Ethanol-Extracted Brazilian Propolis Exerts Protective Effects on Tumorigenesis in Wistar Hannover Rats

Abstract

The present study was conducted over a course of 104 weeks to estimate the carcinogenicity of ethanol-extracted Brazilian green propolis (EEP). Groups of 50 male and 50 female Wistar Hannover rats, 6-week-old at commencement were exposed to EEP at doses of 0, 0.5 or 2.5% in the diet. Survival rates of 0.5% and 2.5% EEP-treated male and female rats, respectively, were significantly higher than those of respective control groups. Overall histopathological evaluation of neoplasms in rat tissues after 2 years showed no significant increase of tumors or preneoplastic lesions in any organ of animals administered EEP. Significantly lower incidences of pituitary tumors in 0.5% EEP male and 2.5% EEP female groups, malignant lymphoma/leukemia in both 2.5% EEP-treated males and females and total thyroid tumors in 0.5% EEP male group were found. Administration of EEP caused significant decreases of lymphoid hyperplasia of the thymus and lymph nodes in 2.5% EEP-treated rats, tubular cell hyperplasia of kidneys in all EEP groups, and cortical hyperplasia of adrenals in EEP-treated females. In the blood, significant reduction of neutrophils in all EEP-treated males and band neutrophils in 2.5% EEP-treated females was found indicating lower levels of inflammation. Total cholesterol and triglicerides levels were significantly lower in the blood of 2.5% EEP-treated female rats. In conclusion, under the conditions of the 2-year feeding experiment, EEP was not carcinogenic, did not induce significant histopathological changes in any organ, and further exerted anti-inflammatory and antitumorigenic effects resulting in increase of survival of Wistar Hannover rats.

Chemopreventive Action by Ethanol-extracted Brazilian Green Propolis on Post-initiation Phase of Inflammation-associated Rat Colon Tumorigenesis

“…Recently, Kakehashi et al demonstrated that 2-year administration of 2.5% EEP in the diet exerted anticarcinogenic potential and significantly reduced the incidence of several naturally occurring tumors in male and female rats (38). These results taken together with the results of the present study suggest that propolis could be developed as a supportive product targeting patients with IBD, including patients with ulcerative colitis and Crohn's disease, who may continuously need anti-inflammatory drugs.…”

“…A previous study showed the median lethal dose (LD 50 ) of propolis and its flavonoids in an acute oral toxicity test to be 4-8 g/kg in rats, and no adverse effects were seen in rats administered 2.74 g/kg b.w./day for 60 days via their drinking water (37). Two-year feeding of 2.5% EEP, corresponding to 1-2 g/kg/day, revealed no carcinogenicity in any organs in male or female rats (38). Therefore, daily intake of 0.42-0.44 g/kg of EEP and WEP by rats appears to be well below toxic levels.…”

Effect of Aqueous Extract of Selected Plants on Liver, Bone and Kidney Markers of 7,12-Dimethylbenz(A)Anthracene (DMBA) Treated Albino-Rats

“…This shows the plants concentrate may not pose hepatic damage since the concentration of albumin and total protein were within range and may be viable in hoisting hypoalbuminemia that may happen in breast tumour patients. The total protein and albumin concentration of this study was similar to those of Kakehashi, et al [18], which demonstrated that total protein and albumin was 68-69g/l and 31-34g/l respectively, in tumorigenic wistar rats. Although it was higher than those animals treated with Punica granatum (albumin as 27.2-31.8g/l and total protein as 42.4-54.6g/l) [19].…”

“…This manner validates that the concentrate possesses no deleterious impact on total bilirubin and conjugated bilirubin concentration. The total bilirubin concentration of this present study was higher than Baccharis dracunculifolia (3.42µmol/l) [18] but lower than Punica granatum (18.29-22.25µmol/l) [19] treated mammary tumorigenic animals.…”

Pueraria mirifica Exerts Estrogenic Effects in the Mammary Gland and Uterus and Promotes Mammary Carcinogenesis in Donryu Rats

“…An automated hematology analyzer (Sysmex XE-2100, Mitsubishi Chemical Visuals, Osaka, Japan) and an automatic analyzer (Olympus AJ-5200, Tokyo, Japan) were employed for hematological and biochemical analyses of blood serum as previously described [36]. …”