Gentian Root Extraction And Purification Of Effective Components And Antioxidant Research

In this paper, we studied the optimum extraction process conditions of flavonoids from yellow gentian root by using microwave-assisted ethanol solvent method. And the extracted flavonoids was purified by using macroporous resin. Moreover, we analysized the concentration of gentiopicrin and flavonoids compounds quantitatively. The antioxidant activity of the products before and after purified was compared, too. The main results were showed as follows:1. Through the single factor and orthogonal experiment, the best process conditions for the extraction of flavonoid were as follows:microwave power was 300w, microwave time was 8 min, the ethanol concentration was 35%, the ratio of material to solvent was 1:20, extraction frequency was once. Under the optimal conditions, the yield of extraction of flavonoid was 4.85%.2. AB-8 resin was chosed to use as polymeric adsorbent in the static adsorption and desorption experiments. The best adsorption static conditions were as follows:pH value was 6, adsorption time was 9 h, the maximum adsorption amount was 30.13mg/g, desorption of ethanol concentration was 70%, volume of ethanol was 140 mL, desorption time was 30 min. sample Liquid flow velocity was 2.00mL/min, eluent velocity was 2.00 mL/min. The concentration of total flavonoids was 0.202mg/mL after purification. It was increased about 10 times.3. The antioxidant activity of the extracted products were studied by DPPH and FRAP methods. The results showed that the antioxidant activity of purified products were better than that of rude extracted products. However, the antioxidant activity of all products was inferior to the reference substance Vc.4. The optimal extracted process of gentiopicrin was studied using microwave-assisted and ultrasonic-assisted methods. By the single factor and orthogonal experiment, the optimal process conditions were obtained. The results of ultrasonic-assisted method were shown as follows:the ethanol concentration was 70%, the ratio of material to solvent was 1:30, ultrasonic time was 45 min, ultrasonic temperature was 35?.Under the optimal conditions, the yield of extraction was 5.08%. The results of microwave-assisted method were shown as follows:the ethanol concentration was 70%, the microwave power was 400 W, microwave time was 9 min, the ratio of material to solvent was 1:30, ultrasonic time was 45 min, ultrasonic temperature was 35?.Under the optimal conditions, the yield of extraction was 5.16%. The microwave-assisted method was better than ultrasonic-assisted method.5. Macroporous resin HPD-100 was chosed to use as adsorbent in the puridied of gentiopicrin experiments. The best adsorption static conditions were that pH value was 6 and adsorption time was 2 h using 70% ethanol as eluents. The desorption time was 4 h. The diameter height ratio was 1.5:28.3, sample concentration was 1.72mg/mL. The volume of washing water was 3 BV and volume of washing ethanol was 250mL. The concentration of gentiopicrin was increased to 4.7712mg/mL from0.3659mg/mLafter purification. It was increased about 13 times.6. The antioxidant activity of the extracted gentiopicrin products were studied by DPPH and FRAP methods. The results showed that the antioxidant activity of purified products were better than that of rude extracted products. However, the antioxidant activity of all products was inferior to the reference substance Vc and better than BHT.