Search

Phytochemical research of the 80% EtOH whole plant extract of Alpinia vietnamicaH.Ð. Tran, Luu & Skornick resulted in the isolation and structural elucidation of seven compounds 1–7, including two flavones quercetin‐3‐O‐α‐l‐rhamnosyl (1→2)‐α‐l‐rhamnoside (1) and diosmetin (2), three flavanones pinocembrin (3), alpinetin (4) and 5‐O‐methylnaringenin (5), and two chalcones cardamonin (6) and helichrysetin (7). The isolated compounds have shown biological effects at different levels. Two chalcones 6–7showed cytotoxicity toward four cancer cell lines KB, MCF7, A549, and HepG2, especially compound 7strongly inhibited the growth of A549 cancerous cells with the IC50of 6.81 µm. Flavone 1strongly exhibited antioxidative activity to scavenge DPPH radicals with the IC50of 51.68 µm. Flavone 2and flavanone 4moderately inhibited enzyme α‐glucosidase with the IC50values of 296.34–324.64 µm. Flavonoids from Alpinia vietnamica, and their biological activities.

The influence of single metal doping (K, Ca, Ga, Ni, Cu) on the electronic and optical characteristics of graphitic carbon nitride (g‐C3N4) was explored utilizing a semi‐empirical tight‐binding‐based quantum chemistry technique (GFN2‐xTB). The calculated results of interaction energy, analyzing the charge transfer, and the bond order revealed that chemical bonds were formed between the metal atom and g‐C3N4. Furthermore, the bond formation between doped metal atoms with g‐C3N4is predominantly covalent, except for K. The fractional occupation density analysis of the M/g‐C3N4systems shows different distributions of active electrons across the material systems. The frontier molecular orbitals (HOMO, LUMO) distribution utilized to assess the photogenerated electron and hole recombination of the catalytic systems. Due to the efficient separation of the photogenerated electron‐hole pairs, Ni/g‐C3N4exhibits the highest photocatalytic activity among the studied systems. On the basis of more extensive electronic and optical property calculations including ionization potential, electron affinity, global electrophilicity index, band gap energy, and UV‐VIS spectra, the Ni/g‐C3N4photocatalyst's high activity can be explained and interpreted.

Herein we reported a method for copper pivalate mediated, directed functionalization of orthoC−H bonds in (2‐methylthio)aniline benzamides. Diaryl disulfides were used for thiolation, while successful phenoxylation was obtained with phenol as the coupling agent. Our report marks a rare example for flexible transformation of benzamide C(sp2)−H bonds into the corresponding unsymmetrical diaryl ethers and thioethers.

This study aims to evaluate axonal injury in supratentorial acute stroke patients and predict motor function recovery.

Dammarenolic‐acid derivatives experimentally demonstrated possessing inhibition activity towards α‐glucosidase might be used as the evidence to retrieve an inhibitory mechanism and subjected for computational screening on other diabetes‐related proteins, e.g. tyrosine phosphatase 1B. Seven structures reported in our preceding work (denoted as 1‐7)were subjected for an in silicoinvestigation in this study on inhibitability towards protein structure PDB‐3W37 by molecular docking simulation. The computer‐based results see a good agreement with those from laboratory‐based reports, with the order of static stability: 3‐3W37> 1‐3W37> 7‐3W37> 2‐3W37> 6‐3W37~ 5‐3W37~ 4‐3W37(negligible activity). Together, experiment‐theory reveals the most promising candidates are 1‐3and 7. The in‐theory order for most promising inhibitors regarding protein structure UniProt‐PTP1B is: 1‐PTP1B> 6‐PTP1B> 4‐PTP1B. Quantity‐structure relationship analyses (i.e. QSARIS and ADMET) expect 1‐3as compounds with sufficient bio‐ and pharma‐compatibility. Altogether, the results specify 1as the most promising candidate for multi‐purpose inhibition towards diabetes‐based proteins, thus encouraging elevated efforts for validation and further development for application.

A series of substituted 4H-pyrano[2,3-d]pyrimidines were synthesized from corresponding substituted 4H-pyrans by ring-closing reaction with acetic anhydride or acetic acid in the presence of trifluoroacetic acid as catalyst. The successive alkylation reaction of lactam N–H bond on pyrimidine-4-one ring was carried out using propargylic bromide in dry acetonitrile in the presence of anhydrous potassium carbonate. Three procedures applied for this purpose, including MW-assisted heating conditions at power of 100 W, under conventional heating conditions in water bath at 50 °C, and under ultrasound-assisted heating conditions at 50 °C. Dry acetonitrile was used as reaction solvent. Excellent yields of N-propargyl-4H-pyrano[2,3-d]pyrimidine derivatives were obtained. The single-crystal X-ray structure of compound 6ahas been recorded, and the study helps to confirm the structure of synthesized N-propargyl derivative of 4H-pyrano[2,3-d]pyrimidines 6a–6p.

Graphical abstract:

A series of novel and previously synthesized lupane type С2‐benzylidene derivatives was evaluated on α‐glucosidase enzyme inhibition. Most of the tested compounds exhibited significantly better activity (1.8‐700 times higher) than the standard drug acarbose. The structure‐activity relationship indicated that the type of benzylidene moiety and C28‐substituent of lupane core plays an important influence on the activity. Methyl 2‐furfurylidene betulonate, m‐iodo‐benzylidene betulonic acid and 3‐pyridinylideno‐betulonic acid hydrazide have been founded as effective α‐glucosidase inhibitors and deserve further attention.

Chromatographic separation of ethyl acetate extract of the stingless bee Lisotrigona furvapropolis, that collected in Khanh Hoa province, led to isolation of five cycloartane‐type triterpenes including cycloartenone (1), cycloartenol (2), (24E)‐3β‐hydroxycycloart‐24‐en‐26‐al (3), mangiferonic acid (4) and mangiferolic acid (5). Mango plant (Mangifera indica) was suggested to be a resin source of the propolis. The propolis EtOH extract showed good antimicrobial activity on Gram (+) strain E. feacalisand fungus C. albicans. Among the isolated compounds, compound 3displayed selective activity against three Gram (+) strains and C. albicansover Gram (‐) strains with all MIC values of 64 μg/mL. However, the propolis EtOH extract was not active against LU‐1 and MCF‐7 cancer cell lines. Only compound 5exhibited moderate activity on LU‐1 cancer cell line with IC50of 13.33 μg/mL.

Background: Helicteres hirsuta has been used traditionally as a useful agent for hepatoprotective treatment. The aim of the current study is to isolate chemical constituents from the EtOAc extract of H. hirsuta stem and evaluate the capacity of the isolated compounds against hydroperoxide damaged rat liver cells. Methods: Column chromatography was used for phytochemical isolation whereas MTT method was applied for intracellular antioxidative assay. Results: Phytochemical analysis of the EtOAc extract of H. hirsuta stem led to the isolation and determination of four triterpenoids betulin (1), bentulinic acid (2), alphitolic acid (3), and oleanolic acid (4), together with two steroids stigmast-4-ene-6β-ol-3-one (5), and β-sitostenone (6), whereas EtOAc extract of its leaf was composed of three steroids cucurbitacin D (11), cucurbitacin I (12), and simiarenol (13), four flavonoids tiliroside (14), potengriffioside A (15), kaempferide (16), and isokaempferide (17), along with two carotenoids lutelin (18), and β-carotene (19). Isolated compounds 3, 5, 6, 16, and 17 were found in genus Helicteres for the first time, while carotenoids 18, and 19 were never isolated from family Sterculiaceae before. Phytochemicals derived H. hirsuta species are also useful agents for antioxidative drugs, e.g, flavonol 17 induced the significant EC50 value of 22.24 ± 0.14 μg/mL, as compared with that of positive control curcumin (EC50 19.33 ± 0.77 μg/mL), against hydroperoxide damaged rat liver cells. Conclusion: Antioxidative activity of the EtOAc extract of H. hirsuta stem against hydroperoxide is mostly based on the role of flavonoids.

A phytochemical study of the ethyl acetate extract (EtOAc) of Styrax annamensisleaves resulted in the isolation and determination of six known compounds, including three nor‐neolignans type 2‐phenylbenzofurans egonol (1), egonoic acid (2) and (–)‐machicendiol (3), two lignans styraxin (4) and vladinol D (5), and a triterpenoid pomolic acid (6). The chemical structures of these compounds were determined by NMR spectroscopies, and MS data. This is the first time to isolate these compounds from S. annamensisspecies. Compounds 3and 5have also been observed from genus Styraxfor the first time.

A phytochemical study of the EtOAc extract of Garcinia mackeanianaleaves has resulted in the isolation and determination of five xanthones, consisting of norathyriol (1), mangiferin (2), allanxanthone C (3), garcinone E (4), and bannanxanthone E (5). The structures of these xanthones have been determined by NMR‐spectra and MS spectroscopic data. These isolated compounds were separated from G. mackeanianaspecies for the first time. In the antimicrobacterial assay against the growth of bacterium Staphylococcus aureus, compounds 3‐4showed the significant IC50values of 5.41, and 4.29 μM/mL, respectively.

This article assesses the impact of climate change on the fishing activities of businesses, households and fishermen in the Northern coastal villages of Vietnam. From the data published by the state agencies and case studies in some fishing villages in the Northern region, this article assumes that the coastal fishing villages has a long history, making important contributions to the economic and social development. In recent years, fishing activities have expanded but are also affected by the consequences of climate change. Aware of this problem, businesses, households and fishermen have many measures to respond, but the effectiveness is still not high. Therefore, the study suggests that the government should pay more attention to improving the ability to predict early, accurately the location and evolution of rain, storm, etc. Exploiters need to be more proactive in equipping rescue equipment on ships and boats when going out to sea.

Novel 1,4-pyranonaphthoquinone derivatives were successfully synthesized viathe microwave-assisted three-component reaction of 1,4-naphthoquinone, malononitrile, and various arylaldehydes in ethanol in the presence of 4-(dimethylamino)pyridine (DMAP) as a catalyst, and subsequently evaluated in terms of their antimicrobial and antifungal activities. This synthetic procedure has the notable advantages of environmental friendliness, short reaction time, good yield, and convenient operation.

A modification of the Lecompte procedure was used successfully for total correction in 2 boys aged 3 and 6 months with double-outlet left ventricle. The operative procedure and short-term results are evaluated.

A new benzofurane 7-methoxy-2-(3-hydroxy-4-methoxyphenyl)-benzofuran-5-carboxylate (1) and 5 known compounds, such as propacin (2), hisbiscolatone A (3), heliclactone (4), rosmarinic acid (5), and syringaldehyde (6), were isolated from methanol extract of the Helicteres hirsutastems. Their structures were elucidated by spectroscopic analysis as Nuclear Magnetic Resonance (NMR) and Mass Spectroscopy (MS) Furthermore, compounds 1to 6were evaluated for their cytotoxic activity against 4 human cancer cell lines such as Lu-1, MCF7, HepG2, and KB. The results showed that compound 2exhibited moderate cytotoxic activity against Lu-1, MCF7, HepG2, and KB cell lines with IC50values of 43.97 ± 2.12, 46.53 ± 0.75, 52.63 ± 0.24, and 56.37 ± 1.04 µg/mL, respectively. This is the first report of compounds 2to 6from H. hirsuta.

Background:Measurements of liver iron concentration (LIC) by magnetic resonance imaging (MRI) have become established and validated in several research intensive centers. However, challenges remain with translating these measurement methodologies for routine clinical use. Current methods involve many steps presenting multiple opportunities for human error and can lead to systematic severe measurement error. Artificial neural networks (ANNs) can be trained to replace human input into image processing and may have a role in providing a simple, robust, and low cost solution for LIC measurement.

Betulin was converted to the corresponding alkyne-functionalized esters and amides and subsequently deployed as substrates for a ‘click’ chemistry-mediated coupling with 3'-azido-3'-deoxythydimine (AZT) to furnish a novel betulin–triazole–AZT hybrid compounds. Eleven new hybrids were thus successfully prepared and evaluated as cytotoxic agents, revealing an interesting anticancer activity in KB and HepG2 cancer cell lines.

Dihydroartemisinin was converted to its corresponding alkyne-functionalized esters, which were subsequently deployed as substrates for a ‘click’ chemistry-mediated coupling with 3′-azido-3′-deoxythydimine (AZT) to furnish novel triazole–artesunate–AZT hybrid compounds. Moreover, various substituted triazole–artemisinin hybrids were synthesized based on ‘click’ chemistry between propargyl-substituted derivatives and artemisinin containing a 2-hydroxypropane unit. Fourteen new hybrids were thus successfully prepared and evaluated as cytotoxic agents, revealing an interesting anticancer activity of four triazole–artemisinin derivative hybrids in KB and HepG2 cancer cell lines.