iv. mezioborové setkênè mladðch biologů ... - Chemické listy

Chem. Listy 98, 271 – 314 (2004) IV. Amerika 2004.
complexes, promyeolocytic leukemia nuclear bodies (PML NBs).
The gene product, PML protein, is essential for proper formation
and integrity of PML NBs. Although the biochemical function of
PML and PML NBs remain still unclear, there is an evidence for
its contribution in response to a variety of cell states like cancer,
apoptosis, and viral infections.
It is known that type I and II interferons (IFNs)
dramatically increase the transcription of the PML gene
through an IFN-stimulated response elements (ISRE and GAS)
present in the PML gene promoter. Additionally, IFNs
increases expression of other structural component of PML
NBs, Sp100, which is mediated by the same response
elements. The up-regulation of these proteins, which are the
main structural components of PML NBs, can contribute to the
observed increase in the number of PML NBs.
In this study we have shown that trichostatin A, an
inhibitor of protein deacetylases, strongly reduces IFNstimulated
increase of PML NBs number. Consistently with
this observation, trichostatin A also inhibits IFN-induced upregulation
of the main structural components of PML NBs –
PML and Sp100. Although TSA-induced protein
hyperacetylation has an overall stimulatory effect on gene
expression, our findings indicate that the IFN-induced
activation of these two genes is inhibited at some stage by
acetylation event of an unknown regulatory component.
A BIOLOGICALLY ACTIVE COMPOUND FROM THE
SEEDS OF Tamarindus indica
M. VODENIČAROVÁ a , S. PÁVEK a , A. LOJEK b , and A.
EBRINGEROVÁ c
a CPN s.r.o., Dolní Dobrouč 56102, b Institute of Biophysics,
Kralovopolska 135, 616 65 Brno, c Institute of Chemistry,
Slovak Academy of Sciences, Dúbravska cesta 9, 842 38
Bratislava, Slovak Republic
vodenicarova@contipro.cz
Tamarindus indica is a large tree growing in tropical and
subtropical regions. It is one of the most important plant
resources as food materials and all parts of the plant have
therapeutic uses 1,2 . The germ obtained from the seed contains
high molecular xyloglucan. Xyloglucan has an
immunostimulating effect, but there was not obtained an
antioxidative activity in alcoholic and water extract prepared
from germ. Seed coats are a byproduct of tamarind gum
production and are reported to be a low-cost source of
antioxidants extractable with methanol, ethanol and
ethylacetate. In these extracts, a variety of dihydroxy types of
benzene derivatives has been identified as the main
component 3 .
This study reports on the composition and general
structural and molecular characteristics as well as various
biological activities of the compound isolated from the seed
coats by aqueous alkali extraction and isopropanol extraction.
The water – soluble alkali extracted material of tamarind seed
coat (AEMTSC) comprises a high molecular mass heteroxylan
(Mp ~ 90 kDa) closely associated with phenolic compounds. It
exhibited significantly higher antioxidative activity as
measured by total peroxyl radical trapping antioxidant
parameter (TRAP) and DPPH radical scavenging method in
comparison to isopropanol extract. The antioxidative capacity
is comparable with trolox. The reduction of phospholipid
peroxidation in the presence of AEMTSC is more than 90 %
for concentration of AEMTSC more than 0,05 % (wt.).
AEMTSC is fully soluble in water and represents a potent
natural additive in cosmetic and pharmacy.
REFERENCES
1. Lanhers M. C., Fleurentin J., Guillemni F.:
Ethnopharmacol. 18, 42 (1996).
2. Shankaracharya N. B.: J. Food Sci. Technol. 35, 193
(1998).
3. Tsuda T., Watanabe M., Ohshima K., Yamamoto A.,
Kawakishi S., Osawa T.: J. Agric. Food Chem. 42, 2671
(1994).
CHELERYTHRINE INHIBITION OF OXIDATIVE
BURST IN DMSO-DIFFERENTIATED HL-60 CELLS
PRECEDES PROTEIN KINASE C INHIBITION
JIŘÍ VRBA and MARTIN MODRIANSKÝ
Institute of Medical Chemistry and Biochemistry, Faculty of
Medicine, Palacký University, Hněvotínská 3, 775 15 Olomouc
Chelerythrine (CHE), a quaternary benzophenanthridine
alkaloid with anti-inflammatory properties, is known to inhibit
protein kinase C (PKC)-dependent phosphorylation. We
examined the effect of CHE and three other alkaloids,
sanguinarine (SA), dihydrosanguinarine (dihSA) and
dihydrochelerythrine (dihCHE), on PKC-dependent oxidative
burst in DMSO-differentiated HL-60 cells. Phorbol myristate
acetate (PMA) directly activates PKC thus triggering NADPH
oxidase assembly and oxidative burst. Both CHE and SA
inhibit PMA-induced oxidative burst, monitored as superoxide
radical generation, with IC50 of 2.9 µM and 1.8 µM,
respectively. Western blotting analyses of the whole cell lysate
obtained from PMA-activated differentiated HL-60 cells in the
presence or absence of alkaloids showed that inhibition of
PKC activity required at least ten-fold higher concentrations of
CHE (> 30 µM) or SA (> 20 µM) than those necessary for
inhibition of PMA-induced superoxide generation.
Staurosporine, a potent PKC inhibitor, inhibits both oxidative
burst and PKC activity with comparable effectiveness. DihSA
and dihCHE at concentrations > 30 µM affected neither PMAinduced
oxidative burst nor PKC activity. Comparison of
effects displayed by CHE and SA with those displayed by their
dihydro derivatives accentuates the requirement for the
presence of C=N+ region in the molecules, while slight
difference in side chains seems to be inessential. As low
concentrations of CHE do not affect the phosphorylating
activity of PKC, which directly activates NADPH oxidase
assembly via phosphorylation of p47 phox , we conclude that
CHE inhibits oxidative burst in DMSO-differentiated HL-60
cells primarily by direct inhibition of NADPH oxidase.
This research was supported by grant MSM 151100003.
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