Résumé:
"This study was conducted to search for the preventive effect of medicinal plant Ruta montana
extract on oxidative stress induced by doxorubicine (DOX) and its properties to reverse
doxorubicin resistance in ovarian cancer cell line (A2780). Organic extracts were obtained by
maceration with three solvents: petroleum ether, ethyl acetate and butanol. The yields were:
15,04%, 3,55% and 25,14%.respectively. A phytochemical screening in methanol extract
revealed that the plant contain the flavonoids, saponins, tannins, coumarins, reducing component
and the alkaloids. The quantitative study showed that the butanolic extract (BERM) has
significant amount of flavonoids (80.85±0.78mg EQ / g dry extract), followed by ethyl acetate
extract (AEERM) (15.27 ±0.62 EQ / g dry extract) and petroleum ether extract has the lowest
flavonoids content (PEERM) (9.71±1.13 mgEQ/g dry extract). When the total phenolic contents
was: 687.5, 595.83 and 146.33 mg EGA / g dry extract, in the BERM, AEERM and PEERM
respectively. The qualitative analysis of the three methanolic crude extract via thin layer
chromatography (TLC) has shown the presence of the anthocyanidin 3-glycosids, flavons et
flavonols glycosids (hétérosids), flavonols avec 3-OH libre, flavonons ou aurons, isoflavons, the
phénolic acids, Flavonols et 4-OH chalcons. The évaluation of antioxidant activity by the
reduction of free radical DPPH method showed that The highest DPPH radical scavenging
activity was observed with AEERM (IC50 = 0.126 ± 0.002 mg/ ml), followed by BERM (0.135
± 0.0006 mg/ ml) and PEERM (IC50 =0.185± 0.002 mg/ ml). The study of preventive effect of
AEERM on oxidative stress induced by DOX in wistar rats clearly show that DOX (15 mg/kg
i.p) induced animal cardiotoxicity characterized by an increase of cardiac enzyme activity
(CKMB, LDH, l’ALAT et l’ASAT) in serum, the increase in the concentration of
malondialdéhyde (MDA), antioxydant enzyme activity, catalase (CAT) and Glutathion- Stransférase (GST) and a decrease of cardiac cytosolic reduced glutathione (GSH) with a different
pathological changes in the heart. However pretreated animals with EAERM (100 mg/kg orally
during 15 days), showed a decrease of cardiac enzymes activities 24 %, 35, 69%, 21,25 % et
8,10 % respectively to CKMB, LDH, l’ALAT and l’ASAT. The preatretment with the extract
improved antioxidant status in the heart by a decrease in the cardiac MDA concentration by 29,7
% and activity of antioxydants enzymes by 17,91% et 29,78% respectively to CAT et la GST.
In addition, the pretreated rats by the extract showed an increase of GSH level (83,76 %)
compared with DOX-treated animals. Histological study shows that the extract resulted in a
reduction of severe cardiac damages observed in DOX-treated animals. The reversal of
multidrug resistance for DOX in human ovarian adenocarcinoma, cell lines (A2780 DX3) using
MTT assay showed that AEERM was very effective at reversing the resistant in dose dependent
manner with the Reversion Factor (RF =8.62, 05.77 and 02.30 respectively for the
concentrations 40, 10 and 2.5 mg/ml) followed by BERM (FR=05.07 and 02.43 for the
concentrations 40 and 10 mg/ml respectively), then the PEERM had the lowest reversal
resistance effect (RF betwen 1.01 to 1.08). The present study suggests that AEERM can
ameliorate the oxidative stress involved in the pathogenesis of doxorubicine- induced
cardiotoxicity and can reverse the multidrug resistance for DOX."
