Preparation And Antioxidant Capacities Of Total Polyphenol From Cudrania Tricuspidata

The stem and root of Cudrania tricuspidata(Carr.)Bur. have been applied as traditional Chinese medicine for its pharmacological functions such as antitumor, antiinflamination, antioxidant, analgesic effect etc. Flavonoids and other polyphenols are the main active ingredients within this herb. In this thesis, preparation process and antioxidant capacities of total polyphenol from Cudrania tricuspidata(CTE) were explored. These investigations may provide important clues for research and further application of CTE as potential phytomedicine.A preparation method of CTE was developed at first using macroporous resin chromatography. Separation characteristics of four types of macroporous resins, D101, AB-8, LX-38 and LX-60 were screened. Dynamic absorption/desorption experiments revealed that AB-8 possessed better separation properties. The optimal process parameters were developed as follows: The stem and root of Cudrania tricuspidata was extracted twice with 75% ethanol solution(8 fold volume) under reflux for 1.5h, condensed to final concentration of 0.5 g/ml as counted by material amount, uploaded to a AB-8 column(bed volume, BV) and eluted with water followed by 50%, 70% ethanol(each 5 BV), successively, 50% and 75% ethanol elutes were collected, condensed and dried to give final CTF1 and CTF2 extract, respectively. One main ingredient, oxyresveratrol was separated and identified from CTF1, using LX2000 resin and C-18 reverse phase silica columns. The content of oxyresveratrol in CTF1 and CTF2 was determined to be 212.5 and 198.7mg/g, respectively by HPLC analysis. The content of total flavonoid in CTF1 and CTF2 was determined to be 56.5% and 46.3% respectively by UV method, using rutin as reference substance.Antioxidant capacities of CTE were further assessed by 2,2-diphenyl-1-picrylhydrazyl radical(DPPH●) and 2,2′-azinobis-(3-ethylbenzothiazoline- 6-sulphonate) radical cation(ABTS●+) scavenging assays, together with oxyresveratrol and rutin. They all possessed notable concentration-dependent antioxidant activities. By comparisons of their half inhibition concentration(IC50, mg/ml) data, the order of the antioxidant activity against DPPH● was as follow: rutin(9.7)﹥oxyresveratrol(11.2) ﹥CTF1(19.1)﹥CTF2(25.3); the order of the antioxidant activity against ABTS●+ was oxyresveratrol(29.7) ﹥CTF1(49.3)﹥CTF2(60.1) ﹥ rutin(181.6). Both CTF1 and CTF2(which add up to be CTE) showed strong antioxidant capacities as that of rutin, with oxyresveratrol and other flavonoids as the major bioactive ingredients.