Hue University Journal of Science: Natural Science

Optimization of catalytic asymmetric intermolecular cyclopropanation of diazo acetocy acetone and styrene by using p-Nitro-Ru(II)-Diphenyl-pheox complex

Thi Loan Chi Le, Seiji Iwasa — Tue, 17 Jun 2025 00:00:00 +0000

The chiral cyclopropane ring is an important pharmacophore in pharmaceuticals and bioactive natural products, making libraries of these building blocks a valuable resource for drug discovery and development. Furthermore, the cyclopropyl ketone groups found in natural products have important biochemical properties, but only a-diazo acetophenone is developed as a ketone source, reported with 67% and 86% enantioselectivity yields. Therefore, this study presents a process to synthesise chiral cyclopropane of diazo acetoxy acetone and styrene catalysed by asymmetric p-nitro-Ru-¬dialkyl-pheox complex. This procedure was optimised under suitable solvent and temperature conditions and achieved high yields, excellent stereoisomer selectivity of more than 99:1, and enantioselectivity up to 95%. This is our exclusive published result, demonstrating the effectiveness of this catalyst in the reaction to produce highly stereoselective cyclopropanes. In addition, the study also has sufficient evidence on the mechanism of chiral cyclopropane formation with preferential trans product.

Extraction and enrichment of flavonoid and evaluation of antioxidant activity of Passiflora foetida extract

Tue, 17 Jun 2025 00:00:00 +0000

Passiflora foetida L., commonly known as Lạc tiên in Vietnam, is a widely used medicinal plant in Vietnamese traditional medicine to treat diseases such as sedation, fever reduction, liver cooling, nervous breakdown, heart palpitations, and insomnia. In this study, the appropriate conditions for the extraction of P. foetida L. were determined as follows: 80% ethanol as the solvent, the solvent-to-material ratio of 10:1, the extraction temperature of 80 °C, the extraction time of 120 minutes, and the number of extractions 3 times. Activated charcoal was employed to remove chlorophyll before enriching flavonoids in the extract with Diaion HP20 resin. The enrichment process utilised 10% ethanol as the loading solvent with an extract-to-resin ratio of 16:30 (w/w). The elution with 70% ethanol increased the flavonoid content in the extract to 13.89%. Furthermore, the enriched extract exhibited strong antioxidant activity, with an IC₅₀ value of 34.25 µg/mL.

Inhibitability of compounds from Lactuca indica l. towards enzyme alpha-glucosidase based on quantum chemical calculation and docking simulation

Tue, 17 Jun 2025 00:00:00 +0000

Diabetes causes excessively high blood sugar levels and disrupts metabolism in the body. Inhibiting the α-glucosidase enzyme is one of the treatments for diabetes. In this study, the compounds from Lactuca indica L. in the n-hexane extract were screened in silico to identify potential inhibitors of the 3W37 protein of the α-glucosidase enzyme. Eleven compounds (1–11) from the extract were identified by using the GC-MS method. The geometric structures of these compounds were optimised, and their quantum parameters were determined with the natural bond orbital method. The binding sites 1 and 2 of the protein were identified as favourable for molecular docking, and the inhibitory potential of the compounds was ranked in descending order as follows: 3 > 8 > 10 > 5 > 7 > 6 > 11 > 4 > 1 > 9 > 2. These compounds comply with Lipinski’s Rule of Five and exhibit pharmacokinetic and toxicity properties, including good absorption, no hepatic metabolism, renal excretion, and safety for the human body. These results will guide experimental studies to develop new approaches for supporting diabetes treatment.

Impact of the "Chuom" model on aquatic resources and water environment in Cau Hai Lagoon and Nay Lagoon, Hue City

Cong Tuan Le, Hue Nguyen Van — Tue, 17 Jun 2025 00:00:00 +0000

This research assesses the impact of the Chuom model on the aquatic resources and water environment to serve as a basis for sustainable use of aquatic resources. This model is based on a traditional fishing mode called Chuom or Cha Rao in Vietnam and is used in both freshwater (Nay Lagoon) and brackish water (Cau Hai Lagoon). The results show that the model is effective in attracting fish species. The number of economic fish species inside the Chuom area is larger than that outside, with the Cau Hai Lagoon having nine species against five species and the Nay Lagoon having 13 species against 11 species. The model also increases the fish mass and the density of zooplankton inside the Chuom. Water quality parameters such as pH, NH₃, and DO in the Chuom area are similar to those outside. It is necessary to have an official program to develop the Chuom model in the localities.

Electrochemical analysis of sildenafil citrate on electrode modified with nitrogen and sulfur-doped reduced graphene oxide

Thi Thanh Xuan Ngo, Duc Anh Le, Quang Man Nguyen — Tue, 17 Jun 2025 00:00:00 +0000

In this study, nitrogen and sulfur-doped reduced graphene oxide (rGO(N.S)) was prepared with the hydrothermal method. The rGO(N.S) material was characterized with X-ray diffraction and Raman spectroscopy. A glassy carbon electrode was modified with the rGO(N.S) material to develop a novel electrochemical sensor for analysing sildenafil citrate (SDC). The electrochemical parameters of the differential pulse voltammetry technique such as accumulation potential, accumulation time, pulse amplitude, and potential step were investigated and optimized, showing a relatively low detection limit of SDC.

Hydroxyapatite production from animal bone sources

Tue, 17 Jun 2025 00:00:00 +0000

In this study, the bone char composition of cows, buffaloes, pigs, and goats was studied. The samples were characterized by using X-ray diffraction, thermal analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The main component is hydroxylapatite (Ca₅(OH)(PO₄)₃) with the following content: 67.7% in buffalo bones, 65.2% in cow bones, 58% in pig bones, and 48% in goat bones. The bone char exhibits a nano-sized morphology ranging from fibres to granules depending on the calcination temperature and animal bone type. The bone char is suitable as a starting material for producing organic nano phosphate fertilizer.

Iridoid glycosides from Gomphandra tonkinensis Gagnep.

Tue, 17 Jun 2025 00:00:00 +0000

Four iridoid glycosides, namely sweroside (1), loganin (2), triplostoside A (3), and gomphandranoside C (4), were isolated from the roots of Gomphandra tonkinensis Gagnep. collected in Thua Thien Hue. The chemical structures of isolated compounds were determined based on 1D-NMR and 2D-NMR spectral data and compared with previously published information. Compound 1 exhibits the ability to inhibit diabetes-related enzymes (α-amylase and α-glucosidase) with IC₅₀ values of 331.1 ± 8.6 µg/mL and 344.2 ± 6.0 µg/mL, respectively. Compound 2 has α-glucosidase inhibitory activity with an IC₅₀ value of 270.9 ± 9.7 µg/mL. Triplostoside A (3) is isolated from the genus Gomphandra for the first time.

CeO2-Pr2O3 rare earth oxide nano materials for application as a bioproduct in Angelica sinensis cultivation

Tue, 17 Jun 2025 00:00:00 +0000

In this study, CeO₂-Pr₂O₃ nano fertilizer was manufactured and utilised as a plant growth stimulant for Angelica sinensis. CeO₂-Pr₂O₃ was synthesised from cerium(IV) nitrate and praseodymium(III) nitrate as precursors via the ultrasonic-assisted co-precipitation method. The morphology and structure of the nanomaterials were characterised by using XRD, IR, EDX, SEM, and TEM. The composite CeO₂-Pr₂O₃ substantially affected the growth and development of Angelica sinensis. After 90 days of application, the plants treated with CeO₂-Pr₂O₃ nanomaterials exhibited significantly enhanced growth performance: plant height reached 37.8 cm (an increase of 36.0%); leaf number reached 37.9 leaves/plant (an increase of 37.3%), and canopy diameter reached 49.5 cm (an increase of 31.6%) compared with the control. Additionally, Angelica sinensis plants supplemented with CeO₂-Pr₂O₃ demonstrated improved morphological characteristics, including stronger stems, thicker and greener leaves, deeper purple stem colouration, and more vigorous root systems with a greater number of lateral and main roots. These findings suggest that CeO₂-Pr₂O₃ nanomaterials possess a notable plant growth-promoting effect on Angelica sinensis.

Compatibility and optimization of antigen content to develop combined acellular diphtheria-tetanus-pertussis (DTaP) vaccine at Institute of Vaccines and Medical Biologicals

Tue, 17 Jun 2025 00:00:00 +0000

Compatibility between components and the amount of antigens in combination vaccines are important factors determining the safety, efficacy, and stability of that vaccine. To develop the diphtheria-tetanus-acellular pertussis (DTaP) vaccine at the Institute of Vaccines and Medical Biologicals (IVAC), we evaluated the compatibility among the components and optimized the amount of antigens in the vaccine formulation. The antigen components, including tetanus antigen (T), diphtheria antigen (D), and recombinant pertussis toxoid (rPT), together with filamentous haemagglutination factor (FHA), and aluminum hydroxide adjuvant, were evaluated for compatibility by using physicochemical and immunological methods. Design Expert version 12 software was used to optimize the amount of each antigen in the DTaP vaccine formulation. The results show that the components are compatible with each other. The optimal DTaP vaccine formula contains 40 Lf/mL D, 20 Lf/mL T, 10 µg/mL rPT, 20 µg/mL FHA, and 0.6 mg Al³⁺/mL respectively, corresponding to the diphtheria potency of 94,47 IU/mL, tetanus potency of 107,86 IU/mL, and pertussis potency of 9,65 IU/mL. The DTaP vaccine developed by IVAC meets the standard of the Vietnamese Pharmacopoeia V, 2018, of the Ministry of Health, and WHO.

Effect of fabrication technique on optical properties of carbon nano-dots from gac fruit (momordica cochinchinensis spreng) skin

Xuan Diem Ngoc Le, Thanh Tien Do, Khoa Quang Ngo — Tue, 17 Jun 2025 00:00:00 +0000

In this study, we fabricated carbon dots (CDs) solutions from the skin of the Gac fruit by using the hydrothermal method. The samples were fabricated at 190 °C for 6, 8, 10, 12, 14, and 16 hours. We investigated the structural properties of the obtained CDs via X-Ray diffraction (XRD), and the optical properties of the samples were accessed via UV–Vis absorption, photoluminescence, FTIR spectra, and the quantum yield. The results show that the CDs absorb light at the wavelength of 276 nm and emit at the wavelength of 430 nm. The FTIR spectrum clarifies that the functional groups on the surface of the carbon core are hydroxyl and carbonyl. The results indicate that the quantum yield varies with the treatment time and reaches a maximal value (5,06%) at 190 °C and 14 hours.

Biodiversity of fish species composition in coastal waters of Ha Tinh province

Hoang Dinh Trung, Thi Bao Chau Ngo — Tue, 17 Jun 2025 00:00:00 +0000

The study was conducted through four surveys from May 2023 to February 2025 at eight sampling sites. A total of 206 fish species were recorded, belonging to 129 genera, 64 families, and 20 orders across two subclasses (Chondrichthyes and Actinopterygii). Among them, the order Acanthuriformes was dominant, comprising 45 species (21.84% of the total species) and 14 families (21.88% of the total families). Besides, 171 species listed in the IUCN Red List (2024) under various threat categories were identified: one species as Endangered (EN), six as Vulnerable (VU), 150 as Least Concern (LC), four as Near Threatened (NT), and ten as Data Deficient (DD). According to the Vietnam Red Data Book (2007), one species (0.49%) was classified as Critically Endangered (CR). Three species (accounting for 1.46%) are listed in the Vietnam Red Data Book (2024) under the Vulnerable (VU) category. Additionally, 24 species (11.65%) were identified as having economic value, and 25 species (12.14%) are commonly cultured for commercial purposes. These findings provide important baseline data for the sustainable management and conservation of fish resources in the region.

Determination of Hg(II) with square-wave anodic stripping voltammetry method on AuNPS/ErGO-GCE electrode

Tue, 17 Jun 2025 00:00:00 +0000

In this study, Hg(II) was determined on a modified AuNPs/ErGO-GCE electrode with the square-wave anodic stripping voltammetry (SqW-ASV) method. The morphology of the material modifying the electrode was characterized with EDX-mapping and HR-TEM. Additionally, several parameters of the SqW-ASV method, including pulse amplitude (ΔE), square wave frequency (f), potential change step (r), deposition potential (E_dep.), and deposition time (t_dep.), were investigated. Under optimized conditions: acetate buffer (ABS), pH = 5 and KCl 0.1 M, r from –0.2 to +0.8 V, E_dep: –0.9 V, t_dep: 240 s, DE: 30 mV and f: 30 Hz, the linear range of Hg(II) concentration was from 5.0 to 49,5 ppb, and the detection limit of Hg(II) was 1.89 ppb.