ABSTRACT
PURPOSE: The carcinogenic action of polycyclic aromatic hydrocarbons (PAHs) can be inhibited by endogenous or exogenous compounds. This study was designed to elucidate the modifying action of 3 endogenous inhibitors- ascorbic acid (vit C) used alone, and selenium (Se) used in combination with glutathione (GSH). MATERIALS AND METHODS: Chemical carcinogenesis was induced by benzo[a]pyrene(BaP). A hundred wistar rats were divided into 3 groups: the first group (G I) consisted of 42 animals, representing the control group. The two experimental groups (G II and G III) consisted of 38 and 20 rats, respectively. All groups were injected with BaP(10.08 mg subcutaneously-s.c). The first experimental G II was given only vit C (520 mg in 2% sugar solution per os - p.o.). The second experimental G III was given Se (0.1 mg p.o.) with GSH (200 mg p.o.). Tumor incidence and mean survival time were determined. Histological examination of the developed and excised tumors took place following death. The carcinogenic potency (CP) and anticarcinogenic potency (AP) of the substances used were calculated. RESULTS: A statistically significant difference regarding the mean survival time in the two experimental groups (238.4-/+31 days and 344.9-/+48 days, respectively) compared to the control group (183.8-/+28 days) was found (p < 0.001). The CP of each of the 3 groups was 54.3, 41.2, and 28.9 units, respectively. The AP of vit C used alone was 13.1 units, representing a significant anticarcinogenic effect. The combination of Se + GSH showed an AP of 25.4 units, resulting in a significant prolongation of the mean survival time, which is considered a potent anticarcinogenic effect. Furthermore, a statistically significant difference was found also when the mean survival time of G III animals was compared with G II. CONCLUSION: Vit C on its own and Se in combination with GSH represent strong endogenous inhibitors that can inhibit/reduce the carcinogenic action of BaP-induced carcinogenesis in wistar rats. The combination therapy used offered better in vivo results.
ABSTRACT
Extracts of plants have been widely tested for possible anticarcinogenic properties. In the present study a traditional remedy, consisting of an aqueous extract of mixed parts of the tree Abies alba and its mistletoe Viscum album se abies was tested on benzo(alpha)pyrene(BaP)-induced tumors in Wistar rats and on the L-1210 malignant cell line. Two main groups of male Wistar rats subcutaneously injected by 10 mg of BaP, a dose inducing 100% carcinogenesis, a control group (C-G, 15 rats) and a treatment group(TR-G, 18 rats), were used for the study. Five animals bearing BaP-induced tumors were also tested (TR-1-G). Animals of the TR-G were orally administered with the aqueous extract at doses of 50 ml/kg b.w, from the day of BaP injection and of the TR-1-G, from the 120th day of injection, till death. L-1210 malignant cells in cultivation, were administered with a powder obtained by condensation and lyophilization of the extract, at various concentrations and cytotoxicity was measured by the microculture tetrazolium assay. Autopsy of the rats, revealed metastasis in the lungs of the animals of all groups and the tumors developed were histologically identified as leiomyosarcomas. The results indicated that the extract of the above plants possess anticarcinogenic effects, documented by: a) its antiproliferative effects on L-1210 cells (IC50 = 49.6 +/- 1.4 micrograms/ml), b) the significant prolongation of life and reduction of tumor growth rate of the animals of the TR-G in comparison to the C-G, c) the inhibition by 16.6% of tumor induction in the TR-G and d) the prolongation of life and the necrotic effects of the extract on the tumors of the animals in the TR-1-G. The antiproliferative effects of the Abies alba and Viscum album se abies extract may be due to the lectins and thionins contained in Viscum album, as well as to the monoterpenes contained in Abies alba. Soft tissue tumors sensitive to the extract, are widespread among human organs, even in larynx, and are usually resistant to chemotherapy.
