Antiatherogenic effects of kaempferol and rhamnocitrin.
Atherosclerosis is a chronic inflammatory disease of the arterial wall. Kaempferol and rhamnocitrin (kaempferol 7-O-methyl ether) are two anti-inflammatory flavonoids commonly found in plants. The aim of this study is to investigate the function of kaempferol and rhamnocitrin on prevention of atherosclerosis. Chemical analyses demonstrated that kaempferol and rhamnocitrin were scavengers of DPPH (1,1-diphenyl-2-picrylhydrazyl) with IC50 of 26.10 +/- 1.33 and 28.38 +/- 3.07 microM, respectively. Copper-induced low-density lipoprotein (LDL) oxidation was inhibited by kaempferol and rhamnocitrin, with similar potency, as measured by decreased formation of malondialdehyde and relative electrophoretic mobility (REM) on agarose gel, while rhamnocitrin reduced delayed formation of conjugated dienes better than kaempferol. Cholesterol-laden macrophages are the hallmark of atherogenesis. The class B scavenger receptor, CD36, binds oxidized low-density lipoprotein (oxLDL), is found in atherosclerotic lesions, and is up-regulated by oxLDL. Addition of kaempferol and rhamnocitrin (20 microM) caused significant reductions in cell surface CD36 protein expression in THP-1-derived macrophages (p < 0.05). Reverse transcription quantitative PCR (RT-Q-PCR) showed that kaempferol and rhamnocitrin (20 microM) decreased oxLDL-induced CD36 mRNA expression (p < 0.01 and p < 0.05, respectively). Kaempferol- and rhamnocitrin-treated macrophages also showed reduction in 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanide perchlorate (DiI)-labeled oxLDL uptake. Current evidences indicate that kaempferol and rhamnocitrin not only protect LDL from oxidation but also prevent atherogenesis through suppressing macrophage uptake of oxLDL.
Tu
Yi-Chen
YC
Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan 717, Taiwan.
Lian
Tzi-Wei
TW
Yen
Jui-Hung
JH
Chen
Zong-Tsi
ZT
Wu
Ming-Jiuan
MJ
D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000737:chemistry; D050197:Atherosclerosis / Q000517:prevention & control*; D001713:Biphenyl Compounds; D018955:CD36 Antigens / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000008:administration & dosage / Q000737:chemistry; D015870:Gene Expression; D006801:Humans; D020128:Inhibitory Concentration 50; D044949:Kaempferols / Q000008:administration & dosage* / Q000737:chemistry*; D015227:Lipid Peroxidation / Q000187:drug effects; D008077:Lipoproteins, LDL / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D010084:Oxidation-Reduction; D010851:Picrates / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D000893:Anti-Inflammatory Agents; D001713:Biphenyl Compounds; D018955:CD36 Antigens; D005419:Flavonoids; D044949:Kaempferols; D008077:Lipoproteins, LDL; D010851:Picrates; D012333:RNA, Messenger; C099252:oxidized low density lipoprotein; C006552:kaempferol; C004931:1,1-diphenyl-2-picrylhydrazyl