Some Antioxidant Properties of Components from the Flower of Ochna integerrima and Their Beneficial Effects on HaCaT Keratinocytes and in Silico Analysis on Tyrosinase.

Four compounds, luteolin (1), 6-γ,γ-dimethylallylquercetin 7-O-ß-D-glucopyranoside (2), 6-γ,γ-dimethylallylkaempferol 7-O-ß-D-glucopyranoside (3), and 6-γ,γ-dimethylallyldihydrokaempferol 7-O-ß-D-glucoside (4), were isolated for the first time from AcOEt extract of the O. integerrima flower. We then evaluated the antioxidant effects of AcOEt, butanol, and MeOH extracts and their effects on H2 O2 against oxidative stress in HaCaT keratinocyte cell lines. Furthermore, 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH⋅) radical scavenging activities of 1-4 were determined and their mechanisms of action on tyrosinase were predicted by in silico studies. The results revealed that the AcOEt extract and 1-3 exhibited good DPPH⋅ radical scavenging activity. Furthermore, this extract also had a significant protective effect against H2 O2 -induced oxidative stress in HaCaT cells. In silico studies indicated that the activity of 1-3 may be due to tyrosinase inhibition with MM-GBSA free binding energies of -78.9, -70.1, and -71.1 kcal mol-1 , respectively, compared to 4 with an energy -56.9 kcal mol-1 .

Cycloartane-type triterpenoids from the whole plants of Macrosolen bidoupensis.

One new cycloartane-type triterpenoid, named macrobidoupoic acid A (as an C-24 epimeric mixture, 4a, 4 b), together with three known ones (1-3), were clarified by different chromatography from the M. bidoupensis whole plants. Triterpenoids (1, 3 & 4) were detected for the first time from the Macrosolen genus. Chemical structures of them were illuminated using HR-ESI-MS, and NMR (1 D & 2 D) assessments. The cytotoxic properties of triterpenoids (3 & 4) were examined against two human cancer cell lines (A549, and RD) by MTT assay. As results shown, triterpenoids (3 & 4) possessed moderate cytotoxic activity against A549 and RD cancer cells (IC50 ranged from 5.44 to 39.52 µM).

Alpha-Glucosidase Inhibitory Diterpenes from Euphorbia antiquorum Growing in Vietnam.

Bioactive-guided phytochemical investigation of Euphorbia antiquorum L. growing in Vietnam led to the isolation of five ent-atisanes, one seco-ent-atisane, and one lathyrane (ingol-type). The structures were elucidated as ent-1α,3α,16ß,17-tetrahydroxyatisane (1), ethyl ent-3,4-seco-4,16ß,17-trihydroxyatisane-3-carboxylate (2), ent-atisane-3-oxo-16ß,17-acetonide (3), ent-3α-acetoxy-16ß,17-dihydroxyatisane (4), ent-16ß,17-dihydroxyatisane-3-one (5), calliterpenone (6), and ingol 12-acetate (7). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them, 1 is a new compound while 2 is an ethylated artifact of ent-3,4-seco-4,16ß,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound 3 showed the most significant inhibitory activity against alpha-glucosidase with an IC50 value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that 3 could retard the enzyme function by noncompetitive.

Nanostructured Er2O3 thin films grown by metalorganic chemical vapour deposition.

Metalorganic chemical vapor deposition (MOCVD) of nanostructured Er2O3 thin films was performed using the Er-tris-guanidinate precursor [Er(DPDMG)3] (DPDMG = diisopropyl-2-dimethylamidoguanidinato) as the Er source and oxygen. Film deposition was carried out on Si(100) and quartz glass substrates and the process parameters namely temperature, pressure and oxygen flow rate were varied. The resulting thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) for investigating the crystallinity and morphology, respectively. The chemical composition of the film was investigated by X-ray photoelectron spectroscopy (XPS) measurements. Transmittance and absorption spectra of the 600 degrees C film grown on glass substrates were performed by UV-vis measurements revealing more than 80% transmittance. The potential of Er2O3 thin films as gate dielectrics was verified by carrying out capacitance-voltage (C-V) and current-voltage (I-V) measurements. Dielectric constants estimated from the accumulation capacitance were found to be in the range of 10-12 in AC frequencies of 1 MHz down to 10 kHz and the leakage current of the order of 2 x 10(-8) A/cm2 at the applied field of 1 MV cm(-1) was measured for films deposited under optimised process conditions. The low leakage current and high dielectric constant implies good quality of the Er2O3 layers relevant for high-k applications. These layers were found to be paramagnetic with a slightly reduced magnetic moment of the Er3+ ions.

Chemical constituents with their alpha-glucosidase inhibitory activity from the whole plant of Ceratophyllum demersum.

From Ceratophyllum demersum growing in Vietnam, twelve compounds were isolated and structurally elucidated, including six previously undescribed compounds, demersones A-D (1-4), acetylvelutins A and B (8 and 9), together with six known compounds, (+)-cyclocolorenone (5), 1-hydroxycyclocolorenone (6), 10-hydroxycyclocolorenone (7), retusin (10), betulinic acid (11), and lupeol (12). The chemical structures and stereochemistry of 1-12 were identified through analysis of spectroscopic data (1D and 2D NMR and HRESIMS), ECD data, and DFT calculation. Notably, this is the first time that humulene-type (1 and 2), guaiane-type (3), and aromadendrane-type (4-7) sesquiterpenoids have been reported in this genus. Compounds 8 and 9 are the first examples of 8-acetoxyflavones found in nature. Upon evaluation of the alpha-glucosidase of 1-3 and 5-12, it was found that 12 exhibited the highest potential with an IC50 value of 15.4 ± 1.1 µM. The molecular docking of 3 and 8 was further studied.

In vitro and in silico docking and molecular dynamic of antimicrobial activities, alpha-glucosidase, and anti-inflammatory activity of compounds from the aerial parts of Mussaenda saigonensis.

Twelve compounds were isolated from Mussaenda saigonensis aerial parts through phytochemical analysis and the genus Mussaenda is the first place where the compounds 4-6 and 11-12 have been found. Based on the ability to inhibit NO production in RAW264.7 cells, compound 2 has demonstrated the strongest anti-inflammatory activity in vitro with an IC50 of 7.6 µM, as opposed to L-NMMA's IC50 of 41.3 µM. Compound 12 was found to be the most effective inhibitor of alpha-glucosidase enzyme in vitro, with an IC50 value of 42.4 µM (compared to 168 µM for acarbose). Compounds 1-12 were evaluated in vitro for antimicrobial activity using the paper dish method. Compound 11 demonstrated strong antifungal activity against M. gypseum with a MIC value of 50 µM. In silico docking for antimicrobial activity, pose 90 or compound 11 docked well to the 2VF5 enzyme, PDB, which explains why compound 11 had the highest activity in vitro. Entry 2/pose 280 demonstrated excellent anti-inflammatory activity in silico. The stability of the complex between pose 280 and the 4WCU enzyme for anti-inflammatory activity has been assessed using molecular dynamics over a simulation course ranging from 0 to 100 ns. It has been found to be stable from 60 and 100 ns. The Tyr 159 (95%, H-bond via water bridge), Asp 318 (200%, multiple contacts), Met 273 (75%, hydrophobic interaction via water bridge), and Gln 369 (75%, H-bond via water bridge) interacted well within the time range of 0 to 100 ns. It has more hydrophilic or polar pharmacokinetics.

Correction: Antimicrobial and alpha-glucosidase inhibitory flavonoid glycosides from the plant Mussaenda recurvata: in vitro and in silico approaches.

[This corrects the article DOI: 10.1039/D4RA00666F.].

Antimicrobial and alpha-glucosidase inhibitory flavonoid glycosides from the plant Mussaenda recurvata: in vitro and in silico approaches.

Seven flavonoid glycosides were isolated from the aerial portions of Mussaenda recurvata during a phytochemical analysis. This comprised one novel component, ecurvoside, and six well-studied compounds, namely astragalin, isoquercitrin, nicotiflorin, rutin, hesperidin, and neohesperidin. The chemical structures of compounds were identified using spectroscopic techniques and a comparison with previously published studies. Alpha-glucosidase inhibition testing was carried out on all isolated compounds. The compounds evaluated have IC50 values between 35.6 and 239.1 g mL-1, indicating a moderate degree of inhibition. In vitro antimicrobial activities of compounds 1-7 have screened against the bacteria Pseudomonas aeruginosa (P. aeruginosa), methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus faecalis (Strep. faecalis), and fungi: Candida albicans (C. albicans), Trichophyton mentagrophytes (T. mentagrophytes), and Microsporum gypseum (M. gypseum), where compound 6 showed excellent activity against fungi T. mentagrophytes with an MIC value of 12.5 µM. In accordance with the molecular docking study, ecurvoside (1) or pose 472 interacted well with the 3TOP enzyme: PDB and the molecular dynamic simulations proved that the complex of ecurvoside and 3TOP has a stable simulation time of 50-100 ns and the significant residual amino acids in 3TOP are relative to interactions more than one time such as Asp 960, Glu 961, Lys 1088, Glu 1095, Arg 1097, Gly 1102, Thr 1103, Gln 1109, Glu 1178: A chain and Glu 1095, Thr 1101, and Asp 1107: B chain. The docking studies of compounds 1-7 to the enzyme 2VF5 explain the general mechanism to inhibit bacteria and proved that compound 6 (pose 370) inhibited stronger than compound 7 (pose 362) and compound 5 (pose 280), and compounds 1 to 4 do not interact well with 2VF5.

Heptaellipside A, a rare new 2,28-bidesmosidic lupane-type saponin from the leaves of Heptapleurum ellipticum.

For the first time, phytochemical constituents of the leaves of Heptapleurum ellipticum were investigated. One rare new 2,28-bidesmosidic lupane-type saponin, named heptaellipside A (1), along with four other lupane-type analogs (2-5) were purified by combining differently chromatographic methods. All of the separated compounds (1-5) were communicated for the first time from H. ellipticum. The structures of them were definitely illustrated following extensive and comprehensive UV/VIS, FTIR, HRMS/ESI, and NMR techniques. Further, all isolated compounds were evaluated for their α-glucosidase and α-amylase inhibition. As the results, compound 3 respectively exhibited stronger in both inhibitory activities against α-glucosidase and α-amylase (IC50 values of 15.53 and 26.93 µM), than the acarbose standard (IC50 values of 214.50 and 143.48 µM).

Comtrifosides A and B, two new triterpenoid saponins from the leaves of Combretum trifoliatum.

The phytochemical composition of the Combretum trifoliatum leaves was studied for the first time. Two new triterpenoid saponins, named comtrifoside A (1) and comtrifoside B (2), together with two other saponins (3-4) were purified by variously chromatographic techniques. For the first time, compound 3 was informed from the Combretum genus, as well as all of the isolated compounds (1-4) were reported from C. trifoliatum. The chemical structures of them were clearly characterised using extensive UV-VIS, IR, HRMS-ESI, and NMR experimental data. The in vitro anti-inflammatory activities of 1 & 2 were examined against NO overproduction in LPS activation of RAW264.7.

Chemical compositions and biological activities of Serevenia buxifolia essential oil leaves cultivated in Vietnam (Thua Thien Hue).

Serevenia buxifolia is an evergreen citrus plant and has attracted considerable attention due to its bioactive components and biological activities. In the present study, the essential oil (EO) from S. buxifolia cultivated in Vietnam was demonstrated to exhibit the in vitro antioxidant, thrombolytic, anti-hemolysis, anti-inflammatory, and antidiabetic activities. Briefly, the gas chromatography coupled to mass spectrometry analysis revealed that the leaf EO of S. buxifolia was composed of 33 components, with the main constituents being ß-carypphyllene (32.5%), and elixene (9.8%). The extracted oil possessed a fairly high free radical scavenging activity against 2, 2-diphenyl-1-picrylhydrazyl (DPPH), with an IC50 value of 190.7 µg/mL compared with positive control, α-tocopherol, IC50 value of 42.6 µg/mL. The EO also exhibited thrombolytic activity: the percentage of inhibition was found to be 70.75% at 100 µL, in comparison with 87.2% for the positive control, streptokinase. For hemolytic activity, the percentage of inhibition of the EO was from 27.4% to 59.6% at concentrations from 10 to 100 µg/mL, respectively. The results of in vitro anti-inflammatory activity indicated that the EO of S. buxifolia leaves effectively protects the heat-induced denaturation, with an IC50 value of 40.25 µg/mL. The EO also exhibited antidiabetic potential, with IC50 values of 87.8 and 134.9 µg/mL against α-amylase and α-glucosidase, respectively. It is noteworthy that the potent biological activities of the obtained S. buxifolia oil increased in a dose-dependent manner. The results achieved show that the EO of S. buxifolia leaves can be a potential source for oxidative stress, inflammatory, and diabetic management.

Cycloartanes from leaves of Combretum quadrangulare growing in Vietnam.

Two new cycloartanes, combretic acid C (1) and combretanone I (3), were isolated from the leaves of Combretum quadrangulare Kurz, together with the previously-reported combretic acids A-B (2 and 5) and combretanone A (4). An extensive set of spectroscopic methods were used to elucidate the structures of these compounds. Cytotoxicity against the K562 cancer cell line was evaluated. Compound 1 showed strong activity, with an IC50 value of 9.7 µM. The other compounds showed moderate activity. Alpha-glucosidase inhibition was also evaluated. The isolated compounds showed moderate inhibition, with IC50 values in the range 102.2-194.7 µM.

In vitro anti-inflammatory, in silico molecular docking and molecular dynamics simulation of oleanane-type triterpenes from aerial parts of Mussaenda recurvata.

Bioactive-guided investigation of the aerial parts of Mussaenda recurvata Naiki, Tagane, and Yahara (Rubiaceae) led to the isolation of four triterpenes, including two new triterpenes recurvatanes A and B (1 and 2), along with two known compounds 3ß,6ß,23-trihydroxyolean-12-en-28-oic acid (3) and 3ß,6ß,19α,23-tetrahydroxyolean-12-en-28-oic acid (4). The chemical structures of the compounds were identified from spectroscopic data and by comparison with the literature. A comprehensive review of NMR data of the oleanane-type triterpenes bearing 3-hydroxy and 4-hydroxymethylene groups indicated the characteristic spectroscopic features in this series. Compounds 1-4 were evaluated for the inhibitory NO production in LPS-stimulated RAW264.7 cells. Compounds 2 and 3 showed a moderate reduction of nitrite accumulation with IC50 values of 55.63 ± 2.52 and 60.08 ± 3.17 µM, respectively. Molecular docking model dedicated to compound 3 or pose 420, which is the best candidate among docking poses of compounds 1-4 interacted well with the crystal structure of enzyme 4WCU: PDB. The best ligand molecule, pose 420 in terms of binding energy obtained from docking studies on molecular dynamics (MD) simulations for 100 ns exhibited non-bonding interactions with the protein and remained stable inside the active site.

Bioactive-Guided Phytochemical Investigations, In Vitro and In Silico Alpha-Glucosidase Inhibition of Two Vietnamese Medicinal Plants Dicranopteris linearis and Psychotria adenophylla.

Little is known about the chemical and biological profiles of Dicranopteris linearis and Psychotria adenophylla. No previous studies have investigated alpha-glucosidase inhibition using extracts from D. linearis and P. adenophylla. In this paper, bioactive-guided isolation procedures were applied to the plants D. linearis and P. adenophylla based on alpha-glucosidase inhibition. From the most active fractions, 20 compounds (DL1-DL13 and PA1-PA7) were isolated. The chemical structures were elucidated using spectroscopic data and compared with those available in the literature. These compounds were evaluated for alpha-glucosidase inhibition, while a molecular docking study was performed to elucidate the mechanisms involved. Consequently, D. linearis and P. adenophylla might serve as a good potential for developing new antidiabetic preparations.

Lasibidoupins A and B, two new compounds from the stems of Lasianthus bidoupensis V.S. Dang & Naiki.

From the Lasianthus bidoupensis stems, two new compounds, including one new 9,10-anthraquinone, lasibidoupin A (1), and one new 6,7-benzocoumarin, lasibidoupin B (2), together with one known compound, 11-O-methyldamnacanthol (3) were isolated using chromatographic method. Their structures were determined by extensive HRMS, and NMR assignments. Compound 3 was reported for the first time from this species. New compounds (1 & 2) were tested for the cytotoxicity against three human cancer cell lines (MCF-7, HeLa, and NCI-H460) by SRB assay. As results, 1 & 2 exhibited significant cytotoxic activity against all cancer cell lines (IC50 ranged from 0.058 ± 0.003 to 0.177 ± 0.014 µM).

A new oleanane-skeleton triterpene isolated from Coffea canephora.

Extensive fractionation of n-hexane extract from the dried powdered-trunks of Coffea canephora Pierre ex A.Froehner (Rubiaceae) led to the isolation of a new oleanane-skeleton triterpene, coffecanolic acid (1), along with three known analogues sumaresinolic acid (2), oleanolic acid (3), and 3-O-acetyloleanolic acid (4). The chemical structures were elucidated using FT-IR, 1D and 2D NMR and HR-ESI-MS data analysis. The isolated compounds were assayed for in vitro α-glucosidase inhibitory activity by determining their half-maximal inhibitory concentration (IC50, µM). Compounds 1-4 exhibited higher inhibitory activities when compared with acarbose, a positive control. Compound 1 was found to be the most potent molecule against α-glucosidase, with the IC50 = 83.0 ± 1.2 µM, which improved by 2.5-fold over acarbose (IC50 = 209.8 ± 0.3 µM) in this assay.[Formula: see text].

Macrotricolorin A, a new diarylpropanoid from the Vietnamese plant Macrosolen tricolor (Lecomte) Danser.

From the Vietnamese plant Macrosolen tricolor (Lecomte) Danser, one new diarylpropanoid, named macrotricolorin A (1) together with three diarylheptanoids including bisdemethoxycurcumin (2), demethoxycurcumin (3) and curcumin (4), were isolated. Their structures were elucidated by intensive analyses of their IR, UV, HR-ESI-MS and NMR (1 D & 2 D) spectra. It is the first time that diarylalkanoids have been reported from the genus Macrosolen. Compound 1 exhibited anti-inflammatory activity against the nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 with an IC50 value of 27.54 ± 1.75 µM.

Cytotoxic activity and phytochemical composition of Stereospermum binhchauensis V.S. Dang leaves.

For the first time, the cytotoxic and phytochemical investigation of the leaves of Stereospermum binhchauensis V.S. Dang, a new species discovered in Viet Nam were finalized and led to purify nine compounds, including one furancoumarin (1), one chromone (3), two triterpenoids (2, 4), two flavonoids (5, 8), two flavanoids (6, 7) and one iridoid (9) using various chromatography methods. Their structures were verified by HR-ESI-MS, NMR experiments and compared with previous literatures. For the first time, compounds (5-8) were realized from the genus Stereospermum, while compounds (1, 2, 3, 4 & 9) were designated from the species S. binhchauensis. Furthermore, the furancoumarin, chromone and flavanoid classes were notified for the first time from the genus Stereospermum.

Helicteres binhthuanensis V.S.Dang (Malvaceae, Helicteroideae), a new species from southern Vietnam.

Helicteres binhthuanensis V.S.Dang, sp. nov. from Ham Thuan Bac District, Binh Thuan Province, Vietnam is described and illustrated. It is morphologically similar to H. angustifolia, which is a common species in mainland southeast Asia, and H. sphaerotheca, which is endemic to the Northern Territory, Australia, but differs from both by several salient characters such as leaf and calyx size, androgynophore length, petal color, and fruit shape. Photographs, a vernacular name, a preliminary conservation assessment, and a table of morphological characters comparing this new species to two closely related species also are provided.

Markhasphingolipid A, new phytosphingolipid from the leaves of Markhamia stipulata var. canaense V.S. Dang.

From the leaves of Markhamia stipulata var. canaense V.S. Dang, one new phytosphingolipid, named markhasphingolipid A (6) together with five known compounds, 4',7-O-dimethylapigenin (1), narigenin (2), tectoquinone (3), mollic acid (4), 1-hexadecanoyl-sn-glycerol (5) were classified by various chromatographic methods. Their structures were designated by IR, UV, HR-ESI-MS, HR-ESI-MS/MS and NMR experiments. All compounds were recognized for the first time from this species. The cytotoxicity of all n-hexane fractions and isolated compounds (5 & 6) against three human cancer cell lines (HeLa, HepG2, and MCF-7) were evaluated by SRB assay. All n-hexane fractions expressed cytotoxic effect on three tested cancer cell lines (at the concentration of 100 µg/mL, percent of cytotoxicity ranged from 55.81% to 95.83%) as well as compound 5 (IC50 ranged from 48.51 to 63.30 µM) whereas fraction H.I and compound 6 did not show activity.[Formula: see text].