Samy, Mamdouh NLe Goff, GéraldineLopes, PhilippeGeorgousaki, KaterinaGumeni, SentiljanaAlmeida, CelsoGonzález, IgnacioGenilloud, OlgaTrougakos, IoannisFokialakis, NikolasOuazzani, Jamal2023-01-252023-01-252019-06-15http://hdl.handle.net/10668/14131The strain Streptomyces osmaniensis CA-244599 isolated from the Comoros islands was submitted to liquid-state fermentation coupled to in situ solid-phase extraction with amberlite XAD-16 resin. Elution of the trapped compounds on the resin beads by ethyl acetate afforded seven metabolites, osmanicin (1), streptazolin (2), streptazone C (3), streptazone B1 (4), streptenol C (5), nocardamine (6) and desmethylenylnocardamine (7). Osmanicin (1) is a newly reported unusual scaffold combining streptazolin (2) and streptazone C (3) through a Diels-Alder type reaction. Experimental evidence excluded the spontaneous formation of 1 from 2 and 3. The isolated compounds were evaluated for their ability to inhibit elastase using normal human diploid fibroblasts. Compound 1 exhibited the most potent activity with an IC50 of 3.7 μM.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Streptomyces osmaniensisalkaloidselastase inhibitionin situ solid-phase extractionosmanicinAlkaloidsBiosynthetic PathwaysCell SurvivalDose-Response Relationship, DrugFermentationFibroblastsHumansMagnetic Resonance SpectroscopyModels, MolecularMolecular ConformationMolecular StructurePancreatic ElastasePolyketidesRNA, Ribosomal, 16SStreptomycesresearch article31208056open access10.3390/molecules241222391420-3049PMC6630352https://www.mdpi.com/1420-3049/24/12/2239/pdf?version=1560584916https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6630352/pdf