Secondary metabolites from the co-culture of Penicillium janthinellum and Penicillium raistrickii

A total of 17 compounds, including a hitherto unidentified carotane sesquiterpenoid ( 1 ) and 16 known compounds ( 2 – 17 ), were isolated from the co-culture of Penicillium janthinellum and Penicillium raistrickii . Structural elucidation was achieved by a range of techniques including nuclear magnetic resonance (NMR), high-resolution electrospray ionization mass spectrometry (HRESIMS) and electronic circular dichroism (ECD) calculations. Subsequently, the binding interaction of the compounds toward Keap1 (Kelch-like ECH-associated protein 1) was evaluated by affinity ultrafiltration-ultra performance liquid chromatography-mass spectrometry (AU-UPLC-MS). This approach revealed that compounds 4 – 6 , 9 – 11 , and 13 – 16 exhibited potential binding interactions toward Keap1. Molecular docking simulations showed binding energies ranging from –7.6 to –10.2 kcal/mol. These results indicated that compounds 4 – 6 , 9 – 11 , and 13 – 16 exhibited affinity for the Keap1 protein. These findings provide a foundation to establish whether these compounds possess potential antioxidant activity mediated through modulation of the Keap1–Nrf2 pathway.