Search

The roots/rhizomes of Cimicifuga racemosa L. (Nutt.) (black cohosh) have traditionally been used to treat menopausal symptoms through an unknown mechanism of action. In an effort to determine if black cohosh had additional health benefits, methanol extracts were investigated for their potential to scavenge reactive oxygen species and to protect against menadione-induced DNA damage. These extracts effectively scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals. In addition, the extracts showed dose-dependent decreases in DNA single-strand breaks and oxidized bases induced by the quinone menadione using the comet (single-cell gel electrophoresis assay) and fragment length associated repair enzyme assays, respectively. Bioassay-directed fractionation of the methanolic extracts using the DPPH assay as a monitor led to the isolation of nine antioxidant active compounds: caffeic acid (1), methyl caffeate (2), ferulic acid (3), isoferulic acid (4), fukinolic acid (5), cimicifugic acid A (6), cimicifugic acid B (7), cimicifugic acid F (8), cimiracemate A (9), and cimiracemate B (10). Six of these antioxidants were found to reduce menadione-induced DNA damage in cultured S30 breast cancer cells with the following order of potency: methyl caffeate (2) > caffeic acid (1) > ferulic acid (3) > cimiracemate A (9) > cimiracemate B (10) > fukinolic acid (5). These data suggest that black cohosh can protect against cellular DNA damage caused by reactive oxygen species by acting as antioxidants. 50 7022 7028 Cited By :67

Traditional taxonomic methods of botanical identification that rely primarily on morphological observations cannot be used efficiently when only powdered plant materials are available. Thus, our objectives were to determine if we could apply a molecular approach to: a) produce unique DNA profiles that are characteristic of the species, and b) determine if the geographical area or time of collection influences these DNA profiles. Towards this end, random amplified polymorphic DNA (RAPD) analyses were performed on a number of botanicals currently used for women's health. The test materials included samples from three species each of the genera Cimicifuga (Actaea) and Trifolium, as well as samples of Vitex agnus-castus L., Glycyrrhiza glabra L., Gingko biloba L., Valeriana officinalis L., Angelica sinensis (Oliv.) Diels, Viburnum prunifolium L., Humulus lupulus L., Vaccinium macrocarpon Ait., Panax ginseng C.A. Mey. Cimicifuga racemosa (L.) Nutt. and Trifolium pratense L. are currently under clinical investigation in our basic research laboratories and medical clinic for the relief of post-menopausal symptoms. Characteristic profiles produced with the OPC-15 primer could distinguish the three Cimicifuga species: C racemosa, C. americana and C. rubifolia. Similar results were obtained with the three Trifolium species: Trifolium pratense L., Trifolium incarnatum L., and Trifolium repens L. Accessions of cultivated T. pratense collected from the same field at different times, produced identical profiles. Accessions of Cimicifuga species collected from different geographical areas produced similar but not identical DNA profiles however, species-specific DNA fragments were identified. These results demonstrate that RAPD analysis can be applied to distinguish species when only powdered material is available for testing. This methodology can be applied to identify species of commercial value regardless of collection time or geographic area. 9 757 762 Cited By :26

Studies were conducted using an ovariectomized rat model to determine the estrogenic and antiestrogenic activity of Trifolium pratense L. (red clover) extracts. A red clover extract, standardized to contain 15% isoflavones was administered by gavage [250, 500 and 750 mg/(kg·d)] to virgin, ovariectomized 50-d-old Sprague-Dawley rats, for 21 d in the presence and absence of 17β-estradiol [50μg/(kg·d)]. Estrogenic effects included an increase in uterine weight, vaginal cell cornification and mammary gland duct branching. Red clover produced a dose-dependent increase in uterine weight and differentiated vaginal cells at the two higher doses, but it did not stimulate cell proliferation in the mammary glands. Neither antiestrogenic nor additive estrogenic properties were observed in any of the tissues studied. These data suggest that red clover extract is weakly estrogenic in the ovariectomized rat model. 132 27 30 Cited By :62

purified daidzein at 200 mg/kg diet Previous studies have shown an inhibitory effect of soy on mammary carcinogenesis, but it is unclear which component of soy provides this beneficial effect. The present study was undertaken to compare the anti-tumor effects of soy protein isolate and those of its isoflavones: genistein and daidzein. Six groups of female Sprague-Dawley rats were fed modified corn starch AIN76A diets supplemented with: no additional agents (control) purified genistein at 200 mg/kg diet a combination of genistein and daidzein at 100 mg/kg diet each soy protein isolate enriched in isoflavones (SPI+) or soy protein isolate depleted of isoflavones (SPI-). Mammary carcinomas were induced by 7,12-dimethylbenz[a]anthracene (DMBA) injected one week after the animals started eating the experimental diets. At the end of the study (120 days post-DMBA treatment), no significant differences were found among the six groups with respect to tumor incidence or survival. However, there was a significant (p < 0.05) reduction in tumor multiplicity in the daidzein (5.45) and SPI+ (5.45) groups, when compared to the control group (8.05). The most effective diet was the SPI-, which produced a highly signifi-cant (p < 0.01) reduction in tumor multiplicity (4.05). Tumor latency was increased from 53 days in the control group to 68 days in the daidzein group and to 72 days in the SPI-group. Both SPI groups, but not the genistein or daidzein groups, up-regulated transcriptional expression of the anti-oxidant enzymes NAD(P)H:quinone reductase (QR) and glutathione S-transferase (GST) Ya2. These results suggest that the mode of chemopreventive action of soy protein isolate is distinct from that of the main soy isoflavones. Furthermore, isoflavone-depleted soy may be more beneficial than isoflavone-enriched soy in preventing mammary tumors in these experimental animals. 40 24 34 Cited By :8

Eight botanical preparations that are commonly used for the treatment of menopausal symptoms were tested for estrogenic activity. Methanol extracts of red clover (Trifolium pratense L.), chasteberry (Vitex agnus-castus L.), and hops (Humulus lupulus L.) showed significant competitive binding to estrogen receptors α (ERα) and β (ERβ). With cultured Ishikawa (endometrial) cells, red clover and hops exhibited estrogenic activity as indicated by induction of alkaline phosphatase (AP) activity and up-regulation of progesterone receptor (PR) mRNA. Chasteberry also stimulated PR expression, but no induction of AP activity was observed. In S30 breast cancer cells, pS2 (pres enelin-2), another estrogen-inducible gene, was up-regulated in the presence of red clover, hops, and chasteberry. Interestingly, extracts of Asian ginseng (Panax ginseng C.A. Meyer) and North American ginseng (Panax quinquefolius L.) induced pS2 mRNA expression in S30 cells, but no significant ER binding affinity, AP induction, or PR expression was noted in Ishikawa cells. Dong quai [Angelica sinensis (Oliv.) Diels] and licorice (Glycyrrhiza glabra L.) showed only weak ER binding and PR and pS2 mRNA induction. Black cohosh [Cimicifuga racemosa (L.) Nutt.] showed no activity in any of the above in vitro assays. Bioassay-guided isolation utilizing ER competitive binding as a monitor and screening using ultrafiltration LC-MS revealed that genistein was the most active component of red clover. Consistent with this observation, genistein was found to be the most effective of four red clover isoflavones tested in the above in vitro assays. Therefore, estrogenic components of plant extracts can be identified using assays for estrogenic activity along with screening and identification of the active components using ultrafiltration LC-MS. These data suggest a potential use for some dietary supplements, ingested by human beings, in the treatment of menopausal symptoms. 49 2472 2479 Cited By :327

Melanoma transformation progresses in a multistep fashion from precursor lesions such as congenital naevi. Exposure to ultraviolet (UV) light promotes this process. Betulinic acid (BA) was identified by our group as a selective inhibitor of melanoma that functions by inducing apoptosis. The present study was designed to investigate the effect of BA and UV-C (254 nm) on cultured congenital melanocytic naevi (CMN) cells, using the single-cell gel electrophoresis (comet) assay to detect DNA damage. Exposure to UV light induced a 1.7-fold increase in CMN cells (P=0.008) when compared with controls. When a p53 genetic suppressor element that encodes a dominant negative polypeptide (termed GSE56) was introduced into the CMN cells, the transfected cells were more sensitive to UV-induced DNA breakage. This suggests that p53 can protect against UV-induced DNA damage and subsequent melanoma transformation. Pretreatment with BA (3 μm) for 48 h resulted in a 25.5% reduction in UV-induced DNA breakage in the CMN cells (P=0.023), but no changes were observed in the transfected cells. However, Western blot analysis revealed no changes in the p53 or p21 levels in BA-treated cells, suggesting that BA might mediate its action via a non-p53 pathway. These data indicate that BA may have an application as a chemopreventive agent in patients with congenital naevi. © 2001 Lippincott Williams & Wilkins. 11 99 104 Manufacturers: Indofine, United States Cited By :33

There are conflicting reports on the effect of soy and its components on mammary carcinogenesis in adult female rats, mainly because of different rodent models that are used in chemoprevention studies. The present study was undertaken to compare the tumor-preventative effects of soy protein isolate (SPI) and two of its isoflavones in a "standard" model that had been used for the identification of many chemopreventive agents. Six groups of female Sprague-Dawley rats were provided with modified cornstarch AIN-76A diets supplemented as follows: no additional agents (control), purified genistein (200 mg/kg diet), purified daidzein (200 mg/kg diet), genistein + daidzein (100 mg/kg diet each), SPI containing normal levels of isoflavones (SPI-n), or SPI depleted of isoflavones (SPI-d). Mammary carcinomas were induced by 7,12-dimethyl-benz[a]anthracene (DMBA) introduced 1 wk after the animals began consuming the experimental diets. At the end of the study (120 days after DMBA treatment), no significant differences were found among the six groups with respect to tumor incidence or survival, nor was there a significant reduction in tumor multiplicity in the genistein or genistein + daidzein group. However, there was a 32% reduction in tumor multiplicity in the daidzein and SPI-n groups relative to the control group (P < 0.05). The most effective diet was SPI-d, which produced a 50% reduction in tumor multiplicity relative to the control (P < 0.01). The difference between the SPI-d group and the daidzein or SPI-n group was not significant. Median tumor latency was increased from 53 days in the control group to 68 days in the daidzein group and to 72 days in the SPI-d group, but these differences were not statistically significant. These results show that daidzein and SPI (with normal or low levels of isoflavones) are effective inhibitors of DMBA-induced mammary tumors in adult rats. 41 75 81 Manufacturers: Indofine, United States Protein Technologies, United States Cited By :85

The roots of Lavandula stoechas ssp. stoechas afforded eleven known triterpenes, two steroids and two aromatics, in addition to two new triterpenes, 18-hydroxy-27-norolean-12,14-dien-30-al-28-oic acid and 3 beta -Iiydroxy-1-oxo-olean-12-ene-30-al-28-oic acid. Their structures were determined by spectroscopic analyses. The chloroform extract and some isolated compounds were evaluated for their growth inhibitory activity against several mammalian cell lines.

The present study was undertaken to determine if in vitro inhibition of one or both of the two most dominant mammalian DNA topoisomerases (topos) is common among chemopreventive agents. To determine if an agent was a topo I inhibitor, we employed the DNA relaxation and nicking assays. For potential topo II inhibitors, we used the DNA unknotting and linearisation assays. 14 of 30 agents (47%) were ineffective in all four assays (IC50 >100 μg/ml), and 11 (37%) inhibited topo II catalytic activity. The sensitivity of the topo II assay was 63%, selectivity 93%, positive predictive value 91%, and total accuracy 77%. For chemopreventive efficacy, the positive predictive value of the unknotting assay was 92%, and the total accuracy was 60%. These data suggest that reduced topo II activity is a desirable property of many known chemopreventive agents. We conclude that the unknotting assay could be a valuable addition to the in vitro tests presently used to select chemopreventive agents. Copyright (C) 2000 Elsevier Science Ltd. 36 2146 2156 Manufacturers: Sigma, United States Cited By :39

For the discovery of new cancer chemopreventive agents, we have studied the potential of plant extracts to inhibit phorbol ester-induced ornithine decarboxylase (ODC) activity in cell culture. Four active rotenoids were obtained from the African plant Mundulea sericea (Leguminosae). These isolates were highly potent when evaluated for inhibition of chemically induced preneoplastic lesions in mammary organ culture and inhibition of papillomas in the two-stage mouse skin model, and they appear to function by a unique mechanism at the level of ODC messenger RNA expression. Based on our findings, rotenoids can be regarded as promising new chemopreventive or anticancer agents. © 1995 Nature Publishing Group. 1 260 266 Cited By :97

For the discovery of new cancer chemopreventive agents, we have studied the potential of plant extracts to inhibit phorbol ester-induced ornithine decarboxylase (ODC) activity in cell culture. Four active rotenoids were obtained from the African plant Mundulea sericea (Leguminosae). These isolates were highly potent when evaluated for inhibition of chemically induced preneoplastic lesions in mammary organ culture and inhibition of papillomas in the two-stage mouse skin model, and they appear to function by a unique mechanism at the level of ODC messenger RNA expression. Based on our findings, rotenoids can be regarded as promising new chemopreventive or anticancer agents. © 1995 Nature Publishing Group. 1 Cited By :8

1 Cited By :2

Brassinin [3-(S-methyldithiocarbamoyl aminomethyl indole], a phytoalexin first identified as a constituent of cabbage, was synthesized and evaluated for cancer chemopreventive activity. Dose-dependent inhibition of 7,12-dimethylbenz [a]anthracene (DMBA)-induced preneoplastic lesion formation was observed with mouse mammary glands in organ culture, as was dose-dependent inhibition of DMBA-induced mouse skin tumors that were promoted by treatment with 12-O-tetradecanoylphorbol-13-acetate. Cyclobrassinin is a biologically derived product of the oxidative cyclization of brassinin, and was as active as the parent compound in inhibiting the formation of preneoplastic mammary lesions in culture however, 2-methyibrassinin was not significantly active in this process. Therefore, oxidative cyclization may be an effective metabolic activation step. As judged by these tumor inhibition studies in conjunction with potential to induce phase II enzymes in mice or cell culture, brassinin may be effective as a chemopreventive agent during both the initiation and promotion phases of carcinogenesis. This is the first report documenting the chemopreventive potential of structurally novel indole-based phytoalexins that are naturally occurring in cruciferous vegetables, and the synthetic route described herein has proven amenable for scale-up production. The bifunctional structural nature of brassinin, bearing both an indole nucleus and a dithiocarbamoyl-aminomethyl moiety, is notably similar to the individual structural elements of other known chemopreventive agents such as indole-3-carbinol or benzylisothiocyanate. The favorable biological activity demonstrated by the compound may originate from the presence of these two moieties. © 1995 Oxford University Press. 16 399 404 Cited By :175

Brassinin, a pkytoalexin, is found in Chinese cabbage. Previously, we showed that brassinin significantly inhibited dimethylbenz(a)anthracene (DMBA)-induced mammary lesions in organ culture. Moreover, it was an effective inhibitor against two stage skin carcinogenesis. In the present study, we synthesized several analogs of brassinin and evaluated their effectiveness in the mouse mammary gland organ culture model. Results showed that cyclobrassinin, also a naturally occurring brassinin analog, was more effective than brassinin. Spirobrassinin and N-ethyl-2,3-dihydrobrassinin also significantly inhibited mammary lesion formation. However, none of the methyl substituted analogs were effective. The effects of brassinin may, in part, be mediated by induction of phase II detoxifying enzymes such as quinone reductase. 14 1209 1213 Cited By :63