In vitro anti-inflammatory and anti-proliferative activity of sulfolipids from the red alga Porphyridium cruentum

A sulfoglycolipiclic fraction (SIF) isolated from the red microalga Porphyridium cruentum was analyzed for fatty acid composition and assayed for ability to inhibit, in vitro, the generation of superoxide anion in primed leucocytes and the proliferation of a panel of human cancer cell-lines, Results demonstrated that SF contained large amounts of palmitic acid (26.1%), arachidonic acid (C20: 4omega-6, 36.8%), and eicopentaenoic (C20:5omega-3, 16.6%) acids, and noticeable amounts of 16:1n-9 fatty acid (10.5%). It strongly inhibited both the production of superoxide anion generated by peritoneal leukocytes primed with phorbol myristate acetate (IC50: 29.5 mug/mL), and the growth of human colon adenocarcinoma DLD-1 and to a lesser extent of human breast adenocarcinoma MCF-7, human prostate adenocarcinoma PC-3, and human malignant melanoma M4 Beu cell-lines, and therefore might have a chemopreventive or chemotherapeutic potential, or both. It was found markedly more cytotoxic than sulfoquinovosyldiacylglycerols from plant used as a standard (STD), due to a stronger ability to inhibit DNA alpha-polymerase (IC50: 378 mug/mL, vs 1784 mug/mL for STD). After a 48-h continuous treatment, IC50 values for growth inhibition were in the range of 20-46 mug/mL instead of 94 to >250 mug/mL for STD, and those for inhibition of metabolic activity were in the range of 34-87 mug/mL instead of >250 mug/mL for STD. The higher anti-proliferative effect was observed on colon adenocarcinoma DLD-1 cells, and the weaker effect was observed on breast adenocarcinoma MCF-7.