Administration Of Indole-3-carbinol Research Articles

Indole-3-carbinol mitigates oxidative stress and inhibits inflammation in rat cerebral ischemia/reperfusion model

Ischemia is a significant pathogenetic factor of stroke with very limited treatment options. The objective of our research was to evaluate the protective properties of indole-3-carbinol (I3C) and its effect on redox status parameters, inflammation, and apoptosis intensity in cerebral ischemia/reperfusion injury (CIRI) in rats. I3C administration to CIRI rats decreased levels of oxidative stress markers and improved aerobic metabolism compared to the animals with CIRI. A decrease in myeloperoxidase activity, proinflammatory cytokines mRNA levels, and expression of redox-sensitive factor Nuclear Factor-κB was observed in rats with CIRI that received I3C. I3C-treated rats with pathology showed decreased caspase activity and apoptosis-inducing factor expression, compared to the animals in the CIRI group. Obtained data indicate that I3C has a neuroprotective and anti-ischemic effect in CIRI that may be related to its antioxidant properties and ability to reduce the inflammatory response and apoptosis.

Protective effect of indole-3-carbinol on testis of a high fat diet induced obesity

ABSTRACT We investigated the effects of obesity caused by a high fat diet (HFD) on rat testes and evaluated the possible protective effects of indole-3-carbinol (IND). We used 24 8–10-week-old 200 g male rats randomly assigned to 4 groups: non-obese control (NC), obese control (OC), non-obese IND group (NI), obese + IND group (OI). Testis samples were examined using stereological, immunohistochemical, biochemical and histological methods. The number of spermatogenic cells, Leydig cells, mean volume of testes and seminiferous tubules was significantly decreased in the OC group compared to the NC group, but these values were increased significantly in the OI group compared to the OC group. We found a significant increase in catalase and myeloperoxidase activities in the OC group compared to the NC group. In the OI group, catalase and myeloperoxidase levels were decreased compared to the OC group. TUNEL-positive cells also were increased in the OC group compared to the NC group (p < 0.05), but these were fewer in the OI group than the OC group. We found marked morphological changes in testicular tissues between the NC and OC groups, as well as between the OI and OC groups. We found that HFD induced obesity was detrimental to rat testes and that administration of IND ameliorated testicular changes caused by obesity.

Indole-3-Carbinol (I3C) Protects the Heart From Ischemia/Reperfusion Injury by Inhibiting Oxidative Stress, Inflammation, and Cellular Apoptosis in Mice.

Strategies for treating myocardial ischemia in the clinic usually include re-canalization of the coronary arteries to restore blood supply to the myocardium. However, myocardial reperfusion insult often leads to oxidative stress and inflammation, which in turn leads to apoptosis and necrosis of myocardial cells, for which there are no standard treatment methods. The aim of this study was to determine the pharmacological effect of indole-3-carbinol (I3C), a phytochemical found in most cruciferous vegetables, in a mouse model of myocardial ischemia/reperfusion injury (MIRI). Our results showed that I3C pretreatment (100 mg/kg, once daily, i. p.) prevented the MIRI-induced increase in infarct size and serum creatine kinase (CK) and lactate dehydrogenase (LDH) in mice. I3C pretreatment also suppressed cardiac apoptosis in MIRI mice by increasing the expression levels of the anti-apoptotic protein Bcl-2 and decreasing the expression levels of several apoptotic proteins, including Bax, caspase-3, and caspase-9. In addition, I3C pretreatment was found to reduce the levels of parameters reflecting oxidative stress, such as dihydroethidium (DHE), malondialdehyde (MDA), reactive oxygen species (ROS), and nitric oxide (NO), while increasing the levels of parameters reflecting anti-oxidation, such as total antioxidant capacity (T-AOC) and glutathione (GSH), in MIRI-induced ischemic heart tissue. I3C pretreatment was also able to remarkably decrease the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) mRNA in ischemic heart tissue. These results demonstrate that administration of I3C protects the heart from MIRI through its anti-apoptotic, antioxidant, and anti-inflammatory effects.

Pharmacokinetic and Pharmacodynamic Properties of Indole-3-carbinol in Experimental Focal Ischemic Injury.

Indole-3-carbinol (I3C) is reported to have neuroprotective properties in an animal model of ischemic stroke. However, the pharmacokinetics of I3C in stroke animals are unknown. Furthermore, the most effective method of I3C delivery for the treatment of stroke has yet to be determined.Therefore, the objective of this study was to evaluatepharmacokinetics and pharmacodynamicsof I3C to discover the most effective delivery route for protecting the brain from ischemic injury. With oral and intravenous administration, the pharmacokinetics and pharmacodynamics of I3C in sham and middle cerebral artery occluded (MCAO) rats were investigated. I3C administration in sham and MCAO rats did not alter the pharmacokinetic parameters such as maximum plasma concentration (Cmax), time to reach Cmax, half-life, area under the curve, mean residential time, volume of distribution, clearance, bioavailability, and tissue distribution. A higher amount of diindolylmethane (DIM) was observed with oral administration of I3C compared to intravenous administration in the plasma (5 fold), brain (4 fold), and cerebrospinal fluid (CSF) (2-3 fold). Orally delivered I3C significantly reduced neurological deficits, brain infarction (20%), blood-brain barrier leakage (15 μg/g), and brain water content (75%) in MCAO rats compared to intravenous administration of I3C. I3C pharmacokinetic parameters were similar in sham and MCAO rats, but I3C and DIM penetration in the brain and CSF was significantly higher in MCAO rats than in sham animals, and I3C oral intake significantly reduced MCAO-induced neurological impairments. Consequently, compared to intravenous treatment, I3C oral delivery is more effective in treating ischemic stroke.

Protective effect of Indole-3-carbinol, an NF-κB inhibitor in experimental paradigm of Parkinson’s disease: In silico and in vivo studies

Parkinson’s disease (PD) is a progressive neurodegenerative disorder, majorly with symptoms of motor dysfunction. Study was performed to explore the effect of nuclear factor κB (NF-κB) inhibitors against neurobehavioral abnormalities and neuroinflammation in PD. Cost effective in silico approaches of docking-based ligand -target complex predictions and optimal physicochemical properties were utilised to identify lead NF-κB inhibitor using database. Our studies revealed the potential hit Indole-3-carbinol (I3C) which was considered for the next phase, pharmacological validations. Intranigral administration of lipopolysaccharide (LPS) in rats is utilized as a neuroinflmmation model of PD. In the present study it caused an impairment in motor functions, its coordination, learning and memory as demonstrated in rotarod apparatus, beam balance test, open field test and Morris water maze test. Chronic administration of I3C for 21 days in intranigral LPS treated rats led to a significant improvement in motor functions, coordination, learning and memory which were associated with a decrease in the activity of inflammatory cytokines such as TNF-α and IL-6. Further, it was found to inhibit NF-κB whose levels increased after LPS administration. Moreover, decreased levels of malondialdehyde and increased levels of reduced glutathione, superoxide dismutase and catalase were observed in cortex and striatum after I3C administration in LPS rats. These results suggest a possible neuroprotective effect of I3C via amelioration of LPS-induced behavioural alterations, oxidative damage and neuroinflammation which in turn is attributed to its potent antioxidant and anti-inflammatory (NF-κB inhibition) property. The effect produced by I3C (50 mg/kg) was found to be comparable with levodopa-carbidopa combination (LD:CD) while, I3C (50 mg/kg) in combination with LD:CD exhibited a potentiating effect in improving motor impairments and cognitive deficit. The results thus depict I3C as a promising agent to delay neurodegeneration of the neurons in PD with improvement in motor functions and cognitive function.

Indole-3-Carbinol (I3C) enhances the sensitivity of murine breast adenocarcinoma cells to doxorubicin (DOX) through inhibition of NF-κβ, blocking angiogenesis and regulation of mitochondrial apoptotic pathway

Various epidemiological and preclinical studies have already established the cancer chemopreventive potential of naturally occurring glucosinolate breakdown product Indole-3-Carbinol (I3C) as well as its abilities to induce selective cell death towards malignant cell. Therefore, the objective of the present study is to improve the therapeutic efficacy and prevention of doxorubicin (DOX)-induced toxicity, by the concurrent use of Indole-3-Carbinol (I3C). In this study, I3C was administered (20 mg/kg b.w., p.o.) to breast adenocarcinoma (Ehrlich ascites carcinoma) induced solid tumor bearing mice alone as well as in combination with DOX (5 mg/kg b.w., i.p.) in concomitant and pretreatment schedule. The results showed that concurrent administration of I3C and DOX significantly (P < 0.05) improved therapeutic efficacy as evidenced by reduction of tumor size and enhancement of host survivability. Oral administration of I3C significantly (P < 0.05) inhibited the expression of NF-κβ in both tumor cells and cardiac tissue as well as maximizes the therapeutic outcome in terms of tumor cell killing and toxicity. In addition, I3C sensitized tumor cells to DOX-therapy by down-regulating the expression of anti-apoptotic protein Bcl-2 and by up-regulating molecules like Bax, cytochrome c, caspases, which led to PARP cleavage and apoptosis. Significant inhibition of angiogenesis along with reduction in the serum levels of VEGF-A and MMP-9 further contribute to the sensitization accomplished by I3C. Moreover, we also found that I3C provided additional host survival advantages by attenuated DOX-induced toxicities through modulation of Nrf2/ARE pathway and promoted expression of cytoprotective proteins HO-1, NQO1 and GSTπ in cardiac tissue. In addition, I3C significantly attenuated DOX-induced inflammation by down-regulation of NF-kβ, iNOS, COX-2 and IL-6 in cardiac tissue. Thus, the present study clearly suggested therapeutic benefit of I3C in combination with DOX by augmenting anticancer efficacy and diminishing toxicity to the host.

Prevention of doxorubicin (DOX)-induced genotoxicity and cardiotoxicity: Effect of plant derived small molecule indole-3-carbinol (I3C) on oxidative stress and inflammation

Doxorubicin (DOX) is an anthracycline group of antibiotic available for the treatment of broad spectrum of human cancers. However, patient receiving DOX-therapy, myelosuppression and genotoxicity which may lead to secondary malignancy and dose dependent cardiotoxicity is an imperative adverse effect. Mechanisms behind the DOX-induced toxicities are increased level of oxidative damage, inflammation and apoptosis. Therefore, in search of a potential chemoprotectant, naturally occurring glucosinolate breakdown product Indole-3-Carbinol (I3C) was evaluated against DOX-induced toxicities in Swiss albino mice. DOX was administered (5 mg/kg b.w., i.p.) and I3C was administered (20 mg/kg b.w., p.o.) in concomitant and 15 days pretreatment schedule. Results of the present study showed that I3C appreciably mitigated DOX-induced chromosomal aberrations, micronuclei formation, DNA damage and apoptosis in bone marrow niche. Histopathological observations revealed that DOX-intoxication resulted in massive structural and functional impairment of heart and bone marrow niche. However, oral administration of I3C significantly attenuated DOX-induced oxidative stress in the cardiac tissues as evident from decreased levels of ROS/RNS and lipid peroxidation, and by increased level of glutathione (reduced) and the activity of phase-II antioxidant enzymes. Additionally, administration of I3C significantly (P < 0.05) stimulated Nrf2-mediated activation of antioxidant response element (ARE) pathway and promoted expression of cytoprotective proteins heme oxygenase 1 (HO-1), NAD(P)H:quinine oxidoreductase 1 (NQO1) and GSTπ in bone marrow and cardiac tissues. In connection with that, I3C significantly attenuated DOX-induced inflammation by downregulation of pro-inflammatory mediators, viz., NF-kβ(p50), iNOS, COX-2 and IL-6 expression. Moreover, I3C attenuate DOX-induced apoptosis by up-regulation of Bcl2 and down-regulation of Bax and caspase-3 expression in bone marrow cells. Thus, this study suggests that I3C has promising chemoprotective efficacy against DOX-induced toxicities and indicates its future use as an adjuvant in chemotherapy.

Enhancement of colon carcinogenesis by the combination of indole-3 carbinol and synbiotics in hemin-fed rats

The risk of developing colorectal cancer (CRC) could be associated with red and processed meat intake. Experimental data supports that hemin iron, found abundantly in red meat, promotes CRC in mice and rats, while indole-3 carbinol (I3C) and synbiotics (syn) exert anti-carcinogenic activities in most studies of colon carcinogenesis. This study aimed to investigate the modifying effects of I3C and syn (inulin + Bifidobacterium lactis), given separately or together, on dimethylhidrazine (DMH)-induced colon carcinogenesis in hemin-fed rats. All animals were given four subcutaneous DMH injections and then, two weeks after carcinogen exposure, they began a basal diet containing hemin, hemin + I3C, hemin + syn, or hemin + I3C + syn for 23 weeks. The combination of I3C + syn significantly increased fecal water genotoxicity, tumor volume and invasiveness when compared to the hemin-fed control group. The groups fed I3C or syn alone had a significant reduction in the number of preneoplastic aberrant crypt foci (ACF) lesions compared to the hemin-fed group. Dietary I3C also reduced fecal water genotoxicity. Gene expression analysis of colorectal tumors demonstrated that the combination of dietary I3C + syn increased transcript levels for Raf1 and decreased tumor progression and invasiveness related to the genes Cdh1 and Appl1. This analysis also revealed that the Tnf and Cdh1 genes were significantly up- and down-regulated, respectively, in tumors of rats that received I3C, in comparison with the hemin-fed group. These findings reveal that the joint administration of I3C and syn enhanced the development of colon tumors induced by DMH in hemin-fed rats, while they potentially reduced ACF development when given alone.

Intranasal delivery of liposomal indole-3-carbinol improves its pulmonary bioavailability

Indole-3-carbinol (I3C), a constituent of commonly consumed Brassica vegetables, has been shown to have anticancer effects in a variety of preclinical models of lung cancer. However, it has shown only limited efficacy in clinical trials, likely due to its poor oral bioavailability. Intranasal administration of I3C has the potential to enhance the pulmonary accumulation of the drug, thereby improving its availability at the target site of action. In this study, we developed a liposomal formulation of I3C and evaluated its lung delivery and chemopreventive potential in tobacco smoke carcinogen [4-(methylnitro-samino)-1-(3-pyridyl)-1-butanone (NNK)]-treated mice. Intranasal administration of I3C liposomes led to a ∼100-fold higher lung exposure of I3C than the oral route of administration. Further, intranasal delivery of liposomal I3C led to a significant reduction (37%; p<0.05) in the levels of the DNA adduct formation induced by NNK treatment. Liposomal I3C also significantly increased (by 10-fold) the expression of CYP1A1, a cytochrome P450 enzyme known to increase the detoxification of chemical carcinogens by enhancing their metabolism. Overall, our findings demonstrate that intranasal administration of liposomal I3C has the potential to significantly improve the efficacy of I3C for lung cancer chemoprevention.

Involvement of PTEN/Akt signaling and oxidative stress on indole-3-carbinol (I3C)-induced hepatocarcinogenesis in rats

We previously reported that indole-3-carbinol (I3C) had hepatocellular tumor-promoting activity in a short-term (8 weeks) two-stage liver carcinogenesis model in rats. It was suggested that this effect was related to the production of reactive oxygen species (ROS) caused by cytochrome P450 1A (CYP1A) induction. In the present study, 0.5% I3C was administered to DEN-initiated rats for 26 weeks to examine the effect of prolonged administration of I3C and to clarify the possible mechanisms of I3C-induced hepatocarcinogenesis. The number and area of GST-P positive foci, ROS production, TBARS level, 8-OHdG content and mRNA levels of Ahr and Nrf2 gene batteries significantly increased in the DEN-I3C group compared with the DEN-alone group. Furthermore, some GST-P positive preneoplastic foci progressed to hepatocellular adenomas with the prolongation of I3C administration. Lack of PTEN and phospho-Smad2/3 expression and translocations of PDPK1 and phospho-Akt substrates to underneath the cell membrane were observed in the majority of hepatocellular adenomas. In addition, the number of Ki-67 positive cells increased in adenomas compared with the preneoplastic foci. These results suggest that the administration of I3C for 26 weeks in DEN-initiated rats induces tumor progression from hepatocellular altered foci to hepatocellular adenomas by ROS-mediated Akt activation that inhibits the TGF-β/Smad signaling and results in the increased cell proliferation.

Evaluation of antiulcer activity of indole-3-carbinol and/or omeprazole on aspirin-induced gastric ulcer in rats

The present work is an attempt to elucidate the antiulcer activity of indole-3-carbinol (I3C), which is one of the anticarcinogenic phytochemicals found in the vegetables of Cruciferae family such as broccoli and cauliflower, alone or in combination with omeprazole (OMP), a proton pump inhibitor, to diminish the effects of induced acute gastric ulcer by aspirin (ASA) in male albino rats. A total of 48 adult male albino rats were used in the present study. Animals were divided into eight experimental groups (six animals each group). They were given different experimental inductions of ASA at a dose of 500 mg/kg/body weight, OMP at a dose of 20 mg/kg/body weight and I3C at a dose of 20 mg/kg/body weight either alone or in combination with each other orally for a duration of 7 days. Inner stomach features, ulcer index, pH activity, body weight, stomach weight, hematological investigations, serum total protein albumin and reduced glutathione activity were investigated in addition to the histological, histochemical and immunohistochemical stain of cyclooxygenase-2 to the stomach tissue of normal control, ulcerated and treated ulcerated rats. The results of this study revealed that oral administration of ASA to rats produced the expected characteristic mucosal lesions. OMP accelerated ulcer healing but the administration of I3C either alone or in combination with OMP to ASA-ulcerated rats produced a profound protection to the gastric mucosa from injury induced by ASA. Our results suggested that administration of antiulcer natural substances such as I3C in combination with the perused treatment such as OMP is a very important initiative in the development of new strategies in ulcer healing.

Indole-3-carbinol inhibited tobacco smoke carcinogen-induced lung adenocarcinoma in A/J mice when administered during the post-initiation or progression phase of lung tumorigenesis

We studied the chemopreventive efficacy of indole-3-carbinol (I3C), a phytochemical found in cruciferous vegetables, to inhibit tobacco carcinogen-induced lung adenocarcinoma in A/J mice when given following post-initiation or progression protocol. Moreover, we assessed the potential mechanisms responsible for the anticancer effects of I3C. Post-initiation administration of I3C decreased the multiplicity of surface tumors as well as all forms of histopathological lesions, including adenocarcinoma, whereas administration of the compound during tumor progression failed to decrease the multiplicity of surface tumors and early forms of microscopic lesions but reduced the frequency of adenocarcinoma. Mechanistic studies in A549 lung adenocarcinoma cells indicated that the lung cancer preventive effects of I3C are mediated, at least in part, via modulation of the receptor tyrosine kinase/PI3K/Akt signaling pathway.

Chronic Renin Inhibition Normalizes Blood Pressure in Cyp1a1‐Ren2 Transgenic Rats with ANG II‐Dependent Malignant Hypertension

The present study was performed to determine if chronic renin inhibition can normalize blood pressure in Cyp1a1-Ren2 transgenic rats with ANG II-dependent malignant hypertension. Adult male Cyp1a1-Ren2 rats (n=6) were fed a normal diet containing 0.3% indole-3-carbinol (I3C) for 10 days to induce ANG II-dependent malignant hypertension. Subsequently, the rats were treated chronically for 10 days with the renin inhibitor, aliskiren (60 mg/kg/day, sc), while maintaining dietary I3C administration. Systolic blood pressure (SBP) was measured daily by tail-cuff plethysmography and rats were placed in metabolic cages for determination of 24-hr urine flow and electrolyte excretion. Dietary I3C increased SBP (135±3 to 207±10 mmHg, P<0.001) and urine flow (5.6±0.7 to 37.2±10.8 ml/day, P<0.001). Subsequent chronic aliskiren administration normalized SBP within 1 day (108±1 mmHg, P<0.001). SBP remained at normotensive levels throughout the 10 days of chronic aliskiren treatment (125±7 mmHg, P<0.001). Urine flow and sodium excretion increased (from 37.2±10.8 to 56.3±6.1 ml/day, P<0.05, and from 0.89±0.28 to 2.06±0.32 mmol/day, P<0.01, respectively) by day 10 of aliskiren treatment. These findings demonstrate that chronic renin inhibition with aliskiren is highly effective in normalizing the elevated arterial pressure, and increases renal excretory function in ANG II-dependent malignant hypertension.

Transient Induction of ANG II-Dependent Malignant Hypertension Causes Sustained Elevation of Blood Pressure and Augmentation of the Pressor Response to ANG II in CYP1A1-REN2 Transgenic Rats

IntroductionTransgenic rats with inducible expression of the mouse Ren2 renin gene [strain name: TGR(Cyp1a1Ren2)] allow induction of various degrees of ANG II-dependent hypertension. Dietary administration of the aryl hydrocarbon indole-3-carbinol (I3C) at a dose of 0.15% induces a slowly developing form of ANG II-dependent hypertension, whereas dietary administration of a higher dose (0.3%) of I3C results in the development of ANG II-dependent malignant hypertension. Cessation of administration of 0.15% I3C results in the normalization of blood pressure, indicating the reversibility of hypertension induced by this dose of I3C. The present study was performed to determine if ANG II-dependent malignant hypertension is similarly reversible following cessation of dietary administration of 0.3% I3C. MethodsCyp1a1-Ren2 rats (n=6) were fed a normal diet containing 0.3% I3C for 11days to induce malignant hypertension. ResultsCyp1a1-Ren2 rats induced with I3C exhibited pronounced increases in systolic blood pressure (SBP) (132 ± 3–229 ± 11mm Hg, P < 0.001) and marked decreases in body weight (303 ± 4–222 ± 2 g, P < 0.001). When I3C administration was terminated, SBP decreased to 167 ± 4mm Hg (P < 0.01) and body weight increased to normal levels (309 ± 2 g, P < 0.01) within 12days. However, SBP remained significantly elevated (172 ± 1mm Hg, P < 0.01) for up to 3 weeks after termination of dietary administration of 0.3% I3C. In addition, the magnitude of the blood pressure response to intravenous bolus administration of 50 ng of ANG II (50 μL in volume) 3 weeks after cessation of dietary I3C administration was substantially higher than that observed in normotensive control rats (134 ± 1mm Hg, n=6) not previously induced with 0.3% I3C (53 ± 2 versus 38 ± 3mm Hg, P < 0.05). ConclusionsThe present findings demonstrate that transient induction of ANG II-dependent malignant hypertension results in prolonged elevations of arterial blood pressure and marked augmentation of the magnitude of the pressor response to ANG II in Cyp1a1-Ren2 transgenic rats.

Mechanism of inhibition of colitis by indole-3-carbinol (96.19)

Abstract Colitis is an autoimmune disease characterized by acute or chronic inflammation of the large intestine. Currently there is no cure for patients suffering from colitis, and most treatments involve the use of immunosuppressive drugs that can have adverse side-effects or increased toxicity. In the current study, we investigated the effects of indole-3-carbinol (I3C), a component found in a number of cruciferous vegetables. The products of I3C activate the aryl hydrocarbon (AhR) receptor, which has been shown in our laboratory to trigger apoptosis in activated T cells. In the current study, we tested the effect of I3C on a colitis model induced by administration of dextran sodium sulfate (DSS). The data showed that I3C administration reversed the weight loss seen during DSS-induced colitis. I3C treatment also reversed the shortening of the colon caused by DSS, as well decreased the level of immune cell infiltration found in the large intestine of colitis-induced mice. Early analysis of cell populations from the mesenteric lymph node showed that I3C treatment reduced the effects the disease model had on immune cells including T regulatory cells, natural killer cells, and myeloid-derived suppressor cells. In all these immune cell subsets, I3C treatment caused a return of the proportion of these cell populations to a more normal state. Together, the current study suggests that I3C may a serve as a novel treatment modality against colitis.

Genetic Clamping of Renin Gene Expression Induces Hypertension and Elevation of Intrarenal Ang II Levels of Graded Severity in Cyp1a1-Ren2 Transgenic Rats

Transgenic rats with inducible angiotensin II (Ang II)-dependent hypertension (strain name: TGR[Cyp1a1-Ren2]) were generated by inserting the mouse Ren2 renin gene, fused to the cytochrome P450 1a1 (Cyp1a1) promoter, into the genome of the rat. The present study was performed to characterise the changes in plasma and kidney tissue Ang II levels and in renal haemodynamic function in Cyp1a1-Ren2 rats following induction of either slowly developing or malignant hypertension in these transgenic rats. Arterial blood pressure (BP) and renal haemodynamics and excretory function were measured in pentobarbital sodium-anaesthetised Cyp1a1- Ren2 rats fed a normal diet containing either a low dose (0.15%, w/w for 1415 days) or high dose (0.3%, w/w for 1112 days) of the aryl hydrocarbon indole-3-carbinol (I3C) to induce slowly developing and malignant hypertension, respectively. In parallel experiments, arterial blood samples and kidneys were harvested for measurement of Ang II levels by radioimmunoassay. Dietary I3C increased plasma renin activity (PRA), plasma Ang II levels, and arterial BP in a dose-dependent manner. Induction of different fixed levels of renin gene expression and PRA produced hypertensive phenotypes of varying severity with rats developing either mild or malignant forms of hypertensive disease. Administration of I3C, at a dose of 0.15% (w/w), induced a slowly developing form of hypertension whereas administration of a higher dose (0.3%) induced a more rapidly developing hypertension and the clinical manifestations of malignant hypertension including severe weight loss. Both hypertensive phenotypes were characterised by reduced renal plasma flow, increased filtration fraction, elevated PRA, and increased plasma and intrarenal Ang II levels. These I3C-induced changes in renal haemodynamics, PRA and kidney Ang II levels were more pronounced in Cyp1a1-Ren2 rats with malignant hypertension. Chronic administration of the AT1-receptor antagonist, hypertension, the associated changes in renal haemodynamics, and the augmentation of intrarenal Ang II levels. Activation of AT1-receptors by Ang II generated as a consequence of induction of the Cyp1a1-Ren2 transgene mediates the increased arterial pressure and the associated reduction of renal haemodynamics and enhancement of intrarenal Ang II levels in hypertensive Cyp1a1-Ren2 transgenic rats.

A Phase I Study of Indole-3-Carbinol in Women: Tolerability and Effects

We completed a phase I trial of indole-3-carbinol (I3C) in 17 women (1 postmenopausal and 16 premenopausal) from a high-risk breast cancer cohort. After a 4-week placebo run-in period, subjects ingested 400 mg I3C daily for 4 weeks followed by a 4-week period of 800 mg I3C daily. These chronic doses were tolerated well by all subjects. Hormonal variables were measured near the end of the placebo and dosing periods, including determination of the urinary 2-hydroxyestrone/16alpha-hydroxyestrone ratio. Measurements were made during the follicular phase for premenopausal women. Serum estradiol, progesterone, luteinizing hormone, follicle-stimulating hormone, and sex hormone binding globulin showed no significant changes in response to I3C. Caffeine was used to probe for cytochrome P450 1A2 (CYP1A2), N-acetyltransferase-2 (NAT-2), and xanthine oxidase. Comparing the results from the placebo and the 800 mg daily dose period, CYP1A2 was elevated by I3C in 94% of the subjects, with a mean increase of 4.1-fold. In subjects with high NAT-2 activities, these were decreased to 11% by I3C administration but not altered if NAT-2 activity was initially low. Xanthine oxidase was not affected. Lymphocyte glutathione S-transferase activity was increased by 69% in response to I3C. The apparent induction of CYP1A2 was mirrored by a 66% increase in the urinary 2-hydroxyestrone/16alpha-hydroxyestrone ratio in response to I3C. The maximal increase was observed with the 400 mg daily dose of I3C, with no further increase found at 800 mg daily. If the ratio of hydroxylated estrone metabolites is a biomarker for chemoprevention, as suggested, then 400 mg I3C daily will elicit a maximal protective effect.

Chemopreventive Effect of Indole-3-Carbinol on Induction of Preneoplastic Altered Hepatic Foci

: Indole-3-carbinol (I3C) is a cleavage product of glucobrassicanin, a natural compound present in a wide variety of plant food substances including members of the family Cruciferae. I3C is known to possess cancer-chemopreventive potential in various animal models. The present study reveals the protective effect of I3C on the development of diethylnitrosamine (DEN)-initiated and 2-acetylaminofluorene (AAF)-promoted preneoplastic, altered hepatic foci (AHF) in Wistar rats. I3C was given at dose levels of 0.5 and 1 mg/kg body weight for five consecutive days along with DEN and AAF. AHF were scored and analyzed by quantitative stereology using the Image Analysis System from frozen liver sections stained for positive and negative biological markers of AHF, that is, glutathione S-transferase (GST-P), γ-glutamyl transpeptidase (GGT), glucose-6-phosphatase (G6Pase), adenosine triphosphatase (ATPase), and alkaline phosphatase (AlkPase). Results revealed the chemopreventive effect of I3C on the DEN-initiated AHF in Wistar rats. The expression of G6Pase, ATPase, and AlkPase was restored in the I3C-supplemented animal. Similarly the induced expression GST-P and GGT also decreased in the animals with I3C administration. The recovery of altered levels of these biomarkers was of comparatively higher magnitude in the animals given a higher dose of I3C (1 mg/kg body weight) in comparison with the animals given 0.5 mg/kg body weight dose of I3C, although no dose-dependence pattern was recorded in I3C-supplemented groups. These results thus suggest the chemopreventive effect of I3C in rat hepatocarcinogenesis by suppressing DEN- and AAF-induced AHF development.

Indole-3-carbinol modulation of hepatic monooxygenases CYP1A1, CYP1A2 and FMO1 in guinea pig, mouse and rabbit

Indole-3-carbinol (I3C), a major component of cruciferous vegetables, has been shown to be chemoprotective against cancer in a number of animal models and is being evaluated as a potential agent to prevent breast cancer in healthy women. Some concern has been raised related to the long-term use of I3C, as in some models chronic dietary post-initiation exposures promote cancers. I3C administration to rats marked induces several cytochrome P450s (CYPs), especially CYP1A1 (approx. 25-fold), while at the same time inhibiting the expression of FMO1. The consequence is a marked shift in the metabolic profile of drugs such as nicotine and tamoxifen, that are substrates for both monooxygenases. Such an effect could lead to adverse drug reactions in humans. In order to determine if the effect of I3C was manifest in species other than the rat, we fed 2000-ppm I3C to male guinea pigs, mice and rabbits for a period of 4 weeks. In each species, induction of CYP1A1/1A2 expression was observed in the liver but little or no effect on FMO1 was evident, with the possible exception of the rabbit. These data demonstrate that the ability of I3C to both induce CYP1A1 and inhibit FMO1, as observed in the rat, may not be common to other mammals for which FMO1 is the major isoform in the liver.

N-Methoxyindole-3-Carbinol Is a More Efficient Inducer of Cytochrome P-450 1A1 in Cultured Cells Than Indol-3-Carbinol

The well-documented reduction of cancer risk by high dietary cruciferous vegetable intake may in part be caused by modulation of cytochrome P-450 (CYP) expression and activity by indoles. The purpose of the present experiments was to study the mechanism of CYP 1A1 induction by N-methoxyindole-3-carbinol (NI3C) in cultured cells and to compare the CYP-inducing potential of NI3C and indole- 3-carbinol (I3C) administered to rats. NI3C induced 7-ethoxyresorufin-O-deethylase (EROD) activity in Hepa-1c1c7 cells in a concentration-dependent manner with 10-fold higher efficiency than I3C. Inasmuch as NI3C induced binding of the aryl hydrocarbon receptor (AhR) to the dioxin-responsive element and induced expression of endogenous CYP 1A1 mRNA and an AhR-responsive chloramphenicol acetyl transferase construct, we conclude that NI3C can activate the AhR. Besides the induction of CYP 1A1, we observed an inhibition of EROD activity, with a concentration causing 50% inhibition of 6 μM. Oral administration of NI3C at 570 μmol/kg body wt to male Wistar rats increased the hepatic CYP 1A1 and 1A2 protein levels, as well as the EROD and 7-methoxyresorufin O-demethylase activities at 8 and 24 hours after administration, but the responses were less pronounced than after administration of I3C at 570 μmol/kg body wt. Furthermore, NI3C did not induce hepatic 7-pentoxyresorufin O-depentylase activity, as I3C did. Ascorbigen, another indolylic compound formed during degradation of glucobrassicin in the presence of ascorbic acid, was tested in the same animal model, and ascorbigen only weakly induced hepatic CYP 1A1 and 1A2, but not CYP 2B1/2. In conclusion, NI3C is a more efficient inducer of CYP 1A1 in cultured cells than I3C but is less active when administered to rodents.