This work presents a control scheme to control the grid-connected single-phase photovoltaic (PV) ... more This work presents a control scheme to control the grid-connected single-phase photovoltaic (PV) system. The considered system has four 250W solar panels, a non-inverting buck-boost DC-DC converter, and DC-AC inverter with LCL filter. The control system aims to track and operate at the maximum power point (MPP) of PV panels, regulate the voltage of DC link, and supply the grid with a unity power factor. To well achieve these goals, the proposed control system consists of three parts, that are MPP tracking controller module with a fuzzy-based modified incremental conductance (INC) algorithm, a DC-link voltage regulator with a hybrid fuzzy proportional-integral (PI) controller, and a Current Controller module using the linear quadratic regulator (LQR) for grid-connected power. Based on fuzzy control and LQR, this work introduces a full control solution for grid-connected single-phase PV systems. The key novelty of this research is to analyze and prove that the newly proposed method is...
Corrosion test of mild steel (graded JIS-STK400) was investigated in brackish water environment o... more Corrosion test of mild steel (graded JIS-STK400) was investigated in brackish water environment of Phu My industrial port (Ba Ria - Vung Tau Province, Vietnam). Steel sample was exposed in 3 years. X-ray diffraction (XRD) results show that formed rust powder was composed of a-FeOOH, Fe3O4 and a- Fe2O3 in which the amount of first component is larger than second and third one. It demonstrates that natural corrosion products evolved from low to high oxida-tion state of iron by presence of dissolved oxygen in brackish environment. The mechanism of phase conversion is revealed by metallographic of rust layer cross section. a-Fe2O3 (white phase) was gathered at bank of cracking paths where was favouring diffusion of oxygen and water into inner layer. After contacting Fe3O4 (dark gray phase), corrosive agents converted it to a-FeOOH and a-Fe2O3. The phase conversion changes the weight density of materials and creates the porous tunnels in rust scales. The growth of micro tunnels to form the tunnel network allowed internal stress and cracks of rust scales evolved.
Two new butenolide and pentenolide derivatives, dysideolides A-B, were isolated from the marine s... more Two new butenolide and pentenolide derivatives, dysideolides A-B, were isolated from the marine sponge Dysidea cinerea. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D- and 2D-NMR spectroscopy, and CD spectra, as well as by comparing with the NMR data reported in the literature.
International Journal of River Basin Management, 2019
Estuarine/river engineers often encounter a problem that it is hard to specify an upstream bounda... more Estuarine/river engineers often encounter a problem that it is hard to specify an upstream boundary of a delta in the numerical modelling because of lack of good quality discharge data. This paper proposes a practical procedure to simulate tidal propagation and damping over a river stretch using a commonly used shallow-water equation model without imposing an upstream discharge boundary. The interaction between tides and river flows could be easily evaluated by applying seasonally-varying Manning's n friction values. The Hau River, one of the main streams of the Mekong River, is studied by analysing water levels measured at three different locations in the estuary. The nearly straight-line geometry of the Hau River allows us to neglect flood plain sinuosity, making it possible to extract tidal damping induced purely by fluvial influence. A series of analyses, including spectrum analysis and hydrodynamic simulation, suggests that tidal damping in the estuary of the Mekong Delta can be readily reproduced using the numerical model with Manning's n values of 0.025-0.032 [s m-1/3 ] for the flood season and 0.018-0.025 for the dry season. The present study demonstrates that changes in Manning's n value according to river flow conditions result in more reliable estimations than simply using a constant value throughout the year. The proposed procedure will be of great benefit not only for tidal modelling but also river and urban flood simulations, saline intrusion modelling and sea-level rise projections in the estuary of the Mekong River.
Twelve saponins were isolated from the leaves of Acanthopanax koreanum, including one new lupanet... more Twelve saponins were isolated from the leaves of Acanthopanax koreanum, including one new lupanetype triterpene glycoside, named acankoreoside R (1), together with 11 known triterpenoid saponins (2-12). Their structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR), mass spectroscopic data (MS). All of the fractions and isolated saponins were evaluated for antiinflammatory activities in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) by ELISA. Among them, compounds 1-5, 7, 10, and 12 showed strong inhibitions towards interleukin-12 (IL-12) production with IC 50 values ranging from 1.59 to 5.46 lM. Other compounds were weak or inactive toward IL-12 p40 production.
The present paper demonstrates that inundation levels in the Mekong Delta's largest city, Can Tho... more The present paper demonstrates that inundation levels in the Mekong Delta's largest city, Can Tho, are predominantly determined by ocean tides, sea-level rise, and land subsidence. Our analysis of inundation patterns projects that the duration of inundation at an important road in the city will continue to rise from the current total of 72 inundated days per year to 270 days by 2030 and 365 days by 2050. This is attributed to the combined influence of sea-level rise and land subsidence, which causes relative water level rises at a rate of 22.3 mm•yr −1. People in the Mekong Delta have traditionally lived with floods, and thus there is certain resilience among residents in coping with small floods. At present, daily maximum inundation depth, which is generally shallower than 10 cm on the road, seems to be still manageable; however, our analysis indicates that this will start drastically increasing in the coming decades and reach an average depth of 70 cm by 2050. Effective and well-planned actions to mitigate the effects of land subsidence and sea-level rise are urgently required, otherwise, local inhabitants will encounter an unmanageable increase in inundation depth and duration in the coming decades. This study, which considers both sea-level rise and land subsidence, suggests that inundation depth and duration are projected to rise much faster than those indicated by previous studies, which only consider sea-level rise.
Bioorganic & Medicinal Chemistry Letters, 2015
Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), inclu... more Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), including one new sesquiterpene glycoside, kandelside (1), three megastigman glycoside compounds (7-9), 16 known phenolic compounds (2-6 and 10-19). Structures of the isolated compounds were elucidated based on spectral data comparison with reported values. Isolated compounds were also evaluated for their inhibitory effects on the production of pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumor necrosis factor α (TNF-α) in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. Among these compounds, compound 9 exhibited strong inhibitory activity against IL-6 production (IC50=0.07±0.05μM) and moderate inhibitory activity against TNF-α production (IC50=49.86±1.02μM), but exhibited no activity on IL-12 p40 production. Compounds 5 and 6 significantly inhibited IL-12 p40, IL-6, and TNF-α production with IC50 values of 11.68±0.38, 44.52±1.08, and 28.73±0.96μM, respectively.
We consider lexicographic vector equilibrium problems in metric spaces. Sufficient conditions for... more We consider lexicographic vector equilibrium problems in metric spaces. Sufficient conditions for a family of such problems to be (uniquely) well-posed at the reference point are established. As an application, we derive several results on well-posedness for a class of variational inequalities.
Marine-derived natural products from invertebrates comprise an extremely diverse and promising so... more Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50…
Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-D-xylopyranosyl (1→6)-O-β-D-glucopyran... more Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-D-xylopyranosyl (1→6)-O-β-D-glucopyranoside (11), along with 10 known compounds 3,4-dihydroxyallylbenzene (2), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (3), tachioside (4), benzyl-O-β-D-glucopyranoside (5), icariside F2 (6),…
Bioorganic & medicinal chemistry letters, Jan 15, 2015
One new octulosonic acid derivative, chrysannol A (1), along with 17 known compounds (2-18), were... more One new octulosonic acid derivative, chrysannol A (1), along with 17 known compounds (2-18), were isolated from Chrysanthemum indicum flowers. Their structures were determined from 1D NMR, 2D NMR, HR-ESI-MS spectral data, and comparisons with previous reports. The effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compound 8 showed the highest inhibition of NO production of 46.09% at a concentration of 10.0μM. Compounds 7, 10, 11, and 16 inhibited TNF-α secretion at all concentration tested (0.4, 2.0, and 10.0μM), with inhibition values ranging from 22.27% to 33.13%. In addition, compound 8 and 9 decrease COX-2 and iNOS protein on Western blot analysis in dose dependent manner.
Inflammation is important in biomedical research, because it plays a key role in inflammatory dis... more Inflammation is important in biomedical research, because it plays a key role in inflammatory diseases including rheumatoid arthritis and other forms of arthritis, diabetes, heart disease, irritable bowel syndrome, Alzheimer's disease, Parkinson's disease, allergies, asthma, and even cancer. In the present study, we describe the inhibitory effect of crude extracts and steroids isolated from the starfish Astropecten polyacanthus on pro-inflammatory cytokine (Interleukin-12 (IL-12) p40, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α)) production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Among those tested, compounds 5 and 7 showed potent inhibitory effects on the production of all three pro-inflammatory cytokines with IC 50 values ranging from 1.82 ± 0.11 to 7.00 ± 0.16 μM. Potent inhibitory activities were also observed for compound 1 on the production of IL-12 p40 and IL-6 with values of 3.96 ± 0.12 and 4.07 ± 0.13 μM, respectively, and for compounds 3 and 4 on the
Kalopanax pictus (Araliaceae) is a deciduous tree that grows in East Asian countries. Its stem ba... more Kalopanax pictus (Araliaceae) is a deciduous tree that grows in East Asian countries. Its stem bark and leaves have been used in traditional medicine to treat rheumatic arthritis, neurotic pain, and diabetes mellitus. A phytochemical study on a methanol extract of the stem bark of K. pictus resulted in the isolation of three new compounds, 6b,16a-dihydroxy-hederagenin 3-O-b-D-glucuronopyranoside (1), 3-O-b-D-glucuronopyranosyl-28-O-b-D-glucopyranosyl-6b,16a-dihydroxy-oleanolic acid (2), and 3-O-b-D-galactopyranosyl(1?3)-a-L-arabinopyranosyl hederagenin 28-O-b-D-glucopyranosyl-(1?6)-b-D-glucopyranosyl ester (3), along with eight known compounds (4-11). Their structures were established on the basis of chemical and spectroscopic methods (IR, 1D and 2D NMR, and HRESITOFMS). Compounds 1-6 and 8-10 upregulated PPARs transcriptional activity in a dose-dependent manner in HepG2 cells, with EC 50 values in the range 0.20-15.5 lM. Moreover, the specific PPAR transactivational effects of compounds 1-6 and 8-10 on separate PPAR subtypes, PPARa,-c, and-b(d) were further investigated. Com
Bioorganic & Medicinal Chemistry Letters, 2014
Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 2... more Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 24 known compounds (3-26) were isolated from Euphorbia humifusa Willd. The effects of these compounds on soluble epoxide hydrolase (sEH) inhibitory activity were evaluated. Flavonoid compounds (10-21) exhibited high sEH inhibitory activity. Among them, compounds 12, 13, and 19 greatly inhibited sEH enzymatic activity, with IC50 values as low as 18.05±1.17, 18.64±1.83, and 17.23±0.84 μM, respectively. In addition, the effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compounds 3-6, 8, 18, 20-23, and 25-26 inhibited the production of both NO and TNF-α, with IC50 values ranging from 11.1±0.9 to 45.3±1.6 μM and 14.4±0.5 to 44.5±1.2 μM, respectively.
Three new pyrrole oligoglycosides, astebatheriosides A-C (1-3), and a new furan oligoglycoside, a... more Three new pyrrole oligoglycosides, astebatheriosides A-C (1-3), and a new furan oligoglycoside, astebatherioside D (4), were isolated from the starfish Asterina batheri by various chromatographic methods. Their structures were elucidated by spectroscopic and chemical methods. Compounds 2, 3, and 4 moderately inhibited IL-12 p40 production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) with IC 50 values of 36.4, 31.6, and 22.8 lM, respectively.
Anti-inflammatory transcriptional effects of nineteen compounds (1-19) from the soft coral Sinula... more Anti-inflammatory transcriptional effects of nineteen compounds (1-19) from the soft coral Sinularia maxima were evaluated using NF-jB luciferase and reverse transcriptase polymerase chain reaction. Compounds 1, 2, 4, 8, 15, 17, and 18 significantly inhibited TNFa-induced NF-jB transcriptional activity in HepG2 cells in a dosedependent manner, with IC 50 values ranging from 15.81 ± 2.29 to 29.10 ± 1.54 lM. Furthermore, the transcriptional inhibitory function of these compounds was confirmed by a decrease in intercellular adhesion molecule-1 and inducible nitric oxide synthase gene expression levels in HepG2 cells. These results provide a scientific rationale for the use of the soft coral S. maxima warrant further studies to develop new agents for the prevention and treatment of inflammatory.
Two new 2-C-β-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were... more Two new 2-C-β-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were isolated from the methanolic extract of the leaves of Mallotus nanus along with five known flavonoids, kaempferin (3), juglanin (4), quercitrin (5), myricitrin (6), and rhoifolin (7). Their structures were established on the basis of spectral and chemical evidence. Their antioxidant activities were shown to depend on the number of hydroxyl groups, and the location and species of sugar moiety.
A new octanordammarane triterpene, 3β,15α-dihydroxymansumbinol (1) and a novel A-ring contracted ... more A new octanordammarane triterpene, 3β,15α-dihydroxymansumbinol (1) and a novel A-ring contracted oleanane triterpenoid, 2-formyl-(A)1-19α-hydroxy-1-norolean-2,12-dien-28-oic acid (2) were isolated from the roots extract of Rosa rugosa along with fifteen known compounds (3-17). Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, and FTICRMS. The MeOH extract, as well as CH2Cl2 and EtOAc fractions at a concentration of 0.5mg/mL showed potent sucrase inhibitory activity, with inhibition percentage values of 84.67±5.37%, 87.50±2.78%, and 81.91±2.90%, respectively. In addition, compounds 7-13 (1.0 mM) showed potent sucrase inhibitory activity (61.88±3.19% to 84.70±3.07% inhibition), which was comparable to that of the positive control, acarbose, with an inhibition percentage value of 50.96±2.97%. Compounds 1, 2, 4, and 14-17 showed moderate and/or weak inhibitory activities at the same concentration. The α-glucosidase inhibitory activities of the extracts and purified compounds may provide a novel opportunity to develop a new class of antidiabetic agents.
This work presents a control scheme to control the grid-connected single-phase photovoltaic (PV) ... more This work presents a control scheme to control the grid-connected single-phase photovoltaic (PV) system. The considered system has four 250W solar panels, a non-inverting buck-boost DC-DC converter, and DC-AC inverter with LCL filter. The control system aims to track and operate at the maximum power point (MPP) of PV panels, regulate the voltage of DC link, and supply the grid with a unity power factor. To well achieve these goals, the proposed control system consists of three parts, that are MPP tracking controller module with a fuzzy-based modified incremental conductance (INC) algorithm, a DC-link voltage regulator with a hybrid fuzzy proportional-integral (PI) controller, and a Current Controller module using the linear quadratic regulator (LQR) for grid-connected power. Based on fuzzy control and LQR, this work introduces a full control solution for grid-connected single-phase PV systems. The key novelty of this research is to analyze and prove that the newly proposed method is...
Corrosion test of mild steel (graded JIS-STK400) was investigated in brackish water environment o... more Corrosion test of mild steel (graded JIS-STK400) was investigated in brackish water environment of Phu My industrial port (Ba Ria - Vung Tau Province, Vietnam). Steel sample was exposed in 3 years. X-ray diffraction (XRD) results show that formed rust powder was composed of a-FeOOH, Fe3O4 and a- Fe2O3 in which the amount of first component is larger than second and third one. It demonstrates that natural corrosion products evolved from low to high oxida-tion state of iron by presence of dissolved oxygen in brackish environment. The mechanism of phase conversion is revealed by metallographic of rust layer cross section. a-Fe2O3 (white phase) was gathered at bank of cracking paths where was favouring diffusion of oxygen and water into inner layer. After contacting Fe3O4 (dark gray phase), corrosive agents converted it to a-FeOOH and a-Fe2O3. The phase conversion changes the weight density of materials and creates the porous tunnels in rust scales. The growth of micro tunnels to form the tunnel network allowed internal stress and cracks of rust scales evolved.
Two new butenolide and pentenolide derivatives, dysideolides A-B, were isolated from the marine s... more Two new butenolide and pentenolide derivatives, dysideolides A-B, were isolated from the marine sponge Dysidea cinerea. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D- and 2D-NMR spectroscopy, and CD spectra, as well as by comparing with the NMR data reported in the literature.
International Journal of River Basin Management, 2019
Estuarine/river engineers often encounter a problem that it is hard to specify an upstream bounda... more Estuarine/river engineers often encounter a problem that it is hard to specify an upstream boundary of a delta in the numerical modelling because of lack of good quality discharge data. This paper proposes a practical procedure to simulate tidal propagation and damping over a river stretch using a commonly used shallow-water equation model without imposing an upstream discharge boundary. The interaction between tides and river flows could be easily evaluated by applying seasonally-varying Manning's n friction values. The Hau River, one of the main streams of the Mekong River, is studied by analysing water levels measured at three different locations in the estuary. The nearly straight-line geometry of the Hau River allows us to neglect flood plain sinuosity, making it possible to extract tidal damping induced purely by fluvial influence. A series of analyses, including spectrum analysis and hydrodynamic simulation, suggests that tidal damping in the estuary of the Mekong Delta can be readily reproduced using the numerical model with Manning's n values of 0.025-0.032 [s m-1/3 ] for the flood season and 0.018-0.025 for the dry season. The present study demonstrates that changes in Manning's n value according to river flow conditions result in more reliable estimations than simply using a constant value throughout the year. The proposed procedure will be of great benefit not only for tidal modelling but also river and urban flood simulations, saline intrusion modelling and sea-level rise projections in the estuary of the Mekong River.
Twelve saponins were isolated from the leaves of Acanthopanax koreanum, including one new lupanet... more Twelve saponins were isolated from the leaves of Acanthopanax koreanum, including one new lupanetype triterpene glycoside, named acankoreoside R (1), together with 11 known triterpenoid saponins (2-12). Their structures were elucidated by 1D and 2D nuclear magnetic resonance (NMR), mass spectroscopic data (MS). All of the fractions and isolated saponins were evaluated for antiinflammatory activities in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) by ELISA. Among them, compounds 1-5, 7, 10, and 12 showed strong inhibitions towards interleukin-12 (IL-12) production with IC 50 values ranging from 1.59 to 5.46 lM. Other compounds were weak or inactive toward IL-12 p40 production.
The present paper demonstrates that inundation levels in the Mekong Delta's largest city, Can Tho... more The present paper demonstrates that inundation levels in the Mekong Delta's largest city, Can Tho, are predominantly determined by ocean tides, sea-level rise, and land subsidence. Our analysis of inundation patterns projects that the duration of inundation at an important road in the city will continue to rise from the current total of 72 inundated days per year to 270 days by 2030 and 365 days by 2050. This is attributed to the combined influence of sea-level rise and land subsidence, which causes relative water level rises at a rate of 22.3 mm•yr −1. People in the Mekong Delta have traditionally lived with floods, and thus there is certain resilience among residents in coping with small floods. At present, daily maximum inundation depth, which is generally shallower than 10 cm on the road, seems to be still manageable; however, our analysis indicates that this will start drastically increasing in the coming decades and reach an average depth of 70 cm by 2050. Effective and well-planned actions to mitigate the effects of land subsidence and sea-level rise are urgently required, otherwise, local inhabitants will encounter an unmanageable increase in inundation depth and duration in the coming decades. This study, which considers both sea-level rise and land subsidence, suggests that inundation depth and duration are projected to rise much faster than those indicated by previous studies, which only consider sea-level rise.
Bioorganic & Medicinal Chemistry Letters, 2015
Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), inclu... more Chemical investigation of Kandelia candel resulted in the isolation of 19 compounds (1-19), including one new sesquiterpene glycoside, kandelside (1), three megastigman glycoside compounds (7-9), 16 known phenolic compounds (2-6 and 10-19). Structures of the isolated compounds were elucidated based on spectral data comparison with reported values. Isolated compounds were also evaluated for their inhibitory effects on the production of pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumor necrosis factor α (TNF-α) in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells. Among these compounds, compound 9 exhibited strong inhibitory activity against IL-6 production (IC50=0.07±0.05μM) and moderate inhibitory activity against TNF-α production (IC50=49.86±1.02μM), but exhibited no activity on IL-12 p40 production. Compounds 5 and 6 significantly inhibited IL-12 p40, IL-6, and TNF-α production with IC50 values of 11.68±0.38, 44.52±1.08, and 28.73±0.96μM, respectively.
We consider lexicographic vector equilibrium problems in metric spaces. Sufficient conditions for... more We consider lexicographic vector equilibrium problems in metric spaces. Sufficient conditions for a family of such problems to be (uniquely) well-posed at the reference point are established. As an application, we derive several results on well-posedness for a class of variational inequalities.
Marine-derived natural products from invertebrates comprise an extremely diverse and promising so... more Marine-derived natural products from invertebrates comprise an extremely diverse and promising source of the compounds from a wide variety of structural classes. This study describes the discovery of five marine natural products with activity against Trypanosoma species by natural product library screening using whole cell in vitro assays. We investigated the anti-trypanosomal activity of the extracts from the soft corals and echinoderms living in Vietnamese seas. Of the samples screened, the methanolic extracts of several marine organisms exhibited potent activities against cultures of Trypanosoma brucei and T. cruzi (EC50…
Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-D-xylopyranosyl (1→6)-O-β-D-glucopyran... more Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-D-xylopyranosyl (1→6)-O-β-D-glucopyranoside (11), along with 10 known compounds 3,4-dihydroxyallylbenzene (2), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (3), tachioside (4), benzyl-O-β-D-glucopyranoside (5), icariside F2 (6),…
Bioorganic & medicinal chemistry letters, Jan 15, 2015
One new octulosonic acid derivative, chrysannol A (1), along with 17 known compounds (2-18), were... more One new octulosonic acid derivative, chrysannol A (1), along with 17 known compounds (2-18), were isolated from Chrysanthemum indicum flowers. Their structures were determined from 1D NMR, 2D NMR, HR-ESI-MS spectral data, and comparisons with previous reports. The effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compound 8 showed the highest inhibition of NO production of 46.09% at a concentration of 10.0μM. Compounds 7, 10, 11, and 16 inhibited TNF-α secretion at all concentration tested (0.4, 2.0, and 10.0μM), with inhibition values ranging from 22.27% to 33.13%. In addition, compound 8 and 9 decrease COX-2 and iNOS protein on Western blot analysis in dose dependent manner.
Inflammation is important in biomedical research, because it plays a key role in inflammatory dis... more Inflammation is important in biomedical research, because it plays a key role in inflammatory diseases including rheumatoid arthritis and other forms of arthritis, diabetes, heart disease, irritable bowel syndrome, Alzheimer's disease, Parkinson's disease, allergies, asthma, and even cancer. In the present study, we describe the inhibitory effect of crude extracts and steroids isolated from the starfish Astropecten polyacanthus on pro-inflammatory cytokine (Interleukin-12 (IL-12) p40, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α)) production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Among those tested, compounds 5 and 7 showed potent inhibitory effects on the production of all three pro-inflammatory cytokines with IC 50 values ranging from 1.82 ± 0.11 to 7.00 ± 0.16 μM. Potent inhibitory activities were also observed for compound 1 on the production of IL-12 p40 and IL-6 with values of 3.96 ± 0.12 and 4.07 ± 0.13 μM, respectively, and for compounds 3 and 4 on the
Kalopanax pictus (Araliaceae) is a deciduous tree that grows in East Asian countries. Its stem ba... more Kalopanax pictus (Araliaceae) is a deciduous tree that grows in East Asian countries. Its stem bark and leaves have been used in traditional medicine to treat rheumatic arthritis, neurotic pain, and diabetes mellitus. A phytochemical study on a methanol extract of the stem bark of K. pictus resulted in the isolation of three new compounds, 6b,16a-dihydroxy-hederagenin 3-O-b-D-glucuronopyranoside (1), 3-O-b-D-glucuronopyranosyl-28-O-b-D-glucopyranosyl-6b,16a-dihydroxy-oleanolic acid (2), and 3-O-b-D-galactopyranosyl(1?3)-a-L-arabinopyranosyl hederagenin 28-O-b-D-glucopyranosyl-(1?6)-b-D-glucopyranosyl ester (3), along with eight known compounds (4-11). Their structures were established on the basis of chemical and spectroscopic methods (IR, 1D and 2D NMR, and HRESITOFMS). Compounds 1-6 and 8-10 upregulated PPARs transcriptional activity in a dose-dependent manner in HepG2 cells, with EC 50 values in the range 0.20-15.5 lM. Moreover, the specific PPAR transactivational effects of compounds 1-6 and 8-10 on separate PPAR subtypes, PPARa,-c, and-b(d) were further investigated. Com
Bioorganic & Medicinal Chemistry Letters, 2014
Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 2... more Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 24 known compounds (3-26) were isolated from Euphorbia humifusa Willd. The effects of these compounds on soluble epoxide hydrolase (sEH) inhibitory activity were evaluated. Flavonoid compounds (10-21) exhibited high sEH inhibitory activity. Among them, compounds 12, 13, and 19 greatly inhibited sEH enzymatic activity, with IC50 values as low as 18.05±1.17, 18.64±1.83, and 17.23±0.84 μM, respectively. In addition, the effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compounds 3-6, 8, 18, 20-23, and 25-26 inhibited the production of both NO and TNF-α, with IC50 values ranging from 11.1±0.9 to 45.3±1.6 μM and 14.4±0.5 to 44.5±1.2 μM, respectively.
Three new pyrrole oligoglycosides, astebatheriosides A-C (1-3), and a new furan oligoglycoside, a... more Three new pyrrole oligoglycosides, astebatheriosides A-C (1-3), and a new furan oligoglycoside, astebatherioside D (4), were isolated from the starfish Asterina batheri by various chromatographic methods. Their structures were elucidated by spectroscopic and chemical methods. Compounds 2, 3, and 4 moderately inhibited IL-12 p40 production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) with IC 50 values of 36.4, 31.6, and 22.8 lM, respectively.
Anti-inflammatory transcriptional effects of nineteen compounds (1-19) from the soft coral Sinula... more Anti-inflammatory transcriptional effects of nineteen compounds (1-19) from the soft coral Sinularia maxima were evaluated using NF-jB luciferase and reverse transcriptase polymerase chain reaction. Compounds 1, 2, 4, 8, 15, 17, and 18 significantly inhibited TNFa-induced NF-jB transcriptional activity in HepG2 cells in a dosedependent manner, with IC 50 values ranging from 15.81 ± 2.29 to 29.10 ± 1.54 lM. Furthermore, the transcriptional inhibitory function of these compounds was confirmed by a decrease in intercellular adhesion molecule-1 and inducible nitric oxide synthase gene expression levels in HepG2 cells. These results provide a scientific rationale for the use of the soft coral S. maxima warrant further studies to develop new agents for the prevention and treatment of inflammatory.
Two new 2-C-β-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were... more Two new 2-C-β-D-glucopyranosyl benzoic acid derivatives named mallonanosides A (1) and B (2) were isolated from the methanolic extract of the leaves of Mallotus nanus along with five known flavonoids, kaempferin (3), juglanin (4), quercitrin (5), myricitrin (6), and rhoifolin (7). Their structures were established on the basis of spectral and chemical evidence. Their antioxidant activities were shown to depend on the number of hydroxyl groups, and the location and species of sugar moiety.
A new octanordammarane triterpene, 3β,15α-dihydroxymansumbinol (1) and a novel A-ring contracted ... more A new octanordammarane triterpene, 3β,15α-dihydroxymansumbinol (1) and a novel A-ring contracted oleanane triterpenoid, 2-formyl-(A)1-19α-hydroxy-1-norolean-2,12-dien-28-oic acid (2) were isolated from the roots extract of Rosa rugosa along with fifteen known compounds (3-17). Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, and FTICRMS. The MeOH extract, as well as CH2Cl2 and EtOAc fractions at a concentration of 0.5mg/mL showed potent sucrase inhibitory activity, with inhibition percentage values of 84.67±5.37%, 87.50±2.78%, and 81.91±2.90%, respectively. In addition, compounds 7-13 (1.0 mM) showed potent sucrase inhibitory activity (61.88±3.19% to 84.70±3.07% inhibition), which was comparable to that of the positive control, acarbose, with an inhibition percentage value of 50.96±2.97%. Compounds 1, 2, 4, and 14-17 showed moderate and/or weak inhibitory activities at the same concentration. The α-glucosidase inhibitory activities of the extracts and purified compounds may provide a novel opportunity to develop a new class of antidiabetic agents.
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