4th EucheMs chemistry congress

Poster Session 1
s901
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - life sciences
P - 0 0 8 2
AntioxidAnt ProfiLe of red CLover
(trifoLiuM PrAtenSe L.)
S. vLAiSAvLJeviC 1 , B. KAurinoviC 1 , M. PoPoviC 1
1 University of Novi Sad, Chemistry Biochemistry and
Environmental Protection, 21000 Novi Sad, Serbia
It is well-known that polyphenolic compounds are
responsible for the potential antioxidant activity and radical
scavengig capacity of plant. In this context, there is an increasing
interest in the benefical health effects of plant derived
phytoestrogens with special focus on isoflavones. Recent research
has shown that Red clover (Trifolium pratense L.) extract contain
significant high amounts of all four major estrogenic isoflavones
genistein, daidzein and their methyl ether derivatives biochanin.
A and formononetin which are known for their potential bio-active
antioxidant properties and radical scavenging capacity. This
research reports the antioxidative activities of four different
extracts and determination of dominant compound in extract
which showed the best scavenging capacity for the free radical
species such as: 2,2-diphenyl-1-picrylhidrazyl (DPPH · ), nitricoxide
(NO · -· ) and super oxide anion (O ). Free radical scavenging
2
capacity was determined on the basis of the calculated values of
IC The greatest antioxidant effect has an extract which shows
50.
the lowest value of IC . In our case it is ethyl acetate extract:
50
DPPH (IC = 17.82µg/mL), NO 50 · (IC = 20.35µg/mL) and
50
-· O (IC50 =12.90µg/mL). For this reason, this extract was used for
2
the determination of dominant components by HPLC analysis.
Predominant bioactive compounds in extract are isoflavones:
daidzein, genistein, formononetin, biochanin A, such as their
glycosides and they are corresponding with literature data.
Considering the mentioned above results, isoflavones are
probably responsible for the antioxidant activity of Red clover.
Ethyl acetate extract is suitable for isoflavones extraction, because
they are less polar than some other flavonoides which are
responsible for antioxidant activity.
Keywords: Antioxidants;
4 th EucheMs chemistry congress
P - 0 0 8 3
deteCtion of the AntioxidAtive ACtivity in
CoMPoundS LACKinG the tyPiCAL StruCturAL
deterMinAntS
v. zAitSev 1 , e. ShMAtovA 2 , i. tyurenKov 3 ,
A. ozerov 2 , o. oStrovSKii 1 , A. yAnKovA 3 ,
S. KAveLenovA 1
1 Volgograd State Medical University, Basic and Clinical
Biochemistry, Volgograd, Russia
2 Volgograd State Medical University, Pharmaceutical and
Toxicological Chemistry, Volgograd, Russia
3 Volgograd State Medical University, Pharmacology and
Biopharmacy for Postgraduated Students, Volgograd, Russia
At the present day task-oriented search of new antioxidants
(AOs) is somewhat one-sided. Hydrogen donors (e.g., phenolic
or thiol groups), reducing and chelating fragments are supposed
as usual determinants of direct antioxidative activity (AOA).
Therefore, new AOs were sought mostly among phenols, thiols
and chelators. However, El Bakkali et al. have recently shown
AOA can be found in aromatics without the said structural
determinants. Aim of this study was to evaluate AOA for various
compounds lacking typical pharmacophores. To this purpose we
synthesized 20 derivates of adenine or quinazoline with
substituents containing the aromatic rings and hydrogen bond
acceptors. None of these compounds contained phenolic, thiol or
carboxylic groups. None of them showed reducing activity with
phosphomolybdic acid. Prediction of AOA by PASS
(http://www.pharmaexpert.ru/passonline/) was negative for all
synthesized compounds. However, 5 of 20 tested compounds
exhibited AOA detected by the ABTS cation radical
decolourization test. Range of averadge EC values was
25
3,74-8,18 μM for five active compounds. Thus AOA of the new
compounds was slightly less than AOA of the well-known AOs
gallic and ascorbic acids (values of EC were 1,32 and 2,23 μM
25
respectively). Three of newly found AOs (VMA-10-09,
VMA-10-10 and VMA-10-20) contains the same substructure
which absent in inactive compounds. This substructure is
expressed as CC(=O)NC1=CC=C(C=C1)N(C)C in the SMILES
notation or [#6]-[#6](=[#8])-[#7]-c1ccc(cc1)-[#7](-[#6])-[#6] in
the SMARTS notation. Biologically relevant AOA of
VMA-10-09 and VMA-10-10 was tested by copper-induced
oxidative haemolysis assay. Both VMA-10-09 and VMA-10-10
prevented RBC lysis better than quercetin or 2,6-di-tert-butyl-4-
-methylphenol (BHT) taken at the same concentration. Hence we
identified a new structural subfragment might be the determinant
of AOA.
Keywords: Antioxidants; Biological activity; Drug discovery;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc