10 research outputs found
Analytical and Structural Tools of Lipid Hydroperoxides: Present State and Future Perspectives
Mono- and polyunsaturated lipids are particularly susceptible to peroxidation, which results in the formation of lipid hydroperoxides (LOOHs) as primary nonradical-reaction products. LOOHs may undergo degradation to various products that have been implicated in vital biological reactions, and thus in the pathogenesis of various diseases. The structure elucidation and qualitative and quantitative analysis of lipid hydroperoxides are therefore of great importance. The objectives of the present review are to provide a critical analysis of various methods that have been widely applied, and more specifically on volumetric methods, applications of UV-visible, infrared, Raman/surface-enhanced Raman, fluorescence and chemiluminescence spectroscopies, chromatographic methods, hyphenated MS techniques, NMR and chromatographic methods, NMR spectroscopy in mixture analysis, structural investigations based on quantum chemical calculations of NMR parameters, applications in living cells, and metabolomics. Emphasis will be given to analytical and structural methods that can contribute significantly to the molecular basis of the chemical process involved in the formation of lipid hydroperoxides without the need for the isolation of the individual components. Furthermore, future developments in the field will be discussed
Structural Basis of Artemisinin Binding Sites in Serum Albumin with the Combined Use of NMR and Docking Calculations
Artemisinin is known to bind to the main plasma protein carrier serum albumin (SA); however, there are no atomic level structural data regarding its binding mode with serum albumin. Herein, we employed a combined strategy of saturation transfer difference (STD), transfer nuclear Overhauser effect spectroscopy (TR-NOESY), STDātotal correlation spectroscopy (STD-TOCSY), and Interligand Noes for PHArmacophore Mapping (INPHARMA) NMR methods and molecular docking calculations to investigate the structural basis of the interaction of artemisinin with human and bovine serum albumin (HSA/BSA). A significant number of inter-ligand NOEs between artemisinin and the drugs warfarin and ibuprofen as well as docking calculations were interpreted in terms of competitive binding modes of artemisinin in the warfarin (FA7) and ibuprofen (FA4) binding sites. STD NMR experiments demonstrate that artemisinin is the main analyte for the interaction of the A. annua extract with BSA. The combined strategy of NMR and docking calculations of the present work could be of general interest in the identification of the molecular basis of the interactions of natural products with their receptors even within a complex crude extract
Exploration of the Antiplatelet Activity Profile of Betulinic Acid on Human Platelets
Betulinic acid, a natural pentacyclic triterpene acid, presents a diverse mode of biological actions including antiretroviral, antibacterial, antimalarial, and anti-inflammatory activities. The potency of betulinic acid as an inhibitor of human platelet activation was evaluated, and its antiplatelet profile against in vitro platelet aggregation, induced by several platelet agonists (adenosine diphosphate, thrombin receptor activator peptide-14, and arachidonic acid), was explored. Flow cytometric analysis was performed to examine the effect of betulinic acid on P-selectin membrane expression and PAC-1 binding to activated platelets. Betulinic acid potently inhibits platelet aggregation and also reduced PAC-1 binding and the membrane expression of P-selectin. Principal component analysis was used to screen, on the chemical property space, for potential common pharmacophores of betulinic acid with approved antithrombotic drugs. A common pharmacophore was defined between the NMR-derived structure of betulinic acid and prostacyclin agonists (PGI2), and the importance of its carboxylate group in its antiplatelet activity was determined. The present results indicate that betulinic acid has potential use as an antithrombotic compound and suggest that the mechanism underlying the antiplatelet effects of betulinic acid is similar to that of the PGI2 receptor agonists, a hypothesis that deserves further investigation.Esthir Gkani Foundation (Ioannina, Greece)Esthir Gkani Foundation (Ioannina, Greece)Regional Operational Programme of Thessaly-Mainland Greece-Epirus Research and Technological Development in the Region of Epirus Research Program "New Knowledge"Regional Operational Programme of ThessalyMainland GreeceEpirus Research and Technological Development in the Region of Epirus Research Program New Knowledg
Ethyl Acetate Extract of Origanum vulgare L. ssp. hirtum Prevents Streptozotocin-Induced Diabetes in C57BL/6 Mice
Type 1 diabetes (T1D) is an autoimmune disease that develops as a consequence of pancreatic Ī²-cell death induced by proinflammatory mediators. Because Origanum vulgare L. ssp. hirtum (Greek oregano) contains antiinflammatory molecules, we hypothesized that it might be beneficial for the treatment of T1D. An ethyl acetate extract of oregano (EAO) was prepared from the leaves by a polar extraction method. Phytochemical composition was determined by liquid chromatography-UV diode array coupled to ion-trap mass spectrometry with electrospray ionization interface (LC/DAD/ESI-MSn). In vitro immunomodulatory effect of EAO was estimated by measuring proliferation (MTT) or cytokine secretion (ELISA) from immune cells. Diabetes was induced by multiple low doses of streptozotocin (MLDS) in male C57BL/6 mice and EAO was administered intraperitoneally for 10 d. Determination of cellular composition (flow cytometry) and cytokine production (ELISA) was performed on 12th d after diabetes induction. EAO suppressed the function of both macrophages and lymphocytes in vitro. In vivo, EAO treatment significantly preserved pancreatic islets and reduced diabetes incidence in MLDS-challenged mice. Besides down-modulatory effect on macrophages, EAO reduced the number of total CD4+ and activated CD4+CD25+ T cells. Furthermore, EAO affected the number of T helper 1 (Th1) and T helper 17 (Th17) cells through downregulation of their key transcription factors T-bet and RORĪ³T. Because EAO treatment protects mice from development of hyperglycemia by reducing proinflammatory macrophage/Th1/Th17 response, this plant extract could represent a basis for future diabetes therapy
Methanolic extract of Origanum vulgare ameliorates type 1 diabetes through antioxidant, anti-inflammatory and anti-apoptotic activity
Type 1 diabetes (T1D), an autoimmune inflammatory disorder, develops as
a consequence of pancreatic beta-cell destruction and results in
hyperglycaemia. Since current T1D therapy mainly involves insulin
replacement, the aim of the present study was to evaluate the
therapeutic potential of Origanum vulgare L. ssp. hirtum (Greek oregano)
leaf extract rich in biophenols for the treatment of T1D. The
phytochemical profile of methanolic oregano extract (MOE) and aqueous
oregano extract (AOE) was determined by liquid
chromatography/electrospray ion-trap tandem MS (LC/DAD/ESI-MSn), while
their main compounds were quantified by HPLC with diode array detection.
After establishing their potent in vitro antioxidant activity, the
extracts were administered to C57BL/6 mice treated with multiple low
doses of streptozotocin for diabetes induction. While prophylactic AOE
therapy had no impact on diabetes induction, MOE reduced diabetes
incidence and preserved normal insulin secretion. In addition, MOE
scavenged reactive oxygen and nitrogen species and, therefore,
alleviated the need for the up-regulation of antioxidant enzymes. MOE
treatment specifically attenuated the pro-inflammatory response mediated
by T helper 17 cells and enhanced anti-inflammatory T helper 2 and T
regulatory cells through the impact on specific signalling pathways and
transcription factors. Importantly, MOE preserved beta-cells from in
vitro apoptosis via blockade of caspase 3. Finally, rosmarinic acid, a
predominant compound in MOE, exhibited only partial protection from
diabetes induction. In conclusion, acting as an antioxidant,
immunomodulator and in an anti-apoptotic manner, MOE protected mice from
diabetes development. Seemingly, there is more than one compound
responsible for the beneficial effect of MOE.Ministry of Education, Science and Technological Development, Republic
of Serbia {[}173013]; European Union; Greek National Funds Through the
Operational Program `THESSALY-MAINLAND GREECE AND EPIRUS' of the
National Strategic Reference Framework (NSRF); Greek national funds
through the Operational Program `Education and Lifelong Learning' of the
National Strategic Reference Framework (NSRF)-Research Funding Program:
ARISTEIA II, Investing in knowledge society through the European Social
Fun
Exploration of the Antiplatelet Activity Profile of Betulinic Acid on Human Platelets
Betulinic acid, a natural pentacyclic triterpene acid,
presents
a diverse mode of biological actions including antiretroviral, antibacterial,
antimalarial, and anti-inflammatory activities. The potency of betulinic
acid as an inhibitor of human platelet activation was evaluated, and
its antiplatelet profile against in vitro platelet aggregation, induced
by several platelet agonists (adenosine diphosphate, thrombin receptor
activator peptide-14, and arachidonic acid), was explored. Flow cytometric
analysis was performed to examine the effect of betulinic acid on
P-selectin membrane expression and PAC-1 binding to activated platelets.
Betulinic acid potently inhibits platelet aggregation and also reduced
PAC-1 binding and the membrane expression of P-selectin. Principal
component analysis was used to screen, on the chemical property space,
for potential common pharmacophores of betulinic acid with approved
antithrombotic drugs. A common pharmacophore was defined between the
NMR-derived structure of betulinic acid and prostacyclin agonists
(PGI2), and the importance of its carboxylate group in its antiplatelet
activity was determined. The present results indicate that betulinic
acid has potential use as an antithrombotic compound and suggest that
the mechanism underlying the antiplatelet effects of betulinic acid
is similar to that of the PGI2 receptor agonists, a hypothesis that
deserves further investigation
Phytochemical profile of Rosmarinus officinalis and Salvia officinalis extracts and correlation to their antioxidant and anti-proliferative activity
The goal of this study was to monitor the anti-proliferative activity of Rosmarinus officinalis and Salvia officinalis extracts against cancer cells and to correlate this activity with their phytochemical profiles using liquid chromatography/diode array detection/electrospray ion trap tandem mass spectrometry (LC/DAD/ESI-MSn). For the quantitative estimation of triterpenic acids in the crude extracts an NMR based methodology was used and compared with the HPLC measurements, both applied for the first time, for the case of betulinic acid. Both extracts exerted cytotoxic activity through dose-dependent impairment of viability and mitochondrial activity of rat insulinoma m5F (RINm5F) cells. Decrease of RINm5F viability was mediated by nitric oxide (NO)-induced apoptosis. Importantly, these extracts potentiated NO and TNF-alpha release from macrophages therefore enhancing their cytocidal action. The rosemary extract developed more pronounced antioxidant, cytotoxic and immunomodifying activities, probably due to the presence of betulinic acid and a higher concentration of carnosic acid in its phytochemical profile. (C) 2012 Elsevier Ltd. All rights reserved.Esthir Gkani Foundation, (Ioannina, Greece); Ministry of Education and Science, Republic of Serbia [173013
Deconvoluting the Dual Antiplatelet Activity of a Plant Extract
A thorough evaluation
of the antiplatelet activity profile of hexane
olive leaf extract in human platelets indicated a potent activity
accomplished through a two axis inhibition of platelet activation
triggered both by ADP and thrombin. To delineate the extract components
responsible for this dual activity, an NMR based method was established
to determine and quantify the triterpenoid content leading to the
characterization of uvaol, erythrodiol, and oleanolic acid. The antiplatelet
profile of the total extract and of the 3 determined triterpenoids
was evaluated against in vitro platelet aggregation induced by several
platelet agonists as also on PAC-1 binding and P-selectin membrane
expression both in healthy volunteers and in platelets from patients
with an acute coronary syndrome receiving dual antiplatelet therapy
with aspirin and ticagrelor. The extract was identified to inhibit
ADP-induced platelet activation due to its erythrodiol content and
TRAP-induced platelet activation due to the activity of uvaol and
oleanolic acid