| Potentilla fruticosa L.is a deciduous shrub belonging to the genus Potentilla in the Rosaceae family,mainly distributed in the north temperate zone.it possesses many activities such as hypoglycemic,lipid lowering,antioxidant,and flavonoids is one of the most important active components.At present,organic solvents are the most commonly used extraction and separation solvents in traditional extraction methods.Natural deep eutectic solvents(NADESs)are a new type of green,non-toxic and highly efficient extraction solvent with broad application prospects in the food and pharmaceutical industries.In this paper,different NADESs were prepared,and the ultrasonic extraction process of flavonoids from Potentilla fruticosa L.using NADESs was optimized through single-factor tests and response surface methodology.Meanwhile,in order to improve the medicinal efficacy of flavonoids in Potentilla fruticosa L.,porous silicon particles were prepared by dealloying method,and the loading capacity and sustained release performance of Potentilla fruticosa L.flavonoids on porous silicon were studied.The main research results of this study are as follows:(1)Eight NADESs were prepared using natural organic bases and organic acids as components.The physicochemical properties of the solvents were tested,and all eight solvents were clear,transparent,and viscous liquids.The viscosity of the 70%(v/v)aqueous solution of the NADESs ranged from 1.586 to 1.966 m Pa*s,and the p H values ranged from 1.57 to 1.82.(2)The extraction performance of the prepared NADESs and ethanol/water were compared for the extraction of flavonoids from Potentilla fruticosa L.The results showed that all eight prepared NADESs had higher extraction efficiency for the four flavonoid compounds in Potentilla fruticosa L.than traditional solvents.Among them,the NADES composed of choline chloride and citric acid exhibited the best extraction performance,and it was found that the addition of an appropriate amount of water can significantly reduce the viscosity of the solution system and increase its flavonoid extraction capacity.NADESs with a concentration of 70%exhibited the best extraction performance for Potentilla fruticosa L.flavonoids.(3)The effect of extraction process parameters on the extraction rate of flavonoids from Potentilla fruticosa L.was studied.It was found that increasing the ultrasonic power to 300W was helpful to improve the extraction rate of flavonoids,but excessive ultrasonic power can damage the stability of NADES bonds and the bonding structure of flavonoid compounds,leading to a decrease in flavonoid extraction rate.(4)Based on the single-factor experiment,the response surface methodology was used to optimize the extraction yield of flavonoids from Potentilla fruticosa L.,and the second-order regression models for the extraction rate of flavonoids,DPPH free radical scavenging rate,and glucose consumption rate were obtained.The regression models had good fit and could well predict the extraction process of flavonoids from Potentilla fruticosa L.The optimal extraction conditions were validated by three parallel confirmatory experiments,which were a liquid-to-solid ratio of 40:1 m L/g,ultrasonic power of 318W,and extraction time of 47 min.The extraction rate of flavonoids was 50.26±0.3 mg/g.(5)Porous silicon particles were prepared by the dealloying method,and the etching solution concentration was the key factor affecting the preparation of porous silicon,while the effect of etching time was not significant.The optimal etching conditions were determined as follows:the concentration of Na OH solution in the etching solution was 4mol/L and the etching time was 8h.(6)Surface morphology Observation and physicochemical properties testing was conducted on porous silicon particles.The porous silicon particles were found to have a flower-ball shape with uneven surface wrinkles on the spherical body.Furthermore,there were uniformly distributed and interconnected sieve pores that formed a branching network of channels.The specific surface area of the porous silicon was627.35 m~2/g,and the pore volume and pore diameter were 1.52 cm~3/g and 12.66 nm,respectively.(7)The loading and sustained release performance of Potentilla fruticosa L.flavonoids on porous silicon were studied.After 12 hours of adsorption,the maximum loading capacity of flavonoids on porous silicon reached 721.33 mg/g.The release rate of flavonoids on porous silicon in simulated human intestinal fluid was investigated and it was found that Potentilla fruticosa L.flavonoids could be slowly released with a release rate of 79.01%at 12 hours. |
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