College of Environmental & Resource Science (CERS), Zhejiang University, Hangzhou, 310012, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou, 310012, China.
Environ Microbiol. 2014 May;16(5):1238-51. doi: 10.1111/1462-2920.12226. Epub 2013 Aug 27.
The inhibitory effect of barley straw (Hordeum vulgare) on cyanobacteria has been observed in many field and laboratory studies for over 30 years, although the compounds responsible for this anti-cyanobacterial effect have remained unknown. In this study, a pair of chiral flavonolignans were isolated from barley straw extract using a bioassay-guided isolation procedure against Microcystis sp. The structures of the allelopathic compounds were elucidated by NMR (nuclear magnetic resonance) and HPLC-MS (high performance liquid chromatography-mass spectrometry), and turned out to be salcolin A and B. The enantiomers differ in their anti-cyanobacterial abilities. Both enantiomers exhibited inhibitory effects on Microcystis sp., and the EC50 (concentration for 50% of maximal effect) of salcolin A and B were 6.02 × 10(-5) and 9.60 × 10(-5 ) mol l(-1) , respectively. Furthermore, the modes of actions of the enantiomers were investigated and compared at a single cell level by flow cytometry. Salcolin A was found to induce an increase on cyanobacterial intracellular ROS (reactive oxygen species) levels and to inhibit esterase activity, whereas salcolin B caused leakages of cyanobacterial cytoplasms. Thus, salcolin A was more 'algistatic', and salcolin B was more 'algicidal'. This study suggests that salcolin is the key allelochemical in barley straw's inhibitory effect on cyanobacteria and could be used as an agent in the future control of cyanobacterial harmful algae blooms.
经过 30 多年的研究，在许多野外和实验室研究中都观察到大麦秸秆（Hordeum vulgare）对蓝藻的抑制作用，尽管负责这种抗蓝藻作用的化合物仍然未知。在这项研究中，使用针对蓝藻属的生物测定指导分离程序从大麦秸秆提取物中分离出一对手性类黄酮木质素。通过 NMR（核磁共振）和 HPLC-MS（高效液相色谱-质谱）阐明了这些化感化合物的结构，它们分别是水杨醇 A 和 B。对映异构体在抗蓝藻能力上存在差异。两种对映异构体均对蓝藻属表现出抑制作用，水杨醇 A 和 B 的 EC50（最大效应的 50%浓度）分别为 6.02×10(-5) 和 9.60×10(-5) mol l(-1)。此外，通过流式细胞术在单细胞水平上研究并比较了对映异构体的作用方式。发现水杨醇 A 诱导蓝藻细胞内 ROS（活性氧）水平升高并抑制酯酶活性，而水杨醇 B 导致蓝藻细胞质泄漏。因此，水杨醇 A 更具有“抑藻”作用，而水杨醇 B 更具有“杀藻”作用。本研究表明，水杨醇是大麦秸秆抑制蓝藻作用的关键化感物质，可作为未来控制蓝藻有害藻华的一种手段。
