Nascimento M A, Silva A K, França L C B, Quignard E L J, López J A, Almeida M G
Departamento de Análises Clínicas e Toxicológicas, CCS, UFRN, 59.010-180 Natal, RN, Brazil.
Bioresour Technol. 2006 Aug;97(12):1387-91. doi: 10.1016/j.biortech.2005.07.009. Epub 2005 Oct 11.
Turnera ulmifolia L. is used in Brazilian folk medicine as an anti-inflammatory. Since this activity may be correlated with the presence of antioxidant compounds, a leaf extract was evaluated for its radical scavenging capacity (RSC). The in vitro RSC of a 50% hydroethanolic (HE) extract was evaluated by beta-carotene/linoleic acid coupled oxidation system for the inhibition of oxidation and the lipid peroxidation inhibition in rat brain homogenates, using thiobarbituric acid reactive substances (TBARS) and chemiluminescence (CL). Results indicated, through peroxidation suppression, that this extract exhibited greater antioxidative activity (77.4% +/- 10%) than alpha-tocopherol (58.4% +/- 3.7%). TBARS and CL inhibition was concentration-dependent and Q(1/2) values were 8.2 and 6.0 microg/mL for TBARS and CL, respectively. For alpha-tocopherol these values were 7.1 microg/mL (TBARS) and 9.8 microg/mL (CL). Phenolic compounds may be responsible for this antioxidant capacity.
白花时钟花在巴西民间医学中用作抗炎药。由于这种活性可能与抗氧化化合物的存在有关，因此对一种叶提取物的自由基清除能力（RSC）进行了评估。通过β-胡萝卜素/亚油酸偶联氧化系统，利用硫代巴比妥酸反应性物质（TBARS）和化学发光（CL），评估了50%乙醇水溶液（HE）提取物对大鼠脑匀浆氧化的抑制作用以及脂质过氧化抑制作用的体外RSC。结果表明，通过抑制过氧化作用，该提取物表现出比α-生育酚（58.4%±3.7%）更强的抗氧化活性（77.4%±10%）。TBARS和CL抑制作用呈浓度依赖性，TBARS和CL的Q(1/2)值分别为8.2和6.0μg/mL。对于α-生育酚，这些值分别为7.1μg/mL（TBARS）和9.8μg/mL（CL）。酚类化合物可能是这种抗氧化能力的原因。
