Evaluation of the cytotoxic, anticancer, and genotoxic activities of Acacia nilotica flowers and their effects on N-methyl-N-nitrosourea-induced genotoxicity in mice.

PURPOSE: In this study, two main research objectives were examined: (1) the cytotoxic and anticancer activities of the aqueous methanol extract from Acacia nilotica flowers on three human cancer cells, namely lung A549, breast MCF-7, and leukemia THP-1 cells, and (2) the genotoxic effects of A. nilotica extract and its influence on DNA damage induced by N-methyl-N-nitrosourea (MNU) in mice. METHODS: Mice were orally treated with A. nilotica extract (200, 500, and 800 mg/kg for 4 days) with or without MNU (80 mg/kg intraperitoneally for 24 h). RESULTS: In vitro experiments showed that A549 cells were the most sensitive to A. nilotica extract among the tested cell lines. A. nilotica extract inhibited A549 cell proliferation by blocking the cell cycle at the G2/M phase and accumulating apoptotic cells in the sub-G0/G1 phase in A549 cells. In vivo experiments showed that MNU induced positive and negative genotoxicity in bone marrow cells and spermatocytes, respectively. Negative genotoxicity was observed in A. nilotica extract-treated groups only. However, A. nilotica extract (800 mg/kg) remarkably increased comet tail formation in bone marrow cells. Unexpectedly, the absence of antigenotoxicity was observed in three cotreated groups with A. nilotica extract and MNU compared with the MNU-treated group. Astonishingly, cotreatment with MNU and A. nilotica extract at a dose above 200 mg/kg remarkably increased micronucleus and comet tail formation in bone marrow cells compared with the MNU-treated group. CONCLUSIONS: A. nilotica extract possessed anticancer activity with relative genotoxic effects at high doses.

Chloroform extract of Calliandra portoricensis inhibits tumourigenic effect of N-methyl-N-nitrosourea and benzo(a)pyrene in breast experimental cancer.

Calliandra portoricensis (C. portoricensis) is used in herbal homes in Nigeria to manage breast diseases. We investigated the anti-tumourigenic effects of chloroform extract of C. portoricensis (CP) in breast experimental cancer induced by N-methyl-N-nitrosourea (NMU) and benzo-(a)-pyrene (BaP). Fifty-six female rats were assigned into seven equal groups: Group 1 served as control, group 2 received NMU and BaP (50 mg/kg, each), groups 3 and 4 received [NMU + BaP] and treated with CP at 50 and 100 mg/kg, respectively. Group 5 received CP (100 mg/kg), group 6 received [NMU + BaP] and vincristine (0.5 mg/kg), while group 7 received vincristine (0.5 mg/kg). The NMU and BaP (i.p) were dissolved in normal saline and corn oil, respectively. The CP (oral) and vincristine (i.p) were given thrice and twice per week, respectively for 10 weeks. The [NMU + BaP] intoxication significantly decreased body weight gain by 32% while organo-somatic weight of mammary gland increased by 37%. Also, [NMU + BaP] decreased the activities of mammary catalase, glutathione-s-transferase, glutathione peroxidase, superoxide dismutase and total sulphurhydryl by 34%, 31%, 35%, 35% and 33%, respectively. The [NMU + BaP] increased inflammatory and oxidative stress markers; nitrite, lipid peroxidation and myeloperoxidase by 62%, 57% and 361%, respectively. Strong expression of BCL-2, IL-6, COX 2, ß-catenin and iNOS in [NMU + BaP]-administered rats were observed. Histology revealed glands with malignant epithelial cells and high nucleocytoplasm in [NMU + BaP] rats. Treatment with CP attenuated inflammation, apoptosis and restored cyto-architecture of mammary gland. Overall, CP abates mammary tumourigenesis by targeting cellular pathways of inflammation and apoptosis.

Protective Effects of Antioxidant Chlorophyllin in Chemically Induced Breast Cancer Model In vivo.

Glutathione-related enzymes belong to the protection mechanism of the cells against harmful oxidative damage and chemicals. Glutathione S-transferase (GST) is frequently over-expressed in various cancer cells and is involved in drug resistance. Chlorophyllin is an antioxidant molecule interfering with the GST P1-1 activity. The purpose of this study is to evaluate the short- and long-term protective effects of chlorophyllin as an antioxidant molecule on DNA damage, antioxidant enzyme activities, trace elements, and minerals in chemically induced breast cancer model in vivo. In our study, N-methyl-N-nitrosourea (MNU) was used for inducing breast carcinogenesis in female Sprague-Dawley rats. A total of 36 rats were divided into groups as short term and long term. Each group was divided into four sub-groups as control group received physiological saline solution (n = 3), Chl group (n = 5) received chlorophyllin, MNU group (n = 5) was administered MNU, and Chl + MNU group (n = 5) was treated with both chlorophyllin and MNU. Results illustrated that chlorophyllin had a significant anti-genotoxic effect in the short term, and glutathione-related enzyme activities were protected by chlorophyllin treatment in MNU-induced breast cancer model. Additionally, MNU administration impaired mineral and trace element levels including Na, Mg, K, Fe, Zn, and Co in the liver, kidney, spleen, heart, and tumor tissues; however, adverse effects of MNU were recovered upon chlorophyllin treatment in the indicated tissues of the rats. In conclusion, chlorophyllin can be used as an antioxidant molecule to ameliorate adverse effects of MNU by enhancing antioxidant enzyme activities and regulating trace element and mineral balance in several organs and tumor tissue in the breast cancer model.

Sesquiterpenoid bilobalide inhibits gastric carcinoma cell growth and induces apoptosis both in vitro and in vivo models.

Gastric carcinoma is one of the most aggressive types of cancer that ranks fifth among all cancer incidences and third in cancer mortality. As it exhibits a prolonged asymptomatic condition and high recurrence rate, it is a great challenge to treat gastric cancer. Traditional medicine that utilizes herbal phytochemicals to treat various diseases is a potent alternative for current allopathic treatment. Hence, we evaluated the potency of a phytochemical bilobalide for treating gastric cancer in in vitro and in vivo models. Bilobalide, a sesquiterpenoid, is present in the Ginkgo biloba plant that belongs to the family of Ginkgoaceae. The cytotoxicity effect of bilobalide was evaluated in both gastric cancer (AGS) cells and normal gastric epithelial cells. Apoptosis-inducing property of bilobalide against the AGS cell line was analyzed with different fluorescent staining techniques and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, and cell cycle analysis was carried out by flow cytometry. The in vivo studies were assessed with N-methyl-N-nitrosourea (MNU)-induced gastric cancer in rats. Serum-specific gastric markers were quantified and histopathological analysis of stomach tissue was performed. The expression of target-signaling molecules was analyzed by a reverse-transcription polymerase chain reaction. The in vitro results proved that bilobalide effectively suppressed the AGS cell growth and induced cell death by nuclear damage and apoptosis induction. The bilobalide treatment effectively arrested the cell cycle of AGS cells via inhibiting the PI3K-signaling pathway. Our in vivo results also confirmed that the bilobalide persuasively inhibited the MNU-induced gastric carcinoma via inhibiting the thioredoxin-fold family proteins and inflammatory markers' expression. Overall, our results authentically prove that bilobalide possesses therapeutic potency to cure gastric carcinoma.

Calliandra portoricensis ameliorates ovarian and uterine oxido-inflammatory responses in N-methyl-N-nitrosourea and benzo[a]pyrene-treated rats.

IMPACT STATEMENT: Infertility resulting from reproductive impairment is traumatic in families. Exposure to chemicals may play insidious roles not easily connected to infertility. We examined benzo[a]pyrene (BaP), and N-methyl nitrosourea (NMU)-induced ovarian and uterine toxicity and the role of Calliandra portoricensis in mitigating toxicity. In a bid to illuminate folk medical claims cloaked in mystery, unearthing lost knowledge, advance natural chemopreventive agents, and report new evidence lacking in the literature attributed to CP. Although CP is known to exhibit anticonvulsant, antidiarrheal, antipyretic, antirheumatic, and analgesic effects in humans, its possible roles for mitigating toxicity stemming from inadvertent chemical exposures are reported here. Our findings affirm and further show that CP abates toxic response incumbent on oxidative damage and inflammatory responses associated with NMU and BaP exposure. Development of phytochemical derived from CP may serve as a potential natural therapy against chemical toxicities in individuals inadvertently exposed, and promote human health and reproductive satiety.

Palliative Role of Aqueous Ginger Extract on N-Nitroso-N-Methylurea-Induced Gastric Cancer.

Ginger (Zingiber officinale) is a spice and also an herbal medicine used worldwide for managing GI tract disturbances. However, its role in gastric cancer is sparingly known. This study ensures the standardization of gastric cancer by the induction of N-nitroso N-methyl Urea (MNU) and to determine the role of the aqueous extract of ginger (AGE) in MNU-induced gastric cancer in albino Wistar rats. Accordingly, the anticancer potential of AGE and its possible mode of action were assessed on rats exposed to MNU, by various biochemical and molecular assays. As evidenced by the extent of lipid peroxidation, gastrin levels and histopathological sections in MNU-induced cancerous lesions at 8 wk which was stabilized at 16 wk confirming the induction of gastric carcinoma by the chemical carcinogen. Further, results revealed that AGE alleviated the oxidative stress as evidenced by the stomach antioxidant enzymes (SOD, catalase, GPx, and GR), markers of oxidative stress (TRx, GRx) and Gastrin, a specific marker for gastric cancer and a decreased level of pro-inflammatory markers (NF-kB, TNF-α, IL-6, PGE2) which was further confirmed by histopathological analysis. AGE is responsible to mitigate oxidative stress and inflammation related to gastric cancer and could be used as a potential dietary intervention in gastric cancer therapy.

The natural retinoprotectant chrysophanol attenuated photoreceptor cell apoptosis in an N-methyl-N-nitrosourea-induced mouse model of retinal degenaration.

Retinitis pigmentosa (RP) is an inherited photoreceptor-degenerative disease, and neuronal degeneration in RP is exacerbated by glial activation. Cassia seed (Jue-ming-zi) is a traditional herbal medicine commonly used to treat ocular diseases in Asia. In this report, we investigated the retina-protective effect of chrysophanol, an active component of Cassia seed, in an N-methyl-N-nitrosourea (MNU)-induced mouse model of RP. We determined that chrysophanol inhibited the functional and morphological features of MNU-induced retinal degeneration using scotopic electroretinography (ERG), optical coherence tomography (OCT), and immunohistochemistry analysis of R/G opsin and rhodopsin. Furthermore, TUNEL assays revealed that chrysophanol attenuated MNU-induced photoreceptor cell apoptosis and inhibited the expression of the apoptosis-associated proteins PARP, Bax, and caspase-3. In addition, chrysophanol ameliorated reactive gliosis, as demonstrated by a decrease in GFAP immunolabeling, and suppressed the activation of matrix metalloproteinase (MMP)-9-mediated gelatinolysis. In vitro studies indicated that chrysophanol inhibited lipopolysaccharide (LPS)-induced iNOS and COX-2 expression in the BV2 mouse microglia cell line and inhibited MMP-9 activation in primary microglia. Our results demonstrate that chrysophanol provided neuroprotective effects and inhibited glial activation, suggesting that chrysophanol might have therapeutic value for the treatment of human RP and other retinopathies.

Antimutagenic components in Glycyrrhiza against N-methyl-N-nitrosourea in the Ames assay.

Antimutagenesis against N-nitroso compounds contribute to prevention of human cancer. We have found that Glycyrrhiza aspera ethanolic extract exhibits antimutagenic activity against N-methyl-N-nitrosourea (MNU) using the Ames assay with Salmonella typhimurium TA1535. In the present study, eight purified components from Glycyrrhiza, namely glabridin, glycyrrhetinic acid, glycyrrhizin, licochalcone A, licoricesaponin H2, licoricesaponin G2, liquiritigenin and liquiritin were evaluated for their antimutagenicity against MNU in the Ames assay with S. typhimurium TA1535. Glycyrrhetinic acid, glycyrrhizin, licoricesaponin G2, licoricesaponin H2 and liquiritin did not show the antimutagenicity against MNU in S. typhimurium TA1535. Glabridin, licochalcone A and liquiritigenin reduced revertant colonies derived from MNU in S. typhimurium TA1535 without showing cytotoxic effects, indicating that these compounds possess antimutagenic activity against MNU. The inhibitory activity of glabridin and licochalcone A was more effective than that of liquiritigenin. Thus, Glycyrrhiza contains antimutagenic components against DNA alkylating, direct-acting carcinogens.

α-Chymotrypsin regulates free fatty acids and UCHL-1 to ameliorate N-methyl nitrosourea induced mammary gland carcinoma in albino wistar rats.

This study was undertaken to investigate the effect of α-chymotrypsin on methyl nitrosourea (MNU) induced mammary gland carcinoma in albino wistar rats. Animals were randomized into four groups (six animals in each). Group I (sham control 0.9 % normal saline p.o.); Group II (toxic control, MNU 47 mg/kg, i.v.); Group III (α-chymotrypsin, 5 mg/kg, p.o.); Group IV (α-chymotrypsin, 10 mg/kg p.o.). Toxicity was induced by single i.v. injection of MNU followed by α-chymotrypsin supplementation therapy for 100 days. MNU treatment was evident with increased alveolar bud count, differentiation score, upregulated inflammatory enzymes markers (COX, LOX and NO) antioxidative stress markers (TBARs, SOD, catalase and GSH).MNU associated toxicity was also ascertained by PGP 9.5 and NF-κB expression in the mammary gland tissue followed by FAME analysis for fatty acid profiling. α-chymotrypsin afforded significant protection against the deleterious effects of MNU.

Inhibition of Mammary Cancer Progression in Fetal Alcohol Exposed Rats by ß-Endorphin Neurons.

BACKGROUND: Fetal alcohol exposure (FAE) increases the susceptibility to carcinogen-induced mammary cancer progression in rodent models. FAE also decreases ß-endorphin (ß-EP) level and causes hyperstress response, which leads to inhibition of immune function against cancer. Previous studies have shown that injection of nanosphere-attached dibutyryl cyclic adenosine monophosphate (dbcAMP) into the third ventricle increases the number of ß-EP neurons in the hypothalamus. In this study, we assessed the therapeutic potential of stress regulation using methods to increase hypothalamic levels of ß-EP, a neuropeptide that inhibits stress axis activity, in treatment of carcinogen-induced mammary cancer in fetal alcohol exposed rats. METHODS: Fetal alcohol exposed and control Sprague Dawley rats were given a dose of N-Nitroso-N-methylurea (MNU) at postnatal day 50 to induce mammary cancer growth. Upon detection of mammary tumors, the animals were either transplanted with ß-EP neurons or injected with dbcAMP-delivering nanospheres into the hypothalamus to increase ß-EP peptide production. Spleen cytokines were detected using reverse transcription polymerase chain reaction assays. Metastasis study was done by injecting mammary cancer cells MADB106 into jugular vein of ß-EP-activated or control fetal alcohol exposed animals. RESULTS: Both transplantation of ß-EP neurons and injection of dbcAMP-delivering nanospheres inhibited MNU-induced mammary cancer growth in control rats, and reversed the effect of FAE on the susceptibility to mammary cancer. Similar to the previously reported immune-enhancing and stress-suppressive effects of ß-EP transplantation, injection of dbcAMP-delivering nanospheres increased the levels of interferon-γ and granzyme B and decreased the levels of epinephrine and norepinephrine in fetal alcohol exposed rats. Mammary cancer cell metastasis study also showed that FAE increased incidence of lung tumor retention, while ß-EP transplantation inhibited lung tumor growth in both normal and fetal alcohol exposed rats. CONCLUSIONS: Our results suggest that increase of ß-EP production in the hypothalamus may serve as a potential therapeutic strategy for treating the cancer growth in patients with chronic stress and compromised immune function, such as the patients with FAE.

Modulation of hepatocarcinogenesis in N-methyl-N-nitrosourea treated Balb/c mice by mushroom extracts.

The hepatoprotective potential of edible mushrooms from Mauritius, namely Pleurotus sajor-caju and Agaricus bisporus was evaluated using an N-methyl-N-nitrosourea (MNU)-induced hepatocarcinogenesis Balb/c mice model. Mushroom extracts restored normal weight in MNU treated mice over a 3 month supplementation period. Blood parameter analyses indicated a clear modulation of hemoglobin concentration, leukocyte, platelet, lymphocyte, neutrophil, monocyte and eosinophil counts in MNU-induced mice (p < 0.05). Mushroom extract supplementation effectively reduced oxidative damage in MNU-primed mice, which was marked by a significant decrease in the extent of lipid peroxidation (p < 0.05) and a concomitant increase in the enzymatic antioxidant levels, primarily catalase, superoxide dismutase, glutathione reductase and peroxidase, and FRAP values (p < 0.05). DNA protective effects of the extracts were confirmed by Raman spectroscopy, where, the MNU-DNA interaction, as evidenced by an intense peak at 1254 cm(-1), was normalized. The findings demonstrate hepatoprotective, immunomodulatory and anti-carcinogenic effects and suggest the use of mushrooms as potential dietary prophylactics in cancer chemoprevention.

Fruit peel polyphenols demonstrate substantial anti-tumour effects in the model of breast cancer.

PURPOSE: Fruit and vegetable intake is inversely correlated with cancer; thus, it is proposed that an extract of phytochemicals as present in whole fruits, vegetables, or grains may have anti-carcinogenic properties. Thus, the anti-tumour effects of fruit peel polyphenols (Flavin7) in the chemoprevention of N-methyl-N-nitrosourea-induced mammary carcinogenesis in female rats were evaluated. METHODS: Lyophilized substance of Flavin7 (F7) was administered at two concentrations of 0.3 and 3 % through diet. The experiment was terminated 14 weeks after carcinogen administration, and mammary tumours were removed and prepared for histopathological and immunohistochemical analysis. In addition, using an in vitro cytotoxicity assay, apoptosis and proliferation after F7 treatment in human breast adenocarcinoma (MCF-7) cells were performed. RESULTS: High-dose F7 suppressed tumour frequency by 58 % (P < 0.001), tumour incidence by 24 % (P < 0.05), and lengthened latency by 8 days (P > 0.05) in comparison with the control rats, whereas lower dose of F7 was less effective. Histopathological analysis of tumours showed significant decrease in the ratio of high-/low-grade carcinomas after high-dose F7 treatment. Immunohistochemical analysis of rat carcinoma cells in vivo found a significant increase in caspase-3 expression and significant decrease in Bcl-2, Ki67, and VEGFR-2 expression in the high-dose group. Both doses demonstrated significant positive effects on plasma lipid metabolism in rats. F7 significantly decreased survival of MCF-7 cells in vitro in MTT assay by dose- and time-dependent manner compared to control. F7 prevented cell cycle progression by significant enrichment in G1 cell populations. Incubation with F7 showed significant increase in the percentage of annexin V-/PI-positive MCF-7 cells and DNA fragmentation. CONCLUSIONS: Our results reveal a substantial tumour-suppressive effect of F7 in the breast cancer model. We propose that the effects of phytochemicals present in this fruit extract are responsible for observed potent anti-cancer activities.

Normolipidic dietary fat modifies circulating Renin-Angiotensin system-regulating aminopeptidase activities in rat with breast cancer.

HYPOTHESIS: Renin-angiotensin system (RAS) has been considered not only as a regulator of systemic volume and electrolyte balance but also has been recently involved in various pathological processes such as cancer. In the etiology of breast cancer, dietary factors have been analyzed and especially the influence of dietary fat has been studied, but the underlying mechanisms remain unclear. In this study, we analyzed RAS-regulating enzymes in serum of rats with N-methyl nitrosourea (NMU)-induced breast cancer fed with different diets. STUDY DESIGN: Four groups of rats were injected intraperitoneally with 3 doses of 50 mg/kg body weight of NMU at different days after birth and were fed with an AIN-93 commercial diet or AIN-93 diets with 4% fat constituted respectively by extra virgin olive oil, refined sunflower oil, and refined sunflower oil enriched to 50% with oleic acid. METHOD: After sacrifice, blood and tumor samples were collected by spectrophotometric determinations of RAS-regulating enzymes in plasma and histopathology studies. RESULTS: We show that the type of dietary fat does not influence latency period, incidence of animals with tumors, incidence of mortality, or tumor yield per rat. However, changes were observed in tumor volume and the histopathology. The type of dietary fat also differently modified the enzymes involved in RAS regulation. CONCLUSIONS: It might suggest that one of the mechanisms by which dietary fat affects breast cancer is the modification of the RAS system, which may be consider as a new target for integrative therapies.

Evaluation of the immunological cellular response of Cebus apella exposed to the carcinogen N-methyl-N-nitrosourea and treated with CANOVA®.

The immune response modifier Canova® is a homeopathic remedy indicated for patients with depressed immune system, since this drug appears to increase adaptive immunity and induce an immune response against multiple and severe pathological conditions, including cancer. We evaluated the pattern of immune cellular response in non-human primates of the species Cebus apella exposed to N-methyl-N-nitrosourea (MNU) with and without Canova®. Twelve animals were divided into four groups, with three animals each: negative control and three experimental groups, MNU-alone (35 days); MNU (35 days)-plus-Canova® (3 days) and Canova®-alone (3 days). The animals received MNU orally and Canova® by three intravenous injections. Evaluation of the cellular immune response was performed by immunophenotyping of T-lymphocytes (CD4(+), CD8(+)), B-lymphocytes and natural killer cells. Analysis was also performed of the cell cycle. Our results suggest an increase of T-lymphocytes (CD4(+)CD3(+)) only in the Canova® group, while in the MNU-plus-Canova® group only B-lymphocytes increased.

Green tea extract suppresses N-methyl-N-nitrosourea-induced photoreceptor apoptosis in Sprague-Dawley rats.

BACKGROUND: Retinitis pigmentosa (RP) is a group of inherited neurodegenerative human diseases characterized by the loss of photoreceptor cells by apoptosis and eventual blindness. A single intraperitoneal (ip) injection of N-methyl-N-nitrosourea (MNU) causes photoreceptor cell apoptosis within 7 days in rats. Green tea extract (THEA-FLAN 90S; GTE) is a common herbal supplement with pluripotent properties including antioxidant activity. The purpose of the present study was to evaluate the efficacy of GTE against photoreceptor apoptosis in 7-week-old female Sprague-Dawley rats that received a single ip injection of 40 mg/kg MNU. METHODS: The oral administration of 250 mg/kg/day GTE was initiated 3 days prior to MNU injection and continued once daily throughout the experiment. Rats were sacrificed at 12, 24, and 72 h and 7 days after MNU injection, and the eyes were examined morphologically and morphometrically. The photoreceptor cell ratio, retinal damage ratio, and retinal preservation ratio were used to determine the structural and functional alterations. The number of apoptotic photoreceptor cells per mm(2) was determined in situ by TdT-mediated dUTP-digoxigenin nick end labeling (TUNEL). Our results indicated that oral administration of GTE significantly suppressed the loss of photoreceptor cells morphometrically 7 days after MNU injection. The number of TUNEL-positive cells per mm(2) in MNU-exposed rat central retina with or without GTE administration was 981 vs. 2056 at 24 h after MNU injection. CONCLUSIONS: GTE structurally and functionally suppressed MNU-induced photoreceptor cell apoptosis. These findings indicate that GTE may help to ameliorate the onset and progression of human RP.

Cyanidin-3-glucoside extracted from mulberry fruit can reduce N-methyl-N-nitrosourea-induced retinal degeneration in rats.

PURPOSE: To investigate the effect of cyanidin-3-O-glucoside (C3G) on a rat retinal degeneration (RD) model. MATERIALS AND METHODS: Experimental RD was induced in rats by the intraperitoneal injection of N-methyl-N-nitrosourea (MNU) at 50 mg/kg. C3G extracted from mulberry (Morus alba L.) fruit (50 mg/kg) was orally administered, daily for 1, 2 and 4 weeks after MNU injection. The effects of C3G administration on MNU-induced RD retinas were histologically and functionally assessed by hematoxylin and eosin staining and electroretinography (ERG), respectively. The degree of retinal injury in C3G-administered RD rats was evaluated by immunohistochemistry with an antibody against glial fibrillary acidic protein (GFAP). The preferential protective effect of C3G on scotopic vision was examined by western blot analysis. RESULTS: Marked loss of photoreceptors in the outer nuclear layer (ONL) was observed in RD rats at 2 and 4 weeks after MNU injection, while the ONL in the MNU-induced RD rats given C3G was relatively well preserved. Immunohistochemistry with anti-GFAP showed that retinal injury was also reduced in the retinas of the rats given C3G. Functional assessment by using ERG recordings showed that scotopic ERG responses were significantly increased in RD rats given C3G for 4 weeks (p < 0.01) compared with that of untreated RD rats. In the RD rats given short-term C3G (for 1 and 2 weeks), the increase in ERG responses was not significant. In addition, western blot analysis showed that rhodopsin level in the C3G-administered RD retinas significantly increased compared to that in the non-administered RD retinas (p < 0.05), whereas red/green opsin level did not show any significant difference. CONCLUSIONS: Long-term administration of C3G extracted from mulberry fruit could structurally reduce photoreceptor damage and functionally improve scotopic visual functions in the RD rat model induced by MNU.

Maternal dietary canola oil suppresses growth of mammary carcinogenesis in female rat offspring.

As suggested by rodent studies and studies using human breast cancer cells, dietary canola oil is linked with lower breast cancer risk. Here, we investigated the effect of maternal (pregnancy plus lactation) dietary canola oil on the susceptibility of female Sprague-Dawley rat offspring to mammary carcinogenesis. Although the control diet had 10% soybean oil, the treatment diet was formulated to contain 10% canola oil as a fat source. N-nitroso-N-methylurea was injected to induce mammary cancer in offspring. The offspring of canola-fed dams showed significantly decreased tumor multiplicity (1.0 ± 0.3 vs. 1.9 ± 0.3, respectively; P = 0.04) and tumor volume (1232.5 ± 771.0 mm(3) vs. 6,302.5 ± 1,747.4 mm(3), respectively; P = 0.01), along with increased survival rate (87% vs. 47%, respectively; P = 0.01). In addition, the mRNA expression of development-related gamma-glutamyltransferase 1 was significantly higher in the lactating mammary tissues of the canola group dams and mammary tumor tissues of the offspring [2.5 ± 0.6 vs. 0.5 ± 0.2, respectively (P = 0.01) and 0.98 ± 0.03 vs. 0.56 ± 0.15, respectively (P = 0.05)]. These results suggest a potential anticancer effect of maternal dietary canola oil and may be useful in devising prenatal nutritional strategies to reduce breast cancer risk in humans.

Effect of an extract of Withania somnifera root on estrogen receptor-positive mammary carcinomas.

The chemopreventive activity of an extract of Withania somnifera (WS) roots was examined in female Sprague-Dawley rats that received the mammary carcinogen methylnitrosourea (MNU). The dose of the extract, administered by gavage, was 150 mg/kg body weight daily for 155 days, after injection of MNU. Rats in the treated group (N=15) had an average of 3.47 tumors, and rats in the control group (N=15) had 4.53, a reduction of 23%. The average weights of tumors were 4.98 g for rats in the treated group and 6.30 g for the controls, a difference of 21%. Labeling indices for Ki67 and proliferating cell nuclear antigen (PCNA) markers in cancers of the treated group were 42% and 38% lower, respectively, than those of the corresponding indices for the control group. These results indicate that the root extract significantly reduced the rate of cell division in the mammary tumors.

Effects of astaxanthin supplementation on chemically induced tumorigenesis in Wistar rats.

BACKGROUND: Astaxanthin (ASTA) is a fat-soluble xanthophyll with powerful antioxidant functions. It is extracted from e.g. salmon, an important food source for certain human populations known to have a reduced risk of tumor development. It is possible that ASTA plays a role in cancer chemoprevention in such populations. The purpose of this study was to investigate the effects of dietary ASTA on chemically induced mammary tumorigenesis using N-methyl-N-nitroso-urea (MNU) in immature Wistar rats. METHODS: Thirty-six 37 days old juvenile female Wistar rats were at random allocated to 4 groups of which Groups 1 and 2 received a single dose of 55 mg MNU/kg body weight. The effects of ASTA was evaluated by giving rats of Groups 2 and 4 a dose of 50 mg ASTA/kg/day for the entire duration of the study. Group 3 rats received feed added alimentary oil.Necropsy and histopathological examinations were carried out on each rat 14 months after the administration of MNU. Haematological values and antioxidative status were determined. Oxidative stress was evaluated by monitoring superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in hepatic tissue. Lipid peroxidation and carbonylation of proteins was determined in protein extracts from the liver. RESULTS: Tumor development occurred only in rats of Groups 1 and 2, i.e. MNU exposed animals. Frequency of tumor development in general and average number of tumors per animal were insignificant between these two groups. Mammary gland tumors developed in equal frequencies in Group 1 and 2 rats, respectively. Although only rather few tumors were found in the mammary glands, a substantial number of other tumors were found in Group 1 and 2 rats, but at equal rates.Biochemical analyses showed significant higher levels of GPx, malondialdehyde and dinitrophenylhydrazine in Group 1 rats that for rats in all other groups thus indicating protective effects of ASTA on MNU induced hepatic oxidative stress. CONCLUSIONS: Supplementation with ASTA did not reduce tumorigenesis induced by MNU in Wistar rats. However, supplementation with ASTA seemed to have anti-inflammatory effects.

Protection by Salvia extracts against oxidative and alkylation damage to DNA in human HCT15 and CO115 cells.

DNA damage induced by oxidative and alkylating agents contributes to carcinogenesis, leading to possible mutations if replication proceeds without proper repair. However, some alkylating agents are used in cancer therapy due to their ability to induce DNA damage and subsequently apoptosis of tumor cells. In this study, the genotoxic effects of oxidative hydrogen peroxide (H2O2) and alkylating agents N-methyl-N-nitrosourea (MNU) and 1,3-bis-(2-chloroethyl)-1-nitosourea (BCNU) agents were examined in two colon cell lines (HCT15 and CO115). DNA damage was assessed by the comet assay with and without lesion-specific repair enzymes. Genotoxic agents were used for induction of DNA damage in both cell lines. Protective effects of extracts of three Salvia species, Salvia officinalis (SO), Salvia fruticosa (SF), and Salvia lavandulifolia (SL), against DNA damage induced by oxidative and alkylating agents were also determined. SO and SF protected against oxidative DNA damage in HCT15 cells. SO and SL decreased DNA damage induced by MNU in CO115 cells. In addition to chemopreventive effects of sage plant extracts, it was also important to know whether these plant extracts may interfere with alkylating agents such as BCNU used in cancer therapy, decreasing their efficacy. Our results showed that sage extracts tested and rosmarinic acid (RA), the main constituent, protected CO115 cells from DNA damage induced by BCNU. In HCT15 cells, only SF induced a reduction in BCNU-induced DNA damage. Sage water extracts and RA did not markedly change DNA repair protein expression in either cell line. Data showed that sage tea protected colon cells against oxidative and alkylating DNA damage and may also interfere with efficacy of alkylating agents used in cancer therapy.