Gao D, Tawa R, Masaki H, Okano Y, Sakurai H
Department of Analytical and Bioinorganic Chemistry, Kyoto Pharmaceutical University, Japan.
Chem Pharm Bull (Tokyo). 1998 Sep;46(9):1383-7. doi: 10.1248/cpb.46.1383.
Baicalein (5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavonoid, was found to prevent human dermal fibroblast cell damage induced by reactive oxygen species such as hydrogen peroxide (H2O2), tert-butyl hydroperoxide (BuOOH) and superoxide anions (.O2-) in a concentration-dependent manner, and was more effective than the iron chelator, deferoxamine, hydroxyl radical (.OH) scavengers such as dimethyl sulfoxide (DMSO) and ethanol (EtOH), the lipid peroxidation chain blocker, alpha-tocopherol (Vit. E) and the xanthine oxidase inhibitor, allopurinol. To probe the mechanism of cell defense, the reaction of baicalein with oxygen free radicals was investigated using electron spin resonance (ESR) spectrometry. Baicalein decreased the signal intensities due to the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin adducts of .OH, .O2- and tert-butyl peroxyl (BuOO.) radicals in a concentration-dependent manner. The IC50 values, which are the 50% inhibition concentrations of baicalein for the free radicals, were 10, 45 and 310 microM, respectively. These results suggested that baicalein possesses free radical scavenging ability which prevents the fibroblast damage induced by these free radical species.
黄芩素（5,6,7-三羟基-2-苯基-4H-1-苯并吡喃-4-酮）是一种天然存在的黄酮类化合物，已发现它能以浓度依赖的方式预防由活性氧如过氧化氢（H2O2）、叔丁基过氧化氢（BuOOH）和超氧阴离子（·O2-）诱导的人皮肤成纤维细胞损伤，并且比铁螯合剂去铁胺、羟基自由基（·OH）清除剂如二甲基亚砜（DMSO）和乙醇（EtOH）、脂质过氧化链阻断剂α-生育酚（维生素E）以及黄嘌呤氧化酶抑制剂别嘌呤醇更有效。为了探究细胞防御机制，使用电子自旋共振（ESR）光谱法研究了黄芩素与氧自由基的反应。黄芩素以浓度依赖的方式降低了由于·OH、·O2-和叔丁基过氧自由基（BuOO·）的5,5-二甲基-1-吡咯啉-N-氧化物（DMPO）自旋加合物产生的信号强度。黄芩素对自由基的50%抑制浓度即IC50值分别为10、45和310微摩尔。这些结果表明黄芩素具有自由基清除能力，可防止这些自由基物种诱导的成纤维细胞损伤。
