N-Hydroxy-Phe-Phe, a new dipeptide, and cytotoxic macrocyclic trichothecenes from the lethal toxic mushroom Podostroma cornu-damae

Podostroma cornu-damae, commonly referred to as the red deer's horn mushroom due to its distinct resemblance to the antlers of a deer, is a lethal toxic mushroom that causes vomiting, dehydration, diarrhea, disturbance of consciousness, and even death. In continuation of our research aiming to investigate the novel structural and/or biological principles present in Korean wild mushrooms, a new N-hydroxyphenylalanine-phenylalanine dipeptide, N-hydroxy-Phe-Phe (1), and three known macrocyclic trichothecenes, satratoxin H (2), 12 '-episatratoxin H (3), and roridin F (4), were isolated from the MeOH extract of a plate culture of the poisonous mushroom P. cornu-damae. The chemical structure of the new dipeptide (1) was determined by analyzing 1D and 2D NMR spectra and high-resolution (HR)-electrospray ionization mass spectroscopy (ESIMS), along with a computational method combined with a statistical procedure (DP4+), and its absolute configuration was unambiguously assigned by quantum chemical ECD calculations. To the best of our knowledge, compound 1 is the first dipeptide found in P. cornu-damae. Upon evaluating the cytotoxicity of compounds 1-4 against four human-derived cancer cell lines namely SK-OV-3, SK-MEL-2, A549, and HCT15, 12 '-episatratoxin H (3) displayed potent cytotoxic effects toward all four cell lines tested, with IC50 values ranging from 0.7 to 2.8 nM, which was found to be stronger than that of doxorubicin. Satratoxin H (2) also demonstrated moderate cytotoxic potency against all four cell lines, with IC50 values ranging from 1.93 to 4.22 mu M. Our findings provide experimental data supporting the potential of the poisonous mushroom P. cornu-damae as a source of anticancer agents.