curcumin and hexahydrocurcumin

Curcumin, one of the most precious pharmacologically relevant natural products, has gained considerable attention among scientists for decades because of its multi-pharmacological activities in the clinical. However, critical studies on its pharmacological and toxicological activities are needed to understand how this compound can have these biological functions considering its poor oral bioavailability and the low plasma concentration. Moreover, curcumin undergoes extensive and rapid metabolism in vivo, indicating that the pharmacological activity of consuming curcumin might be mediated partly by its metabolites. And as one of the major curcumin metabolites, hexahydrocurcumin (HHC), exhibits similar or more potent bioactivity than curcumin by in vitro and in vivo studies, such as antioxidant, anti-inflammatory, antitumor and cardiovascular protective properties, which may provide important information for us to have a profound comprehension of the effectiveness of curcumin. This review mainly summarizes the current knowledge and underlying molecular mechanisms of the biological activities of HHC and its potential effects on the development of various human diseases.

Topics: Animals; Anthelmintics; Anti-Inflammatory Agents; Antineoplastic Agents; Antioxidants; Biological Availability; Cardiotonic Agents; Cell Line, Tumor; Curcumin; Humans

Curcumin is poorly absorbed, which is interest in new preparations. However, little is known about variations in its pharmacokinetics and tissue bioavailability between formulations. In this randomized, crossover study we evaluated the relationship between steady-state plasma and rectal tissue curcuminoid concentrations using standard and phosphatidylcholine curcumin extracts. There was no difference in the geometric mean plasma AUCs when adjusted for the 10-fold difference in curcumin dose between the 2 formulations. Phosphatidylcholine curcumin extract yielded only 20% to 30% plasma demethoxycurcumin and bisdemethoxycurcumin conjugates compared to standard extract, yet yielded 20-fold greater hexahydrocurcumin. When adjusting for curcumin dose, tissue curcumin concentrations were 5-fold greater for the phosphatidylcholine extract. Improvements in curcuminoid absorption due to phosphatidylcholine are not uniform across the curcuminoids. Furthermore, curcuminoid exposures in the intestinal mucosa are most likely due to luminal exposure rather than to plasma disposition. Finally, once-daily dosing is sufficient to maintain detectable curcuminoids at steady state in both plasma and rectal tissues.

Topics: Adolescent; Adult; Aged; Anti-Inflammatory Agents, Non-Steroidal; Area Under Curve; Biological Availability; Biotransformation; Cross-Over Studies; Curcumin; Diarylheptanoids; Female; Glucuronides; Healthy Volunteers; Humans; Intestinal Absorption; Male; Middle Aged; Rectum; Young Adult

Age-related macular degeneration (AMD) is a disease of retinal pigment epithelium (RPE) cells. We have previously demonstrated that blue light can damage RPE cells and their underlying mechanisms. We found that hexahydrocurcumin (HHC), a metabolite of curcumin, had better retinal protection than curcumin. However, the involved mechanisms remain unclear.. By exposing ARPE-19 human RPE cells and mouse primary RPE cells to blue light, the intracellular mechanisms of HHC in cells were investigated, including the proliferation of RPE cells and the effects of HHC on activating intracellular protective mechanisms and related factors. Next-generation sequencing (NGS) RNA sequencing revealed the underlying mechanisms involved in the induction and regulation of HHC treatment following blue light exposure.. HHC promoted autophagy by enhancing autophagic flux, reduced oxidative stress and endoplasmic reticulum (ER) stress, and effectively reversed blue light-induced cell death. RNA sequencing-based bioinformatics approaches comprehensively analyze HHC-mediated cellular processes.. Our findings elucidate the mechanisms of HHC against blue light damage in RPE cells and are beneficial for the development of natural metabolite-based preventive drugs or functional foods.

Topics: Animals; Curcumin; Humans; Mice; Oxidative Stress; Retina; Retinal Pigment Epithelium

Hexahydrocurcumin (HHC), a major metabolite of curcumin, possesses several biological activities such as antioxidant, anti-inflammation, and cardioprotective properties. This study aimed to investigate the effect of HHC on high blood pressure, vascular dysfunction, and remodeling induced by N-nitro L-arginine methyl ester (L-NAME) in rats. Male Wistar rats (200-250 g) received L-NAME (40 mg/kg) via drinking water for seven weeks. HHC at doses of 20, 40 or 80 mg/kg or enalapril 10 mg/kg was orally administered for the last three weeks. Blood pressure was measured weekly. Rats induced with L-NAME showed the development of hypertension, vascular dysfunction, and remodeling as demonstrated by an increase in wall thickness, cross-sectional area, and collagen deposition in the aorta. The overexpression of nuclear factor kappa B (NF-кB), vascular cell adhesion molecule 1 (VCAM1), intercellular adhesion molecule 1 (ICAM1), tumor necrosis factor-alpha (TNF-α), phosphorylated-extracellular-regulated kinase 1/2 (p-ERK1/2), phosphorylated-c-Jun N-terminal kinases (p-JNK), phosphorylated-mitogen activated protein kinase p38 (p-p38), transforming growth factor-beta 1 (TGF-β1), matrix metalloproteinase-9 (MMP-9) and collagen type 1 was observed in L-NAME-induced hypertensive rats. Increased oxidative stress markers, decreased plasma nitric oxide (NO) levels and the down-regulation of endothelial nitric oxide synthase (eNOS) expression in aortic tissues were also found in L-NAME-induced rats. Moreover, L-NAME-induced rats showed enhanced synthetic protein expression in aortic tissues. These alterations were suppressed in hypertensive rats treated with HHC or enalapril. The present study shows that HHC exhibited antihypertensive effects by improving vascular function and ameliorated the development of vascular remodeling. The responsible mechanism may involve antioxidant and anti-inflammation potential.

Topics: Animals; Blood Pressure; Curcumin; Enzyme Inhibitors; Hypertension; Male; NG-Nitroarginine Methyl Ester; Nitric Oxide; Oxidative Stress; Rats; Rats, Wistar; Vascular Remodeling

A high dose of dexamethasone induces neurodegeneration by initiating the inflammatory processes that lead to neural apoptosis. A dexamethasone administration model induces overproduction of amyloid-β (Aβ) and tau protein hyperphosphorylation and shows abnormalities of cholinergic function similar to Alzheimer's disease (AD). This study aimed to investigate the protective effect of hexahydrocurcumin on the brain of dexamethasone-induced mice. The results showed that hexahydrocurcumin and donepezil attenuated the levels of amyloid precursor protein and β-secretase mRNA by reverse transcription polymerase chain reaction, decreased the expression of hyperphosphorylated tau, and improved synaptic function. Moreover, we found that hexahydrocurcumin treatment could decrease interleukin-6 levels by attenuating p65 of nuclear factor kappa-light-chain-enhancer (NF-κB) of activated beta cells. In addition, hexahydrocurcumin also decreased oxidative stress, as demonstrated by the expression of 4-hydroxynonenal and thereby prevented apoptosis. Therefore, our finding suggests that hexahydrocurcumin prevents dexamethasone-induced AD-like pathology and improves memory impairment.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Curcumin; Dexamethasone; Disease Models, Animal; Male; Mice, Inbred ICR; Neuroprotective Agents

A hexahydrocurcumin-producing bacterium named 2a1-2b was isolated from human feces. It was observed that the bacterium had more than 99% similarity with Enterococcus avium ATCC14025

Topics: Curcumin; Enterococcus; Feces; Humans; Optical Rotation

Curcuminoids are the main bioactive components of the well-known Asian spice and traditional medicine turmeric. Curcuminoids have poor chemical stability and bioavailability; in vivo they are rapidly metabolized to a set of bioreduced derivatives and/or glucuronide and sulfate conjugates. The reduced curcuminoid metabolites were also reported to exert various bioactivities in vitro and in vivo. In this work, we aimed to perform a comparative evaluation of curcuminoids and their hydrogenated metabolites from a medicinal chemistry point of view, by determining a set of key pharmacokinetic parameters and evaluating antioxidant potential in relation to such properties.Reduced metabolites were prepared from curcumin and demethoxycurcumin through continuous-flow hydrogenation. As selected pharmacokinetic parameters, kinetic solubility, chemical stability, metabolic stability in human liver microsomes, and parallel artificial membrane permeability assay (PAMPA)-based gastrointestinal and blood-brain barrier permeability were determined. Experimentally determined logP for hydrocurcumins in octanol-water and toluene-water systems provided valuable data on the tendency for intramolecular hydrogen bonding by these compounds. Drug likeness of the compounds were further evaluated by a in silico calculations. Antioxidant properties in diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and oxygen radical absorbance capacity (ORAC) assays were comparatively evaluated through the determination of ligand lipophilic efficiency (LLE). Our results showed dramatically increased water solubility and chemical stability for the reduced metabolites as compared to their corresponding parent compound. Hexahydrocurcumin was found the best candidate for drug development based on a complex pharmacokinetical comparison and high LLE values for its antioxidant properties. Development of tetrahydrocurcumin and tetrahydro-demethoxycurcumin would be limited by their very poor metabolic stability, therefore such an effort would rely on formulations bypassing first-pass metabolism.

Topics: Antioxidants; Biological Availability; Biphenyl Compounds; Cell Membrane Permeability; Chemistry, Pharmaceutical; Curcuma; Curcumin; Diarylheptanoids; Glucuronides; Humans; Hydrogenation; Microsomes, Liver; Picrates; Solubility

Hexahydrocurcumin (HHC), a major metabolite of curcumin, has been reported to have protective effects against ischemic and reperfusion damage. The goal of the present research was to examine whether HHC could alleviate brain damage and ameliorate functional outcomes by diminishing the blood-brain barrier (BBB) damage that follows cerebral ischemia/reperfusion.. Middle cerebral artery occlusion was induced for 2 h in rats followed by reperfusion. The rats were divided into three groups: sham-operated, vehicle-treated, and HHC-treated groups. At the onset of reperfusion, the rats were immediately intraperitoneally injected with 40 mg/kg HHC. At 48 h after reperfusion, the rats were evaluated for neurological deficits and TTC staining. At 24 h and 48 h after reperfusion, animals were sacrificed, and their brains were extracted.. Treatment with HHC reduced neurological scores, infarct volume, morphological changes, Evans blue leakage and immunoglobulin G extravasation. Moreover, HHC treatment reduced BBB damage and neutrophil infiltration, downregulated myeloperoxidase, ICAM-1, and VCAM-1, upregulated tight junction proteins (TJPs), and reduced aquaporin 4 expression and brain water content.. These results revealed that HHC treatment preserved the BBB from cerebral ischemia/reperfusion injury by regulating TJPs, attenuating neutrophil infiltration, and reducing brain edema formation.

Topics: Animals; Aquaporin 4; Blood-Brain Barrier; Brain; Brain Edema; Brain Ischemia; Curcumin; Infarction; Infarction, Middle Cerebral Artery; Male; Rats; Rats, Wistar; Reperfusion Injury; Zonula Occludens-1 Protein

This study was to investigate the anti-angiogenic effect of hexahydrocurcumin (HHC) to evaluate gene (p-basic fibroblast growth factor (bFGF)-SAINT-18 & p-vascular endothelial growth factor (VEGF)-SAINT-18 complex)-induced corneal neovascularization (CorNV) in rats.. CorNV was induced in 24 eyes of 24 rats. Four groups (Group A: 0 μg, B: 0.01 μg, C: 0.1 μg, and D: 1 μg) of HHC were prepared and implanted into the rat subconjunctival substantia propria 1.5 mm from the limbus at temporal side. The 1 μg of p-bFGF-SAINT-18 & p-VEGF-SAINT-18 complex were prepared and implanted into the rat corneal stroma 1.5 mm from the limbus at the same side. Inhibition of CorNV was observed and quantified from day 1 to day 60. bFGF and VEGF protein expression were analyzed by biomicroscopic examination, western blot analysis, and immunohistochemistry.. Subconjunctival injection by 1 μg HHC successfully inhibited gene-induced CorNV in rats. bFGF and VEGF protein expression were reduced after 6 days. Meanwhile, the reduction of HLA-DR expression was detected.. Our study showed that the HHC might provide an important anti-angiogenesis factor to inhibit CorNV development at the corneal experimental angiogenesis model.

Topics: Angiogenesis Inhibitors; Animals; Blotting, Western; Conjunctiva; Corneal Neovascularization; Curcumin; Disease Models, Animal; Fibroblast Growth Factor 2; HLA-DR Antigens; Male; Rats; Rats, Sprague-Dawley; Vascular Endothelial Growth Factor A

The purpose of the present experiment was to investigate whether hexahydrocurcumin (HHC) attenuates brain damage and improves functional outcome via the activation of antioxidative activities, anti-inflammation, and anti-apoptosis following cerebral ischemia/reperfusion (I/R). In this study, rats with cerebral I/R injury were induced by a transient middle cerebral artery occlusion (MCAO) for 2 h, followed by reperfusion. The male Wistar rats were randomly divided into five groups, including the sham-operated, vehicle-treated, 10 mg/kg HHC-treated, 20 mg/kg HHC-treated, and 40 mg/kg HHC-treated I/R groups. The animals were immediately injected with HHC by an intraperitoneal administration at the onset of cerebral reperfusion. After 24 h of reperfusion, the rats were tested for neurological deficits, and the pathology of the brain was studied by 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin and eosin (H&E) staining, and terminal deoxynucleotidyltransferase UTP nick end labeling (TUNEL) staining. In addition, the brain tissues were prepared for protein extraction for Western blot analysis, a malondialdehyde (MDA) assay, a nitric oxide (NO) assay, a superoxide dismutase (SOD) assay, a glutathione (GSH) assay, and a glutathione peroxidase (GSH-Px) assay. The data revealed that the neurological deficit scores and the infarct volume were significantly reduced in the HHC-treated rats at all doses compared to the vehicle group. Treatment with HHC significantly attenuated oxidative stress and inflammation, with a decreased level of MDA and NO and a decreased expression of NF-κB (p65) and cyclooxygenase-2 (COX-2) in the I/R rats. HHC also evidently increased Nrf2 (nucleus) protein expression, heme oxygenase-1 (HO-1) protein expression, the antioxidative enzymes, and the superoxide dismutase (SOD) activity. Moreover, the HHC treatment also significantly decreased apoptosis, with a decrease in Bax and cleaved caspase-3 and an increase in Bcl-XL, which was in accordance with a decrease in the apoptotic neuronal cells. Therefore, the HHC treatment protects the brain from cerebral I/R injury by diminishing oxidative stress, inflammation, and apoptosis. The antioxidant properties of HHC may play an important role in improving functional outcomes and may offer significant neuroprotection against I/R damage.

Topics: Animals; Antioxidants; Curcumin; Disease Models, Animal; Inflammation; Rats; Reperfusion Injury; Stroke

Hydrogdnation of curcumin (1), a chemopreventive agent from Turmeric (Curcuma longa L.) yielded three major compounds: 1,7-bis(4-hydroxy-3- methoxyphenyl)heptane-3,5-dione (2), 5-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)heptan-3-one (3), and 1,7-bis(4-hydroxy-3-methoxyphenyl)heptane- 3,5-diol (4). Incubation of compound (2) with Beauveria bassiana ATCC 7159 afforded the hexahydrocurcumin (3) as the sole metabolite while biotransformation.of curcumin (1) with B. bassiana gave metabolites 2-4 along with the curcumin-4'-0-4"'-O-methyl-β-D-glucopyranoside (5) and octahydrocurcumih-4'-O-4"'-O-methyl--β-D-glucopyranoside (6). The bioconversion of curcumin (1) with Rhizopus oryzae ATCC 11145 yielded analogs 2-4 while no transformation of curcumin (1) was observed with Aspergillus niger ATCC 16888. The preparation, structural elucidation and biological activities of these metabolites are reported herein.

Topics: Aspergillus; Beauveria; Biotransformation; Curcuma; Curcumin; Molecular Structure

Curcumin as a natural product has drawn considerable attention in recent years for its multiple pharmacological activities against various diseases, but more studies are required to understand the curcumin pharmacological action considering its low bioavailability. Though numerous reasons contribute to the low bioavailability of curcumin, one of the important reasons is associated with biotransformation of curcumin through either conjugation or reduction depending on curcumin administration route. The orally administered curcumin (CUR) is metabolised into curcumin glucuronidase (CUR-GLR) and curcumin sulphate by conjugation, whereas dihydroxycurcumin, tetrahydrocurcumin, and hexahydrocurcumin (HHC) are formed by reduction after intraperitoneal administration of curcumin. The main aim of the current study was to investigate the pharmacological properties of curcumin and its biotransformed molecules and its inhibitory potential against CagA (cytotoxic-associated gene A) oncoprotein of Helicobacter pylori. All lead molecules followed the Lipinski's five rules for biological activities, except CUR-GLR, whereas druglikeness scores were obtained for all molecules. Subsequently, molecular docking was employed to analyse the binding affinity of molecules with CagA. The docking studies revealed that CUR-GLR has highest binding affinity with CagA, whereas less interactive affinity was observed in HHC. From the virtual screening and docking studies, the current study suggests that the biotransformation of curcumin through conjugation has more potential for inhibition of oncogenic activities of CagA+ H. pylori than reduction.

Topics: Biotransformation; Curcumin; Helicobacter pylori; Molecular Docking Simulation

The aim of the present study was to investigate and compare the anti‑inflammatory activities of curcumin and its three metabolites, tetrahydrocurcumin, hexahydrocurcumin and octahydrocurcumin in lipopolysaccharide (LPS)‑stimulated RAW 264.7 macrophage cells. The results demonstrated that overproduction of nitric oxide (NO) was potently inhibited following treatment with curcumin and its three metabolites. In addition, curcumin and tetrahydrocurcumin significantly inhibited the release of prominent cytokines, including tumor necrosis factor‑α (TNF‑α) and interleukin‑6 (IL‑6); however, hexahydrocurcumin and octahydrocurcumin did not significantly alter cytokine release. Furthermore, the present study investigated the effect of curcumin and its metabolites on the expression of inducible NO synthase (iNOS), cyclooxygenase‑2 (COX‑2) and activated‑nuclear factor kappa B (NF‑κB); the results showed that curcumin and its three metabolites significantly inhibited LPS‑mediated upregulation of iNOS and COX‑2 as well as NF‑κB activation. However, curcumin exerted a more potent effect on LPS‑stimulated RAW 264.7 cells compared to that of its three metabolites, of which tetrahydrocurcuim was found to be the most pharmacologically active. In conclusion, the results of the present study demonstrated that curcumin and its major metabolites inhibited the LPS‑induced inflammatory response via the mechanism of inhibiting NF‑κB translocation to the nucleus.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Line; Cell Survival; Curcumin; Cyclooxygenase 2; Cytokines; Lipopolysaccharides; Macrophages; Male; Mice; NF-kappa B; Nitric Oxide; Nitric Oxide Synthase Type II; Protein Transport; Proteolysis; Rats

We have previously shown that curcumin (CUR) may increase lipid accumulation in cultured human acute monocytic leukaemia cell line THP-1 monocytes/macrophages, but that tetrahydrocurcumin (THC), an in vivo metabolite of CUR, has no such effect. In the present study, we hypothesised that the different cellular uptake and/or metabolism of CUR and THC might be a possible explanation for the previously observed differences in their effects on lipid accumulation in THP-1 monocytes/macrophages. Chromatography with tandem MS revealed that CUR was readily taken up by THP-1 monocytes/macrophages and slowly metabolised to hexahydrocurcumin sulphate. By contrast, the uptake of THC was low. In parallel with CUR uptake, increased lipid uptake was observed in THP-1 macrophages but not with the uptake of THC or another CUR metabolite and structurally related compounds. From these results, it is possible to deduce that CUR and THC are taken up and metabolised differently in THP-1 cells, which determine their biological activity. The remarkable differential cellular uptake of CUR, relative to THC and other similar molecules, may imply that the CUR uptake into cells may occur via a transporter.

Topics: Biological Transport; Carcinogens; Cell Differentiation; Cell Line; Chromatography, High Pressure Liquid; Curcumin; Diarylheptanoids; Glucuronides; Humans; Kinetics; Lipid Metabolism; Macrophages; Monocytes; Sulfates; Tandem Mass Spectrometry; Tetradecanoylphorbol Acetate

To investigate the ability of hexahydrocurcumin (HHC) to enhance 5-fluorouracil (5-FU) in inhibiting the growth of HT-29 cells by focusing on cyclooxygenase (COX)-2 expression.. Antiproliferative effects of HHC and 5-FU, alone and in combination, on growth of HT-29 human colon cancer cells were assessed using 5-diphenyltetrazolium bromide (MTT) reduction assay. In combination treatment, low doses of 5-FU were used combined with various concentrations of HHC to minimize the toxicity and side effects of 5-FU. The therapeutic effects of these drugs on down-regulation of COX-2 mRNA and protein expression were examined using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting analysis.. MTT reduction assay indicated that HHC alone markedly decreased the viability of HT-29 human colon cancer cells compared to control. Semi-quantitative RT-PCR analysis indicated that HHC is a selective COX-2 inhibitor. This finding was supported by the observation that HHC significantly down-regulates COX-2 mRNA expression compared to the control (control: 100.05% ± 0.03% vs HHC: 61.01% ± 0.35%, P < 0.05) but does not alter COX-1 mRNA. In combined treatment, addition of HHC to a low dose of 5-FU exerts a synergistic effect against the growth of HT-29 cells by markedly reducing cell viability to a greater degree than monotherapy. Semi-quantitative RT-PCR indicated that 5-FU at the concentration of 5 μmol/L in combination with HHC at the concentration of 25 μmol/L significantly down-regulates COX-2 mRNA expression when compared with values in cells treated with 5-FU or HHC alone (HHC + 5-FU: 31.93% ± 5.69%, 5-FU: 100.66% ± 4.52% vs HHC: 61.01% ± 0.35%, P < 0.05).. HHC together with 5-FU exerts a synergistic effect and may prove chemotherapeutically useful in treating human colon cancer.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cell Proliferation; Cell Survival; Curcumin; Cyclooxygenase 2; Down-Regulation; Drug Synergism; Fluorouracil; HT29 Cells; Humans; RNA, Messenger

Hexahydrocurcumin, 1-dehydro-[6]-gingerdione, 6-dehydroshogaol and 6-shogaol were evaluated for their antioxidant and anti-inflammatory activities in the present study. The relative antioxidant potencies of ginger compounds decreased in similar order of 1-dehydro-[6]-gingerdione, hexahydrocurcumin>6-shogaol>6-dehydroshogaol in both 1,1-diphenyl-2-picyrlhydrazyl (DPPH) radical-scavenging and trolox equivalent antioxidant capacity (TEAC) assays. All tested compounds could attenuate lipopolysaccharide (LPS)-elicited increase of prostaglandin E2 (PGE(2)) in murine macrophages (RAW 264.7) in a concentration-dependent manner but hexahydrocurcumin of 7μM and 6-shogaol of 7μM. The strongest inhibitory effect was observed for 6-dehydroshogaol and 6-shogaol at 14μM with the inhibition of 53.3% and 48.9%, respectively. Furthermore, both 6-dehydroshogaol and 1-dehydro-[6]-gingerdione significantly suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins in a concentration-dependent fashion. These results contribute to our theoretical understanding of the potential beneficial effects of consuming ginger as a food and/or dietary supplement.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Catechols; Cell Line; Curcumin; Cyclooxygenase 2; Guaiacol; Macrophages; Mice; Nitric Oxide Synthase Type II; Plant Extracts; Zingiber officinale

The effects of hexahydrocurcumin on adenosine diphosphate (ADP)-induced human platelet aggregation were studied. Treatment of human platelet-rich plasma with hexahydrocurcumin resulted in an inhibitory effect on platelet aggregation, suggesting the potential of this compound as an anti-atherosclerogenic agent in humans.

Topics: Curcumin; Humans; Molecular Structure; Platelet Aggregation; Platelet Aggregation Inhibitors

To investigate the effects of hexahydrocurcumin (HHC), and its combination with 5-fluorouracil (5-FU) on dimethylhydrazine (DMH)-induced colon cancer in rats.. Male Wistar rats weighing 100-120 g were used as subject models. Aberrant crypt foci (ACF), early preneoplastic lesions of colon cancer, were induced by subcutaneous injection of DHM (40 mg/kg) twice a week for two weeks. After the first DMH injection, rats were treated daily with vehicle (n = 12), curcumin (CUR) (50 mg/kg) (n = 12), HHC (50 mg/kg) orally (n = 12), and treated weekly with an intraperitoneal injection of 5-FU (50 mg/kg) (n = 12), or a combination of 5-FU plus CUR (n = 12) and HHC (n = 12) at the same dosage(s) for 16 wk. The total number of ACF and large ACF were assessed. Cyclooxygenase (COX)-1 and COX-2 expression were detected by immunohistochemistry in colon tissues. The quantitative data of both COX-1 and COX-2 expression were presented as the percentage of number of positive-stained cells to the total number of cells counted. Apoptotic cells in colon tissues were also visualized using the dUTP-biotin nick end labeling method. Apoptotic index (AI) was determined as the percentage of labeled nuclei with respect to the total number of nuclei counted.. The total number of ACF was highest in the DMH-vehicle group (1558.20 ± 17.37), however, the number of ACF was significantly reduced by all treatments, 5-FU (1231.20 ± 25.62 vs 1558.20 ± 17.37, P < 0.001), CUR (1284.20 ± 25.47 vs 1558.20 ± 17.37, P < 0.001), HHC (1086.80 ± 53.47 vs 1558.20 ± 17.37, P < 0.001), DMH-5-FU + CUR (880.20 ± 13.67 vs 1558.20 ± 17.37, P < 0.001) and DMH-5-FU + HHC (665.80 ± 16.64 vs 1558.20 ± 17.37, P < 0.001). Interestingly, the total number of ACF in the combined treatment groups, the DMH-5-FU + CUR group (880.20 ± 13.67 vs 1231.20 ± 25.62, P < 0.001; 880.20 ± 13.67 vs 1284.20 ± 25.47, P < 0.001) and the DMH-5-FU + HHC group (665.80 ± 16.64 vs 1231.20 ± 25.62, P < 0.001; 665.80 ± 16.64 vs 1086.80 ± 53.47, P < 0.001) were significantly reduced as compared to 5-FU or each treatment alone. Large ACF were also significantly reduced in all treatment groups, 5-FU (111.00 ± 7.88 vs 262.20 ± 10.18, P < 0.001), CUR (178.00 ± 7.33 vs 262.20 ± 10.18, P < 0.001), HHC (186.60 ± 21.51 vs 262.20 ± 10.18, P < 0.001), DMH-5-FU + CUR (122.00 ± 5.94 vs 262.20 ± 10.18, P < 0.001) and DMH-5-FU + HHC (119.00 ± 17.92 vs 262.20 ± 10.18, P < 0.001) when compared to the vehicle group. Furthermore, in the DMH-5-FU + CUR and DMH-5-FU + HHC groups the formation of large ACF was significantly reduced when compared to CUR (122.00 ± 5.94 vs 178.00 ± 7.33, P < 0.005) or HHC treatment alone (119.00 ± 17.92 vs 186.60 ± 21.51, P < 0.001), however, this reduction was not statistically different to 5-FU monotherapy (122.00 ± 5.94 vs 111.00 ± 7.88, P = 0.217; 119.00 ± 17.92 vs 111.00 ± 7.88, P = 0.619, respectively). The levels of COX-1 protein after all treatments were not different from normal rats. A marked increase in the expression of COX-2 protein was observed in the DMH-vehicle group. Over-expression of COX-2 was not significantly decreased by 5-FU treatment alone (95.79 ± 1.60 vs 100 ± 0.00, P = 0.198). However, over-expression of COX-2 was significantly suppressed by CUR (77.52 ± 1.68 vs 100 ± 0.00, P < 0.001), HHC (71.33 ± 3.01 vs 100 ± 0.00, P < 0.001), 5-FU + CUR (76.25 ± 3.32 vs 100 ± 0.00, P < 0.001) and 5-FU + HHC (68.48 ± 2.24 vs 100 ± 0.00, P < 0.001) in the treated groups compared to the vehicle group. Moreover, CUR (77.52 ± 1.68 vs 95.79 ± 1.60, P < 0.001), HHC (71.33 ± 3.01 vs 95.79 ± 1.60, P < 0.001), 5-FU + CUR treatments (76.25 ± 3.32 vs 95.79 ± 1.60, P < 0.001) and 5-FU + HHC (68.48 ± 2.24 vs 95.79 ± 1.60, P < 0.001) markedly decreased COX-2. The combined effects of HHC with 5-FU exhibit a synergistic inhibition by decreasing ACF formation mediated by down-regulation of COX-2 expression.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Colonic Neoplasms; Curcumin; Cyclooxygenase 1; Cyclooxygenase 2; Dimethylhydrazines; Fluorouracil; Gene Expression Regulation, Enzymologic; Immunohistochemistry; Male; Membrane Proteins; Rats; Rats, Wistar

The cytotoxicity of hexahydrocurcumin and its effect on the cell cycle in human colorectal cancer cells SW480 has been studied for the first time. The compound, extracted from Zingiber officinale, was shown to be cytotoxic to colorectal cancer cells. Treatment of SW480 cells with hexahydrocurcumin (100 microM) resulted in a massive accumulation of the cells in the G1/G0 phase of the cell cycle. The cytotoxic effect of hexahydrocurcumin may prove useful in cancer prevention.

Topics: Antineoplastic Agents, Phytogenic; Cell Cycle; Cell Line, Tumor; Curcumin; Drug Screening Assays, Antitumor; Humans; Zingiber officinale