Laboratory for Analysis and Separation of Plant Species (LASEVE), Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada.
J Med Food. 2011 Oct;14(10):1127-34. doi: 10.1089/jmf.2010.0198. Epub 2011 Aug 22.
Brasenia schreberi Gmel. (Cabombaceae) is an aquatic plant that grows in eastern Asia, Australia, Africa, and North and Central America. B. schreberi leaf extracts were obtained by sequential solvent extraction with dichloromethane, methanol, and water. The antioxidant potential of each extract was assessed by using the oxygen radical absorbance capacity (ORAC) assay. With this method, methanol and water extracts were found to be active with mean ± standard deviation values of 7 ± 2 and 5.1 ± 0.5 μmol Trolox® equivalents (TE)/mg, respectively. Two major phenolic compounds, quercetin-7-O-β-D-glucopyranoside and gallic acid, were respectively isolated from the methanolic and water extracts. Both compounds exhibited antioxidant activities, in particular quercetin-7-O-β-D-glucopyranoside (ORAC value, 18 ± 4 μmol TE/μmol). In contrast to its well-known antioxidant homologue quercetin, quercetin-7-O-β-D-glucopyranoside does not inhibit growth of human fibroblasts (WS-1) or murine macrophages (RAW 264.7). Some flavonoids have been reported to possess beneficial effects in cardiovascular and chronic inflammatory diseases associated with overproduction of nitric oxide. Quercetin-7-O-β-D-glucopyranoside possesses anti-inflammatory activity, inhibiting expression of inducible nitric oxide synthase and release of nitric oxide by lipopolysaccharide-stimulated RAW 264.7 macrophages in a dose-dependent manner. Quercetin-7-O-β-D-glucopyranoside also inhibited overexpression of cyclooxygenase-2 and granulocyte macrophage-colony-stimulating factor.
莼菜（Cabombaceae）是一种水生植物，分布于东亚、澳大利亚、非洲以及北美和中美地区。采用二氯甲烷、甲醇和水依次对莼菜叶片进行萃取，以获得提取物。采用氧自由基吸收能力（ORAC）测定法评估各提取物的抗氧化潜力。结果表明，甲醇提取物和水提取物具有活性，其平均±标准偏差值分别为 7±2 和 5.1±0.5 μmol Trolox®当量（TE）/mg。从甲醇提取物和水提取物中分别分离得到两种主要的酚类化合物：槲皮素-7-O-β-D-吡喃葡萄糖苷和没食子酸。这两种化合物均表现出抗氧化活性，特别是槲皮素-7-O-β-D-吡喃葡萄糖苷（ORAC 值为 18±4 μmol TE/μmol）。与广为人知的抗氧化同系物槲皮素不同，槲皮素-7-O-β-D-吡喃葡萄糖苷不会抑制人成纤维细胞（WS-1）或鼠巨噬细胞（RAW 264.7）的生长。一些类黄酮已被报道具有在与一氧化氮过度产生相关的心血管和慢性炎症性疾病中的有益作用。槲皮素-7-O-β-D-吡喃葡萄糖苷具有抗炎活性，可抑制脂多糖刺激的 RAW 264.7 巨噬细胞中诱导型一氧化氮合酶的表达和一氧化氮的释放，并呈剂量依赖性。槲皮素-7-O-β-D-吡喃葡萄糖苷还抑制环氧化酶-2 和粒细胞巨噬细胞集落刺激因子的过度表达。
