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

Pueraria mirifica (PM), a plant whose dried and powdered tuberous roots are now widely used in rejuvenating preparations to promote youthfulness in both men and women, may have major estrogenic influence. In this study, we investigated modifying effects of PM at various doses on mammary and endometrial carcinogenesis in female Donryu rats. Firstly, PM administered to ovariectomized animals at doses of 0.03%, 0.3%, and 3% in a phytoestrogen-low diet for 2 weeks caused significant increase in uterus weight. Secondly, a 4 week PM application to non-operated rats at a dose of 3% after 7,12-dimethylbenz[a]anthracene (DMBA) initiation resulted in significant elevation of cell proliferation in the mammary glands. In a third experiment, postpubertal administration of 0.3% (200 mg/kg body weight (b.w.)/day) PM to 5-week-old non-operated animals for 36 weeks following initiation of mammary and endometrial carcinogenesis with DMBA and N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG), respectively, resulted in significant increase of mammary adenocarcinoma incidence. A significant increase of endometrial atypical hyperplasia multiplicity was also observed. Furthermore, PM at doses of 0.3%, and more pronouncedly, at 1% induced dilatation, hemorrhage and inflammation of the uterine wall. In conclusion, postpubertal long-term PM administration to Donryu rats exerts estrogenic effects in the mammary gland and uterus, and at a dose of 200 mg/kg b.w./day was found to promote mammary carcinogenesis initiated by DMBA.

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

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.

Preventive Effects of Spirogyra neglecta and a Polysaccharide Extract against Dextran Sodium Sulfate Induced Colitis in Mice.

Ulcerative colitis (UC) results from colonic epithelial barrier defects and impaired mucosal immune responses. In this study, we aimed to investigate the modifying effects of a Spirogyra neglecta extract (SNE), a polysaccharide extract (PE) and a chloroform fraction (CF) on dextran sodium sulfate (DSS)-induced colitis in mice and to determine the mechanisms. To induce colitis, ICR mice received 3% DSS in their drinking water for 7 days. Seven days preceding the DSS treatment, oral administration of SNE, PE and CF at doses of 50, 25 and 0.25 mg/kg body weight (low dose), 200, 100 and 1 mg/kg body weight (high dose) and vehicle was started and continued for 14 days. Histologic findings showed that DSS-induced damage of colonic epithelial structure and inflammation was attenuated in mice pre-treated with SNE, PE and CF. Furthermore, SNE and PE significantly protected colonic epithelial cells from DSS-induced cell cycle arrest, while SNE, PE and CF significantly diminished apoptosis. Proteome analysis demonstrated that SNE and PE might ameliorate DSS-induced colitis by inducing antioxidant enzymes, restoring impaired mitochondria function, and regulating inflammatory cytokines, proliferation and apoptosis. These results suggest that SNE and PE could prevent DSS-induced colitis in ICR mice by protection against and/or aiding recovery from damage to the colonic epithelium, reducing ROS and maintaining normal mitochondrial function and apoptosis.

Valerian inhibits rat hepatocarcinogenesis by activating GABA(A) receptor-mediated signaling.

Valerian is widely used as a traditional medicine to improve the quality of sleep due to interaction of several active components with the γ-aminobutyric acid (GABA) A receptor (GABA(A)R) system. Recently, activation of GABA signaling in stem cells has been reported to suppress cell cycle progression in vivo. Furthermore, possible inhibitory effects of GABA(A)R agonists on hepatocarcinogenesis have been reported. The present study was performed to investigate modulating effects of Valerian on hepatocarcinogenesis using a medium-term rat liver bioassay. Male F344 rats were treated with one of the most powerful Valerian species (Valeriana sitchensis) at doses of 0, 50, 500 and 5000 ppm in their drinking water after initiation of hepatocarcinogenesis with diethylnitrosamine (DEN). Formation of glutathione S-transferase placental form positive (GST-P(+)) foci was significantly inhibited by Valerian at all applied doses compared with DEN initiation control rats. Generation of 8-hydroxy-2'-deoxyguanosine in the rat liver was significantly suppressed by all doses of Valerian, likely due to suppression of Nrf2, CYP7A1 and induction of catalase expression. Cell proliferation was significantly inhibited, while apoptosis was induced in areas of GST-P(+) foci of Valerian groups associated with suppression of c-myc, Mafb, cyclin D1 and induction of p21(Waf1/Cip1), p53 and Bax mRNA expression. Interestingly, expression of the GABA(A)R alpha 1 subunit was observed in GST-P(+) foci of DEN control rats, with significant elevation associated with Valerian treatment. These results indicate that Valerian exhibits inhibitory effects on rat hepatocarcinogenesis by inhibiting oxidative DNA damage, suppressing cell proliferation and inducing apoptosis in GST-P(+) foci by activating GABA(A)R-mediated signaling.