Prorocentin-5: A Cytotoxic Polyketide from the Benthic Marine Dinoflagellate Prorocentrum lima

Prorocentrin-5 (1) was isolated from the benthic marine dinoflagellate Prorocentrum lima. A combination of NMR spectroscopy, quantum chemical calculations, and chemical reactions was then employed to elucidate its molecular structure, including the configurations of all stereogenic centers. In cytotoxicity assays, prorocentin-5 exhibited potent activity against the HCT-116 and Neuro2a cell lines, with IC50 values of 4.4 and 2.8 μM, respectively. Furthermore, 1 increased the apoptotic cell population and induced cell cycle arrest, leading to the accumulation of cells in the S or G2/M phase and an accompanying decrease in the G0/G1 phase in HCT-116, Neuro2a, and HepG2 cells.