Endophytic fungi residing symbiotically in plant tissues are promising sources of bioactive natural products. This study explored the anti-inflammatory potential of an endophytic fungus isolated from the Brazilian medicinal plant Poincianella pluviosa (Sibipiruna). The extract from the endophyte FPD13 exhibited potential ex vivo anti-inflammatory effects by inhibiting prostaglandin E2 (PGE2) release by 75.22%. Phytochemical analysis using High-Performance Liquid Chromatography (HPLC), Nuclear Magnetic Resonance (NMR), and Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) enabled the isolation and identification of three compounds, including the macrolide Nigrosporolide, the phenyl-propanol Tyrosol, and the terpene Decarestrictine A. Morphological characteristics and Internal Transcribed Spacers region (ITS) sequencing classified fungus FPD13 as Nigrospora zimmermanii. The results reveal the anti-inflammatory potential and chemical diversity of P. pluviosa endophytes, warranting further investigation into the bioactivity and structure elucidation of their bioactive metabolites.