The Benthic Dinoflagellate Coolia malayensis (Dinophyceae) Produces an Array of Compounds with Antineoplastic Activity in Cells of Tumor Origin.

Abstract

Among aquatic organisms, marine dinoflagellates are essential sources of bioactive metabolites. The benthic dinoflagellate Coolia malayensis produces metabolites that have exhibited substantial and specific cytotoxicity on cancer cells; however, isolation and identification of the purified compounds remain a challenge. This study reports C. malayensis biomass multi-step extraction plus chemical analyses for identifying compounds with antineoplastic activity. Through bio-directed fractionation, the cytotoxicity of extracts and fractions was tested on H1299 (lung), PC-3 (prostate), HeLa (cervical), and MCF-7 (breast) cancer cell lines. Dichloromethane (DCM) phase, hydroalcoholic (HYD) secondary extract, and methanolic (MET) extract showed cytotoxic effects on all cell lines. Active extracts and fractions were analyzed by HPLC-QTOF-MS, ¹H, and ¹³C NMR. Cell lines H1299 and PC-3 treated with fractions F4, F7, and DCM2-AQ-Ch sub-extract showed morphological changes resembling those observed in the apoptosis control, and no signs of necrosis were observed. The selectivity of fraction F7 was above 100 μg mL^-1 for healthy cells, while cytotoxic activity was observed in cancer cells. This fraction was identified as mostly fatty acids (FA) by NMR. Seventeen compounds with reported biological activities, such as antioxidant, analgesic, antiviral, and anticancer, were identified from C. malayensis extracts and fractions. Among them, the phycotoxins gambieric acid A and B, okadaic acid, and dinophysistoxin-1 were detected. Further studies are needed to reveal more significant anti-cancer potential from C. malayensis.