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34 result(s) for "Phan Van Kiem"
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Flavonoids and alkaloids from the rhizomes of Zephyranthes ajax Hort. and their cytotoxicity
A new flavanol derivative, (2 R ,3 R )-3-acetoxy-7-hydroxy-3′,4′-methylenedioxyflavan ( 1 ), was co-isolated from the rhizomes of Zephyranthes ajax Hort. with the following seven known compounds: 7-hydroxyflavan ( 2 ), 7,4′-dihydroxyflavan ( 3 ), 7,4′-dihydroxy-8-methylflavan ( 4 ), 7,3′-dihydroxy-4′-methoxyflavan ( 5 ), 5,4′-dihydroxy-7-methoxy-6-methylflavan ( 6 ), 7-hydroxy-3′,4′-methylenedioxyflavanone ( 7 ) and haemanthamine ( 8 ). Their structures were elucidated by combining 1D-/2D-NMR, CD, UV and HRESIMS data, and comparisons with reported data in literature were made. Among these known compounds, 2 , 3 , 4 , 6 and 7 were isolated from the genus Zephyranthes for the first time. In addition, the cytotoxicity assay indicated that compound 8 has potent cytotoxic activity against human hepatocellular carcinoma (the HepG2 cell line), human lung carcinoma (the SK-LU-1 cell line), human carcinoma in the mouth (the KB cell line), human colon carcinoma (the SW480 cell line) and human stomach gastric adenocarcinoma (the AGS cell line), with IC 50 values ranging from 4.4 to 11.3 µM. This is the first study reporting the cytotoxicity of compound 8 against the SK-LU-1 cancer cell lines.
Three new steroidal saponins from Aspidistra letreae plants and their cytotoxic activities
Three new steroidal saponins, aspiletreins A–C ( 1 – 3 ), together with 2 H -chromen-2-one ( 4 ), and α -tocopherol ( 5 ), were isolated from whole Aspidistra letreae plants collected in Vietnam. Their structures were elucidated by a combination of spectroscopic analyses, including 1D- and 2D-NMR, IR, and HRESIMS, and by comparison with the reported data in the literature. Compounds 1 – 3 exhibited moderate cytotoxicities against the LU-1, HeLa, MDA-MB-231, HepG2, and MKN-7 human cancer cell lines, with IC 50 values ranging from 7.69 ± 0.40 to 20.46 ± 3.11 µM.
Macrolide and phenolic metabolites from the marine-derived fungus Paraconiothyrium sp. VK-13 with anti-inflammatory activity
Five new secondary metabolites, modiolides D-G (1−4) and 1-(2,5-dihydroxyphenyl)-3-methoxy-butan-1-one (8), one new natural product, 1-(2,5-dihydroxyphenyl)-3-hydroxybutan-1-one (7), along with three known compounds, modiolides A (5) and B (6), and 1-(2,5-dihydroxyphenyl)-2-buten-1-one (9) were isolated from a fermentation culture of the marine endophytic fungus Paraconiothyrium sp. VK-13. Their chemical structures were elucidated by the NMR and MS spectroscopic analysis as well as the modified Mosher’s method. Compounds 7 and 9 inhibited the overproduction of proinflammatory mediators NO and PGE2 in LPS-stimulated RAW264.7 cells, with IC50 values ranging from 3.9 to 12.5 µM. The inhibitory effects of 7 and 9 on the release of NO and PGE2 were correlated with their significant suppression of iNOS and COX-2 protein expression, respectively. Furthermore, both compounds 7 and 9 inhibited the mRNA expression of proinflammatory cytokines, including TNF-α, IL-1β, IL-6, and IL-12, with IC50 values in a range of 2.4−12.5 µM.
Aspermicrones A-C, novel dibenzospiroketals from the seaweed-derived endophytic fungus Aspergillus micronesiensis
Chemical investigation of the Kappaphycus alvarezii-derived endophytic fungus Aspergillus micronesiensis lead to the isolation of three novel dibenzospiroketals, aspermicrones A-C (1-3). Their chemical structures were determined by extensive analysis of HR-ESI-MS and NMR spectral data. The absolute configurations of them were determined by experimental and TD-DFT theoretical calculated circular dichroism spectra. Compound 2 exhibited selective cytotoxic effect toward HepG2 cell line (IC50 = 9.9 µM). Additionally, both of compounds 2 and 3 displayed anti-microbial activity against Staphylococcus aureus (MIC = 123.2 µM for each compound). Compound 1 was inactivity in both cytotoxic and anti-microbial assays.
Degalactotigonin, a Steroidal Glycoside from Solanum nigrum, Induces Apoptosis and Cell Cycle Arrest via Inhibiting the EGFR Signaling Pathways in Pancreatic Cancer Cells
Degalactotigonin (1) and three other steroidal compounds solasodine (2), O-acetyl solasodine (3), and soladulcoside A (4) were isolated from the methanolic extract of Solanum nigrum, and their chemical structures were elucidated by spectroscopic analyses. The isolated compounds were evaluated for cytotoxic activity against human pancreatic cancer cell lines (PANC1 and MIA-PaCa2) and lung cancer cell lines (A549, NCI-H1975, and NCI-H1299). Only degalactotigonin (1) showed potent cytotoxicity against these cancer cell lines. Compound 1 induced apoptosis in PANC1 and A549 cells. Further study on its mechanism of action in PANC1 cells demonstrated that 1 significantly inhibited EGF-induced proliferation and migration in a concentration-dependent manner. Treatment of PANC1 cells with degalactotigonin induced cell cycle arrest at G0/G1 phase. Compound 1 induced downregulation of cyclin D1 and upregulation of p21 in a time- and concentration-dependent manner and inhibited EGF-induced phosphorylation of EGFR, as well as activation of EGFR downstream signaling molecules such as Akt and ERK.
Chemical Constituents of Tectus maximus Koch, 1844
Two previously unreported compounds (1 and 2) together with eight known compounds (3-10) were isolated from the methanol extract of sea snail Tectus maximus Koch, 1844. Their chemical structures were determined to be 6-acetoxy-deoxyinosine (1), 6-acetoxy-inosine (2), deoxyinosine (3), inosine (4), adenosine (5), deoxyadenosine (6), deoxyuridine (7), thymidine (8), glycerol arachidonate (9), and arachidonic acid (10) on the basis of HR-ESI-MS and NMR spectroscopic analyses. This is the first report of those compounds from the genus Tectus
Four new lignans obtained from the leaves of Schisandra cauliflora and their effect on skeletal muscle cell proliferation
Plants of the Schisandra genus are commonly used in folk medicinal remedies. Some Schisandra species and their lignans have been reported to improve muscle strength. In the present study, four new lignans, named schisacaulins A–D, together with three previously described compounds ananonin B, alismoxide, and pregomisin were isolated from the leaves of S. cauliflora . Their chemical structures were determined by extensive analyses of HR-ESI–MS, NMR, and ECD spectra. Schisacaulin D and alismoxide significantly stimulated skeletal muscle cell proliferation by increasing the number of fused myotubes and expression of myosin heavy chain (MyHC) which may be good candidates for the treatment of sarcopenia. Graphical Abstract
A New Sesquiterpene from Schisandra sphenanthera
A new sesquiterpene, schisandrathera E (1) and seven dibenzocyclooctadiene lignans as schisantherin D (2), schisantherin B (3), tigloylgomisin P (4), schisphenin E (5), angeloylgomisin H (6), (+)-deoxyschizandrin (7), and (+)-gomisin K3 (8) were isolated from the leaves of Schisandra sphenanthera Rehder & E.H.Wilson. Their structures were elucidated by spectroscopic and mass spectrometric analyses, including 1D-, 2D-NMR, HR-ESI-MS and ECD spectra. Compound 1 displayed moderate cytotoxicity against both PC3 and MCF4 cell lines in MTT assay with IC50 values of 22.60 and 7.80 µM, respectively.
Anti-inflammatory coumarins from Paramignya trimera
Context:Paramignya trimera (Oliv.) Burkill (Rutaceae) has been used to treat liver diseases and cancer. However, the anti-inflammatory effects of this medicinal plant and its components have not been elucidated.Objective: This study investigated chemical constituents of the P. trimera stems and evaluated anti-inflammatory effects of isolated compounds.Materials and methods: Cytotoxicity of isolated compounds (5–40 μM) toward BV2 cells was tested using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) for 24 h. Inhibitory effects of isolated compounds (5-40 μM) on nitrite and PGE2 concentrations were determined using Griess reaction and PGE2 ELISA kit, respectively (pretreated with the compounds for 3 h and then stimulated for 18 h with LPS). Inhibitory effects of compounds (5-40 μM) on iNOS and COX-2 protein expression were evaluated by Western blot analysis (pretreated with the compounds for 3 h and then stimulated for 24 h with LPS).Results: Seven coumarins were isolated and identified as: ostruthin (1), ninhvanin (2), 8-geranyl-7-hydroxycoumarin (3), 6-(6′,7′-dihydroxy-3′,7′-dimethylocta-2′-enyl)-7-hydroxycoumarin (4), 6-(7-hydroperoxy-3,7-dimethylocta-2,5-dienyl)-7-hydroxycoumarin (5), 6-(2-hydroxyethyl)-2,2-dimethyl-2H-1-benzopyran (6), and luvangetin (7). Compounds 1–4 and 7 inhibited NO and PGE2 production in LPS-stimulated BV2 cells, with IC50 values ranging from 9.8 to 46.8 and from 9.4 to 52.8 μM, respectively. Ostruthin (1) and ninhvanin (2) were shown to suppress LPS-induced iNOS and COX-2 protein expression.Discussion and conclusion: The present study provides a scientific rationale for the use of P. trimera in the prevention and treatment of neuroinflammatory diseases. Ostruthin and ninhvanin might have potential therapeutic effects and should be considered for further development as new anti-neuroinflammatory agents.
New nitric oxide production inhibitors from Syzygium bullockii
Three undescribed triterpene glycosides syzybullosides A-C ( 1 – 3 ) along with fourteen known compounds were isolated from the leaves of Syzygium bullockii (Hance) Merr.& L.M. Perry, including six triterpene glycosides ( 1 – 6 ), four phenolics ( 7 – 9 , 17 ), four megastigmanes ( 10–13 ), and three flavonoids ( 14 –1 6 ). The structures of 1 – 17 were elucidated by extensive spectroscopic analysis, including IR, HR-ESI–MS, 1D and 2D NMR spectra. Compounds 1 – 10 and 12–17 inhibited nitric oxide (NO) production in lipopolysaccharide activated RAW264.7 cells with IC 50 values ranging from 1.30 to 13.70 µM, lower than that of the positive control compound, L-NMMA (IC 50  = 33.8 µM). Graphical abstract