Food Science and Human Nutrition Department, Institute of Food and Agricultural Sciences, University of Florida , Gainesville, Florida 32611, United States.
J Agric Food Chem. 2014 Feb 12;62(6):1301-9. doi: 10.1021/jf404621f. Epub 2014 Jan 28.
Nanoparticles have the potential to increase bioavailability of nutraceutical compounds such as (-)-epigallocatechin gallate (EGCG). Ovalbumin was conjugated with dextran using the Maillard reaction. The resultant ovalbumin-dextran (O-D) conjugates were self-assembled with EGCG to form EGCG O-D conjugate nanoparticles at pH 5.2 after heating at 80 °C for 60 min. Ovalbumin in EGCG O-D conjugate nanoparticles was further cross-linked by glutaraldehyde for 24 h at room temperature. EGCG O-D conjugate nanoparticles and cross-linked EGCG O-D conjugate nanoparticles in aqueous suspension had particle sizes of 285 and 339 nm, respectively, and showed a spherical morphology. The loading efficiencies of EGCG in these two nanoparticles were 23.4 and 30.0%, whereas the loading capacities were 19.6 and 20.9%, respectively. These nanoparticles showed positive zeta-potentials in a pH range from 2.5 to 4.0 but had negative charges at pH ≥5.0. EGCG O-D conjugate nanoparticles maintained a particle size of 183-349 nm in simulated gastric fluid (SGF) and 188-291 nm in simulated intestinal fluid (SIF) at 37 °C for 2 h, whereas cross-linked nanoparticles had particle sizes of 294-527 nm in SGF and 206-300 nm in SIF. Limited release of EGCG was observed in both nanoparticle systems in simulated gastric and intestinal fluids without and with digestive enzymes. EGCG O-D conjugate nanoparticles significantly enhanced the apparent permeability coefficient (Papp) of EGCG on Caco-2 monolayers compared with EGCG solution, suggesting that these nanoparticles may improve the absorption of EGCG.
纳米粒子有可能增加营养化合物如（-）-表没食子儿茶素没食子酸酯（EGCG）的生物利用度。卵清蛋白通过美拉德反应与葡聚糖偶联。所得的卵清蛋白-葡聚糖（O-D）缀合物在 pH 5.2 下加热 80°C 60 分钟后与 EGCG 自组装形成 EGCG O-D 缀合纳米粒子。EGCG O-D 缀合纳米粒子中的卵清蛋白进一步在室温下用戊二醛交联 24 小时。EGCG O-D 缀合纳米粒子和交联的 EGCG O-D 缀合纳米粒子在水性悬浮液中的粒径分别为 285nm 和 339nm，并呈现球形形态。这两种纳米粒子中 EGCG 的载药效率分别为 23.4%和 30.0%，而载药量分别为 19.6%和 20.9%。这些纳米粒子在 pH 2.5 至 4.0 范围内显示出正的 ζ 电位，但在 pH≥5.0 时带有负电荷。在 37°C 下，2 小时内，EGCG O-D 缀合纳米粒子在模拟胃液（SGF）中保持粒径为 183-349nm，在模拟肠液（SIF）中保持粒径为 188-291nm，而交联纳米粒子在 SGF 中的粒径为 294-527nm，在 SIF 中的粒径为 206-300nm。在没有和有消化酶的模拟胃液和肠液中，两种纳米粒子体系中均观察到 EGCG 的有限释放。与 EGCG 溶液相比，EGCG O-D 缀合纳米粒子显著提高了 EGCG 在 Caco-2 单层上的表观渗透系数（Papp），表明这些纳米粒子可能改善 EGCG 的吸收。
