Division of Biochemistry, Faculty of Fisheries, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan.
Carbohydr Res. 2012 May 1;352:88-93. doi: 10.1016/j.carres.2012.02.005. Epub 2012 Feb 18.
The antioxidant and macrophage-stimulating activities of polyguluronic acid (PG) and polymannuronic acid (PM) prepared from alginate were examined. A chemiluminescence (CL) method using a luminol analog, L-012, showed that both PM and PG scavenge superoxide produced by hypoxanthine-xanthine oxidase system in a concentration-dependent manner. At 100 μg/ml, PG showed slightly stronger superoxide scavenging activity than PM. In an electron spin resonance (ESR)-spin trapping method in which the Fenton reaction was used as hydroxyl radical generation system, we found that both PM and PG showed potent hydroxyl radical scavenging activity to a similar extent. Because PM and PG showed no chelating activity on Fe(2+), it was confirmed that PM and PG can directly scavenge hydroxyl radical. No significant scavenging activity of PM and PG toward hydrogen peroxide was observed. Interestingly, the macrophage-stimulation activity of PG as measured by nitric oxide (NO)-production from mouse macrophage cell line RAW264.7 cells was evidently stronger than that of PM. Our results suggest that RAW264.7 cells might be able to distinguish the conformational differences between PM and PG, and respond differently to them, whereas the effects of such structural differences between PM and PG on the radical scavenging activities may not be so significant.
本文研究了从褐藻酸钠中制备的聚古罗糖醛酸（PG）和聚甘露糖醛酸（PM）的抗氧化和巨噬细胞刺激活性。使用化学发光（CL）法，用鲁米诺类似物 L-012 显示 PM 和 PG 均可浓度依赖性地清除黄嘌呤-黄嘌呤氧化酶系统产生的超氧阴离子。在 100 μg/ml 时，PG 对超氧阴离子的清除活性略强于 PM。在电子自旋共振（ESR）-自旋捕获法中，我们发现 PM 和 PG 对羟自由基均具有很强的清除活性，程度相似。由于 PM 和 PG 对 Fe(2+) 没有螯合活性，因此可以确认 PM 和 PG 可以直接清除羟自由基。PM 和 PG 对过氧化氢没有明显的清除活性。有趣的是，PG 对 RAW264.7 细胞系产生的一氧化氮（NO）的巨噬细胞刺激活性明显强于 PM。我们的结果表明，RAW264.7 细胞可能能够区分 PM 和 PG 之间的构象差异，并对其做出不同的反应，而 PM 和 PG 之间的这种结构差异对清除自由基活性的影响可能并不那么显著。
