| Anthocyanin is a plant-specific secondary metabolity with a variety of biological activities that related to human health.For example,it has the effect of anti-oxidation,anti-inflammatory and improvement of atherosclerosis.Therefore,some vegetables which are rich in anthocyanin become a new pursuit on people’s dining-table.In order to satisfy the requirements,a number of new varieties of purple vegetables have been cultivated.In this study,six emerging vegetables,purple flower,purple potato,purple leaf lettuce,purple carrot,purple cowpea and purple tomato were selected to study its extraction process,purificationprocess,relevant nutrient content and biological activity in vivo and in vitro.(1)With purple potato as the representative,the anthocyanin was exacted by methods of crushing extraction combined with ultrasonic extraction and the optimum process of the crushing extraction and ultrasonic extraction were explored by orthogonal experiment.The L9(34)orthogonal experiment that was investigated the optimum process of crushing exaction was designed based on the four factor of ethanol pH,ethanol concentration,solid-liquid ratio(W:V)and the crushing time.The orthogonal experiment that was investigated the optimum process of ultrasonic exaction was designed based on the four factor of ethanol pH,ethanol concentration,solid-liquid ratio(W:V)and the ultrasound time.And the single-factor experiment was used to investigate the optimum purification condition of crude extract.The results showed the optimalprocess of crushing extraction was that ethanol concentration was 60%,pH of ethanol was 2,the,ratio of material to liquid was 1:5 and crushing time is 30 s.The optimalprocess of ultrasonicextraction was that ethanol concentration was 60%,pH of ethanol was 2,the,ratio of material to liquid was 1:6 and ultrasonic time was 40 min.The optimal conditions for the purification of anthocyanin by macroporous resin were as follows:the concentration of elution solvent(ethanol)was 60%,the pH of the eluent was 3,the flow rate of elution was 0.6 mL/min,and the temperature of vacuum concentration was 40℃.The anthocyanin of six vegetables were extracted and purified by the optimized process,and the purified anthocyanin was obtained by flash distillation to dry powder.(2)The content of total anthocyanins in the purified anthocyanin from six vegetables was determined by pH differential method,the content of cyanidin-3-O-glucoside was determined by high performance liquid chromatography.In addition,the contents of vitamin C,dietary fiber,total flavonoids and total phenolic acid in six vegetables were determined in the section.The results showed that the highest content of total anthocyanin was purified anthocyanin from purple cauliflower,which was 277.13±15.31 mg/g,and the content of anthocyanin was up to 1.037±0.042 mg/gin fresh vegetables.However,the content of cyanidin-3-O-glucosidein these six vegetables was generally lower.In addition,it was found that there were high content of total flavonoids and total phenolic acid in these vegetables,with the flavonoid content ranging from 0.18±0.031～0.73±0.034 mg RE/g,the total phenolic acid content ranging from 0.12±0.010～0.42±0.055 mg GAE/g.Their dietary fiber and vitamin C levels were found to be similar to those before the breed improvement,suggesting that the modification did not affect their nutritional value but also achieved the purpose of modification.(3)The stability of purifiedanthocyanin from six vegetables under different pH,light and temperature was researched in this section,and the antioxidant activities of the purifiedanthocyanin were measured by DPPH and FRAP methods.The results showed that the purified anthocyanin from several vegetables was most stable when the pH was 2,temperature was 4℃ and protected from light.It was found that the antioxidant activity was positively correlated with the content,and the antioxidant activity of purified anthocyanin from purple cauliflower was the strongest.The TEAC values measured by the two methods were 162.87±15.21 mg/g and 119.95±9.89 mg/g,respectively.Therefore,we chose the purified anthocyanin from purple cauliflower(PAPC)as the object to further in vivo activity.(4)The mice model of depressionbehavior was induced by chronic unpredictable chronic stress(CUMS),and then the mice were treatment by PAPC.After six weeks of treatment,the depression behavior of mice,content of monoamine neurotransmitters in brain tissue,the expression of monoamine oxidase and the related proteins that regulate the expression of brain derived neurotrophic factor(BDNF)were determination.The expression of hippocampal neurons was detected by fluorescence immunohistochemistry,and the dendritic spine and dendritic density of dentate neurons-in hippocampal were observed by Golgi staining.The results showed that PAPC treatment significantly improved depression-like behaviors in mice following CUMS,increased monoamine neurotransmitter(5-hydroxytryptophan,dopamine and norepinephrine)content and inhibited monoamine oxidases A and B in the brain.It also increased the expression of proteins[tyrosine receptor kinase B,extracellular-regulated kinase 1/2(ERK1/2),cAMP-responsive binding element(CREB)and BDNF]in related pathways which regulating BDNF expression.In addition,PAPC increased numbers of nestin-and doublecortin-positive cells in the hippocampus,as well as spine density and total dendritic length in the hippocampal dentate gyrus.We propose that PAPC played anti-depression effect by inhibiting MAO activity,thus increasing monoamine neurotransmitter content and regulating the ERK-CREB-BDNF signaling pathway to up-regulate the expression of BDNF,which alsopromotes neurogenesis and dendrite development in the hippocampus. |
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