Chotsaeng, Nawasit
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Item type:Publication, DBU-Mediated Dimerization: Facile Access to 9,9′-Bifluorenylidenes and Isoindigos(2023-11-14); - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhancing chitosan solubility in alcohol: water mixtures for film-forming systems releasing with turmeric extracts(2021-06-01); Background: Film-forming system (FFS), a non-solid dosage form, are attractive drug delivery system for the topical drug administration due to ability to form a film in situ on a skin after spraying or applying. To minimize drying time, alcohol is often used as a solvent in the system. The aim of this research was to enhance chitosan solubility in alcoholic solution by chemical modification of chitosan, i.e., reductive amination and Michael addition reaction, for film-forming systems with efficient releasing of turmeric extract. Methods: Alcoholic-soluble chitosan derivative (CBA) was synthesized by reductive amination, followed by a Michael reaction. Its structure was investigated by FT-IR, <sup>1</sup>H NMR and XRD techniques. The CBA was incorporated with β-cyclodextrin encapsulated turmeric extract (CDTE) to prepare film-forming solution. Significant Findings: The results confirmed that the CBA was successful prepared, as the new peaks were observed by FT-IR and <sup>1</sup>H NMR, with good solubility in 50% aqueous alcoholic solution. The CBA-based film, derived from the solvent evaporation, exhibited nontoxic to HaCaT cells. Moreover, the films containing CDTE had smooth surfaces and released turmeric extract (74%) more effectively than films containing the extract alone (43%). The CBA-based ethanolic solution (30–50%v/v ethanol) could dry within ~6–9 min and form a thin film on human skin. Conclusions: Thus, the CBA-based solution with CDTE has potential as a film-forming system based on natural products. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Oxidative damage in Echinochloa crus−galli seeds exposed to Diaporthe sp. (Diaporthales, Ascomycota) fungal extract during germination(2024-01-01); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Structure-Activity Relationship Study of Xanthoxyline and Related Small Methyl Ketone HerbicidesXanthoxyline (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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Allelopathic potential of subfractions from aqueous extract of spirulina platensis and denatured c-phycocyanin(2022-01-01); ; 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Dimerization of 3-Chlorooxindoles Mediated by Potassium Ethylxanthate: Synthesis of Isoindigos(2022-08-17); ; Kuhakarn, ChutimaA novel dimerization of 3-chlorooxindoles promoted by potassium ethylxanthate to access isoindigo derivatives is described. The reactions proceeded readily at room temperature in short reaction times. A mechanistic study revealed that the 3-chlorooxindole is initially converted into O-ethyl S-(2-oxo-2,3-dihydro-1H-indol-3-yl) dithiocarbonate, which subsequently undergoes dimerization with elimination of arbon disulfide. In almost all cases, analytically pure isoindigos were isolated in moderate to good yields without a requirement for chromatographic purification. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Inhibitory effects of a variety of aldehydes on Amaranthus tricolor l. And echinochloa crus-galli (L.) beauv.(2018-01-01); ; Thirty-seven commercial aldehydes containing aliphatic chains and aromatic rings as well as heteroaromatic rings were evaluated for their inhibitory activities against Chinese amaranth (Amaranthus tricolor L.) and barnyardgrass (Echinochloa crus-galli (L.) Beauv). Polysorbate 80 (Tween<sup>fi</sup> 80) was used as a surfactant and the research was preliminarily conducted at 400 µM of all aldehydes. Among these aldehydes, (E)-cinnamaldehyde (7) showed the greatest inhibitory effect on seed germination, shoot and root growth of Chinese amaranth by 54.55%, 75.53%, and 85.13% respectively. Similarly, (E)-crotonaldehyde (5), a related α,β-unsaturated aldehyde, inhibited the germination and seedling growth of the tested species at a high percentage. Apart from these two unsaturated aldehydes, no other aliphatic aldehydes had a harmful effect on Chinese amaranth. In terms of benzaldehyde (6), it had no effect on the tested plant; however, many of its derivatives displayed some inhibitory activity. Furthermore, for the ten common heteroaromatic aldehydes, picolinaldehyde (32) had a high inhibitory effect on Chinese amaranth which closely related to the effect of (E)-crotonaldehyde (5) and (E)-cinnamaldehyde (7), whereas, other heteroaromatic aldehydes showed lower effects. In the case of a monocot plant, barnyardgrass, no tested aldehydes reduced seed germination, however, (E)-cinnamaldehyde (7), 2,4,6-trimethoxybenzaldehyde (16) and 4-(dimethylamino)benzaldehyde (24) could inhibit the seedling growth of the plant with low to moderate levels. The herbicidal effects of the most active aldehydes were then further investigated in order to find the minimum concentration of these aldehydes suppressing the germination and growth of the tested plants. At concentrations as low as 50–100 µM some aldehydes could inhibit the seedling growth of the tested species. The structure-activity relationship (SAR) study reported here demonstrates the chemical clues governing the inhibitory activity of aldehydes which could be utilized in the development of highly effective herbicides in the near future. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Ultrasonic emulsification of Cananga odorata nanoemulsion formulation for enhancement of herbicidal potential(2025-12-01); ; ; 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. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, 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); ; - Some of the metrics are blocked by yourconsent settings
Item type:Publication, DBU-Mediated Reaction of 3-Chlorooxindole and 9-Xanthyl Fluorene for Synthesis of 3-Arylidene Oxindole(2025-04-01); ;