羊肚菌多酚的化学生物学表征与抗氧化作用机制研究

Free radical oxidatives (ROS) is considered as one of the most important reasons which would cause cell mutation, organ damage, even severe diseases. According to current scientific reports, excess ROS in human body would induce lipid peroxidation, inflammation, fatty acid over- accumulation etc. eventually lead to cardiovascular disease, arteriosclerosis, cancer, diabetes and aging abnormality. So far, the most effective way to reverse ROS induced organ damage and total content of ROS in human body is through phytochemical administration. Epidemiological studies indicated that polyphenols from plants would be a great potent phytochemicals, which can prevent ROS damage and reduce the amount of ROS in body. Among all plants, fruis, vegetables and fungi are the best source of polyphenols. Morchella angusticeps Peck. is one of fungis which has the highest content of polyphenols and exhibits significant antioxidative activity. However, the molecular mechanism of ROS regulation and antioxidant activity still remain unclear due to their structural complexity. In this study, our purpose is to determine the content and structure characteristics of polyphenols in Morchella angusticeps Peck. and elucidate the molecular mechanism of antioxidant activity both in vitro and in vivo. These results would provide unique insights to explore the relationship between polyphenosl in Morchella angusticeps Peck and human health.

由各种氧自由基所引发的氧化作用，是导致身体中各组分和器官损伤、病变的重要原因之一。现已证实，动脉硬化、心脏病、肿瘤、糖尿病、衰老等近百种疾病的发生和发展均与氧化和自由基的过量产生、积累与脂质过氧化的增加有密切关系。最有效的方法之一是通过营养干预来降低体内氧自由基含量、减少氧化损伤。许多研究证实，植物多酚是很好的抗氧化剂，能够有效地阻断和消除各种氧化损伤而起到保护身体健康的作用。果蔬和食用菌是很好的多酚类物质来源。羊肚菌多酚是羊肚菌子实体中含有的抗氧化活性物质，但由于它的化学组成和结构十分复杂，其调控自由基产生和氧化损伤的抗氧化效果和分子机制还不清楚。本项目拟对黑脉羊肚菌多酚的化学组成、结构表征、抗氧化活性评价进行深入研究，采用细胞模型和动物模型多方位探明多酚在体内的抗氧化作用及分子机制。为揭示羊肚菌多酚类化合物与人体健康的关系提供理论依据。

植物多酚具有很好的抗氧化活性，能够有效地阻断和修复各种氧化损伤而起到保护机体健康的作用。本项目以黑脉羊肚菌（Morchella angusticepes Peck）为材料，全面研究了羊肚菌多酚（游离酚、结合酚）提取工艺、组分鉴定及抗氧化活性评价；分别采用动物模型和细胞模型研究了羊肚菌多酚对D-氨基半乳糖/脂多糖（D-GalN/LPS）诱导急性肝损伤的修复作用和对H2O2诱导的HepG2细胞氧化损伤的保护作用及其机制；同时研究了羊肚菌多酚通过激活p38/MAPK信号通路抑制HepG2细胞增殖和诱导细胞凋亡作用，初步探明了羊肚菌多酚抗氧化活性的分子生物学机制。研究结果表明，羊肚菌多酚以游离酚为主，游离酚含量为6.272±0.016 mg GAE/g DW，结合酚含量为0.618±0.013 mg GAE/g DW，游离酚抗氧化活性高于结合酚；经组分鉴定发现荭草素含量最高。细胞实验结果表明，羊肚菌多酚通过激活HepG2细胞内Nrf2-Keap1-ARE信号通路，启动下游II相解毒酶和细胞保护性蛋白基因表达，参与细胞抗氧化，增强对H2O2诱导的HepG2细胞氧化应激损伤的保护作用；通过激活p38/MAPK信号通路抑制HepG2细胞增殖和诱导细胞凋亡。动物实验结果表明，羊肚菌多酚通过促进Nrf2核转位、增加Nrf2转录和抑制Keap1转录，激活Nrf2/ARE信号通路，对D-GalN/LPS诱导的小鼠急性肝损伤具有一定的修复作用。为揭示羊肚菌多酚类化合物促进人体健康提供理论依据，对于羊肚菌多酚功能活性挖掘与功能食品开发具有重要意义。