尿石素A脂质体的制备:稳定性及体外消化研究

Preparation of urolithin A liposomes:Stability and in vitro digestion studies

尿石素A具有许多优良的生理活性,但其极低的水溶性和生物利用率限制了尿石素A的应用。为克服上述限制,该文采用pH驱动法结合高压均质技术制备尿石素A脂质体(urolithin A liposomes,UA-LPs),并考察其结构特性、稳定性及体外消化特性。结果表明,大豆卵磷脂为20 mg/mL所制得的UA-LPs的平均粒径为(97.46±0.83)nm,多分散系数为(0.27±0.01),Zeta电位为(-40.3±1.06)mV,包埋率为(98.11±0.26)%,负载率为(2.39±0.01)%。UA-LPs在原子力显微镜下为分布均匀的球状结构。热稳定性实验表明,不同大豆卵磷脂浓度的UA-LPs的包埋率均随热处理时间的延长有所下降,20 mg/mL的大豆卵磷脂制备的UA-LPs具有最好的热稳定性,其在80℃处理180 min后仍可保留45%的尿石素A,且粒径、多分散系数变化趋势较小。pH稳定性表明UA-LPs在酸性条件下包埋率较低,随着pH的升高,粒径、多分散系数变化不显著(P>0.05),20 mg/mL的大豆卵磷脂制备的UA-LPs的Zeta电位绝对值上升5.5,稳定性升高。体外模拟消化实验表明,UA-LPs能有效提高尿石素A的转化率以及生物可接受度,其中20 mg/mL大豆卵磷脂制备的UA-LPs的体外转化率相比游离的尿石素A增加了3.26倍,生物可接受度提高2.07倍。因此,利用pH驱动法可以成功制备出UA-LPs,且高大豆卵磷脂浓度的UA-LPs物理稳定性更好,以上研究结果为扩展尿石素A在食品工业及生物医药领域的应用提供依据。

Urolithin A has many excellent physiological activities,but the extremely low water solubility and bioavailability limit its application.To overcome above limitations,the pH-driven method combined with high-pressure homogenization technology was used to pre-pare urolithin A liposomes(UA-LPs),and the structure,stability,and digestion characteristics of UA-LPs were investigated.Results showed that the average particle size of UA-LPs prepared by 20 mg/mL soybean lecithin was(97.46±0.83)nm,the polydispersity in-dex,zeta potential,embedding rate and load rate was(0.27±0.01),(-40.3±1.06)mV,(98.11±0.26)%,and(2.39±0.01)%,respectively.UA-LPs had a spherical structure with uniform distribution under atomic force microscope.Thermal stability exper-iments showed that the embedding rate of UA-LPs with different wall material concentrations decreased with the extension of heating time,and UA-LPs prepared with 20 mg/mL soybean lecithin had the best thermal stability,and 45%of urolithin A were retained after 180 min treatment at 80℃,and the particle size and polydispersity coefficient changed little.The pH stability assays indicated a low embedding rate under acid condition,but the particle size and polydispersity coefficient did not change significantly with the increase of pH(P>0.05).The absolute value of zeta potential of UA-LPs prepared with 20 mg/mL soybean lecithin increased by 5.5,suggesting an in-creased stability.In vitro simulated digestion showed that UA-LPs could effectively improve the conversion rate and bio-acceptability of uro-lithin A,which increased by 3.26 and 2.07 times individually for that prepared with 20 mg/mL soybean lecithin compared with free uro-lithin A.Therefore,UA-LPs can be successfully prepared by pH driving method,and the physical stability of UA-LPs with high wall con-centration is better.Above results can expand the application of urolithin A in the food and biomedicine industry.