Chemical Constituents of the Deep‐Sea‐Derived Penicillium citrinum W22 and Their Ferroptosis Inhibitory Activity

ABSTRACT One new monomeric citrinin analog ( 1 ) and 42 known compounds ( 2–43 ) were isolated from Penicillium citrinum W22. The structure of 1 was determined by detailed analysis of the 1D and 2D nuclear magnetic resonance (NMR), HRESIMS, and time‐dependent density functional theory (TD‐DFT)‐based electronic circular dichroism (ECD) calculation. Penicitrinol A ( 2 ) and methyl 2‐(2‐acetyl‐3,5‐dihydroxy‐4,6‐dimethylphenyl) acetate ( 11 ) significantly inhibited renin‐angiotensin system‐selective lethal 3 (RSL3)‐induced ferroptosis with half maximal effective concentration (EC 50 ) values of 1.6 and 34.0 µM, respectively.