Natural Phenylpropanoids Protect Endothelial Cells Against Oxidized LDL-Induced Cytotoxicity

Abstract

There is increasing evidence that oxidized low-density lipoproteins (Ox-LDL) might be involved in the pathogenesis of atherosclerosis and it has been reported that polyphenols inhibit LDL peroxidation and atherosclerosis. Minimally oxidized LDL (mOx-LDL) induce cytotoxicity in cultured bovine aortic endothelial cells (BAEC). The goal of this study was to test the protective effect of five natural polyphenols isolated from the aerial parts of Marrubium vulgare L. against mOx-LDL-induced cytotoxicity in BAEC. Four phenylpropanoid glycosides (acteoside 1, forsythoside B 2, arenarioside 3, ballotetroside 4) and one non-glycosidic derivative (caffeoyl-l-malic acid 5) were tested. These compounds inhibited both copper (Cu²⁺)- and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced in vitro LDL oxidation and preserved the morphological aspects of BAEC during their incubation with mOx-LDL. Furthermore, they reduced the accumulation of aldehydes in the cultured medium during the incubation of BAEC with mOx-LDL and prevented cellular LDH leakage during this period. These data suggest that natural phenylpropanoids inhibit mOx-LDL-induced cellular toxicity and that inhibition of lipid peroxidation could be a key mechanism in the cytoprotective effect of these molecules.

Key words

Phenylpropanoids - oxidized LDL - cytotoxicity

References

• 1 Seidel V, Bailleul F, Tillequin F. Phenylpropanoid glycosides from Ballota nigra .  Planta Medica. 1996;  62 186-7
• 2 Seidel V, Bailleul F, Libot F, Tillequin F. A phenylpropanoid glycoside from Ballota nigra .  Phytochemistry. 1997;  44 691-3
• 3 Sahpaz S, Garbacki N, Tits M, Bailleul F. Isolation and pharmacological activity of phenylpropanoid esters from Marrubium vulgare .  J Ethnopharmacol. 2002;  79 389-92
• 4 Steinberg D. Low density lipoprotein oxidation and its pathobiological significance.  J Biol Chem. 1997;  272 20 963-6
• 5 Duriez P, Fruchart J C. Free radicals and atherosclerosis. Free radical damage and its control.  In: New comprehensive biochemistry series. Neuberger AL, van Deenen LLM, editors chapter 10 Elsevier Amsterdam, London, New York, Tokyo; 1994: 257-80
• 6 Hayek T, Fuhrman B, Vaya J, Rosenblat M, Belinky P, Coleman R, Elis A, Aviram M. Reduced progression of atherosclerosis in apolipoprotein E-deficient mice following consumption of red wine, or its polyphenols quercetin or catechin, is associated with reduced susceptibility of LDL to oxidation and aggregation.  Arterioscler Thromb Vasc Biol. 1997;  17 2744-52
• 7 Nigdikar S V, Williams N R, Griffin B A, Howard A N. Consumption of red wine polyphenols reduces the susceptibility of low-density lipoproteins to oxidation in vivo .  Am J Clin Nutr. 1998;  68 258-65
• 8 Brown J E, Khodr H, Hider R C, Rice-Evans C A. Structural dependence of flavonoid interactions with Cu²⁺ ions: implications for their antioxidant properties.  Biochem J. 1998;  330 1173-8
• 9 Jessup W, Rankin S M, De Whalley C V, Hoult J R, Leake D S. Alpha-tocopherol consumption during low-density-lipoprotein oxidation.  Biochem J. 1990;  265 399-405
• 10 Van Acker S A, Van den Berg D J, Tromp M N, Griffioen D H, Van Bennekom W P, Van der Vijgh W J, Bast A. Structural aspects of antioxidant activity of flavonoids.  Free Radic Biol Med. 1996;  20 331-42
• 11 Seidel V, Verholle M, Malard Y, Tillequin F, Fruchart J C, Duriez P, Bailleul F, Teissier E. Phenylpropanoids from Ballota nigra L. inhibit in vitro LDL peroxidation.  Phytother Res. 2000;  14 93-8
• 12 Esterbauer H, Wang G, Puhl H. Lipid peroxidation and its role in atherosclerosis.  Br Med Bull. 1993;  49 566-76
• 13 Furman C, Martin-Nizard F, Fruchart J C, Duriez P, Teissier E. Differential toxicities of air (mOx-LDL) or copper-oxidized LDLs (Cu-LDL) toward endothelial cells.  J Biochem Toxicol. 1999;  13 216-323
• 14 Havel R J, Eder H A, Bragdon J H. The distribution and chemical composition of ultra-centrifugally separated lipoproteins in human serum.  J Clin Invest. 1955;  34 1345-53
• 15 Peterson G A. Simplification of the protein assay method of Lowry which is more generally applicable.  Anal Biochem. 1977;  83 346-56
• 16 Furman , Lebeau J, Fruchart J C, Bernier J L, Duriez P, Cotelle N, Teissier E. Di-tert-butylhydroxylated flavonoids protect endothelial cells against oxidized LDL-induced cytotoxicity.  J Biochem Molecular Toxicology. 2001;  15 270-8
• 17 Morel D W, Hessler J R, Chisolm G M. Low density lipoprotein induced by free radical peroxidation of lipid.  J Lip Res. 1983;  24 1070-6
• 18 Thomas J P, Geiger P G, Girotti A W. Lethal damage to endothelial cells by oxidized low density lipoprotein: role of selenoperoxidases in cytoprotection against lipid hydroperoxide- and iron-mediated reactions.  J Lip Res. 1993;  34 479-90
• 19 Lebeau J, Furman C, Fruchart J C, Duriez P, Bernier J L, Teissier E, Cotelle N. Antioxidant properties of di-tert-butylhydroxylated flavonoids.  Free Radic Biol Med. 2000;  29 900-12
• 20 Naito M, Kuzuya M, Iguchi A. Mechanisms of endothelial cell injury induced by oxidatively modified LDL.  J Jap Atheroscl Soc. 1994;  22 257-62