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  • br Materials and methods F philippinensis plants were collec

    2020-06-29


    Materials and methods F. philippinensis plants were collected in August 2014 at a farm in Ninning, Guangxi province, China and identified by Dr. Yimmin Zhao. Voucher specimens (No. 530) were deposited in the Herbarium of Gaunxi Botanical Garden, China. Human recombinant neutrophil elastase (EC 3.4.21.37) and N-methoxysuccinyl-Ala-Ala-Pro-Val-p-nitroanilide were purchased from Enzo Life Sciences Inc. (New York, USA). Tris, oleanolic acid, chloroform-d, methanol-d, and acetone-d6 were purchased from Sigma-Aldrich (St. Louis, MO, USA). Silica gel (230–400 mesh), NP F254, RP-18 F254 thin-layer chromatography (TLC) plates, analytical grade water, acetonitrile, and methanol were obtained from Merck (Darmstadt, Germany). Spherical C18 100 Å reversed phase ampar gels (particle size: 20–40 μm) were obtained from Silicycle (Quebec, Canada). Methanol, acetone, ethyl acetate, chloroform, and n-hexane were purchased from Duksan Co. (Gyenggi, Korea).
    Results and discussion
    Conclusions We undertook a thorough investigation of NE inhibitors from F. philippinensis, which has been used to cure rheumatism. The main components were identified as sixteen flavonoids (1–16) that resulted in a significant dose-dependent decline in NE activity. In the kinetic study, compounds 1–16 exhibited varied kinetic behaviors, particularly the promising isolates (2, 3, 5, 7, and 9), which manifested a competitive, simple, reversible, slow-binding mechanistic behavior against NE. Furthermore, extensive fluorescence quenching experiments showed that the binding affinities of elastase inhibitors are directly proportional to their respective potencies (IC50 values). Our findings highlight the importance of these dietary components and further contribute to observed nutraceutical value of F. philippinensis.
    Disclosure statement
    Acknowledgement This work was supported by the Ministry of Agriculture, Food and Rural Affairs, IPET (315032-04-3-SB010), the National Research Foundation of Korea (NRF) grant funded by the South Korea government (MSIT) (2018R1A2B6001753) and BK21 Plus program supported scholarships for all students.
    Introduction Individuals with neutropenia and taking high doses of corticosteroids, immunosuppressors or chemotherapeutics have an elevated risk of developing opportunistic mycosis [1], [2]. Environmental microorganisms such as Aspergillus fumigatus are constantly inhaled and may cause invasive pulmonary Aspergillosis (IPA) in these patients. In this way, the tissue injuries are induced by the interaction between the host\'s defense and the pathogen virulence [3]. The inhaled spores adhere to the mucus produced by epithelial cells, facilitating their removal. These physical barriers, which are assisted by mechanical defenses such as sneezing and coughing, contribute for the clearance of spores [4]. Phagocytes from the innate immune system essentially mediate the pulmonary defense against A. fumigatus. The alveolar macrophages eliminate conidia, phagocyting them, whereas neutrophils destroy the germinative forms (hyphae) through the production and release of free oxygen radicals [5], [6]. If the immune system is not competent, the conidia germinate, generating hyphae that invade the tissue and lead to the development of IPA. In addition to its ability to grow at several temperatures (thermotolerance) and its production of small conidia (2–3μm), A. fumigatus has several virulence factors. These factors are essential for the establishment and maintenance of IPA. They include: In order to contribute to the study of the pathophysiological mechanisms of IPA, we established a model of neutrophil depletion in mice treated with the monoclonal antibody Gr-1/Ly-6G. Then, we evaluated the follow-up of the pulmonary tissue response in these animals and in immunocompetent mice infected with two strains of A. fumigatus presenting different elastase production patterns.