ORCID Profile
0000-0002-5665-0702
Current Organisations
Academic Center for Education, Culture and Research (ACECR)
,
University of Technology Sydney
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Medicinal and Biomolecular Chemistry | Biological And Medical Chemistry | Organic Chemical Synthesis |
Treatments (e.g. chemicals, antibiotics) | Crop and animal protection chemicals | Chemical sciences
Publisher: American Chemical Society (ACS)
Date: 17-04-2009
DOI: 10.1021/NP900030Y
Abstract: Three known compounds, stemofoline (1), (2'S)-hydroxystemofoline (2), and (11Z)-1',2'-didehydrostemofoline (3), along with two new alkaloids, stemaphylline (4) and stemaphylline-N-oxide (5), have been isolated from a root extract of Stemona aphylla. The structures of these alkaloids were determined on the basis of their spectroscopic data. The analysis of the crude dichloromethane extract by GC-MS in the EIMS mode showed the presence of alkaloids 1-4, the alkaloid 11, and stilbostemin R (12). The crude dichloromethane extract and 4 were tested for their comparative biological activities. The results of their acetylcholinesterase (AChE) inhibitory activities showed that the crude extract had higher activity than that of 4. The insecticidal properties of the crude extract and 4, using a topical application, showed that 4 had an activity similar to the positive control, methomyl, whereas the crude extract had much lower activity. Their antimicrobial activity against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas auruginosa ATCC 27853, and Candida albicans ATCC 90028 was weak (MIC 62.5-125 microg/mL, MBC 125-250 microg/mL, MFC 125 microg/mL) but much higher than that of the crude extract.
Publisher: Informa UK Limited
Date: 02-1994
Publisher: Informa UK Limited
Date: 07-1993
Publisher: Springer Science and Business Media LLC
Date: 2001
Publisher: American Chemical Society (ACS)
Date: 17-02-2009
DOI: 10.1021/NP800806B
Abstract: The semisynthesis of the Stemona alkaloids (3'R)-stemofolenol (1), (3'S)-stemofolenol (2), methylstemofoline (3), and (3'S)-hydroxystemofoline (5) and the unnatural analogues (11E)-methylstemofoline (15) and 3'R-hydroxystemofoline (11) has been achieved starting from (11Z)-1',2'-didehydrostemofoline (4). This synthesis allowed, for the first time, access to diastereomerically enriched s les of 1 and 2 and the assignment of their absolute configurations at C-3'. These compounds were obtained in sufficient quantities to allow for their biological testing. In a quantitative assay as AChE inhibitors, (11Z)-1',2'-didehydrostemofoline (4) and (3'S)-hydroxystemofoline (5) were found to be the most active.
Publisher: Springer Science and Business Media LLC
Date: 02-1992
DOI: 10.1007/BF00671980
Publisher: Elsevier BV
Date: 08-1996
Publisher: Springer Science and Business Media LLC
Date: 31-08-2017
DOI: 10.1038/APS.2016.170
Publisher: MDPI AG
Date: 18-09-2023
Publisher: MDPI AG
Date: 12-05-2023
DOI: 10.3390/MOLECULES28104054
Abstract: Our early work indicated that methanolic extracts from the flowers, leaves, bark, and isolated compounds of Acacia saligna exhibited significant antioxidant activities in vitro. The overproduction of reactive oxygen species (ROS) in the mitochondria (mt-ROS) interfered with glucose uptake, metabolism, and its AMPK-dependent pathway, contributing to hyperglycemia and diabetes. This study aimed to screen the ability of these extracts and isolated compounds to attenuate the production of ROS and maintain mitochondrial function via the restoration of mitochondrial membrane potential (MMP) in 3T3-L1 adipocytes. Downstream effects were investigated via an immunoblot analysis of the AMPK signalling pathway and glucose uptake assays. All methanolic extracts effectively reduced cellular ROS and mt-ROS levels, restored the MMP, activated AMPK-α, and enhanced cellular glucose uptake. At 10 µM, (−)-epicatechin-6 (from methanolic leaf and bark extracts) markedly reduced ROS and mt-ROS levels by almost 30% and 50%, respectively, with an MMP potential ratio 2.2-fold higher compared to the vehicle control. (−)-Epicatechin 6 increased the phosphorylation of AMPK-α by 43%, with an 88% higher glucose uptake than the control. Other isolated compounds include naringenin 1, naringenin-7-O-α-L-arabinopyranoside 2, isosalipurposide 3, D-(+)-pinitol 5a, and (−)-pinitol 5b, which also performed relatively well across all assays. Australian A. saligna active extracts and compounds can reduce ROS oxidative stress, improve mitochondrial function, and enhance glucose uptake through AMPK-α activation in adipocytes, supporting its potential antidiabetic application.
Publisher: Bentham Science Publishers Ltd.
Date: 05-05-2015
DOI: 10.2174/1568009615666150225121508
Abstract: Microparticles (MPs) are released from most eukaryotic cells after the vesiculation of the plasma membrane and serve as vectors of long and short-range signaling. MPs derived from multidrug resistant (MDR) cancer cells carry molecular components of the donor cell such as nucleic acids and proteins, and can alter the activity of drug-sensitive recipient cells through the transfer of their cargo. Given the substantial role of MPs in the acquisition and dissemination of MDR, we propose that the inhibition of MP release provides a novel therapeutic approach. This study characterises the effect of a panel of molecules known to act on MP-biosynthetic pathways. We demonstrate a differential effect by these molecules on MP inhibition that appear dependent on the release of intracellular calcium stores following activation with the calcium ionophore A23187. Calpain inhibitor, PD-150606 a selective inhibitor of Rho-associated, coiled-coil containing protein kinase (ROCK), Y-27632 and the vitamin B5 derivative pantethine, inhibited MP release only upon prior activation with A23187. Calpain inhibitor II showed significant inhibition in the absence of cell activation, whereas the vitamin B5 derivatives cystamine dihydrochloride and cysteamine hydrochloride showed no effect on MP inhibition under either condition. In contrast the classical pharmacological inhibitor of MDR, the calcium channel blocker Verapamil, showed an increase in MP formation on resting cells. These results suggest a potential role for calcium in the mechanism of action for PD-150606, Y-27632 and pantethine. These molecules, together with calpain inhibitor II have shown promise as modulators of MP release and warrant consideration as potential candidates for the development of an alternative therapeutic strategy for the prevention of MP-mediated MDR in cancer.
Publisher: Springer Science and Business Media LLC
Date: 1993
DOI: 10.1007/BF00708755
Publisher: MDPI AG
Date: 07-10-2022
DOI: 10.3390/MOLECULES27196667
Abstract: A novel 4-[4-(pentafluoro-λ⁶-sulfanyl)phenyl]-1,2,4-triazole-3,5-dione (5a) was synthesised as a potential [18F]radio-prosthetic group for radiolabelling peptides and proteins via selective bioconjugation with the phenolic side chains of tyrosine residues. Preliminary conjugation tests revealed the rapid hydrolysis of 5a under semi-aqueous conditions these results led to further investigation into the electronic substituent effects of PTAD derivatives and corresponding hydrolytic stabilities. Five derivatives of 5a with para substituents of varying electron donating and withdrawing effects were synthesised for the investigation. The bioconjugation of these derivatives with model tyrosine was monitored in both aqueous and organic media in the presence of a variety of catalysts. From these investigations, we have found HFIP to be an effective catalyst when used in tandem with DCM as a solvent to give PTAD-tyrosine conjugate products (6a–f) in satisfactory to good yields (54–79%), whereas analogous reactions performed in acetonitrile were unsuccessful. The discovery of this system has allowed for the successful conjugation of electron-deficient PTAD derivatives to tyrosine, which would otherwise be unachievable under aqueous reaction conditions. The inclusion of these electron-deficient, fluorinated PTAD derivatives for use in the PTAD-tyrosine conjugation will hopefully broaden their applicability within fields such as 19F-MRI and PET imaging.
Publisher: CSIRO Publishing
Date: 1992
DOI: 10.1071/CH9920553
Abstract: The imine functionality of the 3-azatricyclo[5.3.1.04,9]undec-2-ene derivatives (3a-c) reacts with dimethyl acetylenedicarboxylate to yield the lactam (5), the amino ester (6), and the oxopyrroline (7) respectively. Crystal structures of (6) [C31H34N2O5, Pca21, a 17.736(1), b 9.8412(4), c 15.584(1) � , Z 4, R 0.032] and (7) [C33H36N2O6, Pca21, a 14.0610(8), b 9.6602(6), c 20.818(1) � , Z 4, R 0.038] were determined. These widely differing modes of reaction result from the nature of the imine C2 substituent present in the starting material(3). Tentative mechanistic explanations are presented.
Publisher: Elsevier BV
Date: 08-2009
Publisher: Springer Science and Business Media LLC
Date: 13-03-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CC00708J
Abstract: An efficient surface modification and bioconjugation strategy for upconversion nanoparticles is reported via supramolecular host–guest self-assembly.
Publisher: MDPI AG
Date: 28-05-2023
DOI: 10.3390/MOLECULES28114396
Abstract: Acacia saligna is native to Western Australia. It has become an introduced and fast-growing plant in other parts of the world due to its ability to adapt to drought, saline and alkaline soils, and hast growing environments. Studies on the bioactivities and phytochemicals of the plant extracts were conducted. However, comprehensive information that links those bioactivities to the identified compounds in the plant’s extracts is still lacking. Data gathered in this review revealed a rich chemical ersity of hydroxybenzoic acids, cinnamic acids, flavonoids, saponins, and pinitols in A. saligna growing in Egypt, Saudi Arabia, Tunisia, South Africa, and Australia. The variability in phytochemical composition and quantity could be attributed to plant parts, growing locations, extraction solvents, and analysis methods. Identified phytochemicals support observed biological activities such as antioxidant, antimicrobial, anticancer, α-glucosidase inhibition, and anti-inflammation in the extracts. The knowledge of chemical structures, biological activities, and possible mechanisms of action of the bioactive phytochemicals identified in A. saligna were discussed. In addition, the structure–activity relationships of dominant active compounds were examined to explain the bioactivities exerted by A. saligna extracts. The review provides valuable insights towards future research and the development of new therapeutics from this plant.
Publisher: Springer Science and Business Media LLC
Date: 12-2016
Publisher: SAGE Publications
Date: 08-2017
DOI: 10.1177/1934578X1701200848
Abstract: This report is an overview of our research on phytochemical, synthetic and biological studies of the Stemona and Stichoneuron species of plants.
Publisher: Springer Science and Business Media LLC
Date: 21-07-2022
Publisher: American Chemical Society (ACS)
Date: 23-04-2010
DOI: 10.1021/NP100137H
Abstract: Semisynthesis of the known Stemona alkaloids oxystemofoline (7) and methoxystemofoline (8) has been achieved starting from (11Z)-1',2'-didehydrostemofoline (6), which confirmed their structures and absolute configurations. The synthesis of (1'R)-hydroxystemofoline (9) helped establish this compound as a natural product from Stemona aphylla. (1'S)-Hydroxystemofoline (10) and a number of related analogues were also prepared. In a TLC bioautographic assay, 9 was found to be the most active acetylcholinesterase inhibitor, but it was not as active as galanthamine.
Publisher: American Chemical Society (ACS)
Date: 03-07-2019
DOI: 10.1021/ACSINFECDIS.9B00055
Abstract: The disturbing increase in the number of bacterial pathogens that are resistant to multiple, or sometimes all, current antibiotics highlights the desperate need to pursue the discovery and development of novel classes of antibacterials. The wealth of knowledge available about the bacterial cell ision machinery has aided target-driven approaches to identify new inhibitor compounds. The main ision target being pursued is the highly conserved and essential protein FtsZ. Despite very active research on FtsZ inhibitors for several years, this protein is not yet targeted by any commercial antibiotic. Here, we discuss the suitability of FtsZ as an antibacterial target for drug development and review progress achieved in this area. We use hindsight to highlight the gaps that have slowed progress in FtsZ inhibitor development and to suggest guidelines for concluding that FtsZ is actually the target of these molecules, a key missing link in several studies. In moving forward, a multidisciplinary, communicative, and collaborative process, with sharing of research expertise, is critical if we are to succeed.
Publisher: American Chemical Society (ACS)
Date: 30-01-2009
DOI: 10.1021/NP800755P
Abstract: Semisynthesis studies starting from (11Z)-1',2'-didehydrostemofoline (4) indicated that the known Stemona alkaloid stemoburkilline is the Z-isomer and not the E-isomer as initially reported. The semisynthesis involved conversion of (11Z)-1',2'-didehydrostemofoline (4) to 11(S),12(S)-dihydrostemofoline (3) followed by a stereoselective base-catalyzed ring-opening reaction to give (Z)-stemoburkilline (8). The same product was obtained using a similar synthetic protocol starting from isostemofoline (6) via a based-catalyzed ring-opening reaction of 11(S),12(R)-dihydrostemofoline (1). A re-examination of the crude root extracts of Stemona burkillii Prain and further NOE studies established stemoburkilline as the Z-isomer (8).
Publisher: MDPI AG
Date: 19-01-2023
DOI: 10.3390/MOLECULES28031028
Abstract: Acacia saligna growing in Australia has not been fully investigated for its bioactive phytochemicals. Sequential polarity-based extraction was employed to provide four different extracts from in idual parts of A. saligna. Bioactive extracts were determined using in vitro antioxidant and yeast α-glucosidase inhibitory assays. Methanolic extracts from barks, leaves, and flowers are the most active and have no toxicity against 3T3-L1 adipocytes. Compound isolation of bioactive extracts provided us with ten compounds. Among them are two novel natural products naringenin-7-O-α-L-arabinopyranoside 2 and (3S*,5S*)-3-hydroxy-5-(2-aminoethyl) dihydrofuran-2(3H)-one 9. D-(+)-pinitol 5a (from barks and flowers), (−)-pinitol 5b (exclusively from leaf), and 2,4-di-t-butylphenol 7 are known natural products and new to A. saligna. (−)-Epicatechin 6, quercitrin 4, and myricitrin 8 showed potent antioxidant activities consistently in DPPH and ABTS assays. (−)-Epicatechin 6 (IC50 = 63.58 μM),D-(+)-pinitol 5a (IC50 = 74.69 μM), and naringenin 1 (IC50 = 89.71 μM) are the strong inhibitors against the α-glucosidase enzyme. The presence of these compounds supports the activities exerted in our methanolic extracts. The presence of 2,4-di-t-butylphenol 7 may support the reported allelopathic and antifungal activities. The outcome of this study indicates the potential of Australian A. saligna as a rich source of bioactive compounds for drug discovery targeting type 2 diabetes.
Publisher: Elsevier BV
Date: 1993
Publisher: Georg Thieme Verlag KG
Date: 03-1998
DOI: 10.1055/S-1998-1626
Publisher: Elsevier BV
Date: 03-2021
Publisher: Elsevier BV
Date: 08-2014
Publisher: Pharmaceutical Society of Japan
Date: 2013
Abstract: Resistance to chemotherapy in cancer patients has been correlated to the overexpression of the ATP-binding cassette (ABC) drug transporters including P-glycoprotein (P-gp) that actively efflux chemotherapeutic drugs from cancer cells. We examined the multidrug resistance reversing property of stemofoline derivatives in drug-resistance human cervical carcinoma (KB-V1) and human leukemic (K562/Adr) cell lines that overexpress P-gp. Didehydrostemofoline and eleven of its derivatives were synthesized and the cytotoxicity and their effect on doxorubicin, vinblastine and paclitaxel sensitivity in drug resistant (KB-V1 and K562/Adr) and drug sensitive (KB-3-1 and K562) cell lines by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay were determined. We found that three out of the twelve stemofoline derivatives including OH-A1, NH-B6 and NH-D6 showed commitment efficiency to increase sensitivity to doxorubicin, vinblastine and paclitaxel in KB-V1 cells and increase sensitivity to doxorubicin, and paclitaxel in K562/Adr cells whereas the effects have not been seen in their parental sensitive cancer cell lines (KB-3-1 and K562). These results indicate that stemofoline derivatives reversed P-gp-mediated multidrug resistance in vitro, and thus could be developed as effective chemosensitizers to treat multidrug-resistant cancers. The molecular mechanism of modulation of P-gp would be further determined.
Publisher: CSIRO Publishing
Date: 1989
DOI: 10.1071/CH9891929
Abstract: 2,6-Dimethylenebicyclo[3.3.1] nonane (1) and acetonitrile react under Ritter reaction conditions to produce exo-ll-acetamido-2,4,endo-ll-trimethyl-3-azatricyclo[5.3.1.04,9 ]undec-2-ene (2)monohydrate whose crystal structure [C15H24N2O.H2O, P 21, a 8.21 3(3), b lO.84l(l),c 8.234(2) �, β 95. 57(2)�, Z 2] was determined with a final R 0.036. The diene (1) reacts similarly with benzonitrile to produce the phenyl-substituted analogue (3). In contrast, the reaction of (1) and benzyl cyanide yields a different type of product, 2-benzoyl-4,endo11-dimethyl-exo-11-phenylacetamido-3-azatricyco[5.3.1.04,9]undec-2-ene (5a), where one of the two nitrile -derived groups has undergone spontaneous oxidation during the one-flask preparation. p- Bromo - and p- chloro-benzyl cyanides behave in a similar manner yielding the adducts (5b,c) respectively.
Publisher: Elsevier BV
Date: 04-1998
Publisher: American Chemical Society (ACS)
Date: 28-08-2004
DOI: 10.1021/NP049791Z
Abstract: Two new dihydrostemofoline alkaloids, 11(S),12(R)-dihydrostemofoline (3) and stemoburkilline (4), along with stemofoline (1) and 2'-hydroxystemofoline (2) have been isolated from a root extract of Stemona burkillii Prain. The structure and relative configuration of 3 have been determined via spectroscopic data and from comparison with synthetic 11(S),12(S)-dihydrostemofoline (5). The configuration of the exo-cyclic alkene group in 4 is tentively assigned as E on the basis of mechanistic considerations.
Publisher: MDPI AG
Date: 15-10-2020
DOI: 10.3390/IJMS21207640
Abstract: Current therapeutic options for obesity often require pharmacological intervention with dietary restrictions. Obesity is associated with underlying inflammation due to increased tissue macrophage infiltration, and recent evidence shows that inflammation can drive obesity, creating a feed forward mechanism. Therefore, targeting obesity-induced macrophage infiltration may be an effective way of treating obesity. Here, we developed cargo-less liposomes (UTS-001) using 1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC (synthetic phosphatidylcholine) as a single-agent to manage weight gain and related glucose disorders due to high fat diet (HFD) consumption in mice. UTS-001 displayed potent immunomodulatory properties, including reducing resident macrophage number in both fat and liver, downregulating liver markers involved in gluconeogenesis, and increasing marker involved in thermogenesis. As a result, UTS-001 significantly enhanced systemic glucose tolerance in vivo and insulin-stimulated cellular glucose uptake in vitro, as well as reducing fat accumulation upon ad libitum HFD consumption in mice. UTS-001 targets tissue residence macrophages to suppress tissue inflammation during HFD-induced obesity, resulting in improved weight control and glucose metabolism. Thus, UTS-001 represents a promising therapeutic strategy for body weight management and glycaemic control.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 2007
Publisher: Wiley
Date: 03-06-2014
DOI: 10.1002/RCM.6935
Abstract: Pyridinium chlorochromate (PCC) is the active ingredient of 'Urine Luck', a commercially available in vitro adulterating agent used to conceal the presence of drugs in a urine specimen. The exposure of codeine and its major glucuronide metabolite codeine-6-glucuronide (C6G) to PCC was investigated to determine whether PCC is an effective masking agent for these opiate compounds. Following the addition of PCC to both spiked and authentic codeine and C6G-positive urine specimens, the s les were monitored using liquid chromatography/mass spectrometry (LC/MS). Stable reaction products were identified and characterized using high-resolution MS analysis and, where possible, nuclear magnetic resonance (NMR) analysis. It was determined that PCC effectively oxidizes codeine and C6G, thus altering the original codeine-to-C6G ratio in the urine specimen. Four reaction products were identified for codeine: codeinone, 14-hydroxycodeinone, 6-O-methylcodeine and 8-hydroxy-7,8-dihydrocodeinone. Similarly, three reaction products were identified for C6G: codeinone, codeine and a lactone of C6G (tentative assignment). Besides addressing the complications added to interpretation, more investigation is warranted to further determine their potential for use as markers for monitoring the presence of codeine and C6G in urine specimens adulterated with PCC.
Publisher: Royal Society of Chemistry (RSC)
Date: 1992
DOI: 10.1039/P29920000861
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A903675J
Publisher: Wiley
Date: 24-10-2014
DOI: 10.1111/BCPT.12331
Abstract: Our previous study reported multi-drug resistance (MDR) reversing properties of synthetic stemofoline derivatives (STFD), OH-A1, NH-B6 and NH-D6 on P-glycoprotein (P-gp) overexpressing leukaemic cells (K562/Adr) however, the mechanism was unclear. In this study, we further investigated whether the STFD reverse MDR through either the inhibition of P-gp function or expression in K562/Adr cells, or both. The P-gp functional studies showed that the STFD increased the accumulation of calcein-AM, rhodamine 123 and [(14) C]-doxorubicin in K562/Adr cells, while the effects have not been seen in their parental sensitive cancer cell line (K562). Further, the STFD did not alter the P-gp expression as determined by Western blotting. This study concludes that the STFD reverse MDR via the inhibition of P-gp function. The efficacy of the STFD to inhibit P-gp function followed the order: NH-B6 > OH-A1 > NH-D6. These compounds could be introduced as candidate molecules for treating cancers exhibiting P-gp-mediated MDR.
Publisher: Elsevier BV
Date: 2009
Publisher: American Chemical Society (ACS)
Date: 02-03-2004
DOI: 10.1021/NP034066U
Abstract: A new pentacyclic Stemona alkaloid, stemocurtisinol (3), with a pyrido[1,2-a]azepine A,B-ring system, and the known pyrrolo[1,2-a]azepine alkaloid oxyprotostemonine (4) have been isolated from a root extract of S. curtisii. The structure and relative stereochemistry of stemocurtisinol was determined by spectral data interpretation and X-ray crystallography. This compound is a diastereoisomer of oxystemokerrin and has the opposite configuration at C-4 and C-19. The in idual alkaloid components showed significant larvicidal activity (IC(50) 4-39 ppm) on mosquito larvae (Anopheles minimus HO).
Publisher: Elsevier BV
Date: 10-1996
Publisher: Informa UK Limited
Date: 03-1996
Publisher: Springer Science and Business Media LLC
Date: 12-2019
DOI: 10.1186/S12906-019-2766-3
Abstract: Acquired immunodeficiency syndrome (AIDS) is caused by the Human immunodeficiency virus type-1 (HIV-1). HIV-1 protease (HIV-1 PR) is an essential enzyme for the HIV replication, and therefore, it is an important target for antiretroviral drugs development, particularly from natural products. Auricularia polytricha (AP) is an edible mushroom with several important therapeutic properties. These properties will be investigated as HIV-1 PR inhibitors. The sequential hexane (APH), ethanol (APE) and water (APW) extracts from AP were screened for inhibitory activity against HIV-1 PR. The extract that consistently showed the strong HIV-1 PR inhibition was further investigated for its phytochemical constituents. The compounds were purified by column chromatography. The isolated compounds were structurally elucidated using 1D and 2D NMR, HRMS, FTIR, and GC/MS techniques. Each compound was screened against HIV-1 PR to determine its inhibitory activity and to provide an explanation for the activity found in the extract. Hexane crude extract of AP (APH) exhibited significant inhibition on HIV-1 PR activity. Four major compounds isolated from APH fraction were identified to be two triacylglycerols, linoleic acid and ergosterol. Moreover, all four compounds showed significant inhibition of HIV-1 PR activity. The findings from this study suggest that AP is a good source of fatty esters, fatty acids and ergosterol. These natural products exhibit anti-HIV-1 properties by blocking HIV-1 PR. These important biological results warrant further development of AP as an alternative antiretroviral drug.
Publisher: Science Alert
Date: 15-10-2012
Publisher: IOP Publishing
Date: 11-01-2012
DOI: 10.1088/0957-4484/23/5/055402
Abstract: Hollow structured CoFe₂O₄ nanospheres were synthesized by a hydrothermal method. The uniform hollow nanosphere architecture of the as-prepared CoFe₂O₄ has been confirmed by field emission scanning electron microscopy and transmission electron microscopy analysis, which give an outer diameter of 200-300 nm and a wall thickness of about 100 nm. CoFe₂O₄ nanospheres exhibited a high reversible capacity of 1266 mA h g⁻¹ with an excellent capacity retention of 93.6% over 50 cycles and an improved rate capability. CoFe₂O₄ could be a promising high capacity anode material for lithium ion batteries.
Publisher: Springer Science and Business Media LLC
Date: 29-08-2016
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/CH17270
Abstract: The reaction of (–)-β-pinene with KCN under a mild bridged Ritter reaction gave (1S,5R,6S)-2,2,6-trimethyl-3-aza-bicyclo[3.3.1]non-3-en-6-yl acetate that subsequently reacted to provide an unexpected (1S,4R,5R,6S)-4-cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonane-6-yl acetate. The structure of the compound was determined by high-resolution mass spectrometry, and IR and NMR spectroscopy and confirmed by single crystal X-ray crystallography. The compound crystallises in the monoclinic P21 space group, with unit cell parameters a 8.6120 (17), b 7.4570 (15), c 11.189 (2) Å, and β 110.16 (3)°.
Publisher: MDPI AG
Date: 29-09-2021
DOI: 10.3390/PH14101001
Abstract: Oxidative stress is associated with several diseases, particularly neurodegenerative diseases, commonly found in the elderly. The attenuation of oxidative status is one of the alternatives for neuroprotection and anti-aging. Auricularia polytricha (AP), an edible mushroom, contains many therapeutic properties, including antioxidant properties. Herein, we report the effects of AP extracts on antioxidant, neuroprotective, and anti-aging activities. The neuroprotective effect of AP extracts against glutamate-induced HT-22 neuronal damage was determined by evaluating the cytotoxicity, intracellular reactive oxygen species (ROS) accumulation, and expression of antioxidant enzyme genes. Lifespan and healthspan assays were performed to examine the effects of AP extracts from Caenorhabditis elegans. We found that ethanolic extract (APE) attenuated glutamate-induced HT-22 cytotoxicity and increased the expression of antioxidant enzyme genes. Moreover, APE promoted in the longevity and health of the C. elegans. Chemical analysis of the extracts revealed that APE contains the highest quantity of flavonoids and a reasonable percentage of phenols. The lipophilic compounds in APE were identified by gas chromatography/mass spectrometry (GC/MS), revealing that APE mainly contains linoleic acid. Interestingly, linoleic acid suppressed neuronal toxicity and ROS accumulation from glutamate induction. These results indicate that AP could be an exciting natural source that may potentially serves as neuroprotective and anti-aging agents.
Publisher: American Chemical Society (ACS)
Date: 12-11-2005
DOI: 10.1021/NP050361Y
Abstract: Six new stemofoline alkaloids, (2'R)-hydroxystemofoline (5), (3'R)-stemofolenol (6), (3'S)-stemofolenol (7), 1',2'-didehydrostemofoline-N-oxide (8), the first C(19) stemofoline alkaloid, methylstemofoline (9), and the first glycosidated Stemona alkaloid, stemofolinoside (10), and three known alkaloids, (2'S)-hydroxystemofoline (2), (11Z)-1',2'-didehydrostemofoline (3), and (11E)-1',2'-didehydrostemofoline (4), have been isolated from a root extract of an unidentified Stemona species. The structure and relative configuration of these new alkaloids have been determined by spectral data interpretation and from semisynthetic studies.
Publisher: Springer Science and Business Media LLC
Date: 17-02-2011
Publisher: American Chemical Society (ACS)
Date: 08-1995
DOI: 10.1021/JA00139A007
Publisher: Elsevier BV
Date: 03-2013
Publisher: American Chemical Society (ACS)
Date: 04-11-2010
DOI: 10.1021/NP100474Y
Abstract: The isolation of two new Stemona alkaloids, 1-hydroxyprotostemonine and stemocurtisine N-oxide, and a new benzofuran, stemofuran L, from the root extracts of Stemona curtisii is reported. The major known alkaloids from this plant extract, stemocurtisine, stemocurtisinol, and oxyprotostemonine, were also isolated along with oxystemokerrine N-oxide. The nonalkaloid components of this extract included a new benzofuran derivative, stemofuran L, the known stemofurans F, J, and K, dihydro-γ-tocopherol, and stigmasterol. Stemocurtisine and stemocurtisinol were converted to their respective N-oxides by oxidation. Stemocurtisine was converted to a tetracyclic derivative by oxidative cleavage of the γ-butyrolactone ring, while stemocurtisinol gave a novel lactam derivative by oxidative cleavage of the C-4 side chain under basic conditions. The acetylcholinesterase inhibitory activities of some known and new alkaloids and their derivatives are also reported. All were 10-20 times less active as acetylcholinesterase inhibitors than the pyrrolo[1,2-a]azepine Stemona alkaloids stemofoline and 1',2'-didehydrostemofoline. None of the stemofuran compounds showed significant antibacterial or antifungal activities.
Publisher: Elsevier BV
Date: 11-2007
Publisher: Elsevier BV
Date: 08-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9MD00237E
Abstract: Tricyclic amides were successfully synthesised from β-caryophyllene via the Ritter reaction. Amides 3c and 6b inhibited proliferation of MDA-MB-231 cells. Compound 6b inhibited cell cycle progression and induced predominantly apoptotic cell death.
Publisher: CSIRO Publishing
Date: 21-11-2018
DOI: 10.1071/CH18347
Abstract: The bacterial cell ision protein FtsZ is conserved in most bacteria and essential for viability. There have been concerted efforts in developing inhibitors that target FtsZ as potential antibiotics. Key to this is an in-depth understanding of FtsZ structure at the molecular level across erse bacterial species to ensure inhibitors have high affinity for the FtsZ target in a variety of clinically relevant pathogens. In this study, we show that FtsZ structures differ in three ways: (1) the H7 helix curvature (2) the dimensions of the interdomain cleft and (3) the opening/closing mechanism of the interdomain cleft, whereas no differences were observed in the dimensions of the nucleotide-binding pocket and T7 loop. Molecular dynamics simulation may suggest that there are two possible mechanisms for the process of opening and closing of the interdomain cleft on FtsZ structures. This discovery highlights significant differences between FtsZ structures at the molecular level and this knowledge is vital in assisting the design of potent FtsZ inhibitors.
Publisher: Elsevier BV
Date: 06-2007
Publisher: Elsevier BV
Date: 11-2007
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/CH16565
Abstract: The poorly soluble racemic compound 6,6a,13,13a-tetrahydropentaleno[1,2-b:4,5-b′]diquinoline (4) has an exceptionally high melting point range of 352–354°C despite its low molar mass (308.38) and a structure containing only 40 atoms (38 of which are C and H). Analysis of the X-ray crystal structure and Hirshfeld surface of 4, along with comparison with its isostructural homologue 2, reveals how this occurs in the absence of Pauling-type hydrogen bonding. Excellent complementarity between homochiral molecules of 4 allows formation of enantiomerically pure layers using C–H⋯π, aromatic π⋯π, and C–H⋯N interactions. The alternating layers of opposite handedness are then crosslinked by means of aza-1,3-peri hydrogen interactions. This bifurcated C–H⋯N⋯H–C motif acts as a molecular clip creating a highly rigid network structure. The role of weaker intermolecular forces in influencing the solubility and bioavailability of potential drug molecules is discussed in the context of the popular Lipinski ‘rule of 5’ guidelines.
Publisher: Elsevier BV
Date: 11-2007
Publisher: Elsevier BV
Date: 02-2005
Publisher: American Chemical Society (ACS)
Date: 08-1994
DOI: 10.1021/CM00044A026
Publisher: Springer Science and Business Media LLC
Date: 03-08-2022
Publisher: Springer Science and Business Media LLC
Date: 09-1999
DOI: 10.1007/BF02903443
Publisher: International Union of Crystallography (IUCr)
Date: 18-07-2009
Publisher: Springer Science and Business Media LLC
Date: 24-07-2018
Publisher: Elsevier BV
Date: 2012
Publisher: American Chemical Society (ACS)
Date: 11-06-2003
DOI: 10.1021/NP020612S
Abstract: A new pentacyclic stemona alkaloid, stemocurtisine (2), with a novel pyrido[1,2-a]azapine A,B-ring system, has been isolated from a root extract of Stemona curtisii. The structure and relative stereochemistry was determined by spectral data interpretation and X-ray crystallography.
Publisher: Elsevier BV
Date: 06-2010
Publisher: Elsevier BV
Date: 10-2021
DOI: 10.1016/J.BMC.2021.116401
Abstract: The emergence of multi-drug resistant bacteria has increased the need for novel antibiotics to help overcome what may be considered the greatest threat to modern medicine. Here we report the synthesis of fifteen novel 3,5-diaryl-1H- pyrazoles obtained via one-pot cyclic oxidation of a chalcone and hydrazine-monohydrate. The synthesised pyrazoles were then screened against Staphylococcus aureus and Escherichia coli to determine their antibacterial potential. The results show that compound 7p is bacteriostatic at MIC 8 µg/mL. The compound is non-toxic against healthy mammalian cells, 3T3-L1 at the highest test concentration 50 µg/mL. Furthermore, compound 7p significantly affected bacterial morphogenesis before cell lysis in Bacillus subtilis when treated above the MIC concentration. From the results, a promising lead compound was identified for future development.
Publisher: American Chemical Society (ACS)
Date: 30-11-2001
DOI: 10.1021/JO010864I
Abstract: An efficient method for preparing conformationally restricted cyclopentenyl-glutamate analogues in a regioselective and diastereoselective manner has been developed using a formal [3 + 2] cycloaddition reaction of dehydroamino acids. Methods for preparing optically active versions of these compounds have also been devised. Of these compounds, (S)-2 is an agonist at the mGlu5 (EC(50) 18 microM) and mGlu2 (EC(50) 45 microM) receptors.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Springer Science and Business Media LLC
Date: 31-03-2021
Publisher: Wiley
Date: 28-11-2015
Abstract: A mesoporous flake-like manganese-cobalt composite oxide (MnCo2O4) is synthesized successfully through the hydrothermal method. The crystalline phase and morphology of the materials are characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller methods. The flake-like MnCo2O4 is evaluated as the anode material for lithium-ion batteries. Owing to its mesoporous nature, it exhibits a high reversible capacity of 1066 mA h g(-1), good rate capability, and superior cycling stability. As an electrode material for supercapacitors, the flake-like MnCo2O4 also demonstrates a high supercapacitance of 1487 F g(-1) at a current density of 1 A g(-1), and an exceptional cycling performance over 2000 charge/discharge cycles.
Publisher: Royal Society of Chemistry (RSC)
Date: 1991
DOI: 10.1039/C39910001012
Publisher: American Chemical Society (ACS)
Date: 02-12-2010
DOI: 10.1021/NP100668S
Abstract: A new stemofoline alkaloid, (2'S)-hydroxy-(11S,12R)-dihydrostemofoline (3), new stemofurans M-R (8-13), and known compounds stemofoline (1), (2'S)-hydroxystemofoline (2), stemofuran E (4), stemofuran F (5), stemofuran J (6), and stilbostemin F (7) have been isolated from the root extracts of Stemona aphylla. The structures and relative configurations of these new compounds have been determined by spectroscopic data interpretation and from semisynthetic studies. These natural and semisynthetic alkaloids were tested for acetylcholinesterase inhibitory activities and were found to be 10-20 times less active than 1',2'-didehydrostemofoline itself. Stemofurans 4, 6, 8, 11, and 13 were tested for their antibacterial and antifungal activities. Three of these showed antibacterial activities against MRSA with MIC values of 15.6 μg/mL.
Publisher: SAGE Publications
Date: 10-2006
DOI: 10.1177/1934578X0600101001
Abstract: Two new tuberostemonine alkaloids, tuberostemonine L (3) and tuberostemonine M (4) and a new stemofoline alkaloid, (3′S)-hydroxystemofoline (5), along with two known alkaloids, (2′S)-hydroxystemofoline (1) and neotuberostemonine (2) have been isolated from a root extract of an unidentified Stemona species (Stemona sp.). The structure and relative configuration of these new alkaloids has been determined by spectral data interpretation, while the 3′S configuration of 5 was determined from NMR analysis of its (R)- and (S)-Mosher esters.
Publisher: Beilstein Institut
Date: 19-06-2019
DOI: 10.3762/BJOC.15.134
Abstract: The one-pot reaction of 2,6-bis(diphenylmethyl)-4-methoxyaniline with tert -butylnitrite, BTEAC and DABSO in the presence of CuCl 2 provided an unexpected 3 H -indazole product 8 . The structure of the compound was determined by HRMS, IR, NMR and further confirmed by single crystal X-ray crystallography. The compound crystallises in the triclinic P -1 space group, with unit cell parameters a = 9.2107 (4), b = 10.0413 (5), c = 14.4363 (6) Å, α = 78.183 (2), β = 87.625 (2), γ = 71.975 (2)°. The formation of 8 proceeded through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate 9 . The molecules of 8 are organised by edge–face Ar–H···π, face–face π···π, and bifurcated OCH 2 –H···N interactions. In addition to these, there are Ar–H···H–Ar close contacts, (edge–edge and surrounding inversion centres) arranged as infinite tapes along the a direction.
Publisher: Informa UK Limited
Date: 1992
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7MD00435D
Abstract: Tricyclic alkaloid-like compounds were synthesised in a few steps, via the bridging Ritter reaction.
Publisher: MDPI AG
Date: 15-05-2023
DOI: 10.3390/APPLIEDCHEM3020016
Abstract: Novel SF5-bearing maleimide and acrylamide derivatives were synthesised as potential [18F]radio-prosthetic groups for radiolabelling peptides and proteins. The efficacy of selected prosthetic groups was first assessed through bioconjugation with protected model amino acid derivatives. These reactions were investigated on an analytical scale via LC-MS across a pH range to quantitatively evaluate this prosthetic group’s reactivity and stability. Model bioconjugate reactions were then replicated using analogous para-substituted derivatives to determine the influence of the electronic effects of -SF5. Finally, the SF5-bearing prosthetic groups were utilised for bioconjugation with cancer-targeting c-RGD peptides. N-aryl maleimides reacted extremely efficiently with the model amino acid N-acetyl-L-cysteine. The subsequent conjugates were obtained as regio-isomeric mixtures of the corresponding thio-succinamic acids in yields of 80–96%. Monitoring the bioconjugate reaction by LC-MS revealed that ring hydrolysis of the intermediate SF5–thio-succinimide conjugate occurred instantaneously, an advantageous quality in minimising undesirable thiol exchange reactions with non-targeted cysteine residues. In contrast, N-aryl acrylamides demonstrated poor solubility in semi-aqueous media ( mM). In turn, synthetic-scale model bioconjugations with Nα-acetyl-L-lysine were performed in methanol, affording the corresponding acrylamide conjugates in modest to high yield (58–89%). Including electron-deficient, fluorinated prosthetic groups for bioconjugation will broaden their applicability within the fields of 19F-MRI and PET imaging.
Publisher: Elsevier BV
Date: 2017
Publisher: Frontiers Media SA
Date: 10-06-2013
DOI: 10.18433/J3989X
Abstract: Intercellular communication is essential to maintain vital physiological activities and to regulate the organism’s phenotype. There are a number of ways in which cells communicate with one another. This can occur via autocrine signaling, endocrine signaling or by the transfer of molecular mediators across gap junctions. More recently communication via microvesicular shedding has gained important recognition as a significant pathway by which cells can coordinate the spread and dominance of selective traits within a population. Through this communication apparatus, cells can now acquire and secure a survival advantage, particularly in the context of malignant disease. This review aims to highlight some of the functions and implications of microparticles in physiology of various disease states, and present a novel therapeutic strategy through the regulation of microparticle production. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.
Publisher: Royal Society of Chemistry (RSC)
Date: 1993
DOI: 10.1039/C39930000322
Publisher: Springer Science and Business Media LLC
Date: 18-04-2012
Location: Iran (Islamic Republic of)
Start Date: 2008
End Date: 10-2011
Amount: $359,000.00
Funder: Australian Research Council
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