Özet:
This study investigates the biochemical and histopathological effects of olive leaf tea (OLT) in mice bearing Ehrlich Ascites Carcinoma (EAC), a widely used experimental tumor model that mimics aggressive breast cancer behavior and systemic oxidative stress. The primary objective of the study was to evaluate the potential protective and supportive role of OLT, detoxification enzyme systems, and tissue integrity, as well as its modulatory effects on chemotherapy-induced toxicity, depending on the timing of administration. Olive leaf tea, rich in phenolic compounds such as oleuropein and hydroxytyrosol, was administered orally at a dose of 400 mg/kg before, during, or after tumor inoculation. Experimental animals were divided into groups, including control, tumor, OLT-treated, 5-fluorouracil (5-FU)-treated, and combined OLT + 5-FU groups. At the end of the experimental period, liver, kidney, and brain tissues were harvested for biochemical analyses, while liver, stomach, duodenum, kidney, and bladder tissues were examined histopathologically. Biochemical evaluations focused on reduced glutathione (GSH) levels, glutathione S-transferase (GST), and carboxylesterase (CaE) activities, which are critical indicators of oxidative balance and xenobiotic detoxification. The results demonstrated that tumor burden caused a significant depletion of hepatic GSH levels, reflecting pronounced oxidative stress. OLT administration, particularly when applied prophylactically before tumor induction, partially restored GSH levels and significantly enhanced GST activity, indicating an improved phase II detoxification capacity. Tumor-associated elevations in CaE activity showed a trend toward normalization in OLT-treated groups, suggesting a beneficial modulation of xenobiotic metabolism. Histopathological examination revealed that OLT administration alone did not induce any pathological alterations in the examined organs. Moreover, combined treatment with OLT and 5-FU markedly reduced chemotherapy-associated hepatic degeneration and gastric lymphocytic infiltration compared to 5-FU treatment alone. These findings indicate that OLT exerts a protective effect against tissue damage induced by both tumor progression and chemotherapeutic stress. In conclusion, this study provides experimental evidence that olive leaf tea supports antioxidant defense systems, enhances detoxification enzyme activity, and preserves tissue morphology in an EAC mouse model. The findings suggest that OLT may serve as a promising nutraceutical adjuvant, particularly when used preventively, to mitigate oxidative stress and reduce chemotherapy-related organ toxicity in cancer management.
