Antioxidative activity of chlorophylls and their efficiencies on food for life

为了阐明植物所必需的叶绿素的抗氧化活性，本文对海洋大型藻类和陆地可食植物的抗氧化活性进行了研究。其中，褐藻和绿叶蔬菜对水溶性自由基引发剂AAPH诱导的亚油酸甲酯过氧化反应表现出较强的抗氧化活性。抗氧化物质的薄层色谱检测方法表明，它们的抗氧化活性与光合色素有关，但尚不清楚是否是类胡萝卜素和chls共同作用的。以水、甲醇和丙酮为流动溶剂，采用反相高效液相色谱法成功分离了亲脂性光合色素，并检测了回收的色素对aaph诱导的脂质过氧化和脂溶性自由基引发剂AMVN诱导的脂质过氧化的抗氧化活性。Chl a…More对AAPH-和amvn诱导的脂质过氧化均表现出较强的抗氧化活性，而Chl c，特别是褐藻Chl，仅对AAPH诱导的脂质过氧化表现出较强的抗氧化活性。此外，类胡萝卜素和chl b的活性不显著。下一步，我们将以菠菜叶为模型实验，对chl的降解过程进行研究。在65℃和100℃加热或酸处理时，Chl a很容易转化为各种降解产物。在长时间煮沸或酸处理过程中，从chl a中释放出Mg^<2+>产生的叶绿素a和叶绿素a的抗氧化活性不显著。经65℃加热，从chl a分子中分离出叶醇基，产生的氯酰基a仍然保持了与chl a相当的抗氧化活性。这表明烹饪过程对chl a的抗氧化活性有重要影响，而chl a分子中的Mg^<2+>可能与chl a分子的抗氧化活性有关。少

In order to elucidate antioxidative activity of chlorophylls (chls), which are essential for all plants, we studied antioxidative activities of marine macroalgae and edible land plants. Among them, the brown algae and green-leafy vegetables showed strong antioxidative activity against methyl linoleate peroxidation induced by water-soluble radical initiator AAPH. A simple detection method on TLC for antioxidative substances indicated that their photosynthetic pigments were participated in their antioxidative activity, although it was still unclear whether both carotenoids and chls were responsible for the potent activity. The lipophilic photosynthetic pigments were successfully separated by a reversed-phase HPLC with water, methanol, and acetone mixture as mobile solvent, and each of the pigments recovered was examined for the antioxidative activity against not only AAPH-induced lipid peroxidation but also against AMVN (lipid-soluble radical initiator)-induced lipid peroxidation. Chl a … More showed strong antioxidative activity against both AAPH- and AMVN-induced lipid peroxidations, while chl c, brown algal particular chl, showed antioxidative activity only against AAPH-induced lipid peroxidation. In addition, carotenoids and chl b did not have significant activity. In the next step, we investigated about chl degradation process by using spinach leaf as the model experiment of food processing and cooking. Chl a was easily converted to various degradation products by heating at 65 and 100C or by acid treatment. Pheophytin a and pheophorbide a, produced by liberating Mg^<2+> from chl a during long-time boiling or acid treatment, did not have significant antioxidative activity. Chloropyllide a, produced by liberating phytol group from chl a molecular during heating at 65C, still maintained potent antioxidative activity, comparable to chl a. This suggests that cooking procedure is important for antioxidative activity of chl a and that Mg^<2+> located in the molecule of chl a would be related to the antioxidative activity. Less