Effects Of Pressurized Hot Water Extraction On The Active Ingredients, Antioxid Ative Ability Of Dioscorea Nipponica Makino

Dioscorea nipponica Makino is Dioscoreaceae Dioscorea L species, it’s main active ingredients dioscin and diosgenin are the raw material for synthetic steroid hormone drugs. Modern research shows that Dioscorea nipponica Makino can regulate immunity, improve cardiovascular function, antitussive and antiasthmatic, treat rheumatoid arthritis. In this study, Dioscorea nipponica Makino was extracted by pressurized hot water extraction technology, and the influence of temperature, time and pH on the active ingredient and antioxidant activity were also researched.The main contents and experimental results are as follows:1. The pressurized hot water extraction technology was used to extract the saponin constituents from Dioscorea nipponica Makino with temperature and time changed. A series of antioxidation tests(DPPH ? scavenging capacity, ? OH scavenging capacity, Fe2+ reducing power) were carried out to explore the contacts between the varies of chemical components and antioxidant activity. The results showed that, ① The antioxidant activity of the extracts(1.0 mg / mL) obtained by pressurized hot water extraction techniques could up to 95.0%; ② With the extraction temperature and time changed, the antioxidant activity, chemical constituents and content also changed significantly, the changes of the total saponin content with the changes of DPPH· scavenging ability and ·OH scavenging capacity seems into a corresponding relationship; ③ Using Design Expert software, with total rate of dioscin as response, the extraction temperature and extraction time of pressurized hot water extraction were optimized, when the extraction temperature was 111℃, extraction time was 36 min, the yield of total saponins of Dioscorea reached 3.56%.2. Based on the Pressurized Hot Water Extraction technology, we used phosphate buffer solution to change the pH of extraction solvents to extract the effective components from Dioscorea nipponica Makino. The extracts obtained under different pH extraction condition, the Dioscorea total saponin and the extract’s antioxidant activity tests(DPPH ? scavenging capacity, ? OH scavenging capacity, Fe2+ reducing power) were all carried out. The results showed that, when the pH of pressurized solvent changed, it would affect active chemical components and antioxidant activity. When the pressurized solvent system was p H 4, the content of total saponins of Dioscorea nipponica Makino reached the maximum value, and the overall antioxidant capacity was the highest; while, the solvent pH in the range of 5 to 8, the level of comprehensive antioxidant of extracts from Dioscorea nipponica Makino copared to the acid extraction conditions(pH1~4) was low, and no significant diosgenin generation. Compared to the strongly acidic conditions in traditional methods, pH 4 phosphate buffer system could be more moderate, the waste treatment and recovery could be more easier,and the extraction also could be more environmentally, friendly and efficient.In summary, pressurized hot water extraction technology for it’s time saving, high efficiency, low energy consumption, has become a necessary technology for the development and utilization of Chinese medicinal herbs, the environmental friendly extraction process has opened up a new way for the modernization of traditional Chinese medicine.