title: Hypolipidemic Effect of a Blue-Green Alga (Nostoc commune) Is Attributed to Its Nonlipid Fraction by Decreasing Intestinal Cholesterol Absorption in C57BL/6J Mice.
abstract: We previously demonstrated that Nostoc commune var. sphaeroids Kützing (NO), a blue-green alga (BGA), exerts a hypolipidemic effect in vivo and its lipid extract regulates the expression of genes involved in cholesterol and lipid metabolism in vitro. The objective of this study was to investigate whether the hypolipidemic effect of NO is attributed to an algal lipid or a delipidated fraction in vivo compared with Spirulina platensis (SP). Male C57BL/6J mice were fed an AIN-93M diet containing 2.5% or 5% of BGA (w/w) or a lipid extract equivalent to 5% of BGA for 4 weeks to measure plasma and liver lipids, hepatic gene expression, intestinal cholesterol absorption, and fecal sterol excretion. Plasma total cholesterol (TC) was significantly lower in 2.5% and 5% NO-fed groups, while plasma triglyceride (TG) levels were decreased in the 5% NO group compared with controls. However, neither NO organic extract (NOE) nor SP-fed groups altered plasma lipids. Hepatic mRNA levels of sterol regulatory element-binding protein 2, 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), carnitine palmitoyltransferase-1α, and acyl-CoA oxidase 1 were induced in 5% NO-fed mice, while there were no significant changes in hepatic lipogenic gene expression between groups. NO, but not NOE and SP groups, significantly decreased intestinal cholesterol absorption. When HepG2 cells and primary mouse hepatocytes were incubated with NOE and SP organic extract (SPE), there were marked decreases in protein levels of HMGR, low-density lipoprotein receptor, and fatty acid synthase. In conclusion, the nonlipid fraction of NO exerts TC and TG-lowering effects primarily by inhibiting intestinal cholesterol absorption and by increasing hepatic fatty acid oxidation, respectively.
authors.affiliation: 1 Department of Nutritional Sciences, University of Connecticut , Storrs, Connecticut, USA .
authors.forename: Chai Siah
authors.initials: CS
authors.lastname: Ku
authors.affiliation: 1 Department of Nutritional Sciences, University of Connecticut , Storrs, Connecticut, USA .
authors.forename: Bohkyung
authors.initials: B
authors.lastname: Kim
authors.affiliation: 1 Department of Nutritional Sciences, University of Connecticut , Storrs, Connecticut, USA .
authors.forename: Tho X
authors.initials: TX
authors.lastname: Pham
authors.affiliation: 1 Department of Nutritional Sciences, University of Connecticut , Storrs, Connecticut, USA .
authors.forename: Yue
authors.initials: Y
authors.lastname: Yang
authors.affiliation: 2 Department of Biological Systems Engineering, University of Nebraska , Lincoln, Nebraska, USA .
authors.forename: Curtis L
authors.initials: CL
authors.lastname: Weller
authors.affiliation: 3 Department of Nutrition and Health Sciences, University of Nebraska , Lincoln, Nebraska, USA .
authors.forename: Timothy P
authors.initials: TP
authors.lastname: Carr
authors.affiliation: 1 Department of Nutritional Sciences, University of Connecticut , Storrs, Connecticut, USA .
authors.forename: Young-Ki
authors.initials: YK
authors.lastname: Park
authors.affiliation: 1 Department of Nutritional Sciences, University of Connecticut , Storrs, Connecticut, USA .
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Lee
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D001688:Biological Products / Q000494:pharmacology*; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D002784:Cholesterol / Q000097:blood / Q000378:metabolism*; D019587:Dietary Supplements; D064429:Fatty Acid Synthases / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D000960:Hypolipidemic Agents / Q000494:pharmacology*; D007408:Intestinal Absorption / Q000187:drug effects*; D050356:Lipid Metabolism / Q000235:genetics; D008055:Lipids / Q000097:blood / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000097:blood; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D050501:Nostoc commune / Q000737:chemistry; D010936:Plant Extracts / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism; D053545:Spirulina; D014280:Triglycerides / Q000097:blood
chemical_list: D000214:Acyl Coenzyme A; D001688:Biological Products; D000960:Hypolipidemic Agents; D008055:Lipids; D008077:Lipoproteins, LDL; D010936:Plant Extracts; D012333:RNA, Messenger; D011973:Receptors, LDL; D014280:Triglycerides; C015901:glutaryl-coenzyme A; D002784:Cholesterol; D002334:Carnitine O-Palmitoyltransferase; D064429:Fatty Acid Synthases
keywords: Nostoc commune var; Spirulina platensis; blue-green algae; hypolipidemia; sphaeroids Kützing