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1.
Okadaic acid (OA) and dinophysistoxin-1 (DTX1) cause diarrheic shellfish poisoning. This article examines the biochemical interactions of the two toxins with novel okadaic acid binding proteins (OABPs) 2.1 and 2.3, originally isolated from the marine sponge Halichondria okadai. First, recombinant OABPs 2.1 and 2.3 were expressed in Escherichia coli BL21 (DE3) cells. Binding assays using [24-3H]OA and the recombinant OABP 2.1 or 2.3 demonstrated the dissociation constant Kd of 1.30 ± 0.56 nM and 1.54 ± 0.35 nM, respectively. Binding of [24-3H]okadaic acid to recombinant OABP2.1 was almost equally replaced with OA and DTX1. OA-induced cytotoxicity in mouse leukemia P388 cells was inhibited in the presence of the recombinant OABPs 2.1 and 2.3 with an EC50 of 92 ± 8.4 nM and 87 ± 13 nM, respectively. These results suggest that the blockage of OA-induced cytotoxicity by OABPs 2.1 and 2.3 may be involved in regulating symbiotic relationships present in the sponge H. okadai.  相似文献   

2.
The dynamics of Dinophysis acuminata and its associated diarrhetic shellfish poisoning (DSP) toxins, okadaic acid (OA) and dinophysistoxin-1 (DTX1) as well as pectenotoxins (PTXs), were investigated within plankton and shellfish in Northport Bay, NY, USA, over a four year period (2008–2011). Over the course of the study, Dinophysis bloom densities ranged from ~104 to 106 cells L−1 and exceeded 106 L−1 in 2011 when levels of total OA, total DTX1, and PTX in the water column were 188, 86, and 2900 pg mL−1, respectively, with the majority of the DSP toxins present as esters. These cell densities exceed – by two orders of magnitude – those previously reported within thousands of samples collected from NY waters from 1971 to 1986. The bloom species was positively identified as D. acuminata via scanning electron microscopy and genetic sequencing (cox1 gene). The cox1 gene sequence from the D. acuminata populations in Northport Bay was 100% identical to D. acuminata from Narragansett Bay, RI, USA and formed a strongly supported phylogenetic cluster (posterior probability = 1) that included D. acuminata and Dinophysis ovum from systems along the North Atlantic Ocean. Shellfish collected from Northport Bay during the 2011 bloom had DSP toxin levels (1245 ng g−1 total OA congeners) far exceeding the USFDA action level (160 ng g−1 total OA of shellfish tissue) representing the first such occurrence on the East Coast of the U.S. D. acuminata blooms co-occurred with paralytic shellfish poisoning (PSP) causing blooms of Alexandrium fundyense during late spring each year of the study. D. acuminata cell abundances were significantly correlated with levels of total phytoplankton biomass and Mesodinium spp., suggesting food web interactions may influence the dynamics of these blooms. Given that little is known regarding the combined effects of DSP and PSP toxins on human health and the concurrent accumulation and depuration of these toxins in shellfish, these blooms represent a novel managerial challenge.  相似文献   

3.
Although a worldwide health problem, leishmaniasis is considered a highly neglected disease, lacking efficient and low toxic treatment. The efforts for new drug development are based on alternatives such as new uses for well-known drugs, in silico and synthetic studies and naturally derived compounds. Oleanolic acid (OA) is a pentacyclic triterpenoid widely distributed throughout the Plantae kingdom that displays several pharmacological activities. OA showed potent leishmancidal effects in different Leishmania species, both against promastigotes (IC50 L. braziliensis 30.47 ± 6.35 μM; IC50 L. amazonensis 40.46 ± 14.21 μM; IC50 L. infantum 65.93 ± 15.12 μM) and amastigotes (IC50 L. braziliensis 68.75 ± 16.55 μM; IC50 L. amazonensis 38.45 ± 12.05 μM; IC50 L. infantum 64.08 ± 23.52 μM), with low cytotoxicity against mouse peritoneal macrophages (CC50 235.80 ± 36.95 μM). Moreover, in silico studies performed to evaluate OA molecular properties and to elucidate the possible mechanism of action over the Leishmania enzyme sterol 14α-demethylase (CYP51) suggested that OA interacts efficiently with CYP51 and could inhibit the ergosterol synthesis pathway. Collectively, these data indicate that OA is a good candidate as leading compound for the development of a new leishmaniasis treatment.  相似文献   

4.
Harmful algal blooms (HABs) are a natural global phenomena emerging in severity and extent. Incidents have many economic, ecological and human health impacts. Monitoring and providing early warning of toxic HABs are critical for protecting public health. Current monitoring programmes include measuring the number of toxic phytoplankton cells in the water and biotoxin levels in shellfish tissue. As these efforts are demanding and labour intensive, methods which improve the efficiency are essential. This study compares the utilisation of a multitoxin surface plasmon resonance (multitoxin SPR) biosensor with enzyme-linked immunosorbent assay (ELISA) and analytical methods such as high performance liquid chromatography with fluorescence detection (HPLC-FLD) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for toxic HAB monitoring efforts in Europe. Seawater samples (n = 256) from European waters, collected 2009–2011, were analysed for biotoxins: saxitoxin and analogues, okadaic acid and dinophysistoxins 1/2 (DTX1/DTX2) and domoic acid responsible for paralytic shellfish poisoning (PSP), diarrheic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP), respectively. Biotoxins were detected mainly in samples from Spain and Ireland. France and Norway appeared to have the lowest number of toxic samples. Both the multitoxin SPR biosensor and the RNA microarray were more sensitive at detecting toxic HABs than standard light microscopy phytoplankton monitoring. Correlations between each of the detection methods were performed with the overall agreement, based on statistical 2 × 2 comparison tables, between each testing platform ranging between 32% and 74% for all three toxin families illustrating that one individual testing method may not be an ideal solution. An efficient early warning monitoring system for the detection of toxic HABs could therefore be achieved by combining both the multitoxin SPR biosensor and RNA microarray.  相似文献   

5.
Dinophysis spp. produce diarrhetic shellfish poisoning (DSP) toxins and pectenotoxins. The extent to which the dinoflagellate cells retain their toxicity in stationary phase, a period when cells are most toxic, and their transition into cell death is not known. Here we present results on the production, recycling, retention, and release of toxins from a monoculture of Dinophysis acuminata during these two important stages. Once stationary phase was reached, cultures were divided between light and dark treatments to identify if light influenced toxin dynamics. Light was required for long-term cell maintenance (>2 months) of D. acuminata in the absence of prey, however, in the dark, cells in stationary phase survived on reserves alone for four weeks before beginning to decline. Cells maintained relatively constant levels of intracellular OA (0.39 ± 0.03 pg/cell, 0.44 ± 0.05 pg/cell), DTX1 (0.45 ± 0.09 pg/cell, 0.64 ± 0.10 pg/cell) and PTX2 (10.4 ± 1.4 pg/cell, 11.0 ± 1.9 pg/cell) in the dark and light treatments, respectively, throughout stationary phase and into culture decline. Toxin production was only apparent during late exponential and early stationary growth when cells were actively dividing. In general, the concentration of dissolved (extracellular) toxin in the medium significantly increased upon culture aging and decline; cells did not appear to be actively or passively releasing toxin during stationary phase, but rather extracellular release was likely a result of cell death. Light availability did not have an apparent effect on toxin production, quotas, or intracellular vs. extracellular distribution. Together these results suggest that a bloom of D. acuminata would retain its cellular toxicity or potency as long as the population is viable, and that cells under conditions of low light (e.g., at the boundary or below euphotic zone) and/or minimal prey could maintain toxicity for extended periods.  相似文献   

6.
Synthesis, structure, and evaluation of in vitro α-glucosidase enzyme inhibition of a new class of diethylammonium salts of aryl substituted thiobarbituric acid is described. This protocol is straight, environmentally benign and efficient, involving Aldol-Michael addition reaction in one pot fashion. The 3D chemical structures of the synthesized compounds were assigned based on spectroscopic methods and X-ray single crystal diffraction analyses. All synthesized compounds 3a-3n were evaluated for their in vitro α-glucosidase enzyme inhibitory activity, whereas acarbose was used as the standard drug (IC50 = 840 ± 1.73 µM). All tested compounds were found to possess varying degree of α-glucosidase enzyme inhibition activity with (IC50 = 19.46 ± 1.84–415.8 ± 4.0 µM). Compound 3i (IC50 = 19.4 ± 1.84 µM) exhibited the highest activity. To the best of knowledge this is the first report of the in vitro α-glucosidase enzyme inhibition by the diethylamonium salts of aryl substituted thiobarbituric acid. Furthermore, molecular docking studies of selected compounds were also performed to see interactions between active compounds and binding sites.  相似文献   

7.
A series of 4-anilinothieno[2,3-d]pyrimidine-based hydroxamic acid derivatives as novel HDACs inhibitors were designed, synthesized and evaluated. Most of these compounds displayed good to excellent inhibitory activities against HDAC1, 3, 6. The IC50 values of compound 10r against HDAC1, HDAC3, HDAC6 was 1.14 ± 0.03 nM, 3.56 ± 0.08 nM, 11.43 ± 0.12 nM. Compound 10r noticeably up-regulated the level of histone H3 acetylation compared to the SAHA. Most of the compounds showed the strong anti-proliferative activity against human cancer cell lines including RMPI8226 and HCT-116. The IC50 values of Compounds 10r and 10t against RPMI8226 was 2.39 ± 0.20 μM, 1.41 ± 0.44 μM, respectively, and the HCT-116 was sensitive to the compounds 10h, 10m, 10r, 10w with the IC50 values <1.9 μM.  相似文献   

8.
Two new dammarane saponins, 2α,3β,12β-trihydroxydammar-20(22),24-diene-3-O-[β-d-glucopyranoxyl(1→2)-β-d-6″-O-acetylglucopyranoside (1, namely damulin C) and 2α,3β,12β-trihydroxydammar-20(21),24-diene-3-O-[β-d-glucopyranoxyl(1→2)-β-d-6″-O-acetylglucopyranoside (2, namely damulin D), were isolated from the ethanol extract of Gynostemma pentaphyllum, which had been heat processed by steaming at 125 °C. The NMR spectroscopic data of the novel saponins were completely assigned by using a combination of 2D NMR experiments including 1H–1H COSY, HSQC, and HMBC. Their cytotoxic activities of human liver adenocarcinoma HepG2 cells were evaluated in vitro. They showed cytotoxicities against HepG2 cell line with IC50 of 40 ± 0.7 and 38 ± 0.5 μg/ml, respectively.  相似文献   

9.
Twenty five derivatives of indole carbohydrazide (125) had been synthesized. These compounds were characterized using 1H NMR and EI-MS, and further evaluated for their α-amylase inhibitory potential. The analogs (125) showed varying degree of α-amylase inhibitory potential.ranging between 9.28 and 599.0 µM when compared with standard acarbose having IC50 value 8.78 ± 0.16 µM. Six analogs, 25 (IC50 = 9.28 ± 0.153 µM), 22 (IC50 = 9.79 ± 0.43 µM), 4 (IC50 = 11.08 ± 0.357 µM), 1 (IC50 = 12.65 ± 0.169 µM), 8 (IC50 = 21.37 ± 0.07 µM) and 14 (IC50 = 43.21 ± 0.14 µM) showed potent α-amylase inhibition as compared to the standard acarbose (IC50 = 8.78 ± 0.16 µM). All other analogs displayed good to moderate inhibitory potential. Structure-activity relationship was established through the interaction of the active compounds with enzyme active site with the help of docking studies.  相似文献   

10.
Mycobacterium tuberculosis l-alanine dehydrogenase (MTB l-AlaDH) is one of the important drug targets for treating latent/persistent tuberculosis. In this study we used crystal structure of the MTB l-AlaDH bound with cofactor NAD+ as a structural framework for virtual screening of our in-house database to identified new classes of l-AlaDH inhibitor. We identified azetidine-2,4-dicarboxamide derivative as one of the potent inhibitor with IC50 of 9.22 ± 0.72 μM. Further lead optimization by synthesis leads to compound 1-(isonicotinamido)-N2,N4-bis(benzo[d]thiazol-2-yl)azetidine-2,4-dicarboxamide (18) with l-AlaDH IC50 of 3.83 ± 0.12 μM, 2.0 log reduction in nutrient starved dormant MTB model and MIC of 11.81 μM in actively replicative MTB.  相似文献   

11.
A new library of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethyl aryl ether derivatives (1 2 3) were synthesized and characterized by EI-MS and 1H NMR, and screened for their α-amylase inhibitory activity. Out of twenty-three derivatives, two molecules 19 (IC50 = 0.38 ± 0.82 µM) and 23 (IC50 = 1.66 ± 0.14 µM), showed excellent activity whereas the remaining compounds, except 10 and 17, showed good to moderate inhibition in the range of IC50 = 1.77–2.98 µM when compared with the standard acarbose (IC50 = 1.66 ± 0.1 µM). A plausible structure-activity relationship has also been presented. In addition, in silico studies was carried out in order to rationalize the binding interaction of compounds with the active site of enzyme.  相似文献   

12.
Current study based on the synthesis of new thiazole derivatives via “one pot” multicomponent reaction, evaluation of their in vitro α-glucosidase inhibitory activities, and in silico studies. All synthetic compounds were fully characterized by 1H NMR, 13C NMR and EIMS. CHN analysis was also performed. These newly synthesized compounds showed activities in the range of IC50 = 9.06 ± 0.10–82.50 ± 1.70 μM as compared to standard acarbose (IC50 = 38.25 ± 0.12 μM). It is worth mentioning that most of the compounds such as 1 (IC50 = 23.60 ± 0.39 μM), 2 (IC50 = 22.70 ± 0.60 μM), 3 (IC50 = 22.40 ± 0.32 μM), 4 (IC50 = 26.5 ± 0.40 μM), 6 (IC50 = 34.60 ± 0.60 μM), 7 (IC50 = 26.20 ± 0.43 μM), 8 (IC50 = 14.06 ± 0.18 μM), 9 (IC50 = 17.60 ± 0.28 μM), 10 (IC50 = 27.16 ± 0.41 μM), 11 (IC50 = 19.16 ± 0.19 μM), 12 (IC50 = 9.06 ± 0.10 μM), 13 (IC50 = 12.80 ± 0.21 μM), 14 (IC50 = 11.94 ± 0.18 μM), 15 (IC50 = 16.90 ± 0.20 μM), 16 (IC50 = 12.60 ± 0.14 μM), 17 (IC50 = 16.30 ± 0.29 μM), and 18 (IC50 = 32.60 ± 0.61 μM) exhibited potent inhibitory potential. Molecular docking study was performed in order to understand the molecular interactions between the molecule and enzyme. Newly identified α-glucosidase inhibitors except few were found to be completely non-toxic.  相似文献   

13.
The variability of toxigenic phytoplankton and the consequent uptake and loss of toxins by the mussel Choromytilus meridionalis was investigated in the southern Benguela at the event scale (3–10 days) in response to the upwelling–downwelling cycle. Phytoplankton and mussel samples were collected daily (20 March–11 April 2007) from a mooring station (32.04°S; 18.26°E) located 3.5 km offshore of Lambert's Bay, within the St Helena Bay region. Rapid changes in phytoplankton assemblages incorporated three groups of toxigenic phytoplankton: (1) the dinoflagellate Alexandrium catenella; (2) several species of Dinophysis, including Dinophysis acuminata, Dinophysis fortii, Dinophysis hastata and Dinophysis rotundata; and (3) members of the diatom genus Pseudo-nitzschia. Analysis of phytoplankton concentrates by LC–MS/MS or LC-FD provided information on the toxin composition and calculated toxicity of each group. Several additional in vitro assays were used for the analysis of toxins in mussels (ELISA, RBA, MBA for PSP toxins; and ELISA for DSP toxins). Good correspondence was observed between methods except for the MBA, which provided significantly lower (approximately 2-fold) estimates of PSP toxins. PSP and DSP toxins both exceeded the regulatory limits in Choromytilis meridionalis, but ASP toxins were undetected. Differences were observed in the composition of both PSP and DSP toxins in C. meridionalis from that of the ingested dinoflagellates (PSP toxins showed an increase in STX, C1,2, and traces of dcSTX and GTX1,4 and a decrease in NEO; DSP toxins showed an increased in DTX1, and traces of PTX2sa, and a decrease in OA). The rate of loss of PSP toxins following dispersal of the A. catenella boom was 0.12 d−1. Variation in the loss rates of different PSP toxins contributed to the change in toxin profile in C. meridionalis. Prediction of net toxicity in shellfish of the nearshore environment in the southern Benguela is limited due to rapid phytoplankton community changes, high variability in cellular toxicity, and the selective uptake and loss of toxins, and/or transformation of toxins.  相似文献   

14.
A new series of coumarin thiazole derivatives 7a-7t were synthesized, characterized by 1H NMR, 13C NMR and element analysis, evaluated for their α-glucosidase inhibitory activity. The majority of the screened compounds displayed potent inhibitory activities with IC50 values in the range of 6.24 ± 0.07–81.69 ± 0.39 μM, when compared to the standard acarbose (IC50 = 43.26 ± 0.19 μM). Structure–activity relationship (SAR) studies suggest that the pattern of substitution in the phenyl ring is closely related to the biological activity of this class of compounds. Among all the tested molecules, compound 7e (IC50 = 6.24 ± 0.07 μM) was found to be the most active compound in the library of coumarin thiazole derivatives. Enzyme kinetic studies showed that compound 7e is a non-competitive inhibitor with a Ki of 6.86 μM. Furthermore, the binding interactions of compound 7e with the active site of α-glucosidase were confirmed through molecular docking. This study has identified a new class of potent α-glucosidase inhibitors for further investigation.  相似文献   

15.
A new ellagitannin, agritannin (1), a new flavone glycoside, agriflavone (2), and another flavone glycoside with spectroscopic data reported for the first time, kaempferol-3-O-[(S)-3-hydroxy-3-methylglutaryl (1→6)]-β-d-glucoside (3), along with 16 known compounds were isolated from the aerial parts of Agrimonia pilosa Ledeb. These compounds were evaluated for PTP1B inhibitory activity. Among them, compounds 9 and 18 displayed potential inhibitory activity against PTP1B with IC50 values of 7.14 ± 1.75 and 7.73 ± 0.24 μM, respectively. In addition, compound 1 showed significant inhibitory effect with an IC50 value of 17.03 ± 0.09 μM. Furthermore, these compounds were tested in AChE inhibitory assays. Most of them were found to have moderate inhibitory effects, with IC50 values ranging from 60.20 ± 1.09 to 92.85 ± 1.12 μM. Except compounds 3, 8, and 18 were inactive.  相似文献   

16.
In this study, twenty-five (25) substituted aryl thiazoles (SAT) 125 were synthesized, and their in vitro cytotoxicity was evaluated against four cancer cell lines, MCF-7 (ER+ve breast), MDA-MB-231 (ER−ve breast), HCT116 (colorectal) and HeLa (cervical). The activity was compared with the standard anticancer drug doxorubicin (IC50 = 1.56 ± 0.05 μM). Among them, compounds 1, 48, and 19 were found to be toxic to all four cancer cell lines (IC50 values 5.37 ± 0.56–46.72 ± 1.80 μM). Compound 20 was selectively active against MCF7 breast cancer cells with IC50 of 40.21 ± 4.15 μM, whereas compound 19 was active against MCF7 and HeLa cells with IC50 of 46.72 ± 1.8, and 19.86 ± 0.11 μM, respectively. These results suggest that substituted aryl thiazoles 1 and 4 deserve to be further investigated in vivo as anticancer leads.  相似文献   

17.
A series of 15 novel compounds incorporating the thieno[2,3-b]thiophene moiety were synthesized. The chemical structures of these compounds were deduced from elemental analyses, 1H NMR, 13C NMR, and ESI-mass spectral data. The enzyme inhibition potential of these compounds was evaluated, in vitro, against β-glucuronidase, xanthine oxidase, and α-chymotrypsin enzymes. The cytotoxicity was evaluated by a cell viability assay utilizing the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) dye. Among the compounds tested, compound 3 was the most potent β-glucuronidase inhibitor with an IC50 value of 0.9 ± 0.0138 μM; it was much more active than the standard, d-saccharic acid 1,4-lactone (IC50 = 45.75 ± 2.16 μM). Compound 12, on the other hand, was the most potent as a xanthine oxidase inhibitor with an IC50 of 14.4 ± 1.2 μM. With the characterization of their mechanism of action and with further testing, these compounds could be useful candidates as anticancer drugs. In addition, the newly synthesized compounds were subjected to POM analyses to get insights about their degree of their toxicity.  相似文献   

18.
Thiadiazole derivatives 124 were synthesized via a single step reaction and screened for in vitro β-glucuronidase inhibitory activity. All the synthetic compounds displayed good inhibitory activity in the range of IC50 = 2.16 ± 0.01–58.06 ± 1.60 μM as compare to standard d-saccharic acid 1,4-lactone (IC50 = 48.4 ± 1.25 μM). Molecular docking study was conducted in order to establish the structure–activity relationship (SAR) which demonstrated that thiadiazole as well as both aryl moieties (aryl and N-aryl) involved to exhibit the inhibitory potential. All the synthetic compounds were characterized by spectroscopic techniques 1H, 13C NMR, and EIMS.  相似文献   

19.
A new α-pyrone was isolated from aerial parts of Hyptis macrostachys Benth. Its structure was determined as 6R-[(5′S,6′S-diacetoxy)-1′Z,3′E-heptenyl]-5,6-dihydro-2H-pyran-2-one, named hyptenolide based on a combination of 1D and 2D NMR techniques and CD data. Hyptenolide inhibited the contractions induced by CCh (IC50 = 1.7 ± 0.3 × 10−4 M) or histamine (IC50 = 0.9 ± 0.05 × 10−4 M) in guinea pig ileum, demonstrating for the first time a pharmacological activity for the pyrone.  相似文献   

20.
Twenty terpenoids, including a new triterpenoid (1) and a new monoterpenoid (20), were isolated from the branches and leaves of Pyrus pashia. The structures of two new compounds were determined to be 2α, 3β, 27-trihydroxyolean-12-en-28-oic acid (1) and (4α)-3-(5,5-dimethyltetrahydrofuranyl)-1-buten-3-ol 3-O-β-d-glucopyranoside (20) on the basis of spectroscopic analysis (IR, HRESIMS, 1D and 2D NMR) and chemical method. Some of the isolated compounds were evaluated for their cytotoxic activity against a panel of human cancer cell lines by MTT assay, using cisplatin as a positive control. Compound 14 exhibited cytotoxic activities against A549 (IC50 = 19.18 ± 4.26 μM), Hela (IC50 = 12.56 ± 3.89 μM), SGC7901 (IC50 = 10.48 ± 1.95 μM) and NHI-1975 (IC50 = 7.38 ± 2.31 μM) cell lines as well as compound 12 displayed cytotoxic activities against A549 (IC50 = 14.71 ± 1.47 μM) and Hela (IC50 = 12.22 ± 1.88 μM) cell lines.  相似文献   

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