Essential oils from Moroccan plants as promising ecofriendly tools to control toxic cyanobacteria blooms

• Published in: Industrial crops and products 2020-01, Vol.143, p.111922, Article 111922
• Main Authors: Zerrifi, Soukaina El Amrani, Kasrati, Ayoub, Redouane, El Mahdi, Tazart, Zakaria, Khalloufi, Fatima El, Abbad, Abdelaziz, Oudra, Brahim, Campos, Alexandre, Vasconcelos, Vitor
• Format: Article
• Language: English
• Subjects: Anti-cyanobacterial activity; Bio-control; Essential oils; Microcystis aeruginosa
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2019.111922

•Essential oils were chosen for inhibitory experiment on Microcystis aeruginosa.•Some essential oils totally inhibited the growth of Microcystis aeruginosa in solid medium.•The inhibition rate of several essential oils was quite similar to that obtained by copper sulphate.•The greatest effectiveness was achieved with Thymus broussonetii essential oil. The use of natural compounds obtained from many plant resources are considered the most promising and eco-friendly alternative approach for controlling harmful algae in aquatic ecosystems. In this study, the anti-cyanobacterial activity of essential oils (EOs) extracted from seven Moroccan aromatic and medicinal plants against unicellular Microcystis aeruginosa has been evaluated. The chemical composition of EOs was analyzed by GC–MS, and a total of 55 constituents were identified accounting for 97.6% to 100% of the total oils. The potential algicidal activity was evaluated qualitatively by the application of the paper disk diffusion method in solid medium and quantitatively by the application of broth microdilution methods in liquid medium. The results of solid medium showed that Chenopodium ambrosioides, Thymus broussonetii, Thymus maroccanus and Thymus satureioides essential oils inhibited totally the growth of Microcystis aeruginosa. While, Thymus Pallidus essential oil exhibited the weakest activity. The growth of the tested cyanobacteria was completely inhibited during the 5-days test period in liquid media by Thymus broussonetii, Thymus maroccanus and Thymus satureioides essential oils, while the lowest inhibition rates was observed with Thymus pallidus essential oil. Regarding the Minimum Inhibitory Concentration and Minimum Bactericidal Concentration values, it appears that Thymus broussonetii essential oil displayed the greatest potency, while the weakest effectiveness was achieved with Thymus pallidus essential oil. These findings provide a platform for the development of new ecofriendly and safer botanical materials, which may be used as effective alternative algicidal agents for controlling toxic cyanobacterial blooms.