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    Characterization of Diaporthe fungal extract composition and phytotoxicity on the aquatic noxious weed Eichhornia crassipes: inhibitory effects on photosynthetic machinery and membrane integrity
    (2025-01-01) ;
    Manichart, Nutcha
    ;
    Thongbang, Muanfan
    ;
    Wichittrakarn, Pattharin
    ;
    Fungal extract-based natural herbicides are a promising avenue for the development of sustainable weed management. The study investigates the herbicidal activity of fungal extracts against the prominent aquatic invasive weed Eichhornia crassipes (water hyacinth). The ethanol crude fraction derived from Diaporthe sp. strain EC010 demonstrated the highest phytotoxicity. Chemical characterization using gas chromatography-mass spectrometry revealed 2(3H)-furanone, dihydro-4-hydroxy- (22.81%), linoelaidic acid (6.87%), and hordenine (6.62%) as major constituents. Phytotoxicity was evaluated by wrapping bioassay under greenhouse conditions. Observable foliar damage, such as necrosis, chlorosis, and depigmentation, occurred within 1 day after treatment (DAT). The rapid onset of visible damage within 1 DAT and the detailed analysis of tissue damage are particularly noteworthy. Lesion progression reflected the phytotoxicity of the extract, increasing to 77.33% visible phytotoxicity at 14 DAT for the highest concentration (8.0% w/v). Microscopic analysis revealed disintegration and complete deformation of epidermal and parenchymal tissues, and treated plants featured extensive aerenchyma spaces. Furthermore, the Diaporthe sp. extract decreased chlorophyll a, b, and carotenoid concentrations while increasing electrolyte leakage and malondialdehyde, indicative of weed deterioration. The current work offers valuable insights for sustainable and eco-friendly strategies in the management of water hyacinth populations in a lentic ecosystem. The findings suggest that Diaporthe sp. extract could serve as a natural herbicide, offering an environmentally friendly alternative to synthetic chemicals in managing water hyacinth.
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    Microparticles of calcium carbonate CaCO3, calcium hydrogen phosphate hydrate CaHPO41.9H2O and tricalcium phosphate Ca3(PO4)2 prepared from golden apple snail shells (Pomacea canaliculata)
    The golden apple snail shell was mechanically milled to transform to 400 mesh sizes of calcium carbonate CaCO3. The obtained CaCO3 was reacted with phosphoric acid by a simple rapid reaction to prepare dicalcium phosphate hydrate CaHPO4<sup>.</sup>1.9H2O. Thermal transformation products of the as-synthesized CaCO3 and CaHPO4<sup>.</sup>1.9H2O samples occurred at above 750 <sup>o</sup>C indicating the temperature condition to synthesize tricalcium phosphate Ca3(PO4)2 by solid state route. The as-synthesized CaCO3 and CaHPO4 powders were well mixed in the mole ratio of 1:2, then calcined at 800 <sup>o</sup>C for 2 hrs. and the obtained product was Ca3(PO4)2. The XRD and FTIR results indicate that the as-prepared CaCO3, CaHPO4 and Ca3(PO4)2 samples without the presence of any phase impurities crystalize in orthorhombic of aragonite, anorthic, rhombohedral phases respectively, The SEM micrographs show nonuniform, wooden fiber-like, grainy rice-like and irregular and non-uniform shapes for the as-prepared CaCO3, CaHPO4 and Ca3(PO4)2 samples respectively.
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    Oxidative damage in Echinochloa crus−galli seeds exposed to Diaporthe sp. (Diaporthales, Ascomycota) fungal extract during germination
    (2024-01-01) ;
    Manichart, Nutcha
    ;
    ;
    Wichittrakarn, Pattharin
    ;
    Yoneyama, Kaori
    This study investigates the inhibitory effects of Diaporthe sp. isolate EC010 extract on barnyardgrass (Echinochloa crus-galli) seed germination and growth. Application of sequential extraction techniques to Diaporthe sp. mycelium resulted in partial separation of the phytotoxic compounds. The ethyl acetate (EtOAc) fraction most greatly reduced seed germination (81.01%), root length (89.18%), and shoot length (84.74%) compared to the control. Chemical characterization using gas chromatography-mass spectrometry revealed major constituents of linoleic acid, butyl ester (9.69%), hexadecanoic acid (7.99%), and 14-pentadecenoic acid (7.86%). With regard to physiological and biochemical indexes, treated seeds exhibited lower imbibition, significantly decreased α-amylase (EC 3.2.1.1) activity (p<0.05), and increased accumulation of malondialdehyde (85.52%) and hydrogen peroxide (141.10%). Moreover, activity of the antioxidant enzymes superoxide dismutase (EC 1.15.1.1) and guaiacol peroxidase (EC 1.11.1.7) was upregulated (67.24 and 61.62%, respectively), while catalase (EC 1.11.1.6) activity was downregulated (-33.75%). The inference is that an imbalance in ROS levels combined with reduced antioxidant potential drives the gradual accumulation of oxidative damage in seed cells and consequent loss of seed viability. All told, these results confirm the Diaporthe extract to induce oxidative stress and inhibit antioxidant enzymes. This study clearly demonstrates the oxidative damage associated with Diaporthe allelochemicals.
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    Effect of crude ethanolic extracts from bottle brush (Callistemon viminalis) against leaf spot fungi and their phytotoxicity on lettuce (lactuca sativa l.)
    (2020-01-01)
    Somnuek, Suriyasit
    ;
    Jaenaksorn, Tanimnun
    ;
    In response to the public concern about environmental problems as well as fungicide residues on agricultural produces especially leaf vegetables, we investigated the potential use of crude extracts from bottle brush (C. viminalis) leaves against leaf spot fungi and their phytotoxicity on lettuce grown in hydroponics. Yield, total phenolic and flavonoid contents of the extract were also evaluated. Regarding the in vitro antifungal assay using poisoned food technique, 3×3 factorial in Completely Randomized Design (CRD) was employed with three replicates. Factor A was 3 crude extracts (50% ethanol, 70% ethanol and 95% ethanol crude extract) while factor B was the 3 concentrations (0, 5,000 and 50,000 ppm) of crude extracts. Results showed that all three crude extracts were significantly effective in inhibiting the mycelial growth and sporulation of leaf spot fungi (Alternaria sp. and Curvalaria sp.). There was a significant interaction between all extracts and their concentration regarding inhibition percent. Increase in crude extract concentrations resulted in a marked increase in their inhibition. The 50,000 ppm gave the highest effectiveness. For phytotoxicity test, all tested crude extracts did not give any negative effects either on seed germination or growth of lettuce grown in hydroponics. Interestingly, growth promotion about 30 percent was achieved on this regard. Based on quantitative assay, the highest yield of crude extract was obtained from 95% ethanol solvent. Highest total phenolic and flavonoid contents were detected at the highest concentration of all crude extracts.
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    Structure-Activity Relationship Study of Xanthoxyline and Related Small Methyl Ketone Herbicides
    Xanthoxyline (1), a small natural methyl ketone, was previously reported as a plant growth inhibitor. In this research, related methyl ketones bearing electron-donating and electron-withdrawing groups, together with heteroaromatics, were investigated against seed germination and seedling growth of Chinese amaranth (Amaranthus tricolor L.) and barnyard grass [Echinochloa crus-galli (L.) Beauv]. The structure-activity relationships (SARs) of methyl ketone herbicides were clarified, and which types and positions of substituents were crucially important for activity were also clarified. Indole derivatives, namely, 3-acetylindole (43) and 3-acetyl-7-azaindole (44) were found to be the most active methyl ketones that highly suppressed plant growth at low concentrations. The molecular docking on the 4-hydroxyphenylpyruvate dioxygenase (HPPD) enzyme indicated that carbonyl, aromatic, and azaindole were key interactions of HPPD inhibitors. This finding would be useful for the development of small ketone herbicides.
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    Allelopathic potential of subfractions from aqueous extract of spirulina platensis and denatured c-phycocyanin
    In this laboratory bioassay, crude aqueous extract of Spirulina platensis (Nordst) Geitl. was extracted with 90% aqueous ethanol and 80% aqueous ethanol to achieve three subfractions, green powder (F1), pale-green powder (F2) and deep-blue powder (F3). Each of these subfractions was evaluated for allelopathic activity on Chinese amaranth (Amaranthus tricolor L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv.). The plant seeds were germinated in vials with three subfractions (250-2000 mg/l concentrations) and distilled water was used as a negative control. The results indicated that subfraction F3 had the highest inhibitory effect on both of the tested plants. All subfractions had an absorbance ratio (A620/A280) lower than the original aqueous extract, suggesting that a denaturation event of the C-phycocyanin (C-PC) component had occurred during the extraction process. After heating a commercial C-PC solution at 90<sup>o</sup>C for 3 h, the absorbance ratio changed to 0.46, and likewise allelopathic assay revealed that the decolorized C-PC solution retained its allelopathic potential on the tested plants. To confirm these findings, S. platensis powder was extracted with distilled water at 90<sup>o</sup>C for 3 h and tested for its allelopathic potential using standard Petri dish assay at concentrations of 0.625-5%. The results showed that the hot aqueous extract had an absorbance ratio of 0.38, and its allelopathic activities were similar to those of the aqueous extract. Furthermore, it was found that although C-PC in aqueous extractions denatured, it still retained its allelopathic potential on the tested plants.
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    Binary Mixtures of Essential Oils: Potent Housefly Adulticides That Are Safe Against Non-Target Species
    (2025-08-01) ;
    Sittichok, Sirawut
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    Moungthipmalai, Tanapoom
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    Murata, Kouhei
    In this study, we investigated the insecticidal potential of Eucalyptus globulus Labill. and Cymbopogon citratus Stapf essential oils (EOs), both alone and in synergistic blends with their primary active compounds, against adult houseflies (Musca domestica L.). Toxicity assessments were also conducted on non-target organisms—dwarf honeybees (Apis florea Fabricius) and guppies (Poecilia reticulata Peters)—to evaluate environmental safety. All binary EO mixtures demonstrated superior efficacy compared to individual EOs and the synthetic pyrethroid α-cypermethrin (1% positive control). The most potent formulation, combining 2.5% (v/v) geranial with 2.5% (v/v) E. globulus EO, exhibited a synergistic effect, achieving complete fly mortality (LT<inf>50</inf>: 0.06 h). This mixture’s mortality index significantly exceeded those of single-component formulations, with a mortality index of 0.22, confirming greater toxicity to flies than α-cypermethrin. Importantly, all the tested EOs and their blends were non-toxic to honeybees and guppies; in comparison, α-cypermethrin caused significant harm. These findings highlight the 2.5% (v/v) geranial + 2.5% (v/v) E. globulus EO blend as a highly effective and environmentally friendly alternative to conventional insecticides. Further research is recommended to optimize its formulation for practical use in sustainable fly management.
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    Impact of Nigrospora oryzae-Derived Natural Products on Photosynthesis and Oxidative Stress in Eichhornia crassipes
    (2025-01-01) ;
    Manichart, Nutcha
    ;
    Wichittrakarn, Pattharin
    ;
    Yoneyama, Kaori
    ;
    Interest in natural herbicides has been growing due to government policies restricting synthetic herbicide use in many countries. In that regard, this study investigates the potential of Nigrospora oryzae extract as a natural herbicide against the aquatic invasive weed Eichhornia crassipes. A stable formulation was developed with a droplet size of 36.44 ± 0.36 nm and a zeta potential of -62.59 mV. Pot-based experiments revealed the N. oryzae extract induced 38.33% phytotoxicity within 24 hours, increasing to 84.72% by 28 days post-treatment. Scanning electron microscopy demonstrated morphoanatomical changes in epidermal tissue and stroma of E. crassipes, such as erosion of epicuticular waxes and degeneration of epidermis cells. The treatment significantly reduced the photosynthetic pigment content while increasing hydrogen peroxide (46.26%), malondialdehyde (17.49%), and proline (19.16%) levels, causing cellular electrolyte leakage. Activities of superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase were significantly elevated (p<0.05), indicating oxidative damage. These findings demonstrate that N. oryzae extract can disrupt growth and photosynthesis and induce oxidative stress in E. crassipes, suggesting its potential as a source of natural herbicide for industrial application.
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    Ultrasonic emulsification of Cananga odorata nanoemulsion formulation for enhancement of herbicidal potential
    A nanoemulsion was fabricated from Cananga odorata essential oil (EO) and stabilized by incorporation of Tween 80 using ultrasonication. The major constituents of the EO were benzyl benzoate, linalool, and phenylmethyl ester. Differing sonication amplitude (20–60%) and time (2–10 min) were assessed for effects on nanoemulsion droplet size and polydispersity index (PI). The smallest droplet size of 43.98 nm (PI 0.222) was obtained using 40% amplitude for 8 min; this nanoemulsion was evaluated for its droplet characteristics and pre-emergence herbicidal activities on Amaranthus tricolor. FT-IR confirmed ultrasonic emulsification to not affect the EO components. Regarding stability, storage at 4 °C was determined appropriate, with droplet size changing slightly after five weeks. Assays of herbicidal potential showed the coarse emulsion and nanoemulsion to both reduce A. tricolor germination and growth, with the nanoemulsion being more effective at a given concentration and the difference in effectivity correlating to droplet size. Remarkably, treatment with 250 ppm nanoemulsion and coarse emulsion respectively resulted in 100% and 63.75% germination inhibition. Both emulsions decreased seed imbibition and alpha-amylase activity. The highest relative electrolyte leakage was achieved in seed treated with the nanoemulsion. Therefore, this ultrasonic-based nanoemulsion may have utility as bioherbicide alternative.
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    High-Energy Emulsified Clove Essential Oil Nanoemulsion as a Natural Herbicidal Product: Germination Suppression and Seed Structure Alteration in Echinochloa crus-galli
    (2026-03-01) ; ;
    Manichart, Nutcha
    ;
    Dimak, Jantra
    ;
    Poonpaiboonpipat, Thanatsan
    Clove (Syzygium aromaticum (L.) Merr. & L.M. Perry) essential oil (EO)-based nanoemulsions may have a promising future in eco-friendly herbicide development. Clove EO was found to have a high eugenol content of 87.27%. Organic-solvent-free nanoemulsions using clove EO as a bioactive ingredient were fabricated using ultrasonication and microfluidization emulsification methods. Fourier-transform infrared spectroscopy confirmed that both emulsification methods did not affect the EO components. The droplet size of optimized nanoemulsions was determined using dynamic light scattering. The smallest size of 66.9 nm was obtained by microfluidization at 20,000 psi and eight passes. Additionally, the smallest droplet size for a sonicated nanoemulsion was 103.9 nm, obtained by ultrasonication at 20% for 6 min. Transmission electron microscopy confirmed the droplet sizes of both optimized nanoemulsions. In a storage test, both optimized nanoemulsions were stored at 4 °C for at least four weeks. Finally, both nanoemulsions were evaluated on pre-emergence herbicidal activities against Echinochloa crus-galli. The results showed that both nanoemulsions inhibited E. crus-galli germination and seedling growth, and additionally, inhibited seed imbibition and α-amylase activity. Micro-morphological and ultrastructural analysis was observed using a scanning electron microscope and an energy dispersive X-ray spectrometer (SEM-EDS). SEM-EDS micrographs of the treated seeds showed that the seed structure was damaged, especially the endosperm, leading to the inhibition of seed germination.