Protective effect of pine (Pinus morrisonicola Hay.) needle on LDL oxidation and its anti-inflammatory action by modulation of iNOS and COX-2 expression in LPS-stimulated RAW 264.7 macrophages.
The protective effects of pine (Pinus morrisonicola Hay.) needle on low-density lipoprotein (LDL) oxidation and nitric oxide production in macrophages as well as its bioactive compounds were investigated. Of the four solvent extracts, the ethyl acetate extract of pine needle (EAE-PN) exhibited the strongest scavenging action on free radicals. EAE-PN significantly inhibited copper-induced LDL oxidation through prolonging the lag phase of conjugated dienes formation and decreasing the relative electrophoretic mobility of LDL. Lipid accumulation and foam cell formation were significantly reduced when EAE-PN (75 microg/mL) was added to the medium co-incubated with macrophages cells and copper-induced LDL. EAE-PN also markedly inhibited reactive oxygen species production in RAW 264.7 cells stimulated with lipopolysaccharide (LPS). As regards NO production in cells, EAE-PN showed dose-dependent inhibitory effect on nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. The inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) protein expressions in LPS-stimulated RAW 264.7 cells were inhibited by EAE-PN. RT-PCR analysis indicated that the iNOS and COX-2 mRNA expression were suppressed by EAE-PN. The major phenolic compounds in EAE-PN were epicatechin and p-coumaric acid by HPLC analysis. The presence of epicatechin and p-coumaric acid in EAE-PN may be partially responsible for the biological action of EAE-PN. Taken together, these results suggest that EAE-PN may provide potential protective effects against LDL oxidation and attenuating excessive NO generation at inflammatory sites; consequently, this may contribute to anti-atherosclerotic and anti-inflammatory effects of EAE-PN.
Yen
Gow-Chin
GC
Department of Food Science and Biotechnology, National Chung Hsing University, 250 Kuokuang Road, Taichung 40227, Taiwan. gcyen@nchu.edu.tw
Duh
Pin-Der
PD
Huang
Din-Wen
DW
Hsu
Chin-Lin
CL
Fu
Timothy Yu-Chi
TY
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants / Q000737:chemistry; D001713:Biphenyl Compounds; D015153:Blotting, Western; D002460:Cell Line; D002839:Chromans / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D051546:Cyclooxygenase 2 / Q000096:biosynthesis; D052246:Cyclooxygenase 2 Inhibitors; D024202:Electrophoretic Mobility Shift Assay; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005419:Flavonoids / Q000737:chemistry; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors*; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects*; D051379:Mice; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry; D010851:Picrates / Q000737:chemistry; D028223:Pinus / Q000737:chemistry*; D059808:Polyphenols; D012333:RNA, Messenger / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts; D013844:Thiazoles