Study On The Improvement Of Bioavailability Of Curcumin By Phytoglycogen

Curcumin（CCM）has a wide range of physiological and pharmacological activities,good heat resistance and high safety.It is also a widely used natural food coloring pigment at home and abroad.However,CCM has extremely low water solubility,poor UV stability,easy degradation under intestinal pH conditions,and poor permeability of intestinal mucosa.These defects lead to low bioavailability of CCM in the body,and thus applications in water-soluble substrates such as foods and pharmaceuticals are greatly limited.In this study,PG-CCM complex nanoparticles were prepared by loading CCM with phytoglycogen（PG）as carrier.The preparation conditions of PG-CCM composites were optimized and their structures were characterized.The stability and biological activity of PG-CCM complex were analyzed.The release of CCM and the absorption of small intestine under gastric and intestinal fluid conditions were studied.The possible ways of improving the bioavailability of CCM by PG-CCM complex were discussed.The main findings are as follows:PG-CCM composite nanoparticles with uniform particle size distribution and electrical neutrality;carrier PG exhibits a smooth spherical structure,while PG-CCM composites exhibit a planar sheet structure;CCM in PG-CCM composites is amorphous The existence of an amorphous structure,hydrogen bonding is the main force of CCM and carrier PG,CCM from the more polar microenvironment to the less polar PG action zone.The PG-CCM complex significantly increases the apparent solubility of CCM.In the low ethanol concentration system（1%,V/V）,when the PG concentration is5%,the CCM concentration is 4 mg/ml,the pH is 7,and the ammonium sulfate ion concentration is 0-20%,the CCM solubility reaches the maximum value（30μg/ml）,the apparent solubility of CCM increased by about 2730 times.Theα-amylase hydrolyzed PG,and the degree of hydrolysis increased,the loading capacity of the hydrolyzate to CCM decreased;the amyloglucosidase hydrolyzed PG,and the hydrolyzate had no significant change in the loading capacity of CCM.Under direct UV irradiation,PG-CCM complex has different degrees of protection for CCM;under indirect UV irradiation,CCM in PG-CCM composite undergoes rapid photolysis.Storage temperature had no significant effect on the stability of CCM in PG-CCM composites,and light significantly reduced its storage stability.There was no significant difference in CCM stability in PG-CCM composites under light-shielded storage conditions.However,under natural light storage conditions,the greater the PG concentration in PG-CCM complex,the better the stability of CCM.The in vitro antioxidant activity of the PG-CCM complex showed a good dose effect.The total reducing power and ABTS+·scavenging activity of different PG-CCM complexes were higher than CCM,but their scavenging activities were lower than CCM.The inhibitory effect of PG-CCM complex on proliferation of A549 cells showed a good dose-effect relationship.Under intestinal fluid conditions（pH 6.9 and 7.2）,the degradation mode of CCM in PG-CCM complex was significantly different from that of CCM,and it had different degrees of protection against CCM in the early stage under intestinal fluid conditions.In the simulated gastrointestinal fluid with continuous pH change without digestive enzyme,the CCM release rate of 5%PG-CCM complex was always less than 1%PG-CCM complex;under pH 2⁵,both complexes existed.Obvious"burst"characteristics.The amylase digestion process significantly promoted the release of CCM from the PG-CCM complex.0-80μM CCM and PG-CCM were not cytotoxic to Caco-2 cells.At 60μM and120 min,the cumulative transport rates of 5%PG-CCM and CCM were 0.615%and0.054%,respectively,which was increased by about 11 times.After the addition of amylase,the cumulative transport rate of 5%PG-CCM reached 1.979%,an increase of about 37 times.The apparent permeability coefficients of CCM,CCM+En,5%PG-CCM,5%PG-CCM+En transport CCM were 3.29×10^-8、2.625×10^-8、3.859×10^-7和1.067×10^-66 cm/s.The above studies show that PG-CCM complex can significantly improve the apparent solubility of CCM,greatly increase the transmembrane transport capacity of CCM,and improve the bioavailability of CCM.At the same time,the anti-ultraviolet degradation ability,antioxidant activity,and cancer cell inhibitory activity of the PG-CCM complex were enhanced.