| Hyperlipidemia is a common metabolic syndrome that is directly related to lipid metabolism disorders,mainly manifested by high levels of TC,TG,LDL-C and low levels of HDL-C in serum.Hyperlipidemia may also induce complications such as diabetes,coronary heart disease and atherosclerosis.Currently,the traditional lipid-lowering drugs are mainly statins and fibrates.If the side effects of these drugs are significant after long-term administration,thus exploring hypolipidemic functional factors from natural products has become a research focus.Garlic polysaccharides have the effects of lowering blood lipids,lowering blood sugar,antioxidation,liver protection and anti-tumor,but it is easily decomposable before reaching the digestive site-colon,leading to reduced oral bioavailability.Liposomes have the effects of improving the stability of active ingredients,mitigating adverse drug reactions,sustained-release,and targeted delivery of drugs.Preparation of garlic polysaccharide liposomes can effectively improve the bioavailability and biological activity of garlic polysaccharides,so that garlic polysaccharide liposomes have good application prospects in the field of reducing blood lipids.In this study,a novel polysaccharide liposome was prepared using garlic polysaccharides,soybean lecithin and cholesterol.The optimal preparation conditions of garlic polysaccharide liposomes were determined by single-factor and response surface tests.The obtained liposomes were characterized in terms of micromorphology,particle size,PDI,Zeta potential,UV spectrum,IR spectrum and stability.In vitro release of garlic polysaccharide liposomes were confirmed through the in vitro release simulation experiment.Then,hyperlipidemia mouse model was constructed to further explore the effect of garlic polysaccharide liposomes on lowering blood lipids in vivo.The main research results are as follows:(1)The garlic polysaccharide liposomes were prepared by reverse phase evaporation method.The optimal preparation conditions for garlic polysaccharide liposomes were determined by single factor and response interview tests,with the membrane material ratio(mass ratio of soybean lecithin to cholesterol),lipid drug ratio(mass ratio of soybean lecithin to garlic polysaccharide),and ultrasound time as factors,and the encapsulation efficiency as the main response value.The results showed that the optimal preparation conditions of garlic polysaccharide liposomes were as follows: film-material ratio of 4:1,lipid-drug ratio of 24:1,ultrasonic time of 14 min,with the maximum encapsulation efficiency of 61.00±0.73%.(2)The physicochemical properties and structural characterization of garlic polysaccharide liposomes were analyzed.The results showed that the garlic polysaccharide liposomes were ivory,translucent liquid.The liposomes observed by transmission electron microscopy appeared as spherical vesicles with uniform dispersion and good stability.Their particle size,polymer dispersity index and zeta potential were 213.50±1.85 nm,0.187±0.005and-21.07±1.27 m V,respectively.UV and IR spectra confirmed that garlic polysaccharides were successfully encapsulated into the lipid material through electrostatic interactions,without the formation of new chemical bonds.After 28 days of storage at 4℃,the garlic polysaccharide liposomes system remained relatively stable.(3)In vitro release experiments showed that garlic polysaccharide liposomes had sustained release effect.The cumulative release rate of garlic polysaccharide liposomes in vitro was 22.91% at 8 hours and 77.40% at 60 hours,which was consistent with the first-order kinetic model.(4)In the lipid-lowering experiment of garlic polysaccharide liposomes in vivo,garlic polysaccharide liposomes can effectively reduce the content of serum TC,TG,LDL-C and increase the content of serum HDL-C in hyperlipidemic mice,showing a good lipid-lowering effect,and the effect is better than garlic polysaccharides.Garlic polysaccharide liposomes can reduce the activities of serum ALT,AST and ALP,and improve the liver damage caused by high-fat diet;increase the activities of liver SOD and GSH-Px,reduce the content of lipid peroxide MDA,inhibit oxidative stress,and reduce lipid peroxidation damage;reduce the activities of HMGCR,ACC and FAS in the liver,increase the activity of LCAT,accelerate the metabolism of lipid in the liver,reduce the accumulation of fat,and play a role in lowering blood lipid. |
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