Epigallocatechin-3-gallate suppresses hemin-aggravated colon carcinogenesis through Nrf2-inhibited mitochondrial reactive oxygen species accumulation.

BACKGROUND: Previous studies have presented evidence to support the significant association between red meat intake and colon cancer, suggesting that heme iron plays a key role in colon carcinogenesis. Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, exhibits anti-oxidative and anti-cancer effects. However, the effect of EGCG on red meat-associated colon carcinogenesis is not well understood. OBJECTIVES: We aimed to investigate the regulatory effects of hemin and EGCG on colon carcinogenesis and the underlying mechanism of action. METHODS: Hemin and EGCG were treated in Caco2 cells to perform the water-soluble tetrazolium salt-1 assay, lactate dehydrogenase release assay, reactive oxygen species (ROS) detection assay, real-time quantitative polymerase chain reaction and western blot. We investigated the regulatory effects of hemin and EGCG on an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon carcinogenesis mouse model. RESULTS: In Caco2 cells, hemin increased cell proliferation and the expression of cell cycle regulatory proteins, and ROS levels. EGCG suppressed hemin-induced cell proliferation and cell cycle regulatory protein expression as well as mitochondrial ROS accumulation. Hemin increased nuclear factor erythroid-2-related factor 2 (Nrf2) expression, but decreased Keap1 expression. EGCG enhanced hemin-induced Nrf2 and antioxidant gene expression. Nrf2 inhibitor reversed EGCG reduced cell proliferation and cell cycle regulatory protein expression. In AOM/DSS mice, hemin treatment induced hyperplastic changes in colon tissues, inhibited by EGCG supplementation. EGCG reduced the hemin-induced numbers of total aberrant crypts and malondialdehyde concentration in the AOM/DSS model. CONCLUSIONS: We demonstrated that EGCG reduced hemin-induced proliferation and colon carcinogenesis through Nrf2-inhibited mitochondrial ROS accumulation.

Effect of sorghum ethyl-acetate extract on benign prostatic hyperplasia induced by testosterone in Sprague-Dawley rats.

Benign prostatic hyperplasia (BPH) is commonly observed in men > 50 years worldwide. Phytotherapy is one of the many treatment options. Sorghum (Sorghum bicolor L.) contains various health-improving phytochemicals with antioxidant and inhibitory activities on cell proliferation, both in vitro and in vivo. To confirm the effects of Donganme sorghum ethyl-acetate extract (DSEE) on BPH, we induced BPH in Spragye-Dawley rats using exogenous testosterone. We measured prostate weight, examined prostrates histopathologically, and analyzed mRNAs associated with male hormones and proteins associated with cell proliferation in the prostate. DSEE inhibited weight gain of the prostate; decreased mRNA expressions of androgen receptor and 5α-reductase II; and improved histopathological symptoms, the protein-expressed ratio of Bax/Bcl-2, and the oxidative status of BPH induced by testosterone in SD rats. Therefore, DSEE may have potential as a preventive or therapeutic agent against BPH.

Effects of gintonin-enriched fraction on hippocampal cell proliferation in wild-type mice and an APPswe/PSEN-1 double Tg mouse model of Alzheimer's disease.

We previously showed that gintonin, an exogenous lysophosphatidic acid (LPA) receptor ligand, attenuated ß-amyloid plaque formation in the cortex and hippocampus, and restored ß-amyloid-induced memory dysfunction. Both endogenous LPA and LPA receptors play a key role in embryonic brain development. However, little is known about whether gintonin can induce hippocampal cell proliferation in adult wild-type mice and an APPswe/PSEN-1 double Tg mouse model of Alzheimer's disease (AD). In the present study, we examined the effects of gintonin on the proliferation of hippocampal neural progenitor cells (NPCs) in vitro and its effects on the hippocampal cell proliferation in wild-type mice and a transgenic AD mouse model. Gintonin treatment increased 5-bromo-2'-deoxyuridine (BrdU) incorporation in hippocampal NPCs in a dose- and time-dependent manner. Gintonin (0.3 µg/ml) increased the immunostaining of glial fibrillary acidic protein, NeuN, and LPA1 receptor in hippocampal NPCs. However, the gintonin-induced increase in BrdU incorporation and immunostaining of biomarkers was blocked by an LPA1/3 receptor antagonist and Ca2+ chelator. Oral administration of the gintonin-enriched fraction (50 and 100 mg/kg) increased hippocampal BrdU incorporation and LPA1/3 receptor expression in adult wild-type and transgenic AD mice. The present study showed that gintonin could increase the number of hippocampal neurons in adult wild-type mice and a transgenic AD mouse model. Our results indicate that gintonin-mediated hippocampal cell proliferation contributes to the gintonin-mediated restorative effect against ß-amyloid-induced hippocampal dysfunction. These results support the use of gintonin for the prevention or treatment of neurodegenerative diseases such as AD via promotion of hippocampal neurogenesis.

Panax ginseng exerts antiproliferative effects on rat hepatocarcinogenesis.

It has been proposed that ginseng has chemopreventive effects against several types of cancer in animals and humans. However, the mechanisms underlying the chemopreventive activities of fresh ginseng against hepatocarcinogenesis have not yet been elucidated. Therefore, we hypothesized that these ginseng species may prevent hepatocarcinogenesis but that the chemopreventive mechanisms may differ by species. To determine the chemopreventive and therapeutic potential of 3 different types of fresh ginseng on hepatocarcinogenesis, Sprague-Dawley rats were injected with diethylnitrosamine and fed diets containing 2% Panax japonicus CA Meyer (JN), P. quinquefolius L (QQ), or P. ginseng CA Meyer (GS) for 10 weeks. Glutathione S-transferase P form (GST-P)-positive foci, a stable marker for rat hepatocarcinogenesis, were shown in all carcinogen-injected rats; but only the GS diet significantly reduced the area and number (62% and 68%, respectively; P < .05) of GST-P-positive foci compared with the diethylnitrosamine control group. In addition, the number of proliferating cell nuclear antigen-positive hepatocytes in the GST-P-positive area was significantly decreased in the GS group but not in the JN or QQ groups. Using cDNA microarray analyses to investigate the underlying molecular mechanisms, we observed that the p53 signaling pathway was altered by the GS diet and that the expression of Cyclin D1, Cyclin G1, Cdc2a, and Igf-1, which are involved in the p53 signaling pathway, was downregulated by the GS diet. Our data demonstrate, for the first time, that GS, but not JN or QQ, induces cell cycle arrest in hepatocarcinogenesis. This study suggests that fresh GS has potential chemopreventive effects and may prove to be a therapeutic agent against hepatocarcinogenesis.

Toxicological evaluation and anti-inflammatory activity of a golden gelatinous sorghum bran extract.

Golden gelatinous sorghum (GGS) is rich in phytochemicals and anti-oxidants. We investigated the toxicity and anti-inflammatory properties of a GGS extract. We observed no toxic effects after a daily dose of up to 5000 mg/kg body weight of the GGS extract administered orally to rats for 14 d. The exposure of mice ears to 12-O-tetradecanoylphorbol-13-acetate (TPA) caused a marked increase in ear thickness, which was significantly inhibited by treating with the GGS extract; this inhibition of inflammatory response was clearly confirmed by a histological analysis. The TPA-induced mice ear edema model, indicated that treating with the GGS extract inhibited the expression levels of such inflammatory mediators as cyclooxygenase-2 and inducible nitric oxide synthase. The nitric oxide level in lipopolysaccharide (LPS)-induced Raw264.7 cells in vitro was lower in the GGS extract-treated group than in the LPS-only treated group. These results suggest that sorghum would be a safe, nontoxic product, and that the GGS extract possessed significant anti-inflammatory activity.

Modifying effect of diallyl sulfide on colon carcinogenesis in C57BL/6J-ApcMin/⁺ mice.

Diallyl sulfide (DAS), a flavoring compound derived from garlic, is considered to have cancer chemopreventive potential in experimental animals and humans. This study was designated to examine possible chemopreventive effects of DAS on colon carcinogenesis using genetically engineered transgenic ApcMin/⁺ mice, a well-established animal model for familial adenomatous polyposis (FAP) and sporadic colorectal cancer. Male C57BL/6J-ApcMin/⁺ mice were divided into three groups. Animals of group 1 were placed on the basal diet (AIN-76A) as non-treated controls. Animals of groups 2 and 3 were given DAS- containing diets (in doses of 100 and 300 ppm, respectively). All mice were sacrificed at the end of week 10 of the experiment. Histopathological investigation revealed that the incidence of colonic polyps was decreased dose-dependently by 19% (13/16) in group 2 and by 32% (13/20) in group 3 compared to the 100% incidence (10/10) in group 1. The multiplicity of colonic polyps per mouse was also slightly decreased by DAS treatment (1.88 ± 0.35 in group 2 and 1.63 ± 0.36 in group 3) compared to 2.00 ± 0.39 in group 1. On the other hand, there were no significant differences in the numbers of total polyps per mouse in the small intestine between the groups. Taken together, we suggest that DAS may exert promising inhibitory effects on colon carcinogenesis in the transgenic ApcMin/⁺ mice.

Elm tree bark extract inhibits HepG2 hepatic cancer cell growth via pro-apoptotic activity.

Control of inflammation is widely accepted as an important strategy for cancer chemoprevention. Anti-inflammatory effects of bark extracts of elm tree (BEE) have been amply reported. Therefore, BEE may be a good candidate cancer chemopreventive agent. Considering the high incidence of hepatic cancer and limited therapeutic approaches for treating this disease, it is important to develop liver cancer-specific chemopreventive agents. To evaluate the chemopreventive potential of BEE, we investigated the growth inhibition effect of BEE on the HepG2 human hepatocellular carcinoma cell line. We performed a cell counting kit-8 assay to determine cell viability, and 4,6-diamino-2-phenylindole staining and flow cytometry to measure apoptotic cell death. Finally, the expression levels of pro- and anti-apoptotic proteins were measured. BEE inhibited the growth of HepG2 cells and induced apoptosis in a dose-dependent manner. Pro-apoptotic activity was promoted via the mitochondrial pathway of apoptosis, as demonstrated by the activation of pro-apoptotic proteins Bax, caspase-9, caspase-3, and poly (ADP-ribose) polymerase as well as the down-regulation of the anti-apoptotic protein Bcl-2. These results suggest that BEE may have potential use in hepatic cancer chemoprevention by suppressing cancer cell growth via pro-apoptotic activity.

Anti-inflammatory and arthritic effects of thiacremonone, a novel sulfur compound isolated from garlic via inhibition of NF-kappaB.

INTRODUCTION: Sulfur compounds isolated from garlic exert anti-inflammatory properties. We recently isolated thiacremonone, a novel sulfur compound from garlic. Here, we investigated the anti-inflammatory and arthritis properties of thiacremonone through inhibition of NF-kappaB since NF-kappaB is known to be a target molecule of sulfur compounds and an implicated transcription factor regulating inflammatory response genes. METHODS: The anti-inflammatory and arthritis effects of thiacremone in in vivo were investigated in 12-O-tetradecanoylphorbol-13-acetate-induced ear edema, carrageenan and mycobacterium butyricum-induced inflammatory and arthritis models. Lipopolysaccharide-induced nitric oxide (NO) production was determined by Griess method. The DNA binding activity of NF-kappaB was investigated by electrophoretic mobility shift assay. NF-kappaB and inducible nitric oxide synthetase (iNOS) transcriptional activity was determined by luciferase assay. Expression of iNOS and cyclooxygenase-2 (COX-2) was determined by western blot. RESULTS: The results showed that topical application of thiacremonone (1 or 2 microg/ear) suppressed the 12-O-tetradecanoylphorbol-13-acetate-induced (1 microg/ear) ear edema. Thiacremonone (1-10 mg/kg) administered directly into the plantar surface of hind paw also suppressed the carrageenan (1.5 mg/paw) and mycobacterium butyricum (2 mg/paw)-induced inflammatory and arthritic responses as well as expression of iNOS and COX-2, in addition to NF-kappaB DNA-binding activity. In further in vitro study, thiacremonone (2.5-10 microg/ml) inhibited lipopolysaccharide (LPS, 1 microg/ml)-induced nitric oxide (NO) production, and NF-kappaB transcriptional and DNA binding activity in a dose dependent manner. The inhibition of NO by thiacremonone was consistent with the inhibitory effect on LPS-induced inducible nitric oxide synthase (iNOS) and COX-2 expression, as well as iNOS transcriptional activity. Moreover, thiacremonone inhibited LPS-induced p50 and p65 nuclear translocation, resulting in an inhibition of the DNA binding activity of the NF-kappaB. These inhibitory effects on NF-kappaB activity and NO generation were suppressed by reducing agents dithiothreitol (DTT) and glutathione, and were abrogated in p50 (C62S)-mutant cells, suggesting that the sulfhydryl group of NF-kappaB molecules may be a target of thiacremonone. CONCLUSIONS: The present results suggested that thiacremonone exerted its anti-inflammatory and anti-arthritic properties through the inhibition of NF-kappaB activation via interaction with the sulfhydryl group of NF-kappaB molecules, and thus could be a useful agent for the treatment of inflammatory and arthritic diseases.

The effect of hydrolyzed gardeniae fructus extract hydrogel on the treatment of ecchymoses in a rat model.

BACKGROUND: Gardeniae fructus (GF) has been used in traditional medicine for the treatment of inflammatory disease. OBJECTIVE: To evaluate the therapeutic effect of GF gel on the resolution of ecchymoses in rats. METHODS AND MATERIALS: Fifty hind limbs (in 25 Sprague-Dawley rats) were evaluated. The ecchymoses were produced by dropping a 100-g weight from a height of 20 cm on the posterior side of the hind limbs 25 times. Then, 0.5 g of hydrolyzed GF extracted gel was applied to the right hind limbs and 0.5 g of gel without GF extract powder was applied to the left hind limbs. The area of the ecchymosis was measured, and histological analysis was performed. RESULTS: The area affected by the ecchymosis after 5 days was 15% in the control group and 2% in the GF gel group (p=.002). The mean duration for the ecchymosis was 5.8 days in the control group and 4.5 days in the GF gel group. The extravasated red blood cells and inflammation were less prominent in the GF gel group than in the control group. CONCLUSION: The results of this study showed that hydrolyzed gel of GF extract, containing genipin, was effective for the treatment of ecchymoses in a rat model.

Inhibition of cell growth and induction of apoptosis via inactivation of NF-kappaB by a sulfurcompound isolated from garlic in human colon cancer cells.

Compounds such as S-allylmercaptocysteine, diallyl disulfide, and S-trityl-L-cysteine isolated from garlic have been known to be effective in chemoprevention. Nuclear transcription factor-kappaB (NF-kappaB) has been known to be an implicated factor in apoptotic cell death of several cancer cells. In this study, we investigated whether a sulfurcompound (named thiacremonone) isolated from garlic could modulate NF-kappaB activity and thereby induce apoptotic cell death of colon cancer cells. Treatment with different concentrations (30 - 150 microg/ml) of thiacremonone for various periods (0 - 48 h) inhibited colon cancer cell (SW620 and HCT116) growth followed by induction of apoptosis in a dose-dependent manner. We also found that thiacremonone modulated tumor necrosis factor-alpha (TNF-alpha) and tetradeanoyl phorbol acetate (TPA)-induced NF-kappaB transcriptional and DNA binding activity. Moreover, thiacremonone suppressed NF-kappaB target anti-apoptotic genes (Bcl-2, cIAP1/2, and XIAP) and inflammatory genes (iNOS and COX-2), whereas it induced apoptotic genes (Bax, cleaved caspse-3, and cleaved PARP) expression. These results suggest that a novel sulfurocompound from garlic inhibited colon cancer cell growth through induction of apoptotic cell death by modulating of NF-kappaB.

Free radical-scavenging activity of Korean red ginseng for erectile dysfunction in non-insulin-dependent diabetes mellitus rats.

OBJECTIVES: To investigate the antioxidant activity of Korean red ginseng (KRG) and its effect on erectile function in non-insulin-dependent diabetes mellitus (NIDDM) rats. Oxidative stress is an important factor in vascular complications of diabetes. METHODS: A total of 84 male Sprague-Dawley rats were included in this study. NIDDM was induced by an intraperitoneal injection of 90 mg/kg of streptozotocin on day 2 after birth. According to the diabetic period, they were classified as either short-term (22 weeks, n = 32) or long-term (38 weeks, n = 32) diabetics. Of those, 20 (10 short-term and 10 long-term) were fed 30 mg/kg of KRG three times weekly for 1 month. The remaining diabetic rats (22 short-term and 22 long-term) and their age-matched controls (n = 10 each for each group) were fed a normal diet. Erectile function was measured after electrostimulation of the cavernous nerve. The total cavernous malondialdehyde and glutathione levels were measured using a spectrophotometric assay. RESULTS: The intracavernous pressure after nerve stimulation and cavernous glutathione level were significantly lower in the long-term than the short-term diabetics with a normal diet and were markedly decreased compared with their age-matched controls (P <0.01 and P <0.05, respectively). The malondialdehyde content was markedly increased in the short-term diabetics compared with the controls (P <0.05). In contrast, erectile function was not impaired in the diabetic group treated with KRG. Furthermore, both glutathione and malondialdehyde levels in those treated with KRG were comparable to their age-matched controls. CONCLUSIONS: Oxidative stress to cavernous tissue may be a contributory factor in erectile dysfunction in diabetics. KRG may preserve potency in the NIDDM rats through its antioxidant activity.

Chemoprevention of colon cancer by Korean food plant components.

Inducible cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS/NOS-2) play pivotal roles as mediators of inflammation involved in early steps of carcinogenesis in certain organs. Therefore, chemoprevention is theoretically possible through inhibition of COX-2 and/or iNOS. In the present study, we examined the chemopreventive effects of indole-3-carbinol (I3C), a constituent of cruciferous vegetables (the family of Cruciferae) such as cabbages, cauliflowers and broccoli on the multiple intestinal neoplasia (Min) genetic mouse model, and on mouse colon carcinogenesis induced by azoxymethane (AOM). The consumption of cruciferous vegetables such as cabbage, broccoli, and Brussels sprouts has been shown to have cancer chemopreventive effects in humans and experimental animals. I3C has been shown to exert a cancer chemopreventive influence in liver, colon, and mammary tissue when given before or concurrent with exposure to a carcinogen. Powdered AIN-76A diets (Harlan Teklad Research Diet, Madison, USA) containing 100 or 300 ppm I3C (group 1 or 2) or the same pellet diets without supplement (group 3) were fed to 6-week-old male C57BL/6J-Apc(Min)(/+) (Min/+) mice (The Jackson Laboratory, Bar Harbor, ME, USA) for 10 weeks. In addition the same diets were given to wild-type normal C57BL/6J-Apc(Min)(/+) littermates after AOM initiation (groups 4-7: 10 mice in each group) for 32 weeks from week 4. At 16 weeks of age, all Min/+ mice (groups 1-3) were sacrificed for assessment of intestinal polyp development. The incidences of the colonic adenomatous polyps in the groups 1-3 were 60% (12/20), 60% (15/25) and 84% (21/25), respectively. A decreasing tendency in multiplicities of the colonic adenomatous polyps in group 1 (I3C 100 ppm; 0.85 +/- 0.22; 61%) and group 2 (I3C 300 ppm; 1.32 +/- 0.28; 94%) was observed when compared with group 3 (control; 1.40 +/- 0.21; 100%). Total number of aberrant crypt foci (ACF)/colon or aberrant crypts (AC)/colon in wild-type mice of group 4 or 5 were decreased significantly compared with those of the AOM alone group (group 6) (P < 0.01). These results suggest that I3C may be a potential chemopreventive agent for colon cancer.

Prevention of nitric oxide-mediated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson's disease in mice by tea phenolic epigallocatechin 3-gallate.

In animal models of Parkinson's disease (PD), the toxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is mediated by oxidative stress, especially by nitric oxide (NO). Inhibition of NO synthase (NOS) activity in the brain produces a neuroprotective effect against PD induced by MPTP Green tea containing high levels of (-)-epigallocatechin 3-gallate (EGCG) was administered to test whether EGCG attenuates MPTP-induced PD in mice through the inhibition of NOS expression. Both tea and the oral administration of EGCG prevented the loss of tyrosine hydroxylase (TH)-positive cells in the substantia nigra (SN) and of TH activity in the striatum. These treatments also preserved striatal levels of dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid (HVA). Both tea and EGCG decreased expressions of nNOS in the substantia nigra. Also tea plus MPTP and EGCG plus MPTP treatments decreased expressions of neuronal NO synthase (nNOS) at the similar levels of EGCG treatment group. Therefore, the preventive effects of tea and EGCG may be explained by the inhibition of nNOS in the substantia nigra.

Promotion of Liver Lesion Development in the Syrian Hamster by Dietary Fat Following Multi-organ Initiation is Inhibited by DHEA-S Administration.

The influence of dietary supplementation with dehydroepiandrosterone-sulphate (DHEA-S) at 0.6% was investigated in male Syrian golden hamsters initiated by treatments with azoxymethane(AOM), and dihydroxy-di-n-propyl nitrosamine (DHPN), timed after transfer from a choline-deficient to a normal diet. These carcinogens respectively target the colon, and the respiratory tract, the liver and pancreas. A total of 75 animals were divided into 6 groups, 1-3 (20 animals each) receiving the initiation protocol of during the first 8 weeks, and 4-6 (5 animals each) given the vehicles alone. The hamsters in groups 2,3 and 5,6 then received a high fat diet (20% corn oil) while DHEA-S was given in addition for 20 weeks to groups 3 and 6. Groups 1 and 4 served as controls on the basal diet. Assessment of development of preneoplastic and neoplastic lesions, after sacrifice at week 28, revealed increase in hepatocellular liver nodules and the index of BrdU incorporation in the hepatocellular cells of the liver in the initiated animals given the high fat diet. This was significantly reduced by the DHEA-S supplementation. Non-significant tendencies for high fat enhancement and hormone protection were also observed for lung and colon tumors.