Institute of Chemistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil.
Department of Biological Sciences, Luiz de Queiroz College of Agriculture, University of São Paulo (USP), Piracicaba, São Paulo, Brazil.
Environ Sci Pollut Res Int. 2021 Oct;28(40):57248-57259. doi: 10.1007/s11356-021-14658-z. Epub 2021 Jun 4.
Due to the public and environmental health impact of cyanotoxins, investigations have been focused on finding environmental friendly algaecides from aquatic plants. The present study had the objective to evaluate the population control and physiological response of Microcystis aeruginosa (Kützing) Kützing (strain BCCUSP232) exposed to Pistia stratiotes L. extracts. Aqueous and ethanolic extracts of P. stratiotes at different concentrations (10, 25, and 50 mg L) were submitted to M. aeruginosa and reduced significantly (p<0.05) the cyanobacterium cell density. The ethanolic extract presented the greatest growth inhibition of the strain at the highest concentration. During exposure to P. stratiotes extracts, intracellular hydrogen peroxide levels, malondialdehyde content, and antioxidant enzymes (peroxidase, catalase, and glutathione S-transferase) activities increased in M. aeruginosa, while total protein concentration decreased when compared to the control group. Superoxide dismutase (SOD) activities presented a sharp decline, suggesting superoxide radical and peroxide accumulation. This implied that SOD was a target for bioactive substance(s) from aqueous and ethanolic extracts of P. stratiotes. Phytochemical screening of the extracts revealed that the ethanolic extract presented 93.36 mg gallic acid equivalent (GAE) per gram dry weight (g DW) total polyphenols and 217.33 mg rutin equivalent (RE) per gram dry weight total flavonoids, and for the aqueous extract, 5.19 mg GAE g DW total polyphenols and 11.02 mg RE g DW total flavonoids were detected. Gas chromatography (GC)/mass spectrometry (MS) analyses of the ethanolic and aqueous extracts presented palmitic acid ethyl ester as major allelochemical. In view of these results, it can be concluded that P. stratiotes showed potential in controlling M. aeruginosa populations.
由于蓝藻毒素对公众健康和环境的影响，人们一直在致力于从水生植物中寻找环保型的杀藻剂。本研究的目的是评估凤眼莲（Pistia stratiotes L.）提取物对铜绿微囊藻（Microcystis aeruginosa （Kützing） Kützing）种群控制和生理响应的影响。将不同浓度（10、25 和 50 mg/L）的凤眼莲水提物和醇提物暴露于铜绿微囊藻中，结果显著降低了蓝藻的细胞密度（p<0.05）。在最高浓度下，醇提物对该菌株的生长抑制作用最大。在暴露于凤眼莲提取物的过程中，铜绿微囊藻细胞内过氧化氢水平、丙二醛含量和抗氧化酶（过氧化物酶、过氧化氢酶和谷胱甘肽 S-转移酶）活性增加，而与对照组相比，总蛋白浓度降低。超氧化物歧化酶（SOD）活性急剧下降，表明超氧自由基和过氧化物的积累。这表明 SOD 是凤眼莲水提物和醇提物中生物活性物质的靶标。提取物的植物化学筛选表明，醇提物每克干重（g DW）总多酚含有 93.36 毫克没食子酸当量（GAE），每克干重总黄酮含有 217.33 毫克芦丁当量（RE），而水提物每克干重总多酚含有 5.19 毫克 GAE，每克干重总黄酮含有 11.02 毫克 RE。醇提物和水提物的气相色谱（GC）/质谱（MS）分析表明，棕榈酸乙酯是主要的化感物质。鉴于这些结果，可以得出结论，凤眼莲具有控制铜绿微囊藻种群的潜力。
