Research On Total Flavonoids From Huangjin Tea: Extraction, Purification, Structural Identification And Antioxidant Effect

Huangjin tea is a kind of functional green tea which has antibacterial,anti-inflammatory and antiviral effects. And flavonoids is one of the importantingredients in it. In this paper, the extraction, purification and antioxidant activity of totalflavonoids in Huangjin tea were syudied, and their structureswere preliminarily identified. The results showed as follows:(1)The optimum technology-combination for ultrasonic assisted extraction of totalflavonoids in the Huangjin tea is obtained by single factor and orthogonal experiment:ultrasonic power by75W,95%ethanol concentration, solid to liquid ratio was1:3,extraction time was20minutes, at this condition, the yield of flavonoids was5.3493%.(2)For eight kinds of macroporous resin and polyamide resin screening, get theoptimum resin for polyamide resin. And further by static and dynamic adsorption test todetermine the optimum adsorption-analytical conditions were: eluent concentration was70%, the sample flow rate was1.5mL/min, the sample liquid concentration was1.5mg/mL. The purity of the flavonoids increased from11%to37%after three times of purification.(3)The structure of the flavonoids was preliminary identified. A method withLC-ESI-QTOF-MS/MS for qualitative analysis, it is concluded that Huangjin teaflavonoids may contain the following materials: chlorogenic acid, p-coumaroyl quinicacid, caffeic acid, rutin, hyperin, vicenin-2, ferulic acid, eriodictyol-O-hexoside,luteoloside. Also, some of the flavonoids content were analyzed, it found thatchlorogenic acid content was0.90%, Caffeic acid content was1.87%, rutin content was0.81%, hyperin content was4.79%, eriodictyol-O-hexoside content was0.08%,luteoloside content was4.07%.(4) Antioxidant activities of total flavonoids were defected: DPPH radicalscavenging capacity, hydroxyl radical scavenging ability, O2-·scavenging effect, theABTS+radical scavenging activity, reducing capacity. The results indicated that theHuangjin tea flavonoids had good antioxidant capacity in vitro: under the sameconcentration, the DPPH radical scavenging activity of Huangjin tea was better than thescavenging activity of VC; the hydroxyl radical scavenging ability and theO2-·scavenging effect were good, and they had a does-effect relationship with theconcentration of the flavonoids; when the concentration was50-100μg/ml, the ABTS+radical scavenging activity of the Huangjin tea was better than the scavenging activity ofVC, and when the concentration was100-250μg/ml, their scavenging activity wereidentical; under the same concentration, the reducing capacity of the Huangjin Tea was aa little lower than the reducing capacity of VC.