Mechanism Of Astaxanthin Encapsulated In Calcium Alginate Microspheres Against Hepatocellular Carcinoma In Vitro

Astaxanthin(AST),a kind of dietary carotenoid with its anti-oxidative property,has aroused great interest in the scientific community because of its benefits in various cancer models both in vitro and in vivo and other diseases.This advantage is closely related to a large number of unsaturated bonds in the molecular structure of astaxanthin.However,due to the existence of these unsaturated bonds,astaxanthin is easily oxidized under high temperature,light and acidic conditions.The instability of astaxanthin reduces the bioavailability of astaxanthin.In addition,similar to most carotenoids,astaxanthin has very low solubility in water.The biological limitations of astaxanthin not only limit the application of astaxanthin,but also limit the exploration of the anti-cancer mechanism of astaxanthin.In view of the above problems,the modified emulsion technology was used to prepare calcium alginate biodegradable material microspheres as astaxanthin carrier.Hepatoma cells(HepG2 cell lines)and normal liver cells(THLE-2 cell lines)were selected as hepatocyte models in vitro.The cell behaviors of two cell lines before and after astaxanthin intervention were compared,and their intrinsic mechanisms were discussed.In this study,astaxanthin alginate(ACA)microspheres were prepared by double emulsion method.Compared with unencapsulated astaxanthin,the prepared astaxanthin alginate microspheres had higher storage stability and antioxidant capacity.The diameter of ACA microspheres was uniform and the average particle size was 724 nm.Considering human absorption system,the optimum preparation conditions of astaxanthin-loaded calcium alginate/chitosan composite(ACAC)microspheres were explored on the basis of ACA microspheres.The results showed that the composite microspheres prepared with 0.1%(w/v)chitosan had high sphericity and smooth surface with an average particle size of 3.1 um.The bioavailability of astaxanthin was increased before and after coating with chitosan,and both had sustained release effect.However,the composite microspheres were more suitable for human absorption system.In order to explore the anti-hepatocellular carcinoma effect of astaxanthin,calcium alginate microspheres with small particle size and simple carrier system were selected as astaxanthin carriers in vitro.The experiment first proved that the carrier had no toxic and side effects on both cell lines(in a larger concentration range),and further proved the anti-hepatocellular carcinoma effect of astaxanthin.The results showed that astaxanthin inhibited the proliferation of HepG2 cells,but had little effect on the growth of THLE-2 cells.When astaxanthin content was 40 ?M,it inhibited the proliferation of hepatocellular carcinoma cells most obviously,and the inhibition rate reached 40% after 96 hours of intervention.It was further proved that astaxanthin inhibited the proliferation of hepatocellular carcinoma cells by inducing apoptosis of hepatocellular carcinoma cells through intracellular ROS content test and apoptotic test.In addition,considering the complex metabolic system of liver,the molecular mechanism of astaxanthin against hepatocellular carcinoma was explored based on the glycometabolism process.The results showed that astaxanthin could effectively inhibit the disordered glycolysis(aerobic glycolysis)in hepatocellular carcinoma cells,that is,hepatocellular carcinoma cells still only undergo glycolysis and anaerobic oxidation under aerobic conditions,but not the tricarboxylic acid cycle in mitochondria(the main energy supply process of normal cells).Therefore,astaxanthin can be used as a new drug for prevention and treatment of hepatocellular carcinoma in combination with related glycometabolism regulating drugs.