Study On Extraction, Separation, Purification, Antioxidant And Antimicrobial Activity Of Mango Polyphenols

In order to make full use of mango, polyphenols was extracted from mango kernel seeds and the optimum extracting method and conditions were comfirmed through single factor and orthogonal test. Macroporous adhesive resin column and Sephadex LH20 column were employed to separate and fractionate the crude extract and the structures of the main compounds were analyzed by HPLC-ESI-MS. The antioxidant and antimicrobial activity of the crude extract and its fracions were also inverstigated. The main results were shown as follows:1. Methods of ethanol refluxing extraction, microwave-assisted extraction and supersonic wave-assisted extraction method were used to extract polyphenols from mango kernel seeds and the optimum extraction conditions were shown as follows:â‘ the optimum extracting condition for ethanol refluxing method was as follows: 60% ethanol as extracting solvent with a solid/solvent ratio of 1∶10 (w/v), extracting for 60 min at 60℃. Under this condition, the extracting yield was 7.16%.â‘¡the optimum extracting condition for microwave-assisted extraction method was as follows: 60% ethanol as extracting solvent with a solid/solvent ratio of 1∶15 (w/v) and microwave power of 385W, extracting for 2.5 min. Under this condition, the extracting yield was 6.85%.â‘¢for ultrasonic-assisted extraction method, the optimum condition was as follows: 60% ethanol as extracting solvent with a solid/solvent ratio of 1∶20, extracting for two times with 60 min per time. Under this condition, the extracting yield was 4.92%.Compared with ethanol refluxing extraction and ultrasonic extraction methods, microwave-assisted extraction has the advantages of faster extraction, lower energy consumption and high extraction yield.2. It was showed that the crude extract could be separated and purified by number 2 macroporous adhesive resin column and Sephadex LH20 column. The optimum adsorption and separation conditions for the crude extract on number 2 macroporous adhesive resin column were confirmed as follows: the feed concentration of 4mg/ml with flow rate of 2BV/h; The desorption solvent was 3BV of 60% ethanol with flow velocity of 2BV/h. HPLC-ESI-MS analysis showed that the main active constituent of mango polyphenols were gallotannins compounds such as tri-O-galloyl-glucose and tetra-O-galloyl-glucose.3.The antioxidant and antimicrobial activity of mango polyphenols were studied. The results showed that the mango polyphenols of fractionâ…¢had effective scavenging effect on the hydroxyl radical (·OH) and the superoxide anion radical (O₂·). The scavenging ratio of·OH was 91.49% in salicylic acid system and 88.79% in DR system when the concentration of the fragment was 0.5mg/ml. The scavenging ratio of O₂·was 89.66%. The inhibition ratio of lipid peroxidation was 61.50% when the concentration of the fraction was 1mg/ml. The fraction had effective antimicrobial activity on four kinds of bacteria tested with MIC of 2-3mg/ml. But it had no remarkable effective antimicrobial activity on yeast and aspergillus niger.