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Permanent URI for this collectionhttps://repository.unesco.gov.ph/handle/123456789/50

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    Physicochemical and biochemical characterization of collagen from Stichopus cf. horrens tissues for use as stimuli-responsive thin films
    Sisican, Kim Marie D.; Torreno, Vicenzo Paolo M.; Yu, Eizadora T.; Conato, Marlon T. (American Chemical Society, 2023-09-20)
    The mutable collagenous tissue (MCT) of sea cucumber, with its ability to rapidly change its stiffness and extensibility in response to different environmental stress conditions, serves as inspiration for the design of new smart functional biomaterials. Collagen, extracted from the body wall of Stichopus cf. horrens, a species commonly found in the Philippines, was characterized for its suitability as stimuli-responsive films. Protein BLAST search showed the presence of sequences commonly found in type VII and IX collagen, suggesting that Stichopus horrens collagen is heterotypic. The maximum transition temperature recorded was 56.0 ± 2 °C, which is higher than those of other known sources of marine collagen. This suggests that S. horrens collagen has better thermal stability and durability. Collagen-based thin films were then prepared, and atomic force microscopy (AFM) imaging showed the visible collagen network comprising the films. The thin films were subjected to thermomechanical analysis with degradation starting at >175 °C. At 100–150 °C, the collagen-based films apparently lose their translucency due to the removal of moisture. Upon exposure to ambient temperature, instead of degrading, the films were able to revert to the original state due to the readsorption of moisture. This study is a demonstration of a smart biomaterial developed from S. cf. horrens collagen with potential applications in food, pharmaceutical, biomedical, and other collagen-based research.
  • Total synthesis and bioactivity evaluation of hydrophobic microcionamide‐inspired peptides
    Inocentes, Carl Rogel V.; Salvador‐Reyes, Lilibeth A.; Villaraza, Aaron Joseph L. (Wiley, 2023-01)
    In this report, we describe the facile synthesis of four microcionamide-inspired peptides where the atypical 2-phenylethylenamine (2-PEA) functional group in the marine natural product, microcionamide A, was replaced with a similarly-aromatic but more easily incorporated tryptophan (Trp) residue. Compounds 1–4 were synthesized using a standard Fmoc-based solid-phase synthesis strategy followed by iodine-mediated on-resin cyclization for disulfide-bridged compounds 1–3. Compound 1 showed antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa, with minimum inhibitory concentrations (MICs) of 9.1 μM and 15 μM, respectively. The inactivity of alanine analogs 2–4 against these pathogens suggests that the N-terminal Val, the cyclic scaffold, the contiguous Ile residues, and consequently, the hydrophobicity of compound 1 are essential for antibacterial activity. Compound 1 also favorably exhibited minimal cytotoxicity against normal mammalian cell lines. In summary, we have synthesized an analog of microcionamide A where replacement of the 2-PEA moiety with a Trp residue retained the antibacterial activity and with favorably low cytotoxicity.