Allegra Mario, Tesoriere Luisa, Livrea Maria A
Department of Pharmaceutical, Toxicological and Biological Chemistry, Università di Palermo, Italy.
Free Radic Res. 2007 Mar;41(3):335-41. doi: 10.1080/10715760601038783.
Production of nitrogen dioxide by the activity of myeloperoxidase (MPO) in the presence of nitrite is now considered a key step in the pathophysiology of low-density lipoprotein (LDL) oxidation. This study shows that betanin, a phytochemical of the betalain class, inhibits the production of lipid hydroperoxides in human LDL submitted to a MPO/nitrite-induced oxidation. Kinetic measurements including time-course of particle oxidation and betanin consumption, either in the presence or in the absence of nitrite, suggest that the antioxidant effect is possibly the result of various actions. Betanin scavenges the initiator radical nitrogen dioxide and can also act as a lipoperoxyl radical-scavenger. In addition, unidentified oxidation product(s) of betanin by MPO/nitrite inhibit(s) the MPO/nitrite-induced LDL oxidation as effectively as the parent compound. In the light of betanin bioavailability and post-absorbtion distribution in humans, present findings may suggest favourable in vivo activity of this phytochemical.
在亚硝酸盐存在的情况下，髓过氧化物酶（MPO）的活性产生二氧化氮现在被认为是低密度脂蛋白（LDL）氧化病理生理学中的关键步骤。本研究表明，甜菜红碱，一种甜菜碱类的植物化学物质，可抑制在MPO/亚硝酸盐诱导的氧化作用下的人LDL中脂质氢过氧化物的产生。动力学测量包括在有或没有亚硝酸盐存在的情况下颗粒氧化和甜菜红碱消耗的时间进程，表明抗氧化作用可能是多种作用的结果。甜菜红碱清除引发自由基二氧化氮，并且还可以作为脂过氧自由基清除剂。此外，MPO/亚硝酸盐对甜菜红碱的未鉴定氧化产物抑制MPO/亚硝酸盐诱导的LDL氧化的效果与母体化合物一样有效。鉴于甜菜红碱在人体内的生物利用度和吸收后分布情况，目前的研究结果可能表明这种植物化学物质具有良好的体内活性。
