| 1. |
- Isroi, Isroi, 1974, et al.
(författare)
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Structural Changes of Oil Palm Empty Fruit Bunch (OPEFB) after Fungal and Phosphoric Acid Pretreatment
- 2012
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1420-3049 .- 1431-5157. ; 17:12, s. 14995-15012
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Tidskriftsartikel (refereegranskat)abstract
- Oil palm empty fruit bunch (OPEFB) was pretreated using white-rot fungus Pleurotus floridanus, phosphoric acid or their combination, and the results were evaluated based on the biomass components, and its structural and morphological changes. The carbohydrate losses after fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 7.89%, 35.65%, and 33.77%, respectively. The pretreatments changed the hydrogen bonds of cellulose and linkages between lignin and carbohydrate, which is associated with crystallinity of cellulose of OPEFB. Lateral Order Index (LOI) of OPEFB with no pretreatment, with fungal, phosphoric acid, and fungal followed by phosphoric acid pretreatments were 2.77, 1.42, 0.67, and 0.60, respectively. Phosphoric acid pretreatment showed morphological changes of OPEFB, indicated by the damage of fibre structure into smaller particle size. The fungal-, phosphoric acid-, and fungal followed by phosphoric acid pretreatments have improved the digestibility of OPEFB's cellulose by 4, 6.3, and 7.4 folds, respectively.
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| 2. |
- Abdissa, Negera, et al.
(författare)
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Cytotoxic Quinones from the roots of Aloe dawei
- 2014
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1431-5157. ; 19:3, s. 3264-3273
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Tidskriftsartikel (refereegranskat)abstract
- Seven naphthoquinones and nine anthraquinones were isolated from the roots of Aloe dawei by chromatographic separation. The purified metabolites were identified by NMR and MS analyses. Out of the sixteen quinones, 6-hydroxy-3,5-dimethoxy-2-methyl-1,4-naphthoquinone is a new compound. Two of the isolates, 5,8-dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione and 1-hydroxy-8-methoxy-3-methylanthraquinone showed high cytotoxic activity (IC50 1.15 and 4.85 µM) on MCF-7 breast cancer cells, whereas the others showed moderate to low cytotoxic activity against MDA-MB-231 (ER Negative) and MCF-7 (ER Positive) cancer cells.
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| 3. |
- Andersson, Pierre, et al.
(författare)
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B-norsteroids from Hymenoscyphus pseudoalbidus
- 2012
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Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 17, s. 7769-7781
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Tidskriftsartikel (refereegranskat)abstract
- Two viridin-related B-norsteroids, B-norviridiol lactone (1) and B-norviridin enol (2), both possessing distinct unprecedented carbon skeletons, were isolated from a liquid culture of the ash dieback-causing fungus Hymenoscyphus pseudoalbidus. Compound 2 was found to degrade to a third B-norsteroidal compound, 1β-hydroxy-2α-hydro-asterogynin A (3), which was later detected in the original culture. The proposed structure of 1 is, regarding connectivity, identical to the original erroneous structure for TAEMC161, which was later reassigned as viridiol. Compound 2 showed an unprecedented 1H-13C HMBC correlation through an intramolecular hydrogen bond. The five-membered B-ring of compounds 1–3 was proposed to be formed by a benzilic acid rearrangement. The known compound asterogynin A was found to be formed from 3 by a β-elimination of water. All compounds were characterized by NMR spectroscopy, LC-HRMS and polarimetry.
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| 4. |
- Barzegar, Hamid Reza, et al.
(författare)
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Water assisted growth of C60 rods and tubes by liquid-liquid interfacial precipitation method
- 2012
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 17:6, s. 6840-6853
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Tidskriftsartikel (refereegranskat)abstract
- C60 nanorods with hexagonal cross sections are grown using a static liquid-liquid interfacial precipitation method in a system of C60/m-dichlorobenzene solution and ethanol. Adding water to the ethanol phase leads instead to C60 tubes where both length and diameter of the C60 tubes can be controlled by the water content in the ethanol. Based on our observations we find that the diameter of the rods/tubes strongly depends on the nucleation step. We propose a liquid-liquid interface growth model of C60 rods and tubes based on the diffusion rate of the good C60 containing solvent into the poor solvent as well as on the size of the crystal seeds formed at the interface between the two solvents. The grown rods and tubes exhibit a hexagonal solvate crystal structure with m-dichlorobenzene solvent molecules incorporated into the crystal structure, independent of the water content. An annealing step at 200 °C at a pressure <1 kPa transforms the grown structures into a solvent-free face centered cubic structure. Both the hexagonal and the face centered cubic structures are very stable and neither morphology nor structure shows any signs of degradation after three months of storage.
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| 5. |
- Dahlgren, Markus K, et al.
(författare)
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Synthesis of 2-(2-Aminopyrimidine)-2,2-difluoroethanols as Potential Bioisosters of Salicylidene Acylhydrazides
- 2010
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 15:6, s. 4207-12
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Tidskriftsartikel (refereegranskat)abstract
- Salicylidene acylhydrazides are inhibitors of type III secretion in several Gramnegative pathogens. To further develop the salicylidene acylhydrazides, scaffold hopping was applied to replace the core fragment of the compounds. The novel 2-(2-aminopyrimidine)-2,2-difluoroethanol scaffold was identified as a possible analog to thesalicylidene acylhydrazide core structure. The synthesis of a library of 2-(2-aminopyrimidine)-2,2-difluoro-ethanols is described in this paper.
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| 6. |
- Eilertsen, Hans Chr, et al.
(författare)
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The effect of freeze/thaw cycles on reproducibility of metabolic profiling of marine microalgal extracts using direct infusion high-resolution mass spectrometry (HR-MS)
- 2014
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 19:10, s. 16373-16380
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Tidskriftsartikel (refereegranskat)abstract
- During normal sample preparation, storage in freezers and subsequent freeze/thaw cycles are commonly introduced. The effect of freeze/thaw cycles on the metabolic profiling of microalgal extracts using HR-MS was investigated. Methanolic extracts of monocultures of Arctic marine diatoms were analyzed immediately after extraction, after seven days of storage at -78 degrees C (one freeze/thaw cycle), and after additional seven days at -20 degrees C (two freeze/thaw cycles). Repeated direct infusion high-resolution mass spectrometry analysis of microalgae extracts of the same sample showed that reproducibility was ca. 90% when a fresh (unfrozen) sample was analyzed. The overall reproducibility decreased further by ca. 10% after the first freeze/thaw-cycle, and after one more freeze/thaw cycle the reproducibility decreased further by ca. 7%. The decrease in reproducibility after freeze-thaw cycles could be attributed to sample degradation and not to instrument variability.
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| 7. |
- Endale, Milkyas, 1980, et al.
(författare)
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Anthraquinones of the roots of Pentas micrantha
- 2013
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1431-5157. ; 18:1, s. 311-321
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Tidskriftsartikel (refereegranskat)abstract
- Pentas micrantha is used in the East African indigenous medicine to treat malaria. In the first investigation of this plant, the crude methanol root extract showed moderate antiplasmodial activity against the W2- (3.37 μg/mL) and D6-strains (4.00 μg/mL) of Plasmodium falciparum and low cytotoxicity (>450 μg/mL, MCF-7 cell line). Chromatographic separation of the extract yielded nine anthraquinones, of which 5,6-dihydroxylucidin-11-O-methyl ether is new. Isolation of a munjistin derivative from the genus Pentas is reported here for the first time. The isolated constituents were identified by NMR and mass spectrometric techniques and showed low antiplasmodial activities.
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| 8. |
- Ghidini, A, et al.
(författare)
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Synthesis of PNA oligoether conjugates
- 2014
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Ingår i: Molecules (Basel, Switzerland). - : MDPI AG. - 1420-3049. ; 19:3, s. 3135-3148
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Tidskriftsartikel (refereegranskat)
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| 9. |
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| 10. |
- Irungu, Beatrice N., et al.
(författare)
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Constituents of the Roots and Leaves of Ekebergia capensis and Their Potential Antiplasmodial and Cytotoxic Activities
- 2014
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Ingår i: Molecules. - : MDPI AG. - 1420-3049 .- 1431-5157. ; 19:9, s. 14235-14246
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Tidskriftsartikel (refereegranskat)abstract
- A new triterpenoid, 3-oxo-12β-hydroxy-oleanan-28,13β-olide (1), and six known triterpenoids 2–7 were isolated from the root bark of Ekebergia capensis, an African medicinal plant. A limonoid 8 and two glycoflavonoids 9–10 were found in its leaves. The metabolites were identified by NMR and MS analyses, and their cytotoxicity was evaluated against the mammalian African monkey kidney (vero), mouse breast cancer (4T1), human larynx carcinoma (HEp2) and human breast cancer (MDA-MB-231) cell lines. Out of the isolates, oleanonic acid (2) showed the highest cytotoxicity, i.e., IC50’s of 1.4 and 13.3 µM against the HEp2 and 4T1 cells, respectively. Motivated by the higher cytotoxicity of the crude bark extract as compared to the isolates, the interactions of oleanonic acid (2) with five triterpenoids 3–7 were evaluated on vero cells. In an antiplasmodial assay, seven of the metabolites were observed to possess moderate activity against the D6 and W2 strains of P. falciparum (IC50 27.1–97.1 µM), however with a low selectivity index (IC50(vero)/IC50(P. falciparum-D6) < 10). The observed moderate antiplasmodial activity may be due to general cytotoxicity of the isolated triterpenoids.
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