| With the development of modern society and living standards,the concept of pursuing nature gradually influences the consumer behavior.Numerous studies have found that many natural compounds,especially flavonoid natural products such as phloretin and glabridin,have various biological activities and therapeutic potential for diseases such as anti-oxidation,anti-cancer,anti-atherosclerosis,anti-cell senescence,etc.In addition,they also show good research prospects in the area of anti-inflammatory,antibacterial,and skin whitening.However,most of these compounds have low levels of solubility and bioavailability in the body,and they are also sensitive to light,heat and acid,which makes them unrealistic to be present at their effective levels in the target tissues,making the practical application of flavonoid natural products suffer great challenges.This topic is devoted to finding suitable drug carriers to improve the practical application of natural hydrophobic small molecules.Through the exploration of the reaction mechanism between carriers and natural compounds,it is expected to contribute to guide the design of better drug delivery systems.1.Benefited from the truth that hydroxypropyl-β-cyclodextrin(HP-β-CD)has a special cavity as hydrophilic outer surface and hydrophobic central,we developed a novel inclusion complex of phloretin with it to overcome the key problem of bad water solubility of phloretin,by a co-evaporation method in the study.It is remarkable that the solubility of phloretin notably increased to 54.08 ± 0.05 mg/mL upon the formation of the inclusion complex,which was 5808 times higher than that of free phloretin in pure water.The results of phase solubility study showed that the stoichiometry of the formed complex was 1:1,together with the characterization data from SEM,TGA,XRD,FT-IR and NMR,we deduced that aromatic ring of phloretin molecule was merged into the cavity of HP-β-CD from the narrow side.Besides,we found that,and it still remained an approximately DPPH radical-scavenging capacity after formed inclusion complex and the stability of phloretin was greatly improved.Therefore,the phloretin/HP-β-CD inclusion complex adds a promising strategy for the clinical application of phloretin in the future.2.Since β-lactoglobulin(β-1g)can solubilize and bind many small hydrophobic molecules,we developed a novel nanocomplex of glabridin by anti-solvent precipitation method for improving the solubility of glabridin.After bound to β-1g,the solubility of glabridin in aqueous solution was enhanced 21 times,in comparison to glabridin alone.Fluorescence spectroscopy,XRD,SEM,FT-IR and CD,molecular docking revealed that glabridin was bound to β-1g by hydrophobic force and hydrogen bond interactions.Furthermore,the nanocomplex still remained a better DPPH radical-scavenging capacity and ABTS radical-scavenging capacity compared to that of free glabridin at the same concentration in vitro tests.Thus,β-1g may fit the choice as a carrier of natural hydrophobic active molecules.3.A novel phloretin/SPI complex was prepared by anti-solvent precipitation method and the reaction process and complex properties of SPI and phloretin were studied.The size of complex formed was 225.2 ±8.8 nm and SPI significantly improved the solubility and thermal stability of phloretin.Besides,the formed complex still remained an approximately DPPH radical-scavenging capacity.The result of fluorescence spectroscopy indicated that hydrophobic interactions played a major role in the formation of phloretin/SPI complex.Therefore,soy protein isolate can be used as a good carrier of natural hydrophobic active molecules. |
