Extraction And Purification Of The Flavonoids From Blueberry And The Anti-aging Effects Of The Flavonoids From Purple Sweet Potato

This thesis optimized the extraction and purification technology of the total flavonoids from blueberry by orthogonal experiment, and then tested the antioxidant activity in vitro of the purification; also investigated the effects of purple sweet potato flavonoids on learning ability and memory in senescent mice which induced by D-galactose and study the protection on oxidative injury in the brains of aging mice.Blueberry also named cowberry, belonging to the vaccinium genus of ericaceae, is a kind of deciduous shrub plant. Blueberry contains a variety of active ingredients, such as anthocyanin, chlorogenic acid and flavonoids, while the flavonoids play a certain role in antioxidant, protect the human body from free radical damage, strengthen vascular elasticity, anti-aging, vision improvement and so on. For the further development and utilization of blueberry, in this paper, the extraction technology of the total flavonoids from blueberry was optimized by orthogonal experiment using lutin as standard compound with ethanol concentration, extraction time, amount of solvent and extraction times as factors and with extraction yield of total flavonoids as index. Four types of macroporous resin (AB-8、NKA-9、NKA-Ⅱ, D101) were used to purify flavonoids with static adsorption capacity and elution ratio as evaluation factors, to screen out the most suitable one. The optimum purification conditions were obtained by investigating the influence of concentration of sample, pH, concentration of eluant and flow rate of elution with L9(34) orthogonal experimental design and recovery as evaluation factor. Then the antioxidant activity of the flavonoids from blueberry was tested by scavenging DPPH·and·OH with VC and lutin as reference substance. The main research results are listed below:1. The best condition for extracting flavonoids from blueberry was that:extracting for45minutes at40℃and560W ultrasonic power with20times of50%ethanol, repeat3times, the extraction yield was4.01%.2. NKA-Ⅱwas the most suitable type of macroporous resin and the optimum conditions were as follows:the concentration of sample was1.355mg·mL-1, the washing pH value was3, the flow rate of70%ethanol was at2mL·min-1, in this condition the purity of total flavonoids can reach41.41%,33.94times than before.3. The antioxidant activity of flavonoids from blueberry for DPPH·and·OH scavenging were0.0217and0.1037mg·mL-1by IC50respectively. The activity of DPPH·scavenging is the same as lutin but weaker than VC while the activity of·OH scavenging is stronger than both. The study showed that the flavonoids from blueberry has strong antioxidant activity.Purple sweet potato, as a new kind of potato imported from Japan by our scientific and technological workers, riches in nutrition especially flavonoids, is a good health food. This paper investigated the effects of purple sweet potato flavonoids on learning ability and memory in senescent mice which induced by D-galactose and study the protection on oxidative injury in the brains of aging mice. ICR mice were randomly divided into6groups(n=10):normal control group(NC)、model group、vitamin C group(100mg·kg-1·d-1)and PSPF groups(50.100、200mg-kg-1·d-1), all the other groups were subcutaneously injected with1g-kg-1·d-1D-galactose for successive42days except NC group to establish the sub-acute senescent model. All groups were given corresponding drugs respectively by gastric irrigation1week later. Then the learning and memory ability of mice were measured by Morris water maze test, the amount of MDA in mouse brain tissue and the activities of SOD and GSH-PX were detected. The research results showed that:compared with the model group, PSPF(100、200mg-kg-1·d-1) can significantly improve aging sign, reduce latency to find the hidden platform and the time of first crossing the non-exits(P<0.05) and increase the number of crossing non-exits (P<0.05). PSPF could also effectively improve the activities of SOD and GSH-PX, reduce the amount of MDA (P<0.05, P<0.01) with dose-dependent tendency. It can be concluded that PSPF can significantly improve the learning and memory ability of senescent mice induced by D-galactose, has the function of delaying senility. The mechanism may be related to its enhancement of activity of antioxidases, scavenging free radicals and improving the antioxidant ability.