotus root.From the experiments of solvent extraction comparison and single factor extraction tests, the optimum extraction conditions for extraction of polyphenol from lotus root were obtained. Furthermore, by the orthogonal tests the optimum extracting conditions were confirmed as follows, pH 3, extracting times 3, liquid material ratio 1:9, 40% ethanol. Under this condition the extracting rate was 0.77%.Polyphenol and catechin were separated from lotus root by using acetic ester as solvent, the optimum conditions were obtained by the response surface analysis(RSA) tests. In this test based on three experimental factors, pH(X1), phase ratio(X2), countercurrent extraction times(X3), the dynamic models give a quantitative base for the extraction of polyphenol and catechin.The thin-layer chromatographic(TLC) method of lotus root polyphenol fraction I was developed by the use of toluene-ethyl acetate-acetic acid (5:3:2, in volume ratio) as a mobile phase. Catechin was developed by ascending technique on the silica gel G plate with thickness of 0.25mm,visualized by FeCl3-K3Fe(CN)6 with blue spots. The results showed that there was catechin in lotus root polyphenol fraction I.High performance liquid chromatography (HPLC) was introduced to analysis lotus root polyphenol fraction I ,the mobile phase was optimized, under this mobile phase the retain time of catechin was 14.715 min. The optimum conditions were as follow: SuplcosILTMC-18 15cm×4.6mm, Sum, methanol-water-acetic acid (10:90:1 in volume ratio) as mobile phase, UV detector 280 nm, flow rate 0.8 ml/min, column temperature 30 ℃, injection volume 10 μl, sensitivity 0.02.In this part ultraviolet spectrometry (UV), infrared spectrometry (IR) and high performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-EI-MS) were introduced to furthermore confirm catechin, the results showed that there was catechin hi fraction I of lotus root polyphenol.The biological activities of different lotus root polyphenol fractions were analyzed. The results showed that lotus root polyphenol traction I and fraction II both had effective antimicrobial action on Seaphlococcus aureus, but had little action on the other bacteria and fungi. Lotus root polyphenol fraction I and fraction II both had the scavenge of *OH and total antioxidant activity, and had antilipooxidant action but higer than tea polyphenol and lower than TBHQ at the same concentration under same purity.