title: Bioactive polar lipids from Chroococcidiopsis sp. (Cyanobacteria).
abstract: Many studies indicate that various bioactive metabolites subsist in cyanobacteria. Glycolipids of cyanobacteria are reported as molecules that exert specific bioactivities. In this study, total lipids of Chroococcidiopsissp., a coccoid cyanobacterium isolated from a Greek cave, were separated into neutral and polar-lipids and the latter were further fractionated by high-performance liquid chromatography (HPLC). Each polar lipid fraction was tested in vitro for its ability to inhibit platelet-activating factor (PAF)- and thrombin-induced washed rabbit platelet aggregation and/or to cause platelet aggregation. The structures of the most active fractions were elucidated by biological assays and identified by electrospray mass spectrometry. One fraction was a potent inhibitor of PAF-induced platelet aggregation. Structural studies of this fraction indicated the existence of phospho-glyco analog of ceramide. Another fraction that was a potent inhibitor of PAF- as well as of thrombin-induced platelet aggregation was structurally elucidated as a phospho-acetylated glyco-analog of diglyceride. The fraction that induced platelet aggregation was identified as a phospho-acetylated-glyco analog of ceramide. These novel bioactive polar lipids in cyanobacteria in regard to the structure and biological activity may contribute to the allergic character of cyanobacteria.
authors.affiliation: Department of Science of Dietetics-Nutrition, Harokopio University, 70 El. Venizelou Str., 176 71, Athens, Greece. antonop@hua.gr
authors.forename: Smaragdi
authors.initials: S
authors.lastname: Antonopoulou
authors.forename: Haralabos C
authors.initials: HC
authors.lastname: Karantonis
authors.forename: Tzortzis
authors.initials: T
authors.lastname: Nomikos
authors.forename: Alexandra
authors.initials: A
authors.lastname: Oikonomou
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Fragopoulou
authors.forename: Adriani
authors.initials: A
authors.lastname: Pantazidou
mesh_terms: D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008055:Lipids / Q000737:chemistry*; D015394:Molecular Structure; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors; D010974:Platelet Aggregation / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000737:chemistry / Q000378:metabolism; D011817:Rabbits; D021241:Spectrometry, Mass, Electrospray Ionization; D013917:Thrombin / Q000378:metabolism
chemical_list: D008055:Lipids; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D013917:Thrombin