Takamatsu Satoshi, Hodges Tyler W, Rajbhandari Ira, Gerwick William H, Hamann Mark T, Nagle Dale G
National Center for Natural Products Research, Department of Pharmacognosy, School of Pharmacy, University of Mississippi, 38677-1848, USA.
J Nat Prod. 2003 May;66(5):605-8. doi: 10.1021/np0204038.
Pure natural products isolated from marine sponges, algae, and cyanobacteria were examined for antioxidant activity using a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) solution-based chemical assay and a 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) cellular-based assay. The DCFH system detects only antioxidants that penetrate cellular membranes. Potent antioxidants were identified and the results from each system compared. The algal metabolites cymopol (1), avrainvilleol (3), and fragilamide (4), and the invertebrate constituent puupehenone (5) showed strong antioxidant activity in both systems. Several compounds were active in the DPPH assay but significantly less active in the DCFH system. The green algal metabolite 7-hydroxycymopol (2) was isolated from Cymopolia barbataand its structure determined. Compound 2 was significantly less active in the DCFH system than cymopol (1). The sponge metabolites (1S)-(+)-curcuphenol (6), aaptamine (7), isoaaptamine (8), and curcudiol (9) and the cyanobacterial pigment scytonemin (10) showed strong antioxidant activity in the DPPH assay, but were relatively inactive in the DCFH system. Thus, cellular uptake dramatically affects the potential significance of antioxidants discovered using only the DPPH assay. The apparent "proantioxidants" hormothamnione A diacetate (11) and Laurencia monomer diacetate (12) require metabolic activation for antioxidant activity. Significant advantages are achieved using both a solution- and cellular-based assay to discover new antioxidants.
从海洋海绵、藻类和蓝细菌中分离出的纯天然产物，通过基于2,2 - 二苯基 - 1 - 苦基肼自由基（DPPH）溶液的化学分析和基于2',7' - 二氯二氢荧光素二乙酸酯（DCFH - DA）的细胞分析来检测其抗氧化活性。DCFH系统仅检测能够穿透细胞膜的抗氧化剂。鉴定出了强效抗氧化剂，并比较了每个系统的结果。藻类代谢产物 cymopol（1）、avrainvilleol（3）和 fragilamide（4），以及无脊椎动物成分 puupehenone（5）在两个系统中均表现出强抗氧化活性。几种化合物在DPPH分析中具有活性，但在DCFH系统中的活性明显较低。从巴氏藻（Cymopolia barbata）中分离出绿藻代谢产物7 - 羟基 cymopol（2）并确定了其结构。化合物2在DCFH系统中的活性明显低于 cymopol（1）。海绵代谢产物（1S）-（+）- 姜黄酚（6）、aaptamine（7）、异aaptamine（8）和姜黄二酚（9）以及蓝细菌色素scytonemin（10）在DPPH分析中表现出强抗氧化活性，但在DCFH系统中相对无活性。因此，细胞摄取显著影响仅使用DPPH分析发现的抗氧化剂的潜在意义。表观“前抗氧化剂”hormothamnione A二乙酸酯（11）和 Laurencia单体二乙酸酯（12）需要代谢激活才能具有抗氧化活性。同时使用基于溶液和细胞的分析来发现新的抗氧化剂具有显著优势。
