Studies On Extraction, Separation And Anti-oxidantion Of Polyphenols From Wild Osmanthus-scented Honey

The research used natural wild osmanthus-scented honey as experiment materials.The experiment is designed to apply response surface analysis method to study the best extracting method of phenolic compounds in wild osmanthus-scented honey.Then, we uesd macroporous resin and polyamide resin to purify polyphenols in crude extractings of wild osmanthus-scented honey, and we used HPLC to study 14 kinds single phenol content in various stages of extraction and separation in wild osmanthus-scented honey by qualitative and quantitative analysis. Based on it, we had a research on the antioxidant ability of honey polyphenols in various stages of extraction and separation, and the specific research contents and results are as follows:First, The experiment is designed to use single factor experiment and response surface method to study ultrasonic assisted extraction for polyphenols in wild osmanthus-scented honey, the results showed that the optimum conditions were hydrochloric acid and ethyl acetate composite solvent, concentration of 62%, solid-liquid ratio of 1:10, ultrasonic time of 21 min, and ultrasonic temperature of 54℃, under these conditions, the average yield of polyphenols wild osmanthus-scented honey was 68.27 mg/10g. Then using traditional organic solvent extraction to carry on the comparative study, the results demonstrated that yield of ultrasonic assisted extraction for polyphenols in wild osmanthus-scented honey is higher, indicating ultrasonic assisted extraction is more suitable for polyphenols extraction in wild osmanthus-scented honey.Second, four different macroporous resin is compared to purify polyphenols in wild osmanthus-scented honey. The experiment results show that XAD-2 resin has the best effect to purify polyphenols in wild osmanthus-scented honey;Adorbtion amount and desorption ratio were 36.9±1.26 mg/g,78.2±1.17% by the use of XAD-2 resin, and the time to acheive balance between the adsorption and desorption is relatively short, XAD-2 resin is relatively suitable for the purification of polyphenols in wild osmanthus-scented honey. The best conditions of applying XAD-2 resin to purify was that the concentration of sample was 2.5 mg/mL, the optimum pH was 6, flow rate of sample was 2 BV/h, The elution agent was 80% ethanol solution, elution flow rate was 2 BV/h,and the amount of eluent was 4 BV. Under this condition, the purity of polyphenols in wild osmanthus-scented honey incresed from 9.52% to 52.8%.After primary polyphenols which was purified by XAD-2 macroporous resin separated and purified by polyamide resin, the polyphenols in the sample had been greatly enriched, and the purity was increased to 84.55%.Third, determine 13 kinds components of polyphenols in wild osmanthus-scented honey by HPLC analysis, including rutin (276.68±0.43 mg/g) as the main component, which was the highest level, cinnamic acid (141.16±1.29 mg/g), which took second place. Celery element (2.47±0.03 mg/g) content was relatively low. The experimental results showed that the extraction process of ethyl acetate, purification process of XAD-2 resin and polyamide resin did not affect the composition of polyphenols in wild osmanthus-scented honey.Four, compare total phenolic contents and antioxidant activity in four sample groups as extracted and separated component. The result proved that different groups had different total phenol content, reduction ability, and antioxidant capacity, and the total phenol content was positively related with reduction ability. Polyphenols in wild osmanthus-scented honey had certain ability to remove DPPH free radicals, superoxide anion and hydroxyl radicals. The results showed that polyphenols in wild osmanthus-scented honey has the very good antioxidant activity in vitro.