GKK1032C, a new alkaloid compound from the endophytic fungus Penicillium sp. CPCC 400817 with activity against methicillin-resistant S. aureus

Five alkaloid compounds (1–5), including one new compound, GKK1032C (1), and four known compounds, pyrrospirones E (2) and F (3), and GKK1032B (4) and A2 (5) were isolated from the culture of endophytic fungus Penicillium sp. CPCC 400817. The planar structures of all compounds were elucidated by NMR and MS spectra. The relative configuration of new compound GKK1032C (1) was deduced from the vicinal J-values and ROESY spectral data. Compound 1 exhibited potent antibacterial activity against methicillin-resistant Staphylococcus aureus with an MIC value of 1.6？μg？ml？1