Preparation And Properties Of Polyphenols-chitosan Microparticles

Chitosan microparticles,one of the most promising materials for the encapsulation and delivery of polyphenols,can improve the chemical stability and bioavailability of polyphenols.Epigallocatechin-3-gallate(EGCG)and procyanidin are the most representative compounds of polyphenols.In this study,EGCG-chitosan microparticles(EGCG-CS-MP)and procyanidin-chitosan microparticles(PC-CS-MP)were prepared.Both of them were collectively called polyphenols-chitosan microparticles,and their biological activities were studied.Firstly,polyphenols-chitosan microparticles were prepared using ionic crosslinking.The preparation conditions were optimized by one-factor-at-a-time method and orthogonal design,and the in vitro release behavior of polyphenols-chitosan microparticles was studied.The results show that the maximum entrapment efficiency and loading capacity of EGCG-CS-MP were 68.4% and 81.92 mg/g,respectively;the maximum entrapment efficiency and loading capacity of PC-CS-MP were 70.5% and 78.33 mg/g,respectively.The micrographs illustrate that polyphenols-chitosan microparticles were regularly spherical in shape with a mean diameter of 60 μm,dispersed evenly,and had no agglomeration or adhesion.The FTIR spectra suggest that the amino groups of chitosan were involved in the ionic crosslinking.The release behavior of EGCG-CS-MP and PC-CS-MP was completed within 5 h and 7 h,respectively;low pH values facilitated the release process;the highest release speeds of EGCG-CS-MP and PC-CS-MP were observed at 37oC and 42oC,respectively;salt concentrations could regulate the release behavior.The release behavior of polyphenols-chitosan microparticles occurred easily in stimulated gastric fluid than that in stimulated intestinal fluid.Then,the antioxidant activity of polyphenols-chitosan microparticles was studied.Both EGCG-CS-MP and PC-CS-MP exhibited strong free radical scavenging activity and reducing power.The DPPH radical scavenging activity of EGCG-CS-MP reached 94.3%,and the ·OH radical scavenging activity of PC-CS-MP was beyond 80%.Afterwards,the antibacterial activity of polyphenols-chitosan microparticles was analyzed.Polyphenols-chitosan microparticles inhibited the growth of Staphylococcus aureus,Micrococcus luteus,Proteus vulgaris,and Pseudomonas aeruginosa,but had no effects on Escherichia coli,Lactobacillus,and Enterococcus faecalis.Finally,the effects of polyphenols-chitosan microparticles on the immunological activity of BALB/c mice were evaluated.There were no obvious adverse effects of polyphenols-chitosan microparticles on the growth and organ weight of BALB/c mice in the tested dosage range.Polyphenols-chitosan microparticles enhanced the spleen T lymphocyte proliferation,indicating that they can improve the immunological activity of BALB/c mice.