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Plant assisted synthesis of CuO/ZnO heterojunction nanocomposites using Mitragyna speciosa (Korth.) Havil leaf extract for photocatalytic activity under full spectrum LED light and antibacterial performance
(2026-07-15)
Phunpueok, Akapong
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Thongpool, Voranuch
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Jaiyen, Sarawut
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Bootchanont, Atipong
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Sukprasit, Nuchita
CuO/ZnO heterojunction nanocomposites were synthesized through a green plant assisted method using Mitragyna speciosa leaf extract as a natural reducing and stabilizing agent. Structural and morphological analyses (XRD, FE-SEM, EDS, UV–vis, and BET) confirmed the formation of CuO/ZnO heterostructures with mesoporous characteristics. The 0.25CuO/0.75ZnO heterojunction nanocomposites exhibited the smallest ZnO crystallite size (∼8.06 nm) and the highest surface area (28.97 m2/g). Photocatalytic performance evaluated by methylene blue degradation under full-spectrum irradiation showed that the 0.25CuO/0.75ZnO heterojunction nanocomposites achieved 92.29% degradation within 90 min with a rate constant of 0.02491 min−1. In addition, the nanocomposites demonstrated strong antibacterial activity, achieving 99.9% reduction of E. coli and >99.9% inhibition of S. aureus . The enhanced performance is attributed to efficient charge separation at the CuO/ZnO heterojunction and the generation of reactive oxygen species.
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Influence of leaf type, genotype, and location on bioactivities and assessment of genetic diversity in teak (Tectona grandis L. f.)
(2026-03-01)
Poeaim, S.
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Phonmakham, J.
Marked variation in biological activities was observed among teak (Tectona grandis L. f.) leaf extracts as influenced by leaf type, tree genotype, and planting location. Fresh leaves generally exhibited stronger antibacterial activity than fallen leaves, with significant differences detected among plus trees originating from Chiang Mai, Phrae, Sukhothai, Lampang, and Khon Kaen and grown at the Thongphaphum and Phitsanulok Silviculture Research Stations. Among all samples, the Phrae plus tree cultivated at Thongphaphum showed the highest antibacterial inhibition against the tested microorganisms. Methanol extracts demonstrated antibacterial, anti-tyrosinase, and anti-inflammatory activities, while sequential extraction of Phrae plus tree leaves using hexane and dichloromethane yielded fractions with potent antibacterial effects, indicating promising potential for the development of new antibacterial agents. Genetic analysis based on sequence-related amplified polymorphism (SRAP) markers revealed similarity coefficients ranging from 0.67 to 1.00, reflecting low to moderate genetic diversity among the studied germplasm, with some samples exhibiting nearly identical genetic profiles. Overall, the observed variation in biological activities was closely associated with both genetic background and environmental conditions, providing valuable information for teak germplasm selection and the utilization of leaf-derived bioactive compounds in product development.
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Microwave-assisted biosynthesis of silver nanoparticles using two marine microalgal extracts and their antimycobacteriosis activity against bacteria isolated from Betta splendens
(2025-12-01)
Manklinniam, Piyapan
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Phunpruch, Saranya
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Sakulkalavek, Aparporn
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Sakdanuphab, Rachsak
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Worananthakij, Worakrit
This study explores the synthesis and antibacterial properties of silver nanoparticles (AgNPs) as a safer, eco-friendly alternative to traditional chemical treatments for bacterial infections. AgNPs were synthesized using aqueous extracts of marine microalgae, Isochrysis galbana and Chaetoceros calcitrans, via conventional and microwave-assisted methods, with the latter accelerating nanoparticle production. Extracts in ethanol, hexane, and acetone were tested, with the ethanolic extract of I. galbana showing the strongest antibacterial effects. The AgNPs exhibited broad-spectrum antibacterial activity against pathogens such as Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and fish pathogens like Aeromonas veronii. Microwave-assisted synthesis with ethanolic extracts resulted in the highest inhibition, particularly against fish and tuberculosis-related pathogens, including Mycobacterium marinum. Nanoparticle formation was confirmed using various characterization methods, including ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), which revealed crystalline structures. Transmission electron microscopy (TEM) analysis revealed that AgNPs varied in size, with an average diameter of less than 50 nm and all particles being smaller than 100 nm. This research demonstrates the potential of AgNPs as an effective alternative to antibiotics, offering targeted bacterial inhibition while reducing the risk of antibiotic resistance. This makes it a promising approach for treating bacterial infections in ornamental fish.
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Ultrasonic-driven synthesis of Cu-chlorophyllin-stabilized silver nanoparticles for high-efficiency antimicrobial surgical suture coatings
(2025-12-01)
Sombutjiraporn, Saran
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Mathaweesansurn, Arjnarong
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Daengngern, Rathawat
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Detsri, Ekarat
A novel Cu-chlorophyllin-stabilized silver nanoparticle (Ag0<inf>NPs</inf>-Chl<inf>Cu</inf>) with potent antimicrobial properties was synthesized for the first time using an ultrasonically driven chemical reduction approach. In this approach, Cu-chlorophyllin (Chl<inf>Cu</inf>) acts as a stabilizing ligand, while sodium borohydride functions as the chemical reductant. The formation mechanism of Ag0-NPs<inf>CHL</inf> was elucidated, revealing that ultrasonic irradiation facilitates the in situ reduction of Ag (I) and its subsequent incorporation into the Chl<inf>Cu</inf> complex. Four pyrrole rings coordinate with Ag0<inf>NPs</inf> through four nitrogen atoms, which serve as adsorption sites for the anchorage of Ag0-NPs<inf>CHL</inf>. Characterization by XPS revealed the presence of Ag-N bonding involving pyrrole units on the FCC structure of Ag0<inf>NPs</inf>. Ag0<inf>NPs</inf>-Chl<inf>Cu</inf> demonstrated a zeta potential of (-) 35.57±3.54 mV with a spherical shape and an average size of 6.72±1.72 nm, resulting in a stable colloidal dispersion with a monodispersed index. The synthesized Ag0-NPs<inf>CHL</inf> nanocomposites were subsequently deposited onto polyamide surgical sutures via an electrostatic Layer-by-Layer (LbL) self-assembly technique. The coated sutures exhibited >99.9 % antibacterial efficiency against E. coli (ATCC25922), S. aureus (ATCC25923), and A. baumanii (ATCC19606). While nanoparticle accumulation was observed in human primary epidermal keratinocyte (HEKa) cells, no cytotoxic effects were detected in the epidermis. This study highlights the effectiveness of Chl<inf>Cu</inf> as a dual stabilizing and coordinating agent for Ag⁰<inf>NPs</inf>, offering a promising approach for developing antimicrobial surgical materials.
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Discovery and characterization of bioactive compounds from Limnophila aromatica: nevadensin and related flavonoids as potent antimicrobial agents
(2025-08-01)
Maswanna, Thanaporn
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Maneeruttanarungroj, Cherdsak
Limnophila aromatica, a traditional medicinal plant, has been previously reported to possess notable antimicrobial properties. However, the specific bioactive constituents responsible for this activity remain largely unidentified. This study aimed to isolate, identify, and evaluate the antibacterial potential of compounds from a 100% ethanolic extract of L. aromatica. The crude ethanolic extract exhibited the highest antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) and was subsequently subjected to Diaion HP-20 column chromatography, followed by preparative HPLC. Seven major peaks were identified using UV-Vis spectra, LC-QTOF-MS, and NMR analyses. The antibacterial efficacy of these isolated compounds was assessed using disc diffusion and broth microdilution assays against Bacillus subtilis, S. aureus, MRSA, Escherichia coli, and Pseudomonas aeruginosa. The isolated compounds were identified as norethindrone acetate, isothymusin, nevadensin, gardenin B, 5,3’-dihydroxy-7,8,2’-trimethoxyisoflavone, jasmolin II, and oleanolic acid. Nevadensin, the predominant compound (79.55%), demonstrated potent bactericidal activity against B. subtilis, S. aureus, and MRSA. Jasmolin II and gardenin B also exhibited promising antibacterial effects. Although the disc diffusion assay was limited by compound diffusion, the broth microdilution method confirmed significant MIC values, ranging from 0.59 to 2.86 mg/ml while the MBC values ranged from 0.59 to 12.72 mg/ml. This study highlights nevadensin and other flavonoids from L. aromatica as potential candidates for the development of alternative antibacterial therapies, particularly against drug-resistant Gram-positive bacteria.
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Antibacterial activity of marine microalgae extracts against pathogen of Siamese fighting fish (Betta splendens)
(2025-01-01)
Manklinniam, Piyapan
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Phunpruch, Saranya
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Worananthakij, Worakrit
Background: Marine microalgae extracts are a promising alternative to commercial drugs because of their antimicrobial properties. Aim: This study aimed to investigate the antibacterial properties of crude extracts containing bioactive compounds derived from Chlorella sp., Isochrysis galbana, and Chaetoceros calcitrans. Methods: Crude extracts from microalgae were obtained via maceration using ethanol and hexane as solvents. Antibacterial activities were initially screened using the agar well diffusion method, whereas antimycobacterial activity was assessed using the microplate 7H11 agar proportion method. Subsequently, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the crude extracts were determined. Gas chromatographymass spectrometry (GC-MS) was used for phytochemical composition analysis to identify significant antimicrobial compounds in the extracts. Results: The ethanolic extract of I. galbana demonstrated detectable antibacterial activity, with an inhibition zone of 12.40 ± 0.06 mm against Bacillus subtilis, 12.22 ± 0.28 mm against Staphylococcus aureus, 11.10 ± 0.11 mm against Pseudomonas aeruginosa, and 10.99 ± 0.33 mm against Aeromonas veronii at 100 mg/ml. Extracts from I. galbana and C. calcitrans inhibited Mycobacterium marinum, suggesting potential benefits for betta fish health. MIC values were 25 mg/ml for A. veronii in the ethanolic extracts of I. galbana, C. calcitrans, Chlorella sp., and C. calcitrans hexane extract. The GC-MS chromatogram of the ethanolic extract of I. galbana revealed the presence of several bioactive compounds. The major components identified include Phthalate, Tetradecanoic acid, Hexadecanoic acid, and Phytol. Conclusion: This study demonstrated the promising antimicrobial potential of crude extracts from marine microalgae, particularly the ethanolic extract of I. galbana, which showed strong activity against both terrestrial and aquatic pathogens. The findings suggest that bioactive compounds in these extracts, especially those from I. galbana and C. calcitrans, can be effective in managing bacterial infections such as A. veronii and M. marinum in betta fish. These results highlight the potential of marine microalgae as natural, sustainable alternatives for disease control in aquaculture.
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Asymmetric dot-patterned wettable and antibacterial wound dressings from bacterial cellulose–alginate composites coated with stearic acid-modified ZnO/chitosan/AgNPs
(2025-01-01)
Ieamviteevanich, Pimchanok
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Onklam, Panida
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Kampechdee, Wariya
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Churiwan, Achana
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Vittayakorn, Naratip
To improve the wound dressing characteristics of bacterial cellulose-based materials and address the issue of asymmetric wound dressing with one hydrophilic side and another hydrophobic side, this study developed a new concept for the fabrication of an asymmetric wettable and antibacterial wound dressing by selective drop coating of stearic acid-modified ZnO, chitosan, and AgNPs to form a dot pattern on both surfaces of a bacterial cellulose–alginate composite (BA-ZnS/Ch/Ag). The coated surface was hydrophobic, with a WCA of 150° due to the formation of a low surface energy zinc stearate (C<inf>17</inf>H<inf>35</inf>COO)<inf>2</inf>Zn) monolayer on the ZnO particles and a high degree of hierarchical roughness. The asymmetric wettable BA-ZnS/Ch/Ag wound dressing maintained good water absorptivity (swelling rate 417%) and natural breathability (water vapor transmission rate 792 g.m−2 day−1) of the superhydrophilic bacterial cellulose-alginate composite that consisted of dense outer surfaces and porous inner layers and simultaneously possessed the superhydrophobic property of the coating area that can reduce the risk of infection from external fluids and improve the blood repellency and anti-adhesion properties. The BA-ZnS/Ch/Ag wound dressing showed good antibacterial activity against S. aureus and E. coli and non-toxicity to human keratinocyte immortal cells (HaCaT), making it suitable for clinical applications.
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Dual-function antimicrobial-antibiofilm peptide hybrid to tackle biofilm-forming Staphylococcus epidermidis
(2024-12-01)
Wongchai, Mathira
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Wongkaewkhiaw, Saharut
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Kanthawong, Sakawrat
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Roytrakul, Sittiruk
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Aunpad, Ratchaneewan
Background: Due to their resistance and difficulty in treatment, biofilm-associated infections are problematic among hospitalized patients globally and account for 60% of all bacterial infections in humans. Antibiofilm peptides have recently emerged as an alternative treatment since they can be effectively designed and exert a different mode of biofilm inhibition and eradication. Methods: A novel antibiofilm peptide, BiF, was designed from the conserved sequence of 18 α-helical antibiofilm peptides by template-assisted technique and its activity was improved by hybridization with a lipid binding motif (KILRR). Novel antibiofilm peptide derivatives were modified by substituting hydrophobic amino acids at positions 5 or 7, and both, with positively charged lysines (L5K, L7K). These peptide derivatives were tested for antibiofilm and antimicrobial activities against biofilm-forming Staphylococcus epidermidis and multiple other microbes using crystal violet and broth microdilution assays, respectively. To assess their impact on mammalian cells, the toxicity of peptides was determined through hemolysis and cytotoxicity assays. The stability of candidate peptide, BiF2_5K7K, was assessed in human serum and its secondary structure in bacterial membrane-like environments was analyzed using circular dichroism. The action of BiF2_5K7K on planktonic S. epidermidis and its effect on biofilm cell viability were assessed via viable counting assays. Its biofilm inhibition mechanism was investigated through confocal laser scanning microscopy and transcription analysis. Additionally, its ability to eradicate mature biofilms was examined using colony counting. Finally, a preliminary evaluation involved coating a catheter with BiF2_5K7K to assess its preventive efficacy against S. epidermidis biofilm formation on the catheter and its surrounding area. Results: BiF2_5K7K, the modified antibiofilm peptide, exhibited dose-dependent antibiofilm activity against S. epidermidis. It inhibited biofilm formation at subinhibitory concentrations by altering S. epidermidis extracellular polysaccharide production and quorum-sensing gene expression. Additionally, it exhibited broad-spectrum antimicrobial activity and no significant hemolysis or toxicity against mammalian cell lines was observed. Its activity is retained when exposed to human serum. In bacterial membrane-like environments, this peptide formed an α-helix amphipathic structure. Within 4 h, a reduction in the number of S. epidermidis colonies was observed, demonstrating the fast action of this peptide. As a preliminary test, a BiF2_5K7K-coated catheter was able to prevent the development of S. epidermidis biofilm both on the catheter surface and in its surrounding area. Conclusions: Due to the safety and effectiveness of BiF2_5K7K, we suggest that this peptide be further developed to combat biofilm infections, particularly those of biofilm-forming S. epidermidis.
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GREEN SYNTHESIS OF ZINC OXIDE NANOPARTICLES FROM LEMON PEEL EXTRACT AND THEIR ANTIBACTERIAL ACTIVITY
(2024-01-01)
Wirunchit, Supamas
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Sakulpeeb, Natchayaporn
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Chutipaijit, Sutee
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Nukaew, Jiti
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Koetniyom, Wantana
This research project aimed to study the extraction of flavonoids from lemon peels using different solvents, namely deionized water (DI water), isopropanol, ethanol, and methanol. Among these, DI water yielded the highest amount of flavonoids. The extracted compounds were then utilized for the synthesis of zinc oxide nanoparticles (ZnO NPs) through a green chemical method. Various amounts of lemon peel extract (10, 15, 20, 25, and 30 ml) were mixed with Zn(NO3)2 during the synthesis process. The ZnO NPs were characterized using UV-VIS spectrophotometry, X-ray diffractometry (XRD), Fourier transform-infrared spectrometry (FT-IR), and Raman spectrometry. The results revealed successful synthesis of ZnO NPs, except for those produced using DI water extract, which exhibited a different structure (wurtzite). Subsequently, the antibacterial properties of the ZnO NPs were tested against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) using the disc diffusion method. The ZnO NPs synthesized from different solvent extracts demonstrated effective inhibition zones against both bacterial strains, indicating their potential as antibacterial agents.
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UTILIZING BANANA PEEL WASTE EXTRACT FOR GREEN SYNTHESIS OF SILVER NANOPARTICLES AND THEIR ANTIBACTERIAL APPLICATION
(2024-01-01)
Sumang, Rattiphorn
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Jarernsuk, Suppanit
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Chutima, Ruangwut
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Vitayakorn, Narathip
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Panpho, Phakakorn
Silver nanoparticles (AgNPs) were successfully produced through a green synthesis method involving the utilization of waste banana peel waste (BPW) extract. BPW has attracted considerable attention for its attributes as a straightforward, environmentally friendly, and non-toxic material. To facilitate this process, BPW powder was created by boiling, blending, and air-drying, serving as both a reducing and capping agent. The biosynthesized AgNPs underwent characterization via UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and Field Emission scanning electron microscopy (FE-SEM). Furthermore, antibacterial activity tests were conducted on cotton fabrics to optimize the process and assess its effectiveness. The results revealed a distinct absorption peak at 420 nm corresponding to AgNPs, a finding corroborated by FE-SEM and energy dispersive spectrometry (EDS). The application of AgNPs from BPW on fabrics exhibited outstanding antibacterial activity by inhibiting the growth of Staphylococcus aureus and Escherichia coli. Overall, the present findings support the use of BPW extraction as a cost-effective, environmentally friendly, and efficient approach for the green synthesis of AgNPs with promising antibacterial properties on fabrics.

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