Hue University Journal of Science: Natural Science

An in silico study of the inhibitory ability of fatty acids and ester derivatives against Streptococcus pneumoniae

2025-06-16T02:16:20+00:00

Some fatty acids and ester derivatives, namely myristic acid (C1), palmitic acid (C2), pentadecanoic acid (C3), linoleic acid (C4), ethyl palmitate (C5), methyl linoleate (C6) and ethyl linoleate (C7), were studied in silico to inhibit respiratory bacteria (S. pneumoniae). Computational approaches were utilised to evaluate the potential of these compounds against protein Q8DQF8. The positions 1, 2 and 3 are identified as the optimal sites for the docking process, and the docking-based simulation predicts the most effective ligand – Q8DQF8 inhibitory systems in the order: C6 (–11,3 kcal.mol^–1) > C3 (–10,9 kcal.mol^–1) > C5 (–10,7 kcal.mol^–1) > C4 (–9,4 kcal.mol^–1) > C2 (–9,0 kcal.mol^–1 > C1 (–8,7 kcal.mol^–1) > C7 (–8,6 kcal.mol^–1). Molecular dynamics simulations for C3, C5 and C6 compounds indicated that C3 exhibits the best interaction with the Q8DQF8 protein. Present results will guide experimental research toward developing new methods to support the treatment of respiratory diseases.

Manganese-based catalytic material on nickel foam substrate for electrochemical glycerol oxidation

2025-08-14T03:42:10+00:00

In this study, a manganese (Mn)-based electrode was synthesised on nickel foam via a hydrothermal method, and its electrocatalytic performance was evaluated for the glycerol oxidation reaction (GOR). The results revealed that Mn@NF exhibited excellent electrocatalytic performance toward GOR, requiring a potential of only 1.35 V vs. RHE to reach a current density of 10 mA.cm⁻² — substantially lower than that required for the oxygen evolution reaction. Furthermore, the catalyst achieved a hydrogen production rate of 0.625 mL.cm⁻².h⁻¹ at a potential of 1.42 V vs. RHE and maintained a stable current output over 10 hours of continuous operation. These findings demonstrate the promising potential of Mn@NF as an efficient electrocatalyst for GOR, offering a new pathway for energy-saving hydrogen production.

Effect of nano-emulsion coating containing lemongrass essential oil and chitosan on Cavendish banana’s (Musa AAA) quality and shelf life

2025-10-06T15:31:19+00:00

Cavendish banana (Musa AAA) is a climacteric fruit with high metabolic activity, making it highly perishable and leading to rapid quality deterioration and reduced shelf life under ambient conditions. In this study, a nano-emulsion-based coating composed of lemongrass essential oil and chitosan (nano TDS-Chi) was applied as a bio-preservative to extend postharvest storage life. The formulation consisted of 0.05% lemongrass essential oil nano-emulsion (nano TDS) and 1.0% chitosan (Chi), applied with three methods: pre-harvest spraying (TTH), post-harvest dipping (STH), and a combined treatment (TTH + STH), with untreated fruit as the control. The results demonstrated that nano TDS-Chi significantly delayed postharvest physiological and biochemical processes. Notably, the combined TTH + STH treatment was the most effective, extending the storage life up to 20 days at ambient temperature (25 °C). Key quality indicators included reduced weight loss (8.62%), delayed accumulation of total soluble solids (peak at 18.71%), maintenance of organic acid content (0.18%), delayed respiration peak (50.68 ml CO₂·kg⁻¹·h⁻¹), and moderated ethylene production (15.73 µL C₂H₄·kg⁻¹·h⁻¹). These findings highlight the potential of nano TDS-Chi as an eco-friendly bio-coating for postharvest preservation, offering a sustainable solution to reduce losses and enhance the economic value of Cavendish bananas.

Flavonoid compounds from Passiflora foetida L. collected in Thua Thien Hue

2025-05-27T05:15:00+00:00

Five flavonoid compounds: vitexin, vitexin 2ʹʹ-O-β-D-glucopyranoside, 2ʺ-O-rhamnosylvitexin, luteolin, and quercetin (1–5) were isolated from the leaves and stems of Passiflora foetida L. growing in Thua Thien Hue Province. Their chemical structures were elucidated by using nuclear magnetic resonance spectra as well as by comparing with the reported spectroscopic data. All the isolated compounds exhibited inhibitory activity against α-amylase and α-glucosidase enzymes with IC₅₀values ranging from 123.6–743.4 µg/mL and 166.3–423.4 µg/mL, respectively. The results show the potential application of P. foetida in developing products to support diabetes treatment.

Effect of extraction solvents on triterpenoid contents and quantification of saponins Rb1, Rb3, and Rd in Rubus cochinchinensis using high-performance liquid chromatography

2025-07-28T08:14:52+00:00

In this study, we evaluated the effect of extraction solvents on the total triterpenoid content and quantified three selected triterpenoid saponins Rb1, Rb3, and Rd in the extract of Rubus cochinchinensis. The total triterpenoid content was determined by using a colorimetric method with vanillin reagent in a perchloric acid medium, and the saponin compounds were quantified by means of high-performance liquid chromatography. Seven solvent systems were investigated, among which ethanol yielded the highest extraction efficiency for the triterpenoids (56.40 ± 0.53 mg oleanolic acid/g). The content of Rb1, Rb3, and Rd was 327.58 ± 2.84, 324.95 ± 7.91, and 135.17 ± 1.09 μg/g, respectively. Compared with well-known medicinal plants such as Korean Red Ginseng and Panax quinquefolius, R. cochinchinensis demonstrated superior levels of triterpenoid saponins. These findings suggest that R. cochinchinensis is a promising natural source for the development of biologically active products, particularly in the fields of pharmaceuticals and functional foods.

Study on the electronic properties and carrier mobility in two-dimensional Janus material SMoGeZ₂ (Z = N, P, As) by using density functional theory

2025-12-11T12:58:18+00:00

The successful fabrication of asymmetric two-dimensional Janus monolayers has opened up a new potential research direction. In this paper, we use density functional theory to study the properties of Janus monolayer SMoGeZ₂ (Z = N, P, As), including stability, electronic properties, mechanical properties, and carrier mobility. The results of the cohesive energy and phonon spectrum confirm that the SMoGeZ₂ monolayer has a stable structure. Both PBE and HSE06 calculations show that SMoGeZ₂ is a semiconductor with an indirect band gap. Additionally, this material exhibits isotropic mechanical properties and high mechanical strength. The calculation results demonstrate that the carrier mobility is anisotropic. Electron mobility ranges from 196.38 to 333.29 cm².V⁻¹.s⁻¹, while hole mobility ranges from 82.39 to 312.78 cm².V⁻¹.s⁻¹.

Synthesis and properties of carbon materials and iron-modified carbon materials from Aquilaria crassna wood

2025-12-10T22:52:54+00:00

Carbon materials and Fe-modified carbon materials were synthesised from Aquilaria crassna wood flakes with the pyrolysis method. The obtained materials were characterised with various techniques: X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The photocatalytic activities of the samples were also evaluated through the degradation of methylene blue. The results showed that the carbon materials pyrolysed below 300 °C exhibited morphology and particle size similar to those of the raw material, with a low degree of crystalline phase formation. When the pyrolysis temperature exceeded 400 °C, the materials underwent strong decomposition, and their morphology and particle size changed significantly compared with the precursor. The Fe-modified carbon materials exhibited similar morphology, size, and structure to the unmodified carbon materials, and Fe(III) formed coordination bonds with oxygen-containing functional groups on the carbon surface. A comparison of photocatalytic activity in methylene blue degradation revealed that the Fe-modified carbon material displayed higher photocatalytic activity than the unmodified one, achieving a removal efficiency of 85% after 90 minutes of adsorption and 150 minutes of irradiation.

Inhibitory effects of Homalomena occulta essential oil against Streptococcus pyogenes, Streptococcus pneumoniae, and Candida albicans and formulation of health care products

2025-12-10T03:31:19+00:00

In this study, essential oil was extracted from Homalomena occulta and evaluated for its antimicrobial potential. The essential oil was obtained by means of steam distillation, and its chemical constituents were analysed by using GC–MS. Forty compounds were identified, with linalool, terpinen-4-ol, 3-carene, and α-terpineol being the predominant components, accounting for 25.15, 6.68, 3.60, and 3.55%, respectively. In vitro assays demonstrated that H. occulta essential oil exhibited significant inhibitory activity against the throat pathogen Streptococcus pyogenes and the respiratory pathogen Streptococcus pneumoniae, with MIC values of 400 µg.mL⁻¹ and corresponding MBC values of 400 µg.mL⁻¹ and 800 µg.mL⁻¹, respectively. Additionally, the oil showed strong antifungal activity against Candida albicans, a yeast responsible for mucocutaneous infections, with MIC being 200 µg.mL⁻¹ and MFC being 400 µg.mL⁻¹. Furthermore, preliminary formulation trials were conducted to develop value-added products incorporating H. occulta essential oil, including a medicated balm for alleviating dermatitis, itching, muscle pain, and body warming, as well as aromatic candles with deodorising and relaxation effects. These findings highlight the promising potential of H. occulta essential oil for application in natural health-care product development, ensuring safety and aligning with sustainable development goals.

Effect of drying conditions on quality and bioactive properties of Black ginger bag tea (Distichochlamys orlowii)

2025-11-18T06:26:24+00:00

Black ginger (Distichochlamys orlowii) is a valuable medicinal plant rich in bioactive compounds, exhibiting various health-promoting effects, including antioxidant, anti-inflammatory, antimicrobial, anticancer, and immune-enhancing properties. However, these bioactive compounds are significantly affected by heat during the drying process. This study aimed to evaluate the effects of drying conditions (temperature and time) on the physicochemical, biochemical, and sensory quality of Black ginger bag tea, thereby determining the optimal drying parameters that minimise the loss of bioactive compounds in the final product. Drying experiments were conducted at temperatures ranging from 40 to 60 °C, with the drying times varying from 7 to 11 hours. After drying, the samples were analysed for total soluble solids, reducing sugars, total polyphenols, antioxidant capacity (DPPH – IC₅₀), and sensory attributes. The results indicated that drying at 50 °C for 9 hours produced the highest overall quality, with a safe moisture content of 6.15%, total soluble solids 15.61%, reducing sugars 2.62%, total polyphenols 3.06 mg GAE/g dry weight, and the highest antioxidant capacity (IC₅₀ = 791.11 µg/mL). The final product exhibited a uniform brown-yellow colour, pleasant aroma, and a mildly sweet and pungent flavour, achieving the highest sensory scores. This study provides vital technological parameters to produce high-quality Black ginger bag tea.

Comparison of skull morphology between two chevrotain species of Tragulus genus (Mammalia: Artiodactyla) in Vietnam

2025-08-01T02:39:26+00:00

In Vietnam, two chevrotain species of the genus Tragulus are recorded: the Vietnam chevrotain (T. versicolor) and the Lesser mousedeer (T. kanchil). This study analysed 26 cranial morphological parameters from 27 adult skull specimens (7 T. versicolor and 20 T. kanchil) to identify diagnostic characteristics between the two species. Descriptive statistics, Principal component analysis, Mann-Whitney U test, and MANOVA all revealed clear differences in overall skull morphology. Six skull and jaw length parameters –– basal-palatal length, mandible length, condylobasal length, maxillary lateral length, lower tooth row length, and upper tooth row length –– were the most consistent and distinctive for distinguishing the two species. These findings provide the first set of morphological criteria for identifying and classifying Tragulus species in Vietnam and also support conservation work and specimen identification.

Morpho-anatomical characterisation, saponin content, and ITS-based DNA barcoding of Ngoc Linh ginseng (Panax vietnamensis Ha & Grushv.) cultivated under the forest canopy

2025-09-12T02:35:56+00:00

This study investigated the anatomical characteristics, saponin content, and DNA-ITS barcode markers to establish standardised criteria for identifying Ngoc Linh ginseng (Panax vietnamensis Ha & Grushv.) cultivated under the forest canopy in the Tra Linh Commune, Da Nang City. Morphological and anatomical traits were described. The rhizomes and roots were analysed for the total saponin content and major saponins – G-Rg1, M-R2, G-Rb1, and G-Rd. Genomic DNA was extracted from the leaves, and the internal transcribed spacer (ITS) region was sequenced. The results revealed that cultivated Ngoc Linh ginseng displayed typical species-specific morphological and anatomical features. The total saponin content was 13.81 ± 0.18%, with G-Rg1 at 3.647 ± 0.062%, M-R2 at 3.823 ± 0.054%, G-Rb1 at 0.979 ± 0.017%, and G-Rd at 0.961 ± 0.037%, conforming the requirements of the Vietnamese Pharmacopoeia V. ITS sequences from three samples were registered in GenBank (PV185794–PV185796) and showed 99.42–100% similarity with P. vietnamensis. These findings support a standardised protocol for identifying Ngoc Linh ginseng, enabling its conservation and sustainable development.

Species diversity and composition of benthic animals in coastal waters of Ha Tinh Province

2025-07-17T08:28:39+00:00

The study was conducted through four surveys from May 2023 to February 2025 at eight sampling sites to assess the composition of benthic animals in the coastal waters of Ha Tinh Province. We identified 179 species of benthic animals belonging to 117 genera, 73 families, 28 orders, 8 classes and 4 phyla. Among them, the phylum Mollusca was dominant, comprising 115 species belonging to 75 genera, 47 families, 18 orders, and 3 classes. This was followed by the phylum Arthropoda with 32 species from 18 genera, 9 families, 2 orders and 1 class. The phylum Annelida includes 24 species belonging to 19 genera, 12 families, 5 orders, and 1 class. The phylum Echinodermata includes 8 species belonging to 5 genera, 5 families, 3 orders, and 3 classes. The findings revealed that 17 species (9.50%) were listed in the IUCN Red List (2024) under various threat categories: one species (0.56%) as Endangered, 13 species (7.26%) as Least Concern and three species (1.68%) as Data Deficient. Three species (1.68%) were listed in Appendix II of the CITES Convention (2023). According to the Vietnam Red Data Book (2024), one species was classified as Critically Endangered. One species was listed in the Vietnam Red Data Book (2024) under the Endangered category. Four species were listed in the Vietnam Red Data Book (2024) under the Vulnerable category. Besides, the results pointed out that 51 species (28.49%) were identified as having economic value in the coastal waters of Ha Tinh Province.