Journal Articles - Natural Science - 2020
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PublicationA density functional theory study on silver and bis-silver complexes with lighter tetrylene: are silver and bis-silver carbenes candidates for SARS-CoV-2 inhibition? Insight from molecular docking simulation( 2020)
;Thanh Q. Bui ;Huynh Thi Phuong Loan ;Tran Thi Ai My ;Duong Tuan Quang ;Bui Thi Phuong Thuy ;Vo Duy Nhan ;Phan Tu Quy ;Pham Van Tat ;Duy Quang Dao ;Nguyen Tien Trung ;Lam K. HuynhNguyen Thi Ai NhungRibavirin and remdesivir have been preclinically reported as potential drugs for the treatment of SARS-CoV- 2 infection, while light silver tetrylene complexes (NHEPh–AgCl and (NHEPh–AgCl)2 with E ¼ C, Si, and Ge) have gained significant interest due to their promising applicability on the cytological scale. Firstly, the structures and bonding states of silver–tetrylene complexes (NHE–Ag) and bis-silver–tetrylene complexes (NHE–Ag-bis) were investigated using density functional theory (DFT) at the BP86 level with the def2-SVP and def2-TZVPP basis sets. Secondly, the inhibitory capabilities of the carbene complexes (NHC–Ag and NHC–Ag-bis) and the two potential drugs (ribavirin and remdesivir) on human-protein ACE2 and SARS-CoV-2 protease PDB6LU7 were evaluated using molecular docking simulation. The carbene ligand NHC bonds in a head-on configuration with AgCl and (AgCl)2, whereas, the other NHE (E ¼ Si and Ge) tetrylene ligands bond in a side-on mode to the metal fragments. The bond dissociation energy (BDE) of the NHE–Ag bond in the complex families follows the order of NHC–Ag > NHSi–Ag > NHGe–Ag and NHSi–Ag-bis > NHGe–Ag-bis > NHC–Ag-bis. The natural bond orbital analysis implies that the [NHEPh/AgCl] and [(NHEPh)2/(AgCl)2] donations are derived mainly from the s- and pcontributions of the ligands. The docking results indicate that both the ACE2 and PDB6LU7 proteins are strongly inhibited by silver–carbene NHC–Ag, bis-silver–carbene NHC–Ag-bis, ribavirin, and remdesivir with the docking score energy values varying from 17.5 to 16.5 kcal mol 1 and 16.9 to 16.6 kcal mol 1, respectively. The root-mean-square deviation values were recorded to be less than 2 A in all the calculated systems. Thus, the present study suggests that silver–carbene NHC–Ag and bissilver– carbene NHC–Ag-bis complexes are potential candidates to inhibit ACE2 and PDB6LU7, and thus potentially conducive to prevent infection caused by the SARS-CoV-2 virus. -
PublicationA molecular docking simulation study on potent inhibitors against Rhizoctonia solani and Magnaporthe oryzae in rice: silver-tetrylene and bis-silver-tetrylene complexes vs. validamycin and tricyclazole pesticides( 2020)
;Bui Thi Phuong Thuy ;Tran Thi Ai My ;Nguyen Thi Thanh Hai ;Huynh Thi Phuong Loan ;Le Trung Hieu ;Tran Thai Hoa ;Thanh Q. Bui ;Ho Nhat Tuong ;Nguyen Thi Thu Thuy ;Doan Kim Dung ;Pham Van Tat ;Phan Tu QuyNguyen Thi Ai NhungRice, well known as the most important staple food source worldwide, is highly susceptible to many infectious diseases, especially rice sheath blight caused by fungus Rhizoctonia solani and rice blast caused by fungus Magnaporthe oryzae. The inhibitory ability of silver- and bis-silver-tetrylene complexes, including Ag-E and bis-Ag-E with E = C, Si, Ge, onto protein 4G9M in Rhizoctonia solani and protein 6JBR in Magnaporthe oryzae was theoretically investigated using molecular docking simulation methodology. Two commercial pesticides selected as inhibitory references are validamycin for 4G9M and tricyclazole for 6JBR. The results reveal that bis-silver-tetrylene complexes perform the strongest inhibitory effects towards both proteins. The structures of the complexes exhibit good site–site binding to both proteins given the observations on the hydrogen bond interactions, cation–π bonds, π–π bonds, and ionic interactions, interaction distance between amino acids and ligands, and van der Waals interactions. The inhibitory capacity onto protein 4G9M decreases in the following order: bis-Ag-C > bis-Ag-Si > bis-Ag-Ge > validamycin > Ag-C ≈ Ag-Si ≈ Ag-Ge. The corresponding order observed from the study for protein 6JBR is bis- Ag-C > bis-Ag-Si ≈ bis-Ag-Ge > tricyclazole ≈ Ag-C ≈ Ag-Si ≈ Ag-Ge. The study opens a promising approach to tackle rice blast and rice sheath blight based on a family of silver-tetrylene organometallic chemicals given the theoretical proof of environment-advanced properties and molecule-scaled effectiveness. -
PublicationA new resorcinol derivative from the bark of Aegiceras floridum (Primulaceae)( 2020)
;Huynh-Van-Long Luu ;Thi-Hoai-Thu Nguyen ;Kim-Phi-Phung Nguyen ;Huu-Hung Nguyen ;Ngoc-Hong NguyenThuc-Huy DuongChemical investigation of the Vietnamese plant Aegiceras floridum Roem. & Schult. (Primulaceae) led to the isolation of the new compound 3-methoxy-5-nonylphenol (1) along with five known ones 2,8,10-trihydroxy-6H-benzo[c]chromen-6-one (2), 2-hydroxy-5-methoxy-3-nonylbenzo-1,4-quinone (3), 5-(3-hydroxypropyl)-7-methoxy-3-(methylbenzofuran-2-yl)-3-methoxyphenol (4), 2,8-dihydroxy-7-methoxy-3,9-diundecyldibenzofuran-1,4-dione (5) and 10-hydroxy-4-methoxy-2,11-diundecylgomphilactone (6). The structures were elucidated by analysis of their HRESIMS and NMR data as well as the comparison of their NMR data with those reported in the literature. The cytotoxic activity of selected isolated compounds against some cancer cell lines such as human epithelial carcinoma (HeLa), human lung cancer (NCI-H460), liver hepatocellular carcinoma (HepG2), human breast cancer (MCF-7), and acute T cell leukemia (Jurkat) was evaluated. Among them, 3 showed moderate activities against MCF-7 with an IC50 of 17.77 µM and NCI-H460 with an IC50 of 25.02 µM. The result of DPPH radical scavenging activity assay indicated that compounds 2–4 and 6 revealed weak antioxidant activity. -
PublicationAn overview of phytochemicals and potential health-promoting properties of black walnut( 2020)
;Danh C. Vu ;Trang H. D. NguyenThi L. HoBlack walnut (Juglans nigra L.) is one of the most widely consumed nuts in the United States. The nut has been recognized for its unique, bold flavor, and used as a versatile food ingredient. The objective of this review is to summarize available research data pertaining to phytochemicals present in black walnut and their previously reported health-promoting properties. Black walnut is rich in phenolics and contains higher levels of phytosterols, unsaturated fatty acids and tocopherols than many other commonly consumed nuts. Dietary intervention of these constituents has been associated with a great number of disease-preventive properties. Black walnut has a potential to inhibit the release of proinflammatory mediators in vitro. Similarities in contents of unsaturated fatty acids and tocopherols between black walnut and English walnut suggest that black walnut consumption may produce beneficial effects on cardiovascular disease risks. In addition, the high level of g-tocopherol in black walnut could make the nut a cancer-preventive option. Although evidence has shown black walnut kernel is a rich source of phytochemicals of potential importance to human health, there is a paucity of in vitro and in vivo studies on the bioactivities of these phytochemicals isolated from black walnut and the health-promoting properties of black walnut consumption. Clinical studies are needed to better understand the health benefits of black walnut. -
PublicationChitin Hydrogels Prepared at Various Lithium Chloride/N,N-Dimethylacetamide Solutions by Water Vapor-Induced Phase Inversion( 2020)
;Khoa Dang Nguyen ;Takaomi KobayashiBarbara GawdzikChitin was chemically extracted from crab shells and then dissolved in N,N-dimethylacetamide (DMAc) solvent with lithium chloride (LiCl) at 3, 5, 7, and 10%. The concentrated chitin-DMAc/LiCl solutions were used for the preparation of chitin hydrogels by water vapor-induced phase inversion at 20°C. The coagulation process was investigated while altering the concentration of LiCl in the DMAc solution. The shear viscosity of the chitin solution increased with higher LiCl amounts and decreased when the concentration of LiCl was reduced by adding water to the chitin solution, implying high LiCl concentration delayed the coagulation of chitin solution in the presence of water. The viscoelasticity of the chitin solutions indicated the gel formation intensification was dependent on the dose of LiCl and chitin in the DMAc solution. After the chitin solution was coagulated, the resultant hydrogels had water contents of 387–461% and the tensile strength varied from 285 to 400 kPa when the concentration of LiCl in the hydrogel was adjusted to 3% and 7%, respectively. As for viscoelasticity, the complex modulus of the chitin hydrogels indicated that the increment of the LiCl concentration up to 7% formed the tight hydrogels. Atomic force microscopic (AFM) image revealed the formation of the entanglement network and larger domains of the aggregated chitin segments. However, the hydrogel prepared at 10% LiCl in DMAc solution exhibited weak mechanical properties due to the loose hydrogel networking caused by the strong aggregation of the chitin segments. -
PublicationCoordination complexes of slight tetrylene with platinum(II)-8-hydroxyquinolines: Structure and bonding analysis( 2020)
;Huynh Thi Phuong Loan ;Hoang Van Duc ;Phan Tu Quy ;Bui Thi Phuong Thuy ;Pham Van Tat ;Duong Tuan QuangNguyen Thi Ai NhungThe structure and bonding situation in platinum complexes containing slight tetrylene ligands [{PtCl-C9H6NO}-NHE] (Pt-NHE) with E = C, Si, Ge were examined by DFT calculations with the levels are BP86/def2-SVP and BP86/def2-TZVPP. The predicted equilibrium structure of the ligands NHE in Pt-NHE are bonded in distorted end-on way to PtCl-8-hydroxyquinolines fragment with the bending angle, , exhibits the biggest value in carbenes systems then slightly decrease from Pt-NHC to Pt-NHGe. Bond dissociation energies (BDEs), De (kcal.mol-1), decrease from the carbene complex to the weaker bonded silylene and germylene manners. The BDE when considering dispersion correction at the BP86-D3(BJ)/def2-TZVPP level confirms that Pt-E bond in Pt-NHE belongs to the effect of the bulky group in slight tetrylene NHE and Pt(II)-group fragment which makes the intrinsic Pt-E bond strength decreases from carbene to germylene complexes. The hybridization of atoms E and Pt have large p characters while the hybridization of atom Pt has greater d character which lead to the Pt-E bond possesses not only NHE→{PtCl-C9H6NO} strong -donation but also a significant contribution π-donation NHE→{PtCl-C9H6NO} and weak π-backdonation metal-ligand NHE←{PtCl-C9H6NO} in complexes Pt-NHE. -
PublicationDesign and synthesis of new lupeol derivatives and their α-glucosidase inhibitory and cytotoxic activities( 2020)
;Hoang-Vinh-Truong Phan ;Thuc-Huy Duong ;Duc-Dung Pham ;Hoang-Anh Pham ;Van-Kieu Nguyen ;Thi-Phuong Nguyen ;Huu-Hung Nguyen ;Ngoc-Hong Nguyen ;Pornpat Sam-ang ;Kiettipum PhontreeJirapast Sichaemwere designed, synthesised and evaluated for their a-glucosidase inhibitory and cytotoxic activities. Among synthetic derivatives, lupeol analogues 2b and 2e containing a benzylidene chain exhibited the best activity against a-glucosidase and superior to the positive agent with the IC50 values of 29.4 ± 1.33 and 20.1 ± 0.91 lM, respectively. Lupeol analogues 2d and 3a showed weak cytotoxicity against K562 cell line with the IC50 values of 76.6 ± 2.40 and 94.4 ± 1.51 lM, respectively. -
PublicationDesign, modification of phyllanthone derivatives as anti-diabetic and cytotoxic agents( 2020)
;Ngoc-Hong Nguyen ;Van-Giau Vo ;Hoang-Vinh-Truong Phan ;Thanh-The Ngo ;Jirapast Sichaem ;Thi-Phuong Nguyen ;Huu-Hung Nguyen ;Duc-Dung Pham ;Tien-Cong Nguyen ;Van-Kieu NguyenThuc-Huy DuongTwelve benzylidene derivatives, one Baeyer-Villiger oxidative, six imine derivatives were successfully designed and synthesized from phyllanthone. In the search for potential new anti-diabetic agents, phyllanthone along with its benzylidene and oxidation analogues were evaluated for enzyme inhibition against α-glucosidase. In the benzylidene series, most analogues displayed stronger activity than the mother compound. 1c revealed the strongest activity, outperforming the acarbose positive control with an IC50 value of 19.59 μM. Phyllanthone and its derivatives were then tested for cytotoxic activity against the K562 cell line. The imine analogues displayed the most powerful cytotoxic activity with 3c, 3d having IC50 values of 57.55 and 68.02 μM, respectively. -
PublicationDilatatone, a new chlorinated compound from Parmotrema dilatatum( 2020)
;Hoang-Vinh-Truong Phan ;Asshaima Paramita Devi ;Hoang-Duy Le ;Thanh-Trung Nguyen ;Huu-Hung Nguyen ;Tran-Thai-Duong Le ;Tai Hoang Nguyen ;Jirapast SichaemThuc-Huy DuongChemical investigation of the lichen Parmotrema dilatatum led to the isolation of a new chlorinated compound, named dilatatone (1), along with a known compound, sernanderin (2). Their chemical structures were determined by analysis of their 1D and 2D NMR spectra, HRESIMS, and ECD data. Both compounds showed weak a-glucosidase inhibitor activity. -
PublicationEngineering a homogeneous alloy-oxide interface derived from metal-organic frameworks for selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid( 2020)
;Yu-Te Liao ;Van Chi Nguyen ;Nozomu Ishiguro ;Allison P. Young ;Chia-Kuang TsungKevin C.-W. WuThe selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is an important biomass conversion reaction. However, the multiple intermediates of the reaction make the catalyst design challenging. We engineered an active and selective catalyst with an active interface between Au-Pd alloy nanoparticles (NPs) and cobalt oxide supports via calcination of a composite of NPs encapsulated in metal-organic frameworks (MOFs). The catalyst shows an effective HMF-to-FDCA oxidation with total conversion and 95 % yield by 10 % hydrogen peroxide solution at 90 °C in one hour under atmospheric pressure. The mechanistic study shows that the engineered interface promotes the formation of hydroperoxyl radicals and dioxygen molecules, which accelerate the oxidation of reactive intermediates to FDCA. This work demonstrates the advantage of using MOF composites as a precursor to generate complex but active interfaces with a strong interaction between the metal and metal oxides. -
PublicationGreen synthesis of cobalt-oxide nanoparticle using jumbo Muscadine (Vitis rotundifolia): Characterization and photo-catalytic activity of acid Blue-74( 2020)
;Melvin S. Samuel ;E. Selvarajan ;Thangavel Mathimani ;Needhidasan Santhanam ;Tran Nhat Phuong ;Kathirvel BrindhadeviArivalagan PugazhendhiIn the recent years, plant and microbial extract based nanoparticles (NPs) have become a sophisticated technology serving as an alternative strategy for the purpose of developing materials functionalized by structural diversity and enhanced energy efficiencies. Cobalt oxide nanoparticles (GCoO-NPs) have wide applications in several sectors due to their high resistance to corrosion as well as oxidation, ecofriendly nature, cost effectiveness and nontoxic potential. Plant based particles are credible alternatives as they reduce the burden of complicated and laborious protocols of physiochemical reliance. In this study, GCoO-NPs were synthesized using the grape Jumbo Muscadine (Vitis rotundifolia) using co-precipitation. The synthesized GCoO-NPs were characterized by UV–Vis spectrophotometer, Fourier transform infrared spectroscopy (FTIR), Powder X-ray diffraction (PXRD) and Scanning electron microscopy (SEM). The photocatalytic activity of the GCoO-NPs was estimated by the degradation of Acid Blue-74 (AB-74) dye and the complete degradation of 98% was accomplished at the reaction time of 150 min at pH 10 and 60 mg/100 mL concentration. The outcomes of this study indicated the excellent performance of the GCoO-NPs on par with some of the earlier findings and this can be an appealing aspirant of extreme potential to be employed as a catalyst alternative to the conventional wastewater treatment methods. -
PublicationInvestigation into SARS-CoV-2 Resistance of Compounds in Garlic Essential Oil( 2020)
;Bui Thi Phuong Thuy ;Tran Thi Ai My ;Nguyen Thi Thanh Hai ;Le Trung Hieu ;Tran Thai Hoa ;Huynh Thi Phuong Loan ;Nguyen Thanh Triet ;Tran Thi Van Anh ;Phan Tu Quy ;Pham Van Tat ;Nguyen Van Hue ;Duong Tuan Quang ;Nguyen Tien Trung ;Vo Thanh Tung ;Lam K. HuynhNguyen Thi Ai NhungEighteen active substances, including 17 organosulfur compounds found in garlic essential oil (T), were identified by GC−MS analysis. For the first time, using the molecular docking technique, we report the inhibitory effect of the considered compounds on the host receptor angiotensin-converting enzyme 2 (ACE2) protein in the human body that leads to a crucial foundation about coronavirus resistance of individual compounds on the main protease (PDB6LU7) protein of SARS-CoV-2. The results show that the 17 organosulfur compounds, accounting for 99.4% contents of the garlic essential oil, have strong interactions with the amino acids of the ACE2 protein and the main protease PDB6LU7 of SARS-CoV- 2. The strongest anticoronavirus activity is expressed in allyl disulfide and allyl trisulfide, which account for the highest content in the garlic essential oil (51.3%). Interestingly, docking results indicate the synergistic interactions of the 17 substances, which exhibit good inhibition of the ACE2 and PDB6LU7 proteins. The results suggest that the garlic essential oil is a valuable natural antivirus source, which contributes to preventing the invasion of coronavirus into the human body -
PublicationLuminescence and Thermal-Quenching Properties of Red-Emitting Ca2Al2SiO7:Sm3+ Phosphors( 2020)
;Nguyen Manh Son ;Do Thanh Tien ;Nguyen Thi Quynh Lien ;Vu Xuan Quang ;Nguyen Ngoc Trac ;Tran Thi HongHo Van TuyenCa2Al2SiO7:x.Sm3+ (x = 0.5, 1.0, 1.5, 2.0, 2.5, and 3.5 mol.%) (CAS:x.Sm3+) phosphors were synthesized by a solid-state reaction technique. The structure, photoluminescence properties and thermal stability of phosphors were investigated in detail. Results of X-ray diffraction show that CAS:x.Sm3+ materials have a single-phased tetragonal structure, and an expansion of the unit cell relates to the increasing of Sm3+ concentration. Photoluminescence study displayed that the CAS:x.Sm3+ phosphors reach the highest emission intensity at 1.5 mol.% Sm3+ and achieved the luminescence quenching phenomenon a higher concentration. The dominant interaction mechanism of the concentration quenching process is determined due to the dipole–dipole interaction, and the critical transfer distance (Rc) is 26.7 A ° . The temperature dependence of photoluminescence spectra indicates that the Ca2Al2SiO7:Sm3+ (1.5 mol.%) phosphor possess good thermal stability, and that the activation energy is around 0.12 eV (968 cm 1). Several characteristic vibrations in the 200–1000-cm 1 region were observed by Raman spectra, and the color chromaticity coordinates of the samples were also calculated and discussed. -
PublicationManilkzapotane, a novel dimeric alkylresorcinol derivative from the stem bark of Manilkara zapota( 2020)
;Thuc-Huy Duong ;Nguyen Tien Trung ;Cam-Tu D. Phan ;Van-Kieu Nguyen ;Vassana Musa ;Thanatip Ruksilp ;Ngoc-Hong Nguyen ;Huu-Hung NguyenJirapast SichaemA novel dimeric alkylresorcinol derivative, manilkzapotane (1), along with seven known compounds, lupeol acetate (2), lupeol (3), arjunolic acid (4), ergosterol peroxide (5), taraxerol (6), hederagonic acid (7), and glochidiol (8) were isolated from the stem bark of Manilkara zapota. Their structures were determined on the basis of spectroscopic data. DFT-NMR chemical shift calculations and a modified probability (DP4þ) method were applied to define the relative configuration of 1. To the best of our knowledge, this represents the first isolation of a dimeric alkylresorcinol derivative from the Sapotaceae family. -
PublicationMolecular Docking Studies of Glycyrrhetinic Acid Derivatives as Anti-Colorectal Cancer Agents( 2021)
;Nam Q.H. Doan ;Tuyen N. TruongPhuong T.V. NguyenIn this study, the anti-CRC activities of 40 glycyrrhetinic acid derivatives were proposed and evaluated by the molecular docking method, which allowed the flexibility of both ligand-receptor, with twelve CRC-related targets. The proposed derivatives, which clearly distinguish isomers at position 18 as well as the different tautomers, were divided into five groups including (1) glycyrrhetinic acid and its oxidation derivatives, (2) glycoside derivatives, (3) 3β-amine derivatives, (4) five-membered heterocyclic ring-combined derivatives, and (5) six-membered heterocyclic ringcombined derivatives. Finally, we selected four out of twelve proposed targets related to CRC with good binding affinities to the proposed glycyrrhetinic acid derivatives including Epidermal Growth Factor Receptor (EGFR), Focal Adhesion Kinase (FAK), Lactate Dehydrogenase A (LDHA), and Thymidylate Synthase (TS). From there, we also gained 9/40 derivatives for EGFR (pKd ≥ 9); 10/40 derivatives for FAK (pKd ≥ 10); 9/40 derivatives for LDHA (pKd ≥ 10), and 6/40 derivatives for TS (pKd ≥ 9). The glycoside derivatives showed the best binding affinity (especially the glucuronide derivative 5b), followed by the 3β-amino derivatives (especially the 3β-(phenylamino) derivative 8b) and the five-membered heterocyclic ring-combined derivatives (especially the pyrrole derivative 10a or pyrazole derivative 11.2a), while the six-membered heterocyclic ring-combined derivatives had less potential to inhibit selected targets. -
PublicationNew triterpene sulfates from Vietnamese red alga Tricleocarpa fragilis and their α-glucosidase inhibitory activity( 2020)
;Thi Van Anh Tran ;Van Minh Nguyen ;Thi Ai Nhung Nguyen ;Dat Huy Thanh Nguyen ;Duy Hien Tran ;Thi Phuong Thuy Bui ;Van Tat PhamThe Han NguyenThree new compounds (methyl-3β,25-dihydroxycycloart-23-en-29-oate 3-sulfate (1), methyl-3β-hydroxy-25-methoxycycloart-23-en-29-oate 3-sulfate (2) and 3β-hydroxy-25-methoxycycloart-23-ene 3-sulfate (3)) and a known one (3β-hydroxycycloart-24-en-23-one 3-sulfate (4)) were isolated from Vietnamese red alga Tricleocarpa fragilis. All isolated compounds 1-4 showed potent inhibitory activity against yeast α-glucosidase with IC50 values of 16.62 ± 2.80, 36.34 ± 4.04, 30.19 ± 5.01 and 6.52 ± 0.17 µM, respectively. The docking data showed that the substitutions at C-3 and the differences in the side chain of cycloartane-skeleton could influence the interaction of molecule with enzyme, which was consistent with the experimental findings. -
PublicationParmosidone K, A New Meta depsidone from The Lichen Parmotrema Tsavoense( 2020)
;Thi-Hoai-Thu Nguyen ;Thi-My-Nhung Nguyen ;Thanh-Trung Nguyen ;Huu-Hung Nguyen ;Ngoc-Hong Nguyen ;Dinh-Tri Mai ;Bui-Linh-Chi Huynh ;Cong-Luan TranThuc-Huy DuongFurther phytochemical investigation on P. tsavoense led to one new meta-depsidone, parmosidone K together with one known compound, barbatic acid. Their structures were determined by 1D and 2D NMR analysis, high resolution mass spectroscopy, and comparison their NMR data with those reported in literatures. Parmosidone K was evaluated for α-glucosidase inhibition and revealed the powerful activity with IC50 value of 3.12 µM. -
PublicationPrediction of the Spin-Parities and the Magnetic Moments for the Ground States of Proton-rich Nuclei with Z = 21–30( 2020)
;Nguyen Duy Ly ;Latsamy Xayavong ;Nguyen Kim Uyen ;Vinh N. T. Pham ;T. V. Nhan HaoNguyen Ngoc DuyThe present paper reports on the spin-parities and the magnetic moments for the ground states of 44 proton-rich isotopes with Z = 21−30 and A = 36−57, which are important for studies of either reaction rates in X-ray bursts or nuclear structure. These nuclear properties were calculated based on the single-particle shell model. The spins of the concerned nuclei were compared to available experimental data adopted from the NuDat database to evaluate the variations in the astrophysical rates of the rp-process reactions. We found discrepancies, due to the deformed nuclear structure, between the present results and those reported in the NuDat database. The spin uncertainties result in large variations, 13% – 200%, in the astrophysical rates of the rp-process reactions. In particular, the spin uncertainties of the 44V and the 46−49Mn isotopes significantly affect the astrophysical rates of the reverse reactions of the proton captures 43Ti(p, γ)44V(p, γ)45Cr, 45Cr(p, γ)46Mn(p, γ)47Fe, 47Mn(p, γ)48Fe, 47Cr(p, γ)48Mn(p, γ)49Fe, and 48Cr(p, γ)49Mn(p, γ)50Fe. Moreover, the magnetic moments of most of the isotopes were predicted for the first time. The results show that the magnetic moments are in the order of μp(1f7/2) > μp(2p3/2) > μn(1d3/2) > μn(1f7/2) for the nuclei having an unpaired nucleon in the proton/neutron shells. The present study suggests that reliable calculations and/or measurements for the properties of proton-rich nuclei are highly demanded. -
PublicationScreening for Streptococcus pyogenes antibacterial and Candida albicans antifungal bioactivities of organic compounds in natural essential oils of Piper betle L., Cleistocalyx operculatus L. and Ageratum conyzoides L.( 2020)
;Bui Thi Phuong Thuy ;Le Trung Hieu ;Tran Thi Ai My ;Nguyen Thi Thanh Hai ;Huynh Thi Phuong Loan ;Nguyen Thi Thu Thuy ;Nguyen Thanh Triet ;Tran Thi Van Anh ;Nguyen Thi Xuan Dieu ;Phan Tu Quy ;Nguyen Van Trung ;Duong Tuan Quang ;Lam K. HuynhNguyen Thi Ai NhungChemical composition and bioactivities including bacterial and fungal resistance of the essential oils extracted from leaves of Piper betle L. (T) and Cleistocalyx operculatus L. (V) and aerial parts of Ageratum conyzoides L. (H) were investigated. The components presenting in the essential oils of the natural sources were analysized by a gas chromatography–mass spectrometry. Molecular docking simulation was utilised to support an antimicrobial mechanism of the essential oil compounds on Candida albicans fungus and Streptococcus pyogenes bacteria. This was based on the inhibition of the extracted compounds onto the microbial proteins, i.e. 4ESW and P0C0C7, respectively. There are 32 compounds identified in total in the three essential oils. The most effective inhibitors are the following: (i) chavicol acetate (T3), eugenol acetate (T11) and eugenol (T4) found in Piper betle L.; (ii) precocene II (H10) and precocene I (H6) found in Ageratum conyzoides L.; and (iii) caryophyllene oxide (V15) and cis-Lanceol (V19) found in Cleistocalyx operculatus L.. The overall antifungal and antibacterial capability of the investigated essential oils given indirect justification via their average inhabitability towards the two proteins accords with the order Piper betle L. Ageratum conyzoides L. Cleistocalyx operculatus L.. The results suggest these as promising natural sources for antimicrobial remedies. -
PublicationSubnudatones A and B, new trans-decalin polyketides from the cultured lichen mycobionts of Pseudopyrenula subnudata( 2020)
;Thuc-Huy Duong ;Hung-Huy Nguyen ;Thanh-Trung Le ;Thanh-Nha Tran ;Jirapast Sichaem ;Thanh-Trung Nguyen ;Thi-Phuong Nguyen ;Dinh-Tri Mai ;Huu-Hung NguyenHoang-Duy LeChemical investigation of the cultured polyspore-derived mycobionts of a Pseudopyrenula subnudata lichen led to the isolation of two new compounds, subnudatones A and B (1 and 2), together with four known compounds, 1- (2-hydroxy-1,2,6-trimethyl-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl)ethanone (3), libertalide C (4), aspermytin A (5), and 6,7-dimethoxy-4-hydroxymellin (6). Their chemical structures were elucidated by extensive 1D and 2D NMR analysis and high resolution mass spectroscopy, and comparisons were made with the literature. The absolute configuration of 1 was defined unambiguously using single crystal X-ray crystallography. Compound 1 represents the first dimeric decalin polyketide to be found in nature. The in vitro cytotoxicity of 1 against two cancer cell lines (K562 and MCF-7) was evaluated. Compound 1 showed moderate cytotoxic activity with IC50 values of 23.5 ± 1.0 and 51.9 ± 1.4 μM, respectively.