Extraction Of Curcumin From Low Eutectic Media And Study Of Its Nanoparticle Properties

Curcumin is an acidic polyphenol with pharmacological effects including antioxidant,antibacterial,anti-inflammatory,anti-tumour,immunomodulatory,renal and neuroprotective.In recent years,DES has shown huge potential in the green extraction process of natural products.In this study,we investigated the effect of ultrasonic-assisted DES on the extraction of curcumin using choline chloride DES as the extractant,and established an efficient extraction preparation system for curcumin using choline chloride/levulinic acid as the extractant.We examined the effects of water content,liquid-liquid ratio,extraction temperature,extraction time and ultrasonic power of DES on the extraction rate of curcumin,and determined the optimal extraction parameters as follows:choline chloride/levulinic acid（1:3 molar ratio,20%water content）,16:1liquid-to-material ratio,50°C extraction temperature,37 min extraction time and 253 W ultrasonic power,under which the extraction rate of curcumin reached 60.02 mg/g,which was significantly higher than that in conventional organic solvents.The mesoporous MPDA carrier and the hollow HPDA carrier were prepared using soft template method and hard template method,respectively.Curcumin nano particles PEG-CS@MPDA@CUR and PEG-CS@HPDA@CUR were obtained by loading with curcumin through a large number of active groups on the surface of the carrier and coating with polyethylene glycol modified chitosan.Through characterization by TEM,SEM,DLS and BET,it was found that MPDA carrier and HPDA carrier were regular spheres with obvious porous structures on the surface,with an average particle size of about 100 nm and 110 nm,and the specific surface area of 63.65 m²/g and 48.49 m²/g,respectively.However,the average hydrated particle size of the above two curcumin nanoparticles was 135.4 nm and 150.7 nm,respectively.Through further characterization by FTIR and XRD,it was proved that curcumin was successfully loaded on MPDA and HPDA,with the presence of non-crystal curcumin on the carrier.The adsorption performance test showed that the maximum adsorption capacity of the two carriers for curcumin reached 204.57μg/mg and 220.56μg/mg,respectively;p H responsiveness and in vitro release tests showed that PDA shell layer coated with modified chitosan had p H sensitivity and sustained-release effect.Through the investigation on the stability of curcumin-loaded nanoparticles,the results showed that curcumin-loaded nanoparticles had enhanced light stability,thermal stability,humidity stability and storage stability.Further,compared with free curcumin,curcumin nanoparticles’DPPH free radical scavenging rate increased by 1.25 times,its ABTS free radical scavenging rate increased by 1.35 times,and reducing power increased by 8.38 times.Using MTT method,flow cytometry and live cell and dead cell imaging analysis,it was found that the nanoparticles synthesized in this study had good biocompatibility,PEG-CS@MPDA@CUR containing the same amount of curcumin exhibited stronger anti-tumor effect compared to free curcumin.The apoptosis rate of HCT-116 cancer cells was improved from 37%to 46.8%,and the IC₅₀value was smaller.It was found through cell scratch test that PEG-CS@MPDA@CUR played an effective inhibiting role in the migration of HCT-116 cells.Under the conditions of p H 5.0 and p H 7.4,the migration rate dropped from0.14%to 0.06%and 0.13%.This research is conductive to providing references for applying new DES medium to the efficient extraction of natural products.In addition,the nano-delivery system established in this study can provide useful reference for efficient utilization of active compounds.