penicacid S

Penicacid S is a novel mycophenolic acid derivative isolated from the marine-derived fungus *Penicillium senticosum* RCDB005, which was collected from sediment samples in the South China Sea. It is one of several penicacids (O-W) identified as secondary metabolites with potential antineoplastic properties. In preclinical in vitro studies, penicacid S demonstrated potent anti-proliferative activity against human cancer cell lines, specifically showing significant inhibition of the MOLM-13 acute myeloid leukemia (AML) cell line with IC50 values ranging from 0.13 to 1.13 μM. As a derivative of mycophenolic acid, its mechanism of action is likely associated with the inhibition of inosine monophosphate dehydrogenase (IMPDH), the rate-limiting enzyme in the de novo biosynthesis of guanosine nucleotides. This inhibition leads to the depletion of intracellular guanine nucleotide pools, thereby arresting DNA synthesis and cell proliferation in malignant cells.