Work

Metabolite profiling and in vitro biological activities of an endophytic Cladosporium sp. AUMC 15471 isolated from Origanum syriacum L

Year: 2026

Type: article

Abstract: Background Endophytic fungi associated with the za’atar plant ( O. syriacum L. ) remain largely underexplored despite their potential as sources of bioactive natural products. Objective This study aimed to characterize the endophytic fungus Cladosporium sp. AUMC 15471 recovered from Origanum syriacum leaves and to investigate its chemical profile and biological activities. Methods Identification of Cladosporium sp. was achieved by morphological and molecular approaches. Comprehensive metabolite profiling of the ethyl acetate (EtOAc) crude extract was conducted using complementary chromatographic and mass spectrometric techniques, including gas chromatography–mass spectrometry (GC–MS), high-performance liquid chromatography (HPLC), and liquid chromatography–tandem mass spectrometry (LC–MS/MS). Results GC–MS analysis tentatively annotated 32 volatile and semi-volatile compounds based on mass spectral database matching and retention index comparison, predominantly monoterpenes, sesquiterpenes, and fatty alcohols. Targeted LC–MS/MS analysis detected 11 metabolites that were assigned based on retention time and mass-spectrometric characteristics in comparison with authentic reference standards. Several of these metabolites have not previously been reported in an endophytic Cladosporium sp. associated with O. syriacum . The EtOAc crude extract exhibited moderate antioxidant activity in the DPPH assay (IC 50 = 230.21 ± 5.96 μg/mL). It also showed low cytotoxic activity against HepG2 hepatocellular carcinoma cells (IC 50 = 93.43 μg/mL), with cell death involving both apoptotic and necrotic pathways. In addition, the extract displayed antibacterial activity against six bacterial species comprising five foodborne bacterial pathogens and one an opportunistic equine pathogen, with inhibition rates of 67.37% ± 2.45% against Staphylococcus aureus and 59.39% ± 1.24% against Campylobacter jejuni . Conclusion Collectively, these findings indicate that Cladosporium sp. associated with O. syriacum is a promising source of chemically diverse metabolites with potential biological activities.

Source: Frontiers in Pharmacology

DOI: 10.3389/fphar.2026.1950031