Abstract：
Oral delivery of larger bioactive peptides (>20 amino acids) to the small intestine remains a challenge due to their sensitivity to proteolytic degradation and chemical denaturation during gastrointestinal transit. In this study, we investigated the capacity of crosslinked alginate microcapsules (CLAMs) formed by spray drying to protect Plantaricin EF (PlnEF) (C-EF) in gastric conditions and to dissolve and release PlnEF in the small intestine. PlnEF is an unmodified, two-peptide (PlnE: 33 amino acids; PlnF: 34 amino acids) bacteriocin produced by Lactiplantibacillus plantarum with antimicrobial and gut barrier protective properties. After 2 h incubation in simulated gastric fluid (SGF) (pH 1.5), 43.39 % ± 8.27 % intact PlnEF was liberated from the CLAMs encapsulates, as determined by an antimicrobial activity assay. Transfer of the undissolved fraction to simulated intestinal fluid (SIF) (pH 7) for another 2 h incubation resulted in an additional release of 16.13 % ± 4.33 %. No active PlnEF was found during SGF or sequential SIF incubations when pepsin (2,000 U/ml) was added to the SGF. To test PlnEF release in C-EF contained in a food matrix, C-EF was mixed in peanut butter (PB) (0.15 g C-EF in 1.5 g PB). A total of 12.52 % ± 9.09 % active PlnEF was detected after incubation of PB + C-EF in SGF without pepsin, whereas no activity was found when pepsin was included. Transfer of the remaining PB + C-EF fractions to SIF yielded the recovery of 46.67 % ± 13.09 % and 39.42 % ± 11.53 % active PlnEF in the SIF following exposure to SGF and to SGF with pepsin, respectively. Upon accounting for the undissolved fraction after SIF incubation, PlnEF was fully protected in the CLAMs-PB mixture and there was not a significant reduction in active PlnEF when pepsin was present. These results show that CLAMs alone do not guard PlnEF bacteriocin peptides from gastric conditions, however, mixing them in PB protected against proteolysis and improved intestinal release.
摘要：
将较大的生物活性肽(>20个氨基酸)经口递送至小肠仍然是一个挑战,因为它们在胃肠运输期间对蛋白水解降解和化学变性的敏感性。在这项研究中,我们研究了通过喷雾干燥形成的交联藻酸盐微胶囊（CLAMs）在胃条件下保护PlantaricinEF（PlnEF）（C-EF）以及在小肠中溶解和释放PlnEF的能力。PlnEF是未经修改的，2-肽(PlnE:33个氨基酸;PlnF:34个氨基酸)细菌素由植物乳杆菌产生,具有抗微生物和肠屏障保护特性。在模拟胃液（SGF）（pH1.5）中孵育2小时后，从CLAM封装中释放出43.39%±8.27%完整的PlnEF，通过抗菌活性测定确定。将未溶解的部分转移到模拟肠液（SIF）（pH7）中再孵育2小时，导致额外释放16.13％±4.33％。当将胃蛋白酶(2,000U/ml)添加到SGF中时,在SGF或连续SIF孵育期间没有发现活性PlnEF。为了测试食物基质中所含的C-EF中的PlnEF释放，将C-EF在花生酱(PB)中混合(0.15gC-EF在1.5gPB中)。在不含胃蛋白酶的SGF中孵育PB+C-EF后，检测到总共12.52%±9.09%的活性PlnEF，而当包括胃蛋白酶时没有发现活性。将剩余的PBC-EF级分转移到SIF中，在暴露于SGF和使用胃蛋白酶的SGF后，SIF中的活性PlnEF的回收率为46.67％±13.09％和39.42％±11.53％，分别。在考虑SIF孵育后的未溶解部分后，在CLAMs-PB混合物中PlnEF被完全保护,并且当存在胃蛋白酶时活性PlnEF没有显著降低。这些结果表明，单独的CLAM不能保护PlnEF细菌素肽免受胃病的影响，然而,将它们混合在PB中，以防止蛋白水解并改善肠道释放。
