| Cucurbit[n]uril?Q[n]?has a highly symmetrical hydrophobic cavity and two polar carbonyl modified ports,which can form a stable host-guest inclusion complex by matching corresponding guest molecules with non-bond forces such as cage body action,hydrogen bond and van der waals force,etc.Cucurbit[n]uril is a safe and promising medicinal carrier with good stability and extensive host-guest identification.Flavonoid glycosides have various physiological activities such as anti-tumor,anti-inflammatory,anti-viral,etc.However,due to its poor water solubility,low bioavailability and other defects the further application of flavonoid glycosides has been limited.In this paper,cucurbit[7]uril?Q[7]?and cucurbit[8]uril?Q[8]?were selected as the hosts,natural flavonoid glycosides such as puerarin?PA?,Oroxin A?OA?and Oroxin B?OB?were taken as the guests.The host-guest interaction of flavonoid glycosides and cucurbit[n]urils was studies.The effects of cucurbit[n]urils on the water solubility,stability,antioxidant activity and in vitro release pathway of flavonoid glycosides were investigated.It provides a theoretical basis for the comprehensive development and utilization of flavonoid glycosides.?:UV-Vis spectroscopy was used to investigate the interactions of the Puerarin,Oroxin A and Oroxin B with Q[7]and Q[8].The results showed that the three flavonoid glycosides of puerarin,Oroxin A and Oroxin B did not interact with Q[7],this may be due to the large volume of the above-mentioned flavonoid glycosides,which cannot match the cavity of Q[7].Q[8]can interact with Oroxin A and Oroxin B,with an interaction ratio of 1:1 and 1:2,respectively.Subsequently,the interaction between Q[8]with the two flavonoid glycosides was investigated by mass spectrometry,isothermal titration calorimetry,infrared spectroscopy and nuclear magnetic hydrogen spectrometry,the experimental results obtained are consistent with the experimental results of ultraviolet absorption spectroscopy.The binding constants of Q[8]interacting with Oroxin A and Oroxin B were 1.299×107 L/mol and 8.266×105L2/mol2,respectively.The results of nuclear magnetic hydrogen spectrometric titration showed that the aglycone of the Oroxin A enters the cavity of Q[8]and glucose located at the port of Q[8].The inclusion mode of Q[8]with Oroxin B is that the phenyl of one oroxin B molecule enters the cavity from one end of Q[8],and the second glucose group of another Oroxin B molecule enters into the cavity of Q[8]from the other end,thus forming a host guest complex with an interaction ratio of 1:2.It has not been reported that the sugar groups of glycosides enter into the cavity of Cucurbit[n]uril.?:The effects of Q[8]on the water-solubility,stability,antioxidant activity and cumulative release of Oroxin A and Oroxin B were investigated by ultraviolet absorption spectrum.When the concentration of Q[8]is 100?mol·L-1,the solubility of the Oroxin A and Oroxin B in water increases by 22.7-fold and 1.86-fold,respectively.Q[8]had less effect on the stability of Oroxin B in artificial gastrointestinal fluid,and little influence on oroxin A in artificial gastric juice.However,the degradation rate of Oroxin A in artificial intestinal juice can be slowed down,and the stability of Oroxin A can be enhanced.The two flavonoid glycosides and their inclusion compounds had good scavenging effects on 2,2-diazo-bis-?3-ethylbenzothiazole-6-sulfonic acid?diammonium salt?ABTS?free radicals,and the corresponding IC50 values of Oroxin A and its inclusion compound,Oroxin B and its inclusion compound were 4.65×10-6 mol/L,4.80×10-6 mol/L,5.74×10–6mol·L–1and 5.76×10–6mol·L–1,respectively.It shows that Q[8]has no effect on the antioxidant activity of Oroxin A and Oroxin B.The intervention of Q[8]also improved the cumulative release of two flavonoid glycosides in artificial gastric juice,and the increase of Oroxin A and Oroxin B was 2.24 times and 1.16 times,respectively. |
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