Singe cell oil (SCO) based bioactive compounds: II. Enzymatic synthesis of glucose fatty acid esters using SCOs as acyl group-donors and their biological activities
Sugar fatty acid esters, especially glucose fatty acid esters (GEs), have broad applications in food, cosmetic and pharmaceutical industries. In this research the fatty acid moieties derived from polyunsaturated fatty acid containing single cell oils (SCOs), i.e. those produced from Cunninghamella echinulata, Umbelopsis isabellina and Nannochloropsis gaditana as well as from olive oil and an eicosapentaenoic acid (EPA) concentrate were converted into GEs by enzymatic synthesis, using lipases as biocatalysts. The GE synthesis was monitored using thin-layer chromatography, FT-IR and in situ NMR. It was found that GE synthesis carried out using immobilized Candida antarctica B lipase was very effective reaching high yields, near to 100%. It was shown that EPA-GEs were very effective against several pathogenic bacteria and their activity can be attributed to their high EPA content. Furthermore, C. echinulata-GEs were more effective against pathogens comparing to U. isabellina-GEs, probably due to the presence of gamma linolenic acid (GLA) in the lipids of C. echinulate, which is known for its antimicrobial activity, in higher concentrations. C. echinulata-GEs also showed a strong insecticidal activity against Aedes aegypti larvae, followed by EPA-GEs, olive oil-GEs, and N. gaditana-GEs. All synthesized GEs induced apoptosis of the SKOV-3 ovarian cancer cell line, with the apoptotic rate increasing significantly after 48 h. A higher percentage of apoptosis was observed in the cells treated with EPA-GEs, followed by C. echinulata-GEs, U. isabellina-GEs and olive oil-GEs. We conclude that SCOs can be used in the synthesis of GEs with interesting biological properties.