VNUHCM Journal of Natural Sciences

Phage endolysins: Structure, function and application

2025-07-02T13:55:53+07:00

Antibiotic resistance has emerged and persisted as one of the major threats to public health and the sustainable development of healthcare systems worldwide in recent years. The primary reason why antibiotic resistance is regarded as a global medical crisis lies in the development of new antibiotics is not keeping pace with the emergence of antibiotic-resistant strains. Currently, one of the proposed solutions to this crisis, as suggested by scientists, is the investigation of alternative antimicrobial agents that exhibit high efficacy while also possessing characteristics that limit the emergence of resistance in target pathogenic strains. Among such alternatives, endolysins, a class of enzymes derived from bacteriophages, have garnered considerable research interest. These enzymes are utilized by bacteriophages to degrade the peptidoglycan layer of bacterial cell walls during the infection process. The ability of endolysins to lyse bacterial cells when applied externally, combined with their high specificity at the genus or species level and a low propensity for inducing resistance, renders them promising candidates as substitutes for conventional antibiotics. This review aims to outline the structural features and mechanisms of action of endolysins, and to discuss in depth their characteristics and potential applications across various fields.

Synthesis of methoxystilbenoid derivatives and evaluation of cytotoxicity against breast cancer cell line

2025-06-23T11:43:15+07:00

Breast cancer is currently the most common cancer in women. According to the Global Cancer Observatory (Globocan 2020), there are over 2 million new cases of breast cancer diagnosed each year, accounting for 11.7% of all cancers, with an average of approximately 627,000 deaths due to breast cancer annually. Therefore, the search for new drugs that can treat breast cancer with high efficacy and minimal side effects is a pressing issue and is continuously ongoing worldwide. Stilbenoids, natural compounds commonly found in plants, possessed of various biological activities such as antioxidant, anti-inflammatory, antibacterial, and anticancer properties. Literature has shown that derivatives of methoxylated stilbenoids exhibit strong cytotoxic effects against cancer cells due to the presence of methoxy groups on the benzene ring. This paper reports the successful synthesise of 19 stilbenoid derivatives via Wittig coupling reactions between phosphonium ylides and benzaldehyde derivatives. Compounds 9a, 9b and 12 were reported for the first time for their ¹H-NMR spectral data. The evaluation of cytotoxic activity against MCF-7 breast cancer cells, at the tested concentration of 100 µg/mL showed that 15/19 derivatives exhibited cytotoxicity I% more than 50%. Among them, compound 2 showed the highest cytotoxicity with I% of 78.33 ± 1.52%, compared to the positive control camptothecin (I% 56.90 ± 0.79).

The preparation of bimetallic silver copper–silica nanocomposites for antifungal application against fungi causing root rot disease

2025-06-23T14:54:57+07:00

This paper presented the preparation of AgCu-SiO2 nanocomposite by green chemical reduction method combined with ultrasound. The physicochemical properties of AgCu-SiO2 were analyzed using techniques such as ultraviolet-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry and atomic absorption spectroscopy. The analytical results indicated that the AgCu-SiO2 nanocomposite contained bimetallic nanoparticles of silver and copper, with sizes of 7.52 ± 1.12 nm. These nanoparticles were densely distributed on the silica surface. The antifungal activity of AgCu-SiO2 was compared to monometallic nanocomposites (Ag-SiO2, Cu-SiO2) and a commercial fungicide Ridomil gold 68 WG against Rhizoctonia solani, Fusarium oxysporum and Pythium catenulatum, causing collar rots disease on Solanaceae. The results showed that AgCu-SiO2 exhibited good fungal growth inhibition compared to the monometallic nanocomposites. Specifically, the AgCu-SiO2 nanocomposite with complete fungal inhibition at a concentration of 125 ppm against all three studied fungal strains suggested its potential as an effective alternative to conventional chemical active ingredients in managing root rot disease.

Isolation of some Taxanes in leaves of Taxus wallichiana Zucc. collected at Lam Dong province, Vietnam

2025-06-29T16:39:47+07:00

Taxus wallichiana Zucc. from the Taxaceae family is a woody tree species with dark green, needle-shaped leaves that grow densely along the branches. This tree thrives in temperate climates, found in areas such as the Himalayan mountain range at altitudes between 1800 to 3300 m, and in the hilly regions of Meghalaya and Manipur at around 1500 m. It is a rare and valuable timber species with high medicinal value, primarily due to the presence of taxol, a potent anticancer compound isolated from the bark of the tree. This paper presents the chemical composition of the leaves of Taxus wallichiana Zucc. to contribute data on the chemistry and pharmacological potential of Vietnamese medicinal plants. Using normal-phase silica gel column chromatography combined with preparative thin−layer chromatography, four taxanes were isolated from the CHCl₃−soluble fraction of leaves of Taxus wallichiana Zucc., collected at Lam Dong province in January 2021. The isolated compounds included 10-deacetyl taxinine B (1), taxinine B (2), 2-deacetoxytaxinine J (3), and taxumairone A (4). The chemical structures of these compounds were elucidated by 1D and 2D NMR and MS spectra and comparisons to published data. Compound 4 is reported for the first time in the species Taxus wallichiana Zucc.

Chemical constituents and alpha-glucosidase inhibitory activity of Ficus pumila

2025-06-30T21:48:05+07:00

Phytochemical investigation of Ficus pumila collected in Lam Dong Province led to the isolation of ten compounds comprising four phenolic compounds, 4-hydroxybenzaldehyde (1), methyl 4-hydroxybenzoate (2), vanillic acid (3), 4-hydoxybenzoic acid (4); a furanocoumarin, bergapten (5); three 2-(2-phenylethyl)chromones, 6-hydroxy-2-(2-phenylethyl)chromone (6), 6,7-dimethoxy-2-(2-phenylethyl)chromone (7), 6,7-dimethoxy-2-[2-(4-methoxyphenyl)ethyl)]chromone (8); and two terpenoids, plumericin (9) and 2,7-dimethyl-2E,4E-octadienedioic acid (10). Their structures were identified by analysis of 1D- and 2D-NMR spectra and comparison of the spectral data with relevant literature. It is the first time compounds 2 and 6-10 have been obtained from the plant species. The anti-hyperglycemic activity of all isolated compounds was evaluated by measuring the inhibitory effect against α-glucosidase. Among them, compounds 2, 3, 7, 8 and 10 showed higher inhibitory activity than the positive control acarbose.

Study on the conversion of carbohydrates to 5-hydroxymethylfurfural using catalysts bearing Brønsted and Lewis acid in green chemistry conditions

2025-06-30T22:44:30+07:00

5-Hydroxymethylfurfural (HMF) serves as a prospective intermediary in the synthesis of biofuels. In recent years, researchers have sought environmentally friendly methodologies and appropriate catalysts for the synthesis of HMF under green chemistry conditions. In this study, we synthesized three ionic liquids containing Brønsted acid/Lewis acid centers and one biomass-derived catalyst with Brønsted acid groups from biomass. The efficacy of two types of catalysts was utilized in the procedure for converting carbohydrates into HMF. The research examined the effects of temperature, catalyst mass, recovery, and reuse to identify optimal conditions for the synthesis of HMF. The findings indicated that the 1-(4-sulfonic acid) butyl-3-methylimidazolium zinc chloride (IL3) catalyst exhibited enhanced activity relative to alternative catalysts, achieving a reaction yield of around 88% HMF in 2 hours using EMIMCl as a solvent. The Brønsted acid-based solid catalyst achieved a reaction yield of 52% HMF using 5 mg CA-SO₃H for a duration of 5 hours. This study illustrates the feasibility of synthesizing HMF from fructose utilizing green catalysts (ionic liquids or carbon-based solid acid ), suitable for large-scale production and particularly as a foundational platform for generating biomass-derived biofuels under green chemistry principles.