Adiponectin-Secretion-Promoting Cyclic Peptide-Polyketide Hybrids from a Halophyte-Associated Fungus, Colletotrichum gloeosporioides JS0417

Isolation, Characterization, Genome Annotation, and Evaluation of Tyrosinase Inhibitory Activity in Secondary Metabolites of Paenibacillus sp. JNUCC32: A Comprehensive Analysis through Molecular Docking and Molecular Dynamics Simulation

A potential strain, Paenibacillus sp. JNUCC32, was isolated and subjected to whole-genome sequencing. Genome functional annotation revealed its active metabolic capabilities. This study aimed to investigate the pivotal secondary metabolites in the biological system. Fermentation and extraction were performed, resulting in the isolation of seven known compounds: tryptophol (1), 3-(4-hydroxyphenyl)propionic acid (2), ferulic acid (3), maculosin (4), brevianamide F (5), indole-3-acetic acid (6), and butyric acid (7). Tryptophol exhibited favorable pharmacokinetic properties and demonstrated certain tyrosinase inhibitory activity (IC50 = 999 μM). For further analysis of its inhibition mechanism through molecular docking and molecular dynamics (MD) simulation, tryptophol formed three hydrogen bonds and a pro-Michaelis complex with tyrosinase (binding energy = -5.3 kcal/mol). The MD simulation indicated favorable stability for the tryptophol-mushroom tyrosinase complex, primarily governed by hydrogen bond interactions. The crucial residues VAL-283 and HIS-263 in the docking were also validated. This study suggests tryptophol as a potential candidate for antibrowning agents and dermatological research.

Interconvertible Pyridone Alkaloids from the Marine-Derived Fungus Penicillium oxalicum QDU1

Eleven new pyridone alkaloids, penicipyridones A-K (1-11), and three new tetramic acids, tolypocladenols D-F (12-14), were isolated from rice media cultures of the marine-derived fungus Penicillium oxalicum QDU1. Their structures, including absolute configurations, were determined by comprehensive analyses of spectroscopic data, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction data. Interestingly, several of the penicipyridones undergo interconversions between hydroxy and methoxy groups at C-4 in acidic MeOH solution. Furthermore, in an acidic aqueous solution, OH-4 could be replaced by diverse substituent groups. Compounds 1, 4, 5, 8, 10, 11, and 14 exhibited moderate inhibitory effects on NO production in the LPS-induced RAW264.7 macrophages, with IC₅₀ values ranging from 9.2 to 19 μM.

Preparation of a novel glucose oxidase-N-succinyl chitosan nanospheres and its antifungal mechanism of action against Colletotrichum gloeosporioides

In this work, a new glucose oxidase-N-succinyl chitosan (GOD-NSCS) nanospheres was prepared through the immobilization of glucose oxidase (GOD) on N-succinyl chitosan (NSCS) nanospheres. Compared to the free GOD, GOD-NSCS nanospheres demonstrated the excellent anti-Colletotrichum gloeosporioides activity with the EC₅₀ values of 211.2 and 10.7 μg/mL against mycelial growth and spores germination. The computational biology analysis demonstrated that the substrate presented the similar binding free energy with GOD-NSCS nanospheres (-27.64 kcal/mol) compared with the free GOD (-24.04 kcal/mol), indicating that GOD-NSCS nanospheres had the same oxidation efficiency and produced more H₂O₂. Moreover, the enzyme activity stability of GOD-NSCS nanospheres could be prolonged to 10 d. The cell membrane was destructed by the treatment of H₂O₂ produced by GOD, leading to the cell death. In vivo test, GOD-NSCS nanospheres treatment significantly prolonged the preservation period of mangoes 2-fold. Collectively, these results suggested that GOD-NSCS nanospheres suppresses anthracnose in postharvest mangoes by inhibiting the growth of C. gloeosporioides and might become a potential natural preservative for fruits and vegetables.