The Chemopreventive Effects of Polyphenols and Coffee, Based upon a DMBA Mouse Model with microRNA and mTOR Gene Expression Biomarkers.

Polyphenols are capable of decreasing cancer risk. We examined the chemopreventive effects of a green tea (Camellia sinensis) extract, polyphenol extract (a mixture of blackberry (Rubus fruticosus), blackcurrants (Ribes nigrum), and added resveratrol phytoalexin), Chinese bayberry (Myrica rubra) extract, and a coffee (Coffea arabica) extract on 7,12-dimethylbenz[a]anthracene (DMBA) carcinogen-increased miR-134, miR-132, miR-124-1, miR-9-3, and mTOR gene expressions in the liver, spleen, and kidneys of CBA/Ca mice. The elevation was quenched significantly in the organs, except for miR-132 in the liver of the Chinese bayberry extract-consuming group, and miR-132 in the kidneys of the polyphenol-fed group. In the coffee extract-consuming group, only miR-9-3 and mTOR decreased significantly in the liver; also, miR-134 decreased significantly in the spleen, and, additionally, miR-124-1 decreased significantly in the kidney. Our results are supported by literature data, particularly the DMBA generated ROS-induced inflammatory and proliferative signal transducers, such as TNF, IL1, IL6, and NF-κB; as well as oncogenes, namely RAS and MYC. The examined chemopreventive agents, besides the obvious antioxidant and anti-inflammatory effects, mainly blocked the mentioned DMBA-activated factors and the mitogen-activated protein kinase (MAPK) as well, and, at the same time, induced PTEN as well as SIRT tumor suppressor genes.

Salvadora persica attenuates DMBA-induced mammary cancer through downregulation oxidative stress, estrogen receptor expression and proliferation and augmenting apoptosis.

Naturally occurring phytochemicals especially polyphenolic compounds have received increasing attention as chemopreventive agents. The chemopreventive potential of the ethanolic extract of Salvadora persica L. fruits SP, (the arak tree or miswak) on 7,12-dimethylbenz (a) anthracene (DMBA)-induced mammary carcinogenesis in female albino rats was investigated in this work. Ethanolic extract of SP fruits was supplemented to the experimental groups at a concentration of 500 mg/kg body weight for 22 weeks. Administration of SP extract suppressed DMBA-induced mammary carcinogenesis as revealed by incidence of tumors in histological investigation. There was a significant reduction in cell proliferation and an increase in apoptosis with downregulation of estrogen receptor expression in the mammary tissue of SP-treated animals. Additionally, SP extract prevented the oxidative damage induced in breast tissues of DMBA-treated rats. SP treatment also decreased the viability of MCF-7 breast cancer cells and induced early and late apoptosis and induced S cell cycle arrest. The chemo-preventive properties and anticancer effects of SP could be attributed to its anti-oxidative and a high percentage of phenolic compounds and esters which were detected here in the SP fruit extract.

In Vitro Cytotoxicity and In Vivo Antimammary Tumor Effects of the Hydroethanolic Extract of Acacia seyal (Mimosaceae) Stem Bark.

The present study was designed to evaluate the in vitro and in vivo antitumor effects of A. seyal hydroethanolic extract on breast cancer. The cytotoxicity of A. seyal extract was evaluated using resazurin reduction assay in 9 cell lines. Further, the protective effect of the hydroethanolic extract of A. seyal stem barks was evaluated on 7,12-dimethylbenz(a)anthracene- (DMBA-) induced breast cancer rat model. Incidence, burden, volume, and histological analysis of mammary tumors were measured. The Acacia seyal extract exhibited CC50 of 100 in MCF-7 cells after 24 h. In vivo, no tumors were detected in rats from the control group, while 11 rats out of 12 (91.66%) developed mammary tumors in the DMBA-exposed group receiving only the vehicle. Acacia seyal extract significantly (p < 0.01) and in the dose-dependent manner reduced tumor incidence (3 rats out of 12 at the dose of 300 mg/kg), burden [62.1% (150 mg/kg) and 65.8% (300 mg/kg)], and mass. It protected rats against DMBA-induced breast hyperplasia, with an optimal effect at the dose of 300 mg/kg. Taken altogether, these results suggest that the hydroethanolic extract of Acacia seyal might contain phytoconstituents endowed with antitumoral properties, which could protect against the breast cancer induced in rats.

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.

Uterine responses to feeding soy protein isolate and treatment with 17ß-estradiol differ in ovariectomized female rats.

There are concerns regarding reproductive toxicity from consumption of soy foods, including an increased risk of endometriosis and endometrial cancer, as a result of phytoestrogen consumption. In this study, female rats were fed AIN-93G diets made with casein (CAS) or soy protein isolate (SPI) from postnatal day (PND) 30, ovariectomized on PND 50 and infused with 5 µg/kg/d 17ß-estradiol (E2) or vehicle. E2 increased uterine wet weight (P<0.05). RNAseq analysis revealed that E2 significantly altered expression of 1991 uterine genes (P<0.05). SPI feeding had no effect on uterine weight and altered expression of far fewer genes than E2 at 152 genes (P<0.05). Overlap between E2 and SPI genes was limited to 67 genes. Functional annotation analysis indicated significant differences in uterine biological processes affected by E2 and SPI and little evidence for recruitment of estrogen receptor (ER)α to the promoters of ER-responsive genes after SPI feeding. The major E2 up-regulated uterine pathways were carcinogenesis and extracellular matrix organization, whereas SPI feeding up-regulated uterine peroxisome proliferator activated receptor (PPAR) signaling and fatty acid metabolism. The combination of E2 and SPI resulted in significant regulation of 504 fewer genes relative to E2 alone. The ability of E2 to induce uterine proliferation in response to the carcinogen dimethybenz(a)anthracene (DMBA) as measured by expression of PCNA and Ki67 mRNA was suppressed by feeding SPI (P<0.05). These data suggest that SPI is a selective estrogen receptor modulator (SERM) interacting with a small sub-set of E2-regulated genes and is anti-estrogenic in the presence of endogenous estrogens.

Modulatory effects of Azadirachta indica leaf extract on cutaneous and hepatic biochemical status during promotion phase of DMBA/TPA-induced skin tumorigenesis in mice.

The modulation in biochemical status of skin and hepatic tissue at the time point of commencement of promotion stage of skin carcinogenesis in mice and its intervention with aqueous Azadirachta indica leaf extract (AAILE) were investigated. 7,12-Dimethylbenz(a)anthracene (DMBA, 500 nmol/100 ul of acetone) was applied topically for 2 weeks (twice weekly), followed by phorbol-12-myristate-13-acetate (TPA, 1.7 nmol/100 ul) twice weekly for 6 weeks on the depilated skin of mice and AAILE was administered orally at a dose level of 300 mg/kg body wt thrice a week for 10 weeks. DMBA/TPA treatment upregulated the phase I enzymes in skin and hepatic tissue, as revealed by the increased cytochrome P450 (CYP) and cytochrome b5 (cyt b5) levels and aryl hydrocarbon hydroxylase (AHH) activity when compared to the control group and differentially modulated the activities of phase II enzymes like glutathione-s-transferase (GST), DT-diaphorase (DTD) and uridine diphosphate glucuronosyltransferase (UDP-GT). AAILE treatment decreased the DMBA/TPA-induced increase in cutaneous CYP level and enhanced the DTD and UDP-GT activities when compared with DMBA/TPA group. In the hepatic tissue of AAILE + DMBA/TPA group, an increase in UDP-GT activity was observed when compared to DMBA/TPA group. DMBA/TPA treatment did not alter the skin lipid peroxidation (LPO) level when compared to control group, however, in the animals that received AAILE treatment along with DMBA/TPA, a significant increase in LPO was observed when compared to control group. This was associated with a decrease, in cutaneous reduced glutathione (GSH) level of AAILE + DMBA/TPA group. Enhanced LPO level was observed in the hepatic tissue of DMBA/TPA and AAILE + DMBA/TPA groups when compared to control group. However, no alteration was observed in their hepatic GSH levels. The micronuclei score in hepatic tissue did not exhibit significant inter-group differences. The results of the present study suggest that apart from skin, liver may be affected during DMBA/TPA-induced skin tumorigenesis. AAILE treatment has the ability to modulate these changes potentially influencing the process of tumor formation. These findings seem to be important to carcinogenesis and its intervention with anti-cancer agents.

Effect of the phenolic compounds apigenin and carnosic acid on oral carcinogenesis in hamster induced by DMBA.

OBJECTIVE: To investigate oral carcinogenesis in hamster induced by the topical application of 7,12-dimethyl benzanthracene (DMBA) to evaluate the different lesions produced and the possible preventive effects of the phenolic compounds apigenin (flavone) and carnosic acid (diterpene). MATERIALS AND METHODS: Thirty-two Syrian hamsters were divided into three groups: I: 0.5% DMBA (n = 12); II: 0.5% DMBA + potassium apigenin (n = 8); III: 0.5% DMBA + carnosic acid (n = 12). All the animals were sacrificed after 11 weeks, and a macroscopic and light microscopic study was made of the lesions. RESULTS: The largest number of neoplasms, showing the most aggressive biological behavior, corresponded to the control group. The group treated with potassium apigenin ranked second in tumor incidence, although the tumors were not very aggressive behavior. In the group treated with carnosic acid, only one malignancy was recorded, showing the smallest volume of all the recorded tumor lesions. CONCLUSIONS: Our findings indicate that both potassium apigenin and carnosic acid have chemoprotective effects against carcinogenesis induced by DMBA in hamster.

Human breast adenocarcinoma cytotoxicity and modulation of 7,12-dimethylbenz[a]anthracene-induced mammary carcinoma in Balb/c mice by Acacia catechu (L.f.) Wild heartwood.

OBJECTIVE: The chemopreventive potential of (+)-catechin-rich extract of Acacia catechu (L.f.) Willd. heartwood (AQCE) was evaluated against human breast adenocarcinoma cell line (MCF-7) and 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary carcinoma in Balb/c mice. METHODS: Cell cytotoxicity was investigated using different colorimetric assays. Apoptosis was observed using diphenylamine assay and fluorescent microscopy. AQCE was further evaluated for antitumor activity against DMBA-induced mammary carcinoma. The levels of tumor markers and oxidative stress were measured. Furthermore, level of transcription factors was measured by enzyme-linked immunosorbent assay. RESULTS: The results showed that administration of AQCE showed a dose-dependent growth inhibition response and DNA fragmentation in MCF-7 cells. Tumor multiplicity was significantly decreased to 42.91% with AQCE when compared with DMBA-treated animals. The levels of tumor markers such as total sialic acid and lipid-associated sialic acid were substantially increased after DMBA treatment. However, AQCE treatment restored tumor markers level. AQCE also significantly reduced elevated levels of nitrite and malondialdehyde in DMBA-treated animals. Additionally, AQCE also increased the activities of antioxidant enzymes, viz., catalase, superoxide dismutase, total thiol, reduced glutathione, protein thiol, glutathione peroxidase, glutathione reductase, and glutathione-S-transferase in the mammary tissue and liver mitochondria of DMBA-administered animals. Significant increase in the protein levels of p53, c-jun, and p65 were observed in DMBA-treated mice, whereas less expression was observed in AQCE-treated animals. Eventually, AQCE also significantly improved body weight and maintained the mammary tissue architecture in normal range. CONCLUSIONS: The present data strongly suggest that anticancer potentiality of (+)-catechin-rich AQCE may be attributable to its ability to positively modulate tumor markers as well as the antioxidant system that could decompose the peroxides and, thereby, offer a protection against lipid peroxidation and linked to the expression of transcription factors during DMBA-induced mammary carcinoma.

Anticlastogenic effect of Eryngium foetidum L. assessed by erythrocyte micronucleus assay.

The aim of this study was to investigate the anticlastogenicity as well as the clastogenicity of Eryngium foetidum leaf (EF) using the in vivo mouse peripheral blood erythrocyte micronucleus assay. Eighty ICR male mice were fed AIN-76 diet supplemented with ground freeze-dried EF at 0.0%, 0.8%, 1.6% and 3.2% for 2 weeks prior to the administration of both direct-acting, mitomycin C (MMC), and indirect-acting, 7, 12-dimethylbenz(a) anthracene (DMBA) clastogens. Peripheral blood samples were collected from mice just before administration of clastogen and at 24 and 48 h thereafter for MMC. Blood samples were collected at the same times and after 72 h for DMBA. Then, reticulocytes in blood samples were counted using fluorescent microscopy. The results indicated that EF had no clastogenic effect in mice. All doses of diets supplemented with EF decreased the number of micronucleated peripheral reticulocytes in all the MMC-treated groups in a dose dependent manner, but significant reduction was found only at 1.6% and 3.2% EF in the DMBA-treated groups. It can be concluded that EF has no clastogenicity, but possesses anticlastogenic potential against both direct- and indirect-acting types of clastogen in mice.

The effect of dietary zinc--and polyphenols intake on DMBA-induced mammary tumorigenesis in rats.

BACKGROUND: The aim of the study was to investigate the effect of dietary supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein, on the effectiveness of chemically induced mammary cancer and the changes in the content of selected elements (Zn, Cu, Mg, Fe, Ca) in tumors as compared with normal tissue of the mammary gland. METHODS: Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet and DMBA (7,12-dimethyl-1,2- benz[a]anthracene), were treated with zinc ions (Zn) or zinc ions + resveratrol (Zn + resveratrol) or zinc ions + genistein (Zn + genistein) via gavage for a period from 40 days until 20 weeks of age. The ICP-OES (inductively coupled plasma optical emission spectrometry) technique was used to analyze the following elements: magnesium, iron, zinc and calcium. Copper content in samples was estimated in an atomic absorption spectrophotometer. RESULTS: Regardless of the diet (standard; Zn; Zn + resveratrol; Zn + genistein), DMBA-induced breast carcinogenesis was not inhibited. On the contrary, in the Zn + resveratrol supplemented group, tumorigenesis developed at a considerably faster rate. On the basis of quantitative analysis of selected elements we found--irrespectively of the diet applied--great accumulation of copper and iron, which are strongly prooxidative, with a simultaneous considerable decrease of the magnesium content in DMBA-induced mammary tumors. The combination of zinc supplementation with resveratrol resulted in particularly large differences in the amount of the investigated elements in tumors as compared with their content in normal tissue. CONCLUSIONS: Diet supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein had no effect on the decreased copper level in tumor tissue and inhibited mammary carcinogenesis in the rat. Irrespectively of the applied diet, the development of the neoplastic process in rats resulted in changes of the iron and magnesium content in the cancerous tissue in comparison with the healthy mammary tissue. The application of combined diet supplementation with zinc ions and resveratrol considerably promoted the rate of carcinogenesis and increased the number of DMBA-induced mammary tumors.

Chemopreventive activity of Azadirachta indica on two-stage skin carcinogenesis in murine model.

The present study reports the chemopreventive activity of aqueous Azadirachta indica leaf extract (AAILE) in a murine two-stage skin carcinogenesis model. Skin tumors were induced by topical application of 7,12-dimethylbenz(a)anthracene (DMBA) (500 nmol/100 µL for 2 weeks) followed by 12-O-tetradecanoylphorbol-13-acetate (TPA) (1.7 nmol/100 µL of acetone, twice weekly) as a promoter. Male LACA mice were divided into four groups: control, DMBA/TPA, AAILE and AAILE + DMBA/TPA. AAILE was administered orally at a dose level of 300 mg/kg body weight thrice a week for 20 weeks. 100% tumor incidence was observed in the DMBA/TPA treated animals, whereas the AAILE + DMBA treated animals exhibited a tumor incidence of 58.3% only. A significant reduction in the mean tumor burden (54.5%) and mean tumor volume (45.6%) was observed in the mice that received AAILE along with DMBA/TPA. Topical application of DMBA/TPA to the skin resulted in well-developed carcinomas associated with decreased expression of pro-apoptotic protein such as caspase 3 and enhanced expression of antiapoptotic protein such as bcl-2 when compared with the control counterparts. However, adminstration of AAILE inhibited skin carcinogenesis with induction of pro-apoptotic proteins such as bax, caspase 3, caspase 9 and inhibition of antiapoptotic proteins such as bcl-2. These results suggest that the induction of apoptosis may be one of the mechanisms underlying the chemopreventive effects of A. indica.

Chemopreventive potential of 18beta-glycyrrhetinic acid: an active constituent of liquorice, in 7,12-dimethylbenz(a)anthracene induced hamster buccal pouch carcinogenesis.

Chemoprevention, a useful and attractive approach in experimental oncology, helps to investigate the cancer preventive potential of natural products and synthetic entities. Present study evaluated the chemopreventive potential of glycyrrhetinic acid in 7,12-dimethylbenz(a)anthracene (DMBA) induced hamster buccal pouch carcinogenesis. Oral tumor was developed in the buccal pouch of golden Syrian hamsters by painting with DMBA three times a week for 14 weeks. The tumor incidence and the status of phase I and phase II detoxification enzymes were assessed in hamsters treated with DMBA alone and DMBA+glycyrrhetinic acid treated hamsters. One hundred percent tumor formations, which were histopathologically confirmed as well-differentiated squamous cell carcinoma, were observed in hamsters treated with DMBA alone. Also, the status of detoxification enzymes were markedly altered in the liver and buccal mucosa of hamsters treated with DMBA alone. Oral administration ofglycyrrhetinic acid at a dose of 45 mg kg(-1) body weight to hamsters treated with DMBA completely prevented the tumor formation as well as restored the status of detoxification enzymes. Present study thus demonstrated the chemopreventive potential of glycyrrhetinic acid in DMBA induced oral carcinogenesis.

Chemomodulatory effects of Aegle marmelos against DMBA-induced skin tumorigenesis in Swiss albino mice.

Aegle marmelos is widely used in Indian Ayurvedic medicine for the treatment of diabetes mellitus. In the present study, cancer chemopreventive properties were evaluated on 7, 12-dimethylbenz (a) anthracene (DMBA) induced skin papillomagenesis in Swiss albino mice. A single topical application of DMBA, followed 2 weeks later by repeated application of croton oil till the end of the experiment ( i.e. 16 weeks) caused a 100% tumor incidence. In contrast, mice treated with the AME (50 mg/kg b. wt./animal/day) in the peri-initiational phase (i.e. 7 days before and 7 days after DMBA application; Group IV) and post-initiational phase (from the day of croton oil treatment till the end of the experiment; Group V), exhibited a significant reduction to 70 and 50% respectively. The cumulative number of papillomas after 16 weeks was 67 in the control group, but 26 and 23 in the animals treated with AME at peri-initiational and post-initiational stages, respectively. The tumor burden and tumor yield were significantly decreased (Group IV-3.7, 2.6; Group V- 4.6, 2.3) as compared to carcinogen treated control group (6.7, 6.7). The present study demonstrates the chemopreventive potential of Aegle marmelos fruit extract on DMBA induced skin tumorigenesis in mice.

Anticancer activity of an Indian medicinal plant, Alstonia scholaris, on skin carcinogenesis in mice.

Alstonia scholaris, commonly known as sapthaparna, has been used for centuries in Ayurvedic medicine for treatment of various disorders. The objective of this study was to investigate the possible chemopreventive and anti-oxidative properties of this medicinal plant on two-stage process of skin carcinogenesis induced by a single application of 7, 12-dimethyabenz(a)anthrecene (100 lg/100 ll acetone), and two weeks later, promoted by repeated application of croton oil (1% in acetone/thrice a week) till the end of the experiment (16 weeks) in Swiss albino mice.The tumor incidence, tumor yield, tumor burden and cumulative number of papillomas were found to be higher in the carcinogen treated control (without ASE treatment) as compared to experimental animals (ASE treated). Furthermore, a significant increase in reduced glutathione, superoxide dismutase and catalase but decrease in lipid peroxidation was measured in ASE administered experimental groups than the carcinogen treated control. The present study demonstrates the chemopreventive potential of Alstonia scholaris bark extract in DMBA-induced skin tumorigenesis in Swiss albino mice.

Lantadenes and their esters as potential antitumor agents.

Lantadenes are pentacyclic triterpenoids of the weed Lantana camara. Five new lantadenes (14-18) and their methyl esters (20-24) were synthesized, characterized, and screened for cytotoxicity against four human cancer cell lines. The parent compound (1) and the four most active compounds (15, 16, 21, and 22) were further studied for their in vivo tumor inhibitory potential on squamous cell carcinogenesis in Swiss albino mice induced by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). These results were supported by histopathological studies and discussed in terms of structure-activity relationships. The results inferred the importance of the groups attached to C-22 and C-17 in relation to the antitumor activity of these compounds.

Control of peripheral benzodiazepine receptor-mediated breast cancer in rats by soy protein.

Soy protein is known to have breast tumor suppressing activity. The expression of peripheral benzodiazepine receptors (PBRs), currently renamed as translocator protein (TSPO) and their associated functions, such as nuclear cholesterol uptake and content also have been shown to be increased in breast cancer. Here we investigated whether the breast tumor suppressing effects of soy protein is mediated by down-regulation of PBR expression and function. Breast tumors were induced by gavage administration of a single dose (80 mg/kg) of dimethylbenz[a]anthracene (DMBA) into 50-d old female Sprague Dawley rats, maintained on a standard AIN-76A diet containing either casein or soy protein. Approximately 120 d following DMBA administration, the animals were sacrificed. All tumors were detected by palpation and at autopsy biopsy specimens were taken for histological grading. The ligand binding capacity, expression, and protein levels of PBRs, their nuclear localization and function, such as nuclear cholesterol uptake and content, were significantly increased in the tumors. However, replacement of casein by soy protein in the diet caused a significant decrease in all of these parameters. These data suggest that soy protein inhibits breast tumor development by decreasing the expression of the tumor-promoting gene, which encodes PBRs.

Ocimum sanctum Linn. (Holy Basil) ethanolic leaf extract protects against 7,12-dimethylbenz(a)anthracene-induced genotoxicity, oxidative stress, and imbalance in xenobiotic-metabolizing enzymes.

The present study was designed to evaluate the protective effects of ethanolic Ocimum sanctum leaf extract against 7,12-dimethylbenz[a]anthracene (DMBA)-induced genotoxicity, oxidative stress, and imbalance in xenobiotic-metabolizing enzymes. Four different concentrations of ethanolic O. sanctum leaf extract (100, 200, 300, and 400 mg/kg of body weight) were administered to Wistar rats by intragastric intubation for five consecutive days followed by intraperitoneal injection of DMBA (35 mg/kg of body weight) 90 minutes after the final dose of the extract. Administration of DMBA increased bone marrow micronuclei, phase I enzymes, lipid peroxidation, and protein carbonyl formation. This was accompanied by a significant decrease in the activities of phase II detoxification enzymes and antioxidants in the liver, erythrocytes, and bone marrow. Pretreatment with ethanolic O. sanctum leaf extract at a concentration of 300 mg/kg of body weight significantly reduced micronuclei formation and phase I enzymes as well as lipid and protein oxidation with enhanced antioxidant and phase II enzyme activities. The results of the present study suggest that ethanolic O. sanctum leaf extract inhibits DMBA-induced genotoxicity and oxidative stress by modulating xenobiotic-metabolizing enzymes, reducing the extent of lipid and protein oxidation and up-regulating antioxidant defenses.

Cucurbitane-type triterpenoids from the fruits of Momordica charantia and their cancer chemopreventive effects.

Thirteen cucurbitane-type triterpene glycosides, including eight new compounds named charantosides I (6), II (7), III (10), IV (11), V (12), VI (13), VII (16), and VIII (17), and five known compounds, 8, 9, 14, 15, and 18, were isolated from a methanol extract of the fruits of Japanese Momordica charantia. The structures of the new compounds were determined on the basis of spectroscopic methods. On evaluation of these triterpene glycosides and five other cucurbitane-type triterpenes, 1-5, also isolated from the extract of M. charantia fruits, for their inhibitory effects on the induction of Epstein-Barr virus early antigen (EBV-EA) by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, these compounds showed inhibitory effects on EBV-EA induction with IC(50) values of 200-409 mol ratio/32 pmol TPA. In addition, upon evaluation of compounds 1-5 for inhibitory effects against activation of (+/-)-(E)-methyl-2[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexemide (NOR 1), a nitrogen oxide (NO) donor, compounds 1-3 showed moderate inhibitory effects. Compounds 1 and 2 exhibited marked inhibitory effects in both 7,12-dimethylbenz[a]anthracene (DMBA)- and peroxynitrite (ONOO-; PN)-induced mouse skin carcinogenesis tests.

Induction of apoptosis by 9,10-dimethyl-1,2-benzanthracene in cultured preovulatory rat follicles is preceded by a rise in reactive oxygen species and is prevented by glutathione.

The polycyclic aromatic hydrocarbon (PAH) 9,10-dimethyl-1,2-benzanthracene (DMBA) destroys primordial, primary, and secondary ovarian follicles in rodents, but its effects on antral follicles have received limited attention. PAHs are metabolized to reactive species, some of which can undergo redox cycling to generate reactive oxygen species (ROS). We previously showed that ROS initiate apoptosis in preovulatory follicles cultured without gonadotropin support and that glutathione (GSH) depletion induces apoptosis in the presence of gonadotropins. In the present study, we tested the hypothesis that DMBA induces apoptosis in preovulatory follicles, which is mediated by ROS and prevented by GSH. Preovulatory follicles were isolated from ovaries of 25-day-old rats 48 h after the injection of 10 IU of eCG and were cultured with DMBA in the presence of FSH for 2 to 48 h. DMBA induced granulosa cell (GC) and theca cell (TC) apoptosis at 48 h, as judged by TUNEL and activated caspase-3 immunostaining. DMBA treatment also increased the numbers of GCs and TCs that immunostained for the proapoptotic protein BAX. Follicular ROS levels were significantly increased in DMBA-treated follicles at 12, 24, and 48 h. GSH supplementation protected against and GSH depletion enhanced the induction of apoptosis in GCs and TCs by DMBA. These findings suggest that GSH is a critical protective mechanism against DMBA-induced apoptosis in antral follicles and that ROS generation may mediate DMBA-induced GC apoptosis.

Triterpene acids from Poria cocos and their anti-tumor-promoting effects.

The structures of six new lanostane-type triterpene acids isolated from the epidermis of the sclerotia of Poria cocos were established to be 15alpha-hydroxydehydrotumulosic acid (5), 16alpha,25-dihydroxydehydroeburicoic acid (9), 5alpha,8alpha-peroxydehydrotumulosic acid (10), 25-hydroxyporicoic acid H (11), 16-deoxyporicoic acid B (12), and poricoic acid CM (16) on the basis of spectroscopic methods. On evaluation of these six and 11 other known triterpene acids isolated from the sclerotium, 1-4, 6-8, 13-15, and 17, against the Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells, all of the compounds except for 1, 3, 4, and 8 exhibited inhibitory effects with IC50 values of 195-340 mol ratio/32 pmol TPA. Compound 12 and poricoic acid C (13) exhibited inhibitory effects on skin tumor promotion in an in vivo two-stage carcinogenesis test using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter.