Monounsaturated fatty acid oligomerization is responsible for the agglutination activity of heated virgin olive oil

The present study focuses on the isolation, purification and characterization of a molecule formed when virgin olive oil is heated at 130°C for 24 h in air, that is found to be a strong agglutinin. The hemagglutinating activity of the novel molecule isolated from the heated olive oil was evaluated against human red blood cells (RBCs). Thin layer chromatography (TLC) of the oil mixture showed appearance of high molecular weight molecules, dimers and polymers. ¹³C nuclear magnetic resonance (NMR) and mass chromatography-mass spectroscopy (GC-MS) were used for structure elucidation. A linear oligomerization of monounsaturated fatty acids is involved. Light microscopy and electron microscopy were used to characterize and visualize the agglutination process. Agglutination without lysis or fusion was observed. The unheated olive oil and the isolated compound were also tested in-vitro against normal and malignant colon and breast cells. The results showed the highest reduction of tumor cells with the isolated novel compound. We conclude that virgin olive oil when heated in air produces oligomerization/polymerization of free unsaturated fatty acid possibly oleic acid (OA) that is a strong hemagglutinin against human RBCs with possible anti-cancer properties but with unknown nutritional effects on human health.