Lotus leaf flavonoids (LLF), derived from an abundant agricultural byproduct, were incorporated into zein/chitosan (ZC) matrices to fabricate multifunctional edible films with controlled-release properties for active food packaging applications. LLF-ZC composite films containing different flavonoid loadings (0.1-0.3%, w/v) were prepared and systematically evaluated in terms of physicochemical, mechanical, thermal, structural, and bioactive properties. The incorporation of LLF significantly increased film thickness, density, tensile strength, and thermal stability, while maintaining low water vapor and gas permeability. Structural characterization by SEM, ATR-FTIR, and XRD confirmed good compatibility between LLF and the ZC matrix, mainly attributed to hydrogen bonding and hydrophobic interactions. LLF addition markedly enhanced the antioxidant and antibacterial performance of the films, with DPPH and ABTS radical scavenging activities exceeding 90% at higher LLF contents and concentration-dependent inhibition against Escherichia coli and Staphylococcus aureus. Among the tested formulations, the 0.2% LLF-ZC film exhibited the most balanced overall performance in terms of mechanical strength, barrier properties, and bioactivity. The release behavior of LLF was strongly influenced by the polarity of food simulants, with the highest cumulative release observed in 50% ethanol, followed by water and 95% ethanol. Kinetic analysis indicated that the release profiles were best described by the Peppas-Sahlin and Ritger-Peppas models, demonstrating that Fickian diffusion was the dominant release mechanism. Overall, these results highlight the potential of LLF-ZC films as sustainable active packaging materials, particularly for semi-fatty food systems.

2025-09-01·BIOORGANIC CHEMISTRY

Structure-activity relationship and molecular interaction mechanisms of the ACE-inhibitory tripeptide LL-X

Article

作者: Ma, Zhengkun ; Cai, Mengmeng ; Lan, Xiongdiao ; Yang, Cuicui ; Liu, Pengru

Investigating the molecular interaction mechanisms of angiotensin-converting enzyme (ACE) inhibitory peptides is valuable in antihypertensive drug development. In this study, we designed two novel peptide variants, Leu-Leu-Phe (LLF) and Leu-Leu-Pro (LLP), by substituting the C-terminal tyrosine (Tyr) in casein-derived Leu-Leu-Tyr (LLY) with phenylalanine (Phe) and proline (Pro), respectively, to investigate the impact of C-terminal amino acid properties of peptide on ACE inhibition. The ACE inhibitory activity, inhibition kinetics, peptides-ACE binding mechanisms, and LLF and LLP conformational relationship were systematically investigated with comparative assessment against the LLY. The results showed the ACE inhibitory activity of the synthetic peptide (LLF: IC₅₀ = 168.57 ± 5.11 μM; LLP: IC₅₀ = 96.64 ± 2.93 μM) was significantly lower than that casein-derived tripeptide LLY (IC₅₀ = 44.16 ± 2.45 μM). The Lineweaver-Burk plots and molecular docking indicated that both LLF and LLP were noncompetitive inhibitors, which was consistent with LLY. Molecular dynamics simulations validated their stable binding to the ACE complex. The comparison of the three peptides interacting with ACE using multispectral techniques indicated that LLY resulted in the formation of a greater number of disordered protein structural regions, rendering it more active than the other peptides. Consequently, we concluded that the role of the C-terminal Tyr in the ACE inhibitory peptide LLY is more significant than that of Phe and Pro. This study highlights the crucial influence of C-terminal amino acids on the inhibitory activity of tripeptides, providing an essential theoretical foundation for the rational design of effective ACE inhibitory peptides.

2025-07-01·JOURNAL OF SEPARATION SCIENCE

Application of Molecular Dynamic Simulation in the Enantiorecognition Mechanism of the Pharmaceutically Relevant Leu‐Phe Dipeptides With Four Zwitterionic Chiral Stationary Phases

Article

作者: Carotti, Andrea ; Sardella, Roccaldo ; Klimova, Yana A. ; Kohout, Michael ; Varfaj, Ina ; Asnin, Leonid D.

ABSTRACT:

In order to broaden the applicability of the molecular dynamics technique and to further validate the efficacy of a computational protocol recently developed in our laboratory, the present study aims to elucidate the enantiorecognition mechanisms involving four zwitterionic Cinchona alkaloid‐based CSPs under reversed‐phase (RP) conditions. In this study, we use the enantiomeric dipeptides D‐leucine‐D‐phenylalanine and L‐leucine‐L‐phenylalanine as probes to investigate the properties of CHIRALPAK ZWIX(+) and ZWIX(‐), as well as ZWIX(+A) and ZWIX (−A). The Leu‐Phe dipeptide has considerable potential in the pharmaceutical field due to its potential applications in drug delivery, therapeutics and as a building block for peptidomimetics. Furthermore, Leu‐Phe is one of the few uncapped dipeptides composed of natural amino acids capable of forming stable hydrogels. The in silico protocol was successfully optimized by setting the simulation box size, run time, and number of frames to record to generate molecular dynamics trajectories as informative as possible. Importantly, the analyses were in complete agreement with the experimental EO, providing insights into the driving forces involved in the enantiorecognition mechanism. In particular, salt bridges and hydrogen bonds were confirmed as the primary interactions, while π–π and π–cation interactions were identified as complementary to facilitate the SO–SA association.

100 项与 Leu-Leu-Phe 相关的药物交易

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