21 research outputs found
Određivanje aglikona flavonoida iz vrsta roda Sideritis (Lamiaceae) iz Makedonije pomoću HPLC UV DAD
Flavonoids obtained from Sideritis species (Lamiaceae), S. raeseri and S. scardica, grown in Macedonia were studied. Qualitative and quantitative analyses of the flavonoid aglycones were performed using high-performance liquid chromatography (HPLC) with a UV diode array detector. Extracts were prepared by acid hydrolysis in acetone, reextraction in ethyl acetate and evaporation to dryness; the residue dissolved in methanol was subjected to HPLC analysis.
Isoscutellarein, chryseriol and apigenin were identified in the extracts. Also, a 4’-methyl ether derivative of isoscutellarein was found, together with hypolaetin and its methyl ether derivative, which were identified according to previously isolated glycosides and literature data. Quantitation was performed using calibration with apigenin.
According to this screening analysis, the samples of the genus Sideritis from Macedonia are rich in polyhydroxy flavones and analogous with the previously studied Mediterranean Sideritis species from the Ibero-North African and Greek Sideritis species with respect to the presence of 8-OH flavones and their derivatives.U radu su proučavani flavonoidi dobiveni iz Sideritis vrsta (Lamiaceae), S. raeseri i S. scardica, porijeklom iz Makedonije. Kvalitativna i kvantitativna analiza aglikona flavonoida provedena je pomoću tekućinske kromatografije visoke učinkovitosti (HPLC) s UV detektorom. Ekstrakti su pripravljeni kiselom hidrolizom u acetonu, te ponovnom ekstrakcijom etil-acetatom. Ostatak nakon uparavanja je otopljen u metanolu i analiziran pomoću HPLC.
Usporedbom s ranije izoliranim glikozidima i s literaturnim podacima u ekstraktima su identifirani izoskutelarein, krizeriol, apigenin, 4\u27-metil eterski derivat izoskutelareina, hipolaetin te njegov metil eter. Kvantifikacija je provedena pomoću kalibracijske krivulje za apigenin.
Rezultati ukazuju da su uzorci Sideritis roda iz Makedonije bogati polihidroksiflavonima kao i ranije proučavane mediteranske Sideritis vrste iz sjeverne Afrike i Grčke Sideri
Secondary metabolite production in Hypericum perforatum L. cell suspensions upon elicitation with fungal mycelia from Aspergillus flavus
We investigated the production of phenylpropanoids (phenolic compounds, flavanols, flavonols and anthocyanins) and naphtodianthrones (hypericins) in elicited Hypericum perforatum L. cell suspensions. To determine whether secondary metabolite production could be enhanced, Hypericum cell suspensions were exposed to mycelia extract from the fungus Aspergillus flavus. Elicited Hypericum cell suspension cultures displayed reduced growth and viability and a modification of secondary metabolites production. Anthocyanins were only stimulated in fungal-elicited cell suspensions. Secondary metabolite production in elicited Hypericum cells revealed an antagonism between the flavonoid/naphtodianthrone and anthocyanin pathways. The data suggest a modification of the channeling of the phenylpropanoid compounds. Together, these results represent useful data for monitoring the channeling in different secondary metabolite pathways during the scaled-up production of naphtodianthrones for medicinal uses
Application of a Novel Small-Scale Sample Cleanup Procedure Prior to MALDI-TOF-MS for Rapid Pigment Fingerprinting of Red Wines
This study evaluates the anthocyanin and derived
pigment composition of
Vitis vinifera
red wines of Vranec,
Merlot, and Cabernet Sauvignon produced in 2006, 2007, and
2008 vintages from the Tikve
š
wine region in the Republic of
Macedonia.Their profile was established using matrix-assisted
laser desorption/ionization time-of-flight mass spectrometry
(MALDI-TOF-MS) technique. A total of 22 anthocyanins
and derived pigments have been identified in the samples including 10 anthocyanins, 1 ethyl-bridged flavanol
–
anthocy-
anin adduct, and 11 pyranoanthocyanins. MALDI-TOF-MS
analysis was performed after solid-phase extraction of the
wines by using, for the first time, the Zip-Tip® C18 stationary
phase, introducing a novel small-scale sample cleanup proce-
dure prior to the rapid MALDI-TOF-MS fingerprinting of
wine samples. 2
′
,4
′
,6
′
-Trihydroxyacetophenone (dissolved in
acetonitrile/water 1:1,
v
/
v
) was used as a matrix. The qualitative
screening of anthocyanins and derived pigments with MALDI-
TOF-MS confirmed the presence of glucoside, acetylglucoside,
and
p
-coumaroylglucoside derivatives of anthocyanins in the
wine samples. Furthermore, pyranoanthocyanins formed by
reactions of anthocyanins with pyruvic acid and acetaldehyde,
as well as flavanol
–
pyranoanthocyanins and ethyl-bridged
flavan-3-ol-anthocyanin adduct pigments have been detected
in the samples
Calcium Binding and Transport by Coenzyme Q
Coenzyme Q10 (CoQ10) is one of the essential
components of the mitochondrial electron-transport chain
(ETC) with the primary function to transfer electrons along
and protons across the inner mitochondrial membrane (IMM).
The concomitant proton gradient across the IMM is essential
for the process of oxidative phosphorylation and consequently
ATP production. Cytochrome P450 (CYP450) monoxygenase
enzymes are known to induce structural changes in a variety of
compounds and are expressed in the IMM. However, it is
unknown if CYP450 interacts with CoQ10 and how such an
interaction would affect mitochondrial function. Using voltammetry, UV�vis spectrometry, electron paramagnetic resonance
(EPR), nuclear magnetic resonance (NMR), fluorescence microscopy and high performance liquid chromatography�mass
spectrometry (HPLC�MS), we show that both CoQ10 and its analogue CoQ1, when exposed to CYP450 or alkaline media,
undergo structural changes through a complex reaction pathway and form quinone structures with distinct properties. Hereby, one
or both methoxy groups at positions 2 and 3 on the quinone ring are replaced by hydroxyl groups in a time-dependent manner. In
comparison with the native forms, the electrochemically reduced forms of the new hydroxylated CoQs have higher antioxidative
potential and are also now able to bind and transport Ca2þ across artificial biomimetic membranes. Our results open new
perspectives on the physiological importance of CoQ10 and its analogues, not only as electron and proton transporters, but also as
potential regulators of mitochondrial Ca2þ and redox homeostasis