Browsing by Author "Ntougias, Spyridon"

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Algae and their metabolites as potential Bio-Pesticides
(Frontiers Media, 2022) Asimakis, Elias; Shehata, Awad A.; Eisenreich, Wolfgang; Acheuk, Fatma; Lasram, Salma; Basiouni, Shereen; Emekci, Mevlüt; Ntougias, Spyridon; Taner, Gökçe Taner; May-Simera, Helen; Yilmaz, Mete; Tsiamis, George
An increasing human population necessitates more food production, yet current techniques in agriculture, such as chemical pesticide use, have negative impacts on the ecosystems and strong public opposition. Alternatives to synthetic pesticides should be safe for humans, the environment, and be sustainable. Extremely diverse ecological niches and millions of years of competition have shaped the genomes of algae to produce a myriad of substances that may serve humans in various biotechnological areas. Among the thousands of described algal species, only a small number have been investigated for valuable metabolites, yet these revealed the potential of algal metabolites as bio-pesticides. This review focuses on macroalgae and microalgae (including cyanobacteria) and their extracts or purified compounds, that have proven to be effective antibacterial, antiviral, antifungal, nematocides, insecticides, herbicides, and plant growth stimulants. Moreover, the mechanisms of action of the majority of these metabolites against plant pests are thoroughly discussed. The available information demonstrated herbicidal activities via inhibition of photosynthesis, antimicrobial activities via induction of plant defense responses, inhibition of quorum sensing and blocking virus entry, and insecticidal activities via neurotoxicity. The discovery of antimetabolites also seems to hold great potential as one recent example showed antimicrobial and herbicidal properties. Algae, especially microalgae, represent a vast untapped resource for discovering novel and safe biopesticide compounds
Antifungal and anti-toxigenic activities of Origanum onites and Thymus capitatus essential oils and ethanolic extracts against mycotoxigenic fungi isolated from barley
(Elsevier, 2025) Dammak, Islem; Hamdi, Zohra; Lamine, Myriam; Hajri, Haifa; Basiouni, Shereen; Ntougias, Spyridon; Tsiamis, George; Yilmaz, Mete; Acheuk, Fatma; Emekci, Mevlut
With the purpose of identifying biological substances for controlling Aspergillus-caused aflatoxin B1 and ochratoxin A contamination in cereals, particularly in barley, we assessed the efficiencies of Origanum onites and Thymus capitatus essential oils (EOs) and ethanolic extracts (EEs) under in vitro conditions. NMR and GC-TOF-MS analysis revealed the metabolite profiles with carvacrol being the major component in both EOs, and various terpenes, carbohydrates, phenols, flavonoids, and alcohols in the complex EEs. All tested EOs and EEs completely inhibited mycelial growth, sporulation, and mycotoxin production in vitro, albeit at different concentrations: O. onites EO displayed higher antifungal and anti-mycotoxigenic activities than T. capitatus EO. Notably, O. onites EO effectively protected barley grains from A. flavus, A. niger, and ochratoxin A and aflatoxin B1 contamination, during storage when applied via fumigation. Antioxidant activities of EEs were generally higher than those of EOs, with O. onites EE being the most potent antioxidant mixture
Status and prospects of botanical biopesticides in europe and mediterranean countries
(MDPI, 2022) Acheuk, Fatma; Basiouni, Shereen; Shehata, Awad A.; Dick, Katie; Hajri, Haifa; Lasram, Salma; Yilmaz, Mete; Emekci, Mevlüt; Tsiamis, George; Spona-Friedl, Marina; May-Simera, Helen; Eisenreich, Wolfgang; Ntougias, Spyridon
Concerning human and environmental health, safe alternatives to synthetic pesticides are urgently needed. Many of the currently used synthetic pesticides are not authorized for application in organic agriculture. In addition, the developed resistances of various pests against classical pesticides necessitate the urgent demand for efficient and safe products with novel modes of action. Botanical pesticides are assumed to be effective against various crop pests, and they are easily biodegradable and available in high quantities and at a reasonable cost. Many of them may act by diverse yet unexplored mechanisms of action. It is therefore surprising that only few plant species have been developed for commercial usage as biopesticides. This article reviews the status of botanical pesticides, especially in Europe and Mediterranean countries, deepening their active principles and mechanisms of action. Moreover, some constraints and challenges in the development of novel biopesticides are highlighted