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Influence of Dragon Fruit Peels on the Synthesis of Antibacterial Nano Zinc Oxide (Nano-ZnO) via Green Synthesis Method
(2026-05-20)
Sakulpeeb, Natchayaporn
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Koetniyom, Wantana
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Chutipaijit, Sutee
;
Rahong, Sakon
;
Kayunkid, Navaphun
This research focused on adding value to dragon fruit peel waste by utilizing it in the synthesis of antibacterial nano zinc oxide (Nano-ZnO) through a green synthesis process. In this study, all the dragon fruit peels were extracted using the solvent extraction technique with three different solvents (deionized water, ethanol, and methanol) for 1, 2, 3, 4, and 5 h, respectively. The amount of flavonoids from the extract was determined using UV-Vis spectrophotometer to obtain the optimum extraction time, which was 4 h for DI water as the solvent. Moreover, antibacterial Nano-ZnO was synthesized successfully by a green synthesis process using zinc nitrate Zn(NO3)2 and the extracts. The molecular vibrations as well as the crystal structure and morphology were investigated by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (Raman), X-ray diffraction (XRD), and field emission scanning electron microscopy (FE-SEM), respectively. Additionally, the antibacterial efficacy of the nano-zinc oxide samples was evaluated using disc diffusion method. Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli) were the test agents. The research shows that the X-ray diffraction patterns of all synthesized ZnO nanoparticles (NPs) exhibited a wurtzite (hexagonal) crystal structure. FT-IR spectroscopy confirmed the presence of Zn-O stretching vibrations at approximately 500 cm⁻¹. Furthermore, the FE-SEM reveals that ZnO-yellow particles displayed spherical morphologies with an average particle size of 145 nm. At the same time, ZnO-White and ZnO-Red nanoparticles exhibited a combination of rod-like and elliptical morphologies, with average particle sizes of 168 nm and 321 nm, respectively. In addition, the antibacterial activity demonstrates effective inhibition against S. aureus and E. coli in all three ZnO nanoparticle conditions.
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Microwave-Assisted Biosynthesis of Silver Nanoparticles Using Chlorella sp. for Antibacterial and Cytotoxicity Effects of Breast Cancer Cell Line
(2026-03-01)
Manklinniam, Piyapan
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Pornroongruengchok, Weerawat
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Phunpruch, Saranya
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Phaepilin, Adisorn
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Pook-In, Grissana
Microwave-assisted biosynthesis using marine Chlorella sp. extracts provides a green and efficient route for the production of silver nanoparticles (AgNPs). Compared with the conventional method (24 h), microwave-assisted synthesis reduces the reaction time to less than 7 min while producing smaller and more uniformly distributed nanoparticles. AgNPs were synthesized using extracts obtained with different solvents and directly compared with those produced via the conventional method to substantiate the efficiency of the microwave-assisted approach. UV–visible spectroscopy confirmed rapid nanoparticle formation, exhibiting surface plasmon resonance peaks in the range of 405 to 427 nm. TEM analysis revealed predominantly spherical AgNPs with particle sizes of approximately 10 to 20 nm. The XRD and FTIR analyses confirmed their crystalline structure and stabilization by algal-derived functional groups. The biological activities of the AgNPs were dependent on the extraction solvent. AgNPs synthesized using hexane extracts exhibited pronounced antibacterial activity, achieving minimum inhibitory concentrations as low as 0.31 µg/mL. In addition, the AgNP induced concentration-dependent cytotoxic effects in human breast cancer cell lines. IC<inf>50</inf> values, determined via dose–response analysis, ranged from 0.18 to 0.67 μg/mL in MDA-MB-231 cells and 1.70 to 8.42 μg/mL in MCF-7 cells. These results indicate a potent cytotoxic profile, with MDA-MB-231 cells exhibiting significantly higher sensitivity to the microwave-assisted formulations. Collectively, these findings highlight microwave-assisted algal-mediated biosynthesis as a sustainable and effective platform for generating bioactive AgNPs with promising antibacterial and anticancer potential.
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A Simple and Rapid Synthesis of Spherical Silver Phosphate (Ag3PO4) and Its Antimicrobial Activity in Plant Tissue Culture
(2025-08-01)
Laohavisuti, Nongnuch
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Boonchom, Banjong
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Rungrojchaipon, Pesak
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Boonmee, Wimonmat
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Seesanong, Somkiat
A simple and rapid precipitation process was successfully employed to prepare silver phosphate (SP, Ag<inf>3</inf>PO<inf>4</inf>). Two different phosphate sources: diammonium hydrogen phosphate ((NH<inf>4</inf>)<inf>2</inf>HPO<inf>4</inf>) and dipotassium hydrogen phosphate (K<inf>2</inf>HPO<inf>4</inf>) were applied separately as the precursor, obtaining ((NH<inf>4</inf>)<inf>2</inf>HPO<inf>4</inf>)− and K<inf>2</inf>HPO<inf>4</inf>− derived SP powders, named SP-A or SP-P, respectively. Fourier transform infrared (FTIR) spectra pointed out the vibrational characteristics of P–O and O–P–O interactions, confirming the presence of the PO43– functional group for SP. X-ray diffraction (XRD) patterns revealed that the SP crystallized in a cubic crystal structure. Whereas the field emission scanning electron microscope (FESEM) exposed spherical SP particles. The potentially antibacterial activity of SP-A and SP-P against bacterial Bacillus stratosphericus, yeast Meyerozyma guilliermondii, and fungal Phanerodontia chrysosporium was subsequently investigated. All studied microorganisms were recovered and isolated from the aquatic plant during the tissue culture process. The preliminary result of the antimicrobial test revealed that SP-A has higher antimicrobial activity than SP-P. The superior antimicrobial efficiency of SP-A compared to SP-P may be attributed to its purity and crystallite size, which provide a higher surface area and more active sites. In addition, the presence of potassium-related impurities in SP-P could have negatively affected its antimicrobial performance. These findings suggest that SP holds potential as an antimicrobial agent for maintaining sterility in tissue cultures, particularly in aquatic plant systems. The growth of both B. stratosphericus and M. guilliermondii was suppressed effectively at 30 ppm SP-A, whereas 10 ppm of SP-A can suppress P. chrysosporium development. This present work also highlights the potential of SP at very low concentrations (10–30 ppm) for utilization as an effective antimicrobial agent in tissue culture, compared to a commercial antimicrobial agent, viz., acetic acid, at the same concentration.
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Chemical Analysis and Bioactivities of Gaultheria procumbens L. Essential Oil: Herbicidal, Antioxidant and Antibacterial Activities
(2023-03-02)
Jintanasirinurak, Sumonrat
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Manichart, Nutcha
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Somala, Naphat
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Laosinwattana, Chamroon
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Teerarak, Montinee
The chemical composition of wintergreen (Gaultheria procumbens L.) essential oil (WEO) was identified by gas chromatography-mass spectrometry (GC-MS) and evaluated for its biological activities. Methyl salicylate (100%) was the main compound in the wintergreen essential oil. The herbicidal efficacy of the WEO was confirmed by germination inhibition, radical and shoot length reduction, and phytotoxicity assessment with Echinochloa crus–galli and Amaranthus tricolor seedlings. The WEO significantly reduced the germination and seedling growth of both weeds. It showed highly significant inhibition of seed germination (93.37%) and seedling growth of A. tricolor at the highest dose (6 µL/petri dish) assayed. The WEO was formulated as an emulsifiable concentrate (EC-EO) for post-emergence application, and was applied at a range of concentrations from 10 to 80 mL/L. Both treated plant leaves appeared wilted and slightly discolored within 1 day of application (DAA). The visible weed control efficacy was most remarkable at 80 mL/L treatment, which was a level that ultimately killed the seedlings of both species at 3 DAA, suggesting promising herbicidal potential for the WEO. The WEO showed weak scavenging activity with a high IC<inf>50</inf> value (IC<inf>50</inf> >2×104 and >5×104 ppm) for DPPH scavenging and metal chelating assays, respectively. The WEO showed moderate antibacterial activity, and its zones of inhibition against bacterial test strains were 7.90±0.8 mm and 23.9±0.9 mm for Escherichia coli TISTR 780 and Staphylococcus aureus TISTR 1466, respectively. Therefore, the results suggest the possibility of using WEO as an active ingredient to produce natural herbicides.
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Facile and green synthesis of AgNPs by microwave-assisted method using curcumin biomaterial for improving antibacterial activities of NR/Ag composite sheets
(2022-12-01)
Chotpatiwetchkul, Warot
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Saengsawang, Monthol
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Sriwong, Chaval
Natural rubber (NR)-based composites or hybrid products obtained from NR and several nano-materials are of interest due to their wide range of applications. However, they are easily contaminated with bacteria or fungi that can affect human health, especially those used in food container and on human skin. Herein, we present the composite sheets of NR latex and silver nanoparticles (AgNPs) with exceptionally high antibacterial activities. AgNPs were firstly synthesized by a facile, rapid, and green microwave-assisted method using curcumin as a biomaterial reductant and stabilizer. Then, natural rubbers loaded with AgNPs (NR/Ag) composite sheets were prepared via a simple direct latex mixing-casting process of NR latex and various contents of AgNPs. The result demonstrated that the synthesized AgNPs had a spherical-like shape of 12.25 ± 3.13 nm. All the prepared NR/Ag composite sheets exhibited high performance in antibacterial properties against Staphylococcus aureus and Escherichia coli, and the antibacterial activities were dependent on the loaded AgNPs content. In this study, it is anticipated that these rapid, simple, green, and effective methods can suitably be scaled up for large-scale preparation of the stabilized AgNPs colloid and NR/Ag composite products.

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