Protective role of aqueous turmeric extract against mutagenicity of direct-acting carcinogens as well as benzo [alpha] pyrene-induced genotoxicity and carcinogenicity

Cutaneous Manifestations of Rheumatoid Arthritis: Diagnosis and Treatment

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder characterized by inflammatory arthritis and periarticular structural damage. Available evidence suggests that RA results from complex interactions between genetic susceptibility (e.g., HLA-DRB1), environmental factors (e.g., smoking), and immune dysregulation. Alongside joint-related symptoms, individuals with RA may also experience a wide array of skin issues, including the development of nodules, neutrophilic dermatoses, vasculitis, and vasculopathy. Treatment strategies for these manifestations vary but routinely involve corticosteroids, disease-modifying anti-rheumatic drugs, and biologics, with individualized approaches guided by disease severity. In this review, we provide comprehensive insights into the skin-related issues associated with RA, outlining their clinical characteristics and histopathological findings. Our aim is to facilitate early diagnosis and personalized treatment to improve the quality of life of affected individuals.

Clastogenic effects of cigarette smoke and urethane and their modulation by olive oil, curcumin and carotenoids in adult mice and foetuses

In spite of the overwhelming epidemiological evidence for cigarette smoke (CS) carcinogenicity, less attention has been paid to the effects of CS as a complex mixture. As assessed in a series of experiments in murine models, the whole-body exposure to mainstream CS induced significant increases of micronucleated cells in the respiratory tract, bone marrow and peripheral blood of adult mice as well as in the liver and peripheral blood of foetuses whose mothers had been exposed throughout pregnancy. Urethane was potently clastogenic in the same cells when injected intraperitoneally. The daily administration of extra-virgin olive oil by gavage produced evident and consistent protective effects in all monitored experimental systems. In contrast, sunflower oil exhibited some adverse effects. Curcumin did not produce any significant effect in the bone marrow of both CS-exposed adults and foetuses but it elicited a dose-dependent protective effect traceable in blood erythrocytes. However, the higher curcumin dose further increased the frequency of micronucleated pulmonary alveolar macrophages. The apparent protective effects produced by lycopene and by a carotenoid mix were overwhelmed by those produced by olive oil, and lycopene even exhibited a worsening effect on the frequency of micronucleated erythroblasts in the bone marrow of urethane-treated adult mice.

Potential Role of Curcumin and Its Nanoformulations to Treat Various Types of Cancers

Cancer is a major burden of disease globally. Each year, tens of millions of people are diagnosed with cancer worldwide, and more than half of the patients eventually die from it. Significant advances have been noticed in cancer treatment, but the mortality and incidence rates of cancers are still high. Thus, there is a growing research interest in developing more effective and less toxic cancer treatment approaches. Curcumin (CUR), the major active component of turmeric (Curcuma longa L.), has gained great research interest as an antioxidant, anticancer, and anti-inflammatory agent. This natural compound shows its anticancer effect through several pathways including interfering with multiple cellular mechanisms and inhibiting/inducing the generation of multiple cytokines, enzymes, or growth factors including IκB kinase β (IκKβ), tumor necrosis factor-alpha (TNF-α), signal transducer, and activator of transcription 3 (STAT3), cyclooxygenase II (COX-2), protein kinase D1 (PKD1), nuclear factor-kappa B (NF-κB), epidermal growth factor, and mitogen-activated protein kinase (MAPK). Interestingly, the anticancer activity of CUR has been limited primarily due to its poor water solubility, which can lead to low chemical stability, low oral bioavailability, and low cellular uptake. Delivering drugs at a controlled rate, slow delivery, and targeted delivery are other very attractive methods and have been pursued vigorously. Multiple CUR nanoformulations have also been developed so far to ameliorate solubility and bioavailability of CUR and to provide protection to CUR against hydrolysis inactivation. In this review, we have summarized the anticancer activity of CUR against several cancers, for example, gastrointestinal, head and neck, brain, pancreatic, colorectal, breast, and prostate cancers. In addition, we have also focused on the findings obtained from multiple experimental and clinical studies regarding the anticancer effect of CUR in animal models, human subjects, and cancer cell lines.

Curcumin Ameliorates Benzo[a]pyrene-Induced DNA Damages in Stomach Tissues of Sprague-Dawley Rats

Benzo[a]pyrene (BaP) is a well-known carcinogen formed during the cooking process. Although BaP exposure has been implicated as one of the risk factors for lung cancer in animals and humans, there are only limited data on BaP-induced gastrointestinal cancer. Therefore, this study investigated the protective effects of curcumin on BaP-induced DNA damage in rat stomach tissues. BaP (20 mg/kg/day) and curcumin (50, 100, or 200 mg/kg) were administered daily to Sprague-Dawley rats by oral gavage over 30 days. Curcumin was pre-administered before BaP exposure. All rats were euthanized, and liver, kidney, and stomach tissues were removed at 24 h after the last treatment. We observed that aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glucose levels were significantly reduced in rats treated with high dose co-administration of curcumin (200 mg/kg) compared to BaP alone. The expression levels of cytochrome P450 (CYP) 1A1 and CYP1B1 were significantly increased in the liver of rats treated with BaP. However, co-administration of curcumin (200 mg/kg) with BaP markedly reduced CYP1A1 expression in a dose-dependent manner. Furthermore, plasma levels of BaP-diolepoxide (BPDE) and BaP metabolites were significantly reduced by co-administration of curcumin (200 mg/kg). Additionally, co-administration of curcumin (200 mg/kg) with BaP significantly reduced the formation of BPDE-I-DNA and 8-hydroxydeoxy guanosine (8-OHdG) adducts in the liver, kidney, and stomach tissues. The inhibition of these adduct formations were more prominent in the stomach tissues than in the liver. Overall, our observations suggest that curcumin might inhibit BaP-induced gastrointestinal tumorigenesis and shows promise as a chemopreventive agent.

Potential therapeutic effects of curcumin in gastric cancer

Despite recent advancements in understanding of the biology of gastric cancer, treatment of patients with advanced gastric cancer remains a major problem. Among different type of phytochemicals, curcumin, a welltable -known phytochemical, has been shown to be a promising cancer chemopreventive agent. Pharmacokinetics, safety, and efficacy of curcumin have been evaluated in several clinical trials against numerous diseases, and for the treatment of human cancer. In the present review, we have collected in vitro and in vivo investigations and studied the chemosensitizing and anticancer effects of curcumin against the gastric cancer cells. In summary, curcumin has been found to have efficient chemosensitizing effect and also inhibits viability, proliferation, and migration of gastric cancer cells mainly via cell cycle arrest and induction of apoptosis by both mitochondrial-dependent and -independent pathways.

Chemical constituents and biological research on plants in the genus Curcuma

Curcuma, a valuable genus in the family Zingiberaceae, includes approximately 110 species. These plants are native to Southeast Asia and are extensively cultivated in India, China, Sri Lanka, Indonesia, Peru, Australia, and the West Indies. The plants have long been used in folk medicine to treat stomach ailments, stimulate digestion, and protect the digestive organs, including the intestines, stomach, and liver. In recent years, substantial progress has been achieved in investigations regarding the chemical and pharmacological properties, as well as in clinical trials of certain Curcuma species. This review comprehensively summarizes the current knowledge on the chemistry and briefly discusses the biological activities of Curcuma species. A total of 720 compounds, including 102 diphenylalkanoids, 19 phenylpropene derivatives, 529 terpenoids, 15 flavonoids, 7 steroids, 3 alkaloids, and 44 compounds of other types isolated or identified from 32 species, have been phytochemically investigated. The biological activities of plant extracts and pure compounds are classified into 15 groups in detail, with emphasis on anti-inflammatory and antitumor activities.

Curcumin induced human gastric cancer BGC-823 cells apoptosis by ROS-mediated ASK1-MKK4-JNK stress signaling pathway

The signaling mediated by stress-activated MAP kinases (MAPK), c-Jun N-terminal kinase (JNK) has well-established importance in cancer. In the present report, we investigated the effects of curcumin on the signaling pathway in human gastric cancer BGC-823 cells. Curcumin induced reactive oxygen species (ROS) production and BGC-823 cells apoptosis. Inhibition of ROS generation by antioxidant (NAC or Trion) significantly prevented curcumin-mediated apoptosis. Notably, we observed that curcumin activated ASK1, a MAPKKK that is oxidative stress sensitive and responsible to phosphorylation of JNK via triggering cascades, up-regulated an upstream effector of the JNK, MKK4, and phosphorylated JNK protein expression in BGC-823 cells. However, curcumin induced ASK1-MKK4-JNK signaling was attenuated by NAC. All the findings confirm the possibility that oxidative stress-activated ASK1-MKK4-JNK signaling cascade promotes the apoptotic response in curcumin-treated BGC-823 cells.

Cancer-promoting and Inhibiting Effects of Dietary Compounds: Role of the Aryl Hydrocarbon Receptor (AhR)

Polyaromatic hydrocarbons, heterocyclic aromatic amines and dioxin-like compounds are environmental carcinogens shown to initiate cancer in a number of tissue types including prostate and breast. These environmental carcinogens elicit their effects through interacting with the aryl hydrocarbon receptor (AhR), a ligand activated transcription factor. Naturally occurring compounds found in fruits and vegetables shown to have anti-carcinogenic effects also interact with the AhR. This review explores dietary and environmental exposure to chemical carcinogens and beneficial natural compounds whose effects are elicited by the AhR.

Comparative Evaluation of Anti-Inflammatory Activity of Curcuminoids, Turmerones, and Aqueous Extract of Curcuma longa

Curcuma longa is widely known for its anti-inflammatory activity in traditional system of medicine for centuries and has been scientifically validated extensively. The present study was conducted to evaluate the anti-inflammatory activity of curcuminoids and oil-free aqueous extract (COFAE) of C. longa and compare it with that of curcuminoids and turmerones (volatile oil), the bioactive components of C. longa that are proven for the anti-inflammatory potential. The activity against inflammation was evaluated in xylene-induced ear edema, cotton pellet granuloma models in albino Swiss mice and albino Wistar rats, respectively. The results showed that COFAE of C. longa at three dose levels significantly (P ≤ 0.05) inhibited inflammation in both models, as evidenced by reduction in ear weight and decrease in wet as well as dry weights of cotton pellets, when compared to the vehicle control. The COFAE of C. longa showed considerable anti-inflammatory effects against acute and chronic inflammation and the effects were comparable to those of curcuminoids and turmerones.

Safety evaluation of turmeric polysaccharide extract: assessment of mutagenicity and acute oral toxicity

Curcuma longa Linn. (Zingiberaceae) commonly known as turmeric has long been used for centuries as a spice and household remedy. The present study was carried out to assess the possible mutagenic potential and acute oral toxicity of polysaccharide extract of turmeric rhizome (NR-INF-02) using standard tests. The standard battery of in vitro genotoxicity tests, bacterial reverse mutation test (BRMT), chromosome aberration (CA), and micronucleus (MN) tests were employed to assess the possible mutagenic activity of NR-INF-02 (Turmacin). The results showed no mutagenic effect with NR-INF-02 up to a dose of 5000 µg/mL in BRMT. The results on CA and MN tests revealed the non clastogenic activity of NR-INF-02 in a dose range of 250.36 to 2500 µg/mL with and without metabolic activation (S9). In acute oral toxicity study, NR-INF-02 was found to be safe up to 5 g/kg body weight in Wistar rats. Overall, results indicated that polysaccharide extract of C. longa was found to be genotoxically safe and also exhibited maximum tolerable dose of more than 5 g/kg rat body weight.

Therapeutic uses ofCurcuma longa (turmeric)

Curcuma longa commonly known as tumeric is traditionally used as a spice in Indian food. A wide range of biological activities e.g. anticancer, antimicrobial, antiinflammatory and free radical scavenging activity of the plant suggests a logical basis for its traditional use in foodstuff. Various phytothreapeutic uses ofCurcuma longa have been reviewed.

Multitargeting by turmeric, the golden spice: From kitchen to clinic

Although much has been published about curcumin, which is obtained from turmeric, comparatively little is known about turmeric itself. Turmeric, a golden spice obtained from the rhizome of the plant Curcuma longa, has been used to give color and taste to food preparations since ancient times. Traditionally, this spice has been used in Ayurveda and folk medicine for the treatment of such ailments as gynecological problems, gastric problems, hepatic disorders, infectious diseases, and blood disorders. Modern science has provided the scientific basis for the use of turmeric against such disorders. Various chemical constituents have been isolated from this spice, including polyphenols, sesquiterpenes, diterpenes, triterpenoids, sterols, and alkaloids. Curcumin, which constitutes 2-5% of turmeric, is perhaps the most-studied component. Although some of the activities of turmeric can be mimicked by curcumin, other activities are curcumin-independent. Cell-based studies have demonstrated the potential of turmeric as an antimicrobial, insecticidal, larvicidal, antimutagenic, radioprotector, and anticancer agent. Numerous animal studies have shown the potential of this spice against proinflammatory diseases, cancer, neurodegenerative diseases, depression, diabetes, obesity, and atherosclerosis. At the molecular level, this spice has been shown to modulate numerous cell-signaling pathways. In clinical trials, turmeric has shown efficacy against numerous human ailments including lupus nephritis, cancer, diabetes, irritable bowel syndrome, acne, and fibrosis. Thus, a spice originally common in the kitchen is now exhibiting activities in the clinic. In this review, we discuss the chemical constituents of turmeric, its biological activities, its molecular targets, and its potential in the clinic.

Glutathione regulates caspase-dependent ceramide production and curcumin-induced apoptosis in human leukemic cells

Depletion of intracellular glutathione (GSH) is the prime hallmark of the progression of apoptosis. Previously, we reported that curcumin induces reactive oxygen species (ROS)-mediated depletion of GSH, which leads to caspase-dependent and independent apoptosis in mouse fibroblast cells (F. Thayyullathil et al., Free Radic. Biol. Med.45, 1403-1412, 2008). In this study, we investigated the antileukemic potential of curcumin in vitro, and we further examined the molecular mechanisms of curcumin-induced apoptosis in human leukemic cells. Curcumin suppresses the growth of human leukemic cells via ROS-independent GSH depletion, which leads to caspase activation, inhibition of sphingomyelin synthase (SMS) activity, and induction of ceramide (Cer) generation. Pretreatment of leukemic cells with carbobenzoxy-Val-Ala-Asp fluoromethylketone, a universal inhibitor of caspases, abrogates the SMS inhibition and Cer generation, and in turn prevents curcumin-induced cell death. Curcumin treatment of leukemic cells also downregulates the expression of the inhibitor of apoptosis proteins (IAPs), phospho-Akt, c-Myc, and cyclin D1. Extracellular supplementation with GSH attenuates curcumin-induced depletion of GSH, caspase-dependent inhibition of SMS, Cer generation, and downregulation of IAPs, whereas, L-D-buthionine sulfoximine, a widely used inhibitor of GSH synthesis, potentiates GSH depletion, Cer generation, and apoptosis induced by curcumin. Taken together, our findings provide evidence suggesting for the first time that GSH regulates caspase-dependent inhibition of SMS activity, Cer generation, and apoptosis induced by curcumin in human leukemic cells.

Therapeutic potential of curcumin in gastrointestinal diseases

Curcumin, also known as diferuloylmethane, is derived from the plant Curcuma longa and is the active ingredient of the spice turmeric. The therapeutic activities of curcumin for a wide variety of diseases such as diabetes, allergies, arthritis and other chronic and inflammatory diseases have been known for a long time. More recently, curcumin’s therapeutic potential for preventing and treating various cancers is being recognized. As curcumin’s therapeutic promise is being explored more systematically in various diseases, it has become clear that, due to its increased bioavailability in the gastrointestinal tract, curcumin may be particularly suited to be developed to treat gastrointestinal diseases. This review summarizes some of the current literature of curcumin’s anti-inflammatory, anti-oxidant and anti-cancer potential in inflammatory bowel diseases, hepatic fibrosis and gastrointestinal cancers.

Traditional herbal medicine in far-west Nepal: a pharmacological appraisal

BACKGROUND

Plant species have long been used as principal ingredients of traditional medicine in far-west Nepal. The medicinal plants with ethnomedicinal values are currently being screened for their therapeutic potential but their data and information are inadequately compared and analyzed with the Ayurveda and the phytochemical findings.

METHODS

The present study evaluated ethnomedicinal plants and their uses following literature review, comparison, field observations, and analysis. Comparison was made against earlier standard literature of medicinal plants and ethnomedicine of the same area, the common uses of the Ayurveda and the latest common phytochemical findings. The field study for primary data collection was carried out from 2006-2008.

RESULTS

The herbal medicine in far-west Nepal is the basis of treatment of most illness through traditional knowledge. The medicine is made available via ancient, natural health care practices such as tribal lore, home herbal remedy, and the Baidhya, Ayurveda and Amchi systems. The traditional herbal medicine has not only survived but also thrived in the trans-cultural environment with its intermixture of ethnic traditions and beliefs. The present assessment showed that traditional herbal medicine has flourished in rural areas where modern medicine is parsimoniously accessed because of the high cost and long travel time to health center. Of the 48 Nepalese medicinal plants assessed in the present communication, about half of the species showed affinity with the common uses of the Ayurveda, earlier studies and the latest phytochemical findings. The folk uses of Acacia catechu for cold and cough, Aconitum spicatum as an analgesic, Aesculus indica for joint pain, Andrographis paniculata for fever, Anisomeles indica for urinary affections, Azadirachta indica for fever, Euphorbia hirta for asthma, Taxus wallichiana for tumor control, and Tinospora sinensis for diabetes are consistent with the latest pharmacological findings, common Ayurvedic and earlier uses.

CONCLUSIONS

Although traditional herbal medicine is only a primary means of health care in far-west Nepal, the medicine has been pursued indigenously with complementing pharmacology and the Ayurveda. Therefore, further pharmacological evaluation of traditional herbal medicine deserves more attention.

Modulation of curcumin-induced Akt phosphorylation and apoptosis by PI3K inhibitor in MCF-7 cells

Curcumin has been shown to induce apoptosis in various malignant cancer cell lines. One mechanism of curcumin-induced apoptosis is through the PI3K/Akt signaling pathway. Akt, also known as protein kinase B (PKB), is a member of the family of phosphatidylinositol 3-OH-kinase regulated Ser/Thr kinases. The active Akt regulates cell survival and proliferation; and inhibits apoptosis. In this study we found that curcumin induces apoptotic cell death in MCF-7 cells, as assessed by MTT assay, DNA ladder formation, PARP cleavage, p53 and Bax induction. At apoptotic inducing concentration, curcumin induces a dramatic Akt phosphorylation, accompanied by an increased phosphorylation of glycogen synthase kinase 3beta (GSK3beta), which has been considered to be a pro-growth signaling molecule. Combining curcumin with PI3K inhibitor, LY290042, synergizes the apoptotic effect of curcumin. The inhibitor LY290042 was capable of attenuating curcumin-induced Akt phosphorylation and activation of GSK3beta. All together, our data suggest that blocking the PI3K/Akt survival pathway sensitizes the curcumin-induced apoptosis in MCF-7 cells.

Multi-targeted therapy by curcumin: how spicy is it?

Although traditional medicines have been used for thousands of years, for most such medicines neither the active component nor their molecular targets have been very well identified. Curcumin, a yellow component of turmeric or curry powder, however, is an exception. Although inhibitors of cyclooxygenase-2, HER2, tumor necrosis factor, EGFR, Bcr-abl, proteosome, and vascular endothelial cell growth factor have been approved for human use by the United States Food and Drug Administration (FDA), curcumin as a single agent can down-regulate all these targets. Curcumin can also activate apoptosis, down-regulate cell survival gene products, and up-regulate p53, p21, and p27. Although curcumin is poorly absorbed after ingestion, multiple studies have suggested that even low levels of physiologically achievable concentrations of curcumin may be sufficient for its chemopreventive and chemotherapeutic activity. Thus, curcumin regulates multiple targets (multitargeted therapy), which is needed for treatment of most diseases, and it is inexpensive and has been found to be safe in human clinical trials. The present article reviews the key molecular mechanisms of curcumin action and compares this to some of the single-targeted therapies currently available for human cancer.

Rapid reactive oxygen species (ROS) generation induced by curcumin leads to caspase-dependent and -independent apoptosis in L929 cells

Evidence that curcumin may have anticancer activities has renewed interest in its potential to prevent and treat disease. In this study, we show that curcumin-mediated rapid generation of reactive oxygen species (ROS) leads to apoptosis by modulating different apoptotic pathways in mouse fibroblast L929 cells. We show for the first time that curcumin-induced rapid ROS generation causes the release of apoptosis inducing factor (AIF) from the mitochondria to the cytosol and nucleus, hence, leading to caspase 3-independent apoptosis. However, our studies also show that curcumin induces the release of cytochrome c from mitochondria, causing activation of caspase 3, and concomitant PARP cleavage, which is the hallmark of caspase-dependent apoptosis. Furthermore, curcumin-induced ROS generation leads to the induction of the proapoptotic protein p53 and its effector protein p21 and down-regulation of cell cycle regulatory proteins such as Rb and cyclin D1 and D3. Both glutathione (GSH) and N-acetylcysteine (NAC) pretreatment resulted in the complete inhibition of curcumin-induced ROS generation, AIF release from mitochondria, and caspase activation. Additionally, pretreatment of L929 cells with these antioxidants completely blocked the induction of p53-dependent p21 accumulation. In conclusion, our data show that in addition to caspase 3 activation, curcumin-induced rapid ROS generation leads to AIF release, and the activation of the caspase-independent apoptotic pathway.

Curcumin inhibits FtsZ assembly: an attractive mechanism for its antibacterial activity

The assembly and stability of FtsZ protofilaments have been shown to play critical roles in bacterial cytokinesis. Recent evidence suggests that FtsZ may be considered as an important antibacterial drug target. Curcumin, a dietary polyphenolic compound, has been shown to have a potent antibacterial activity against a number of pathogenic bacteria including Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus. We found that curcumin induced filamentation in the Bacillus subtilis 168, suggesting that it inhibits bacterial cytokinesis. Further, curcumin strongly inhibited the formation of the cytokinetic Z-ring in B. subtilis 168 without detectably affecting the segregation and organization of the nucleoids. Since the assembly dynamics of FtsZ protofilaments plays a major role in the formation and functioning of the Z-ring, we analysed the effects of curcumin on the assembly of FtsZ protofilaments. Curcumin inhibited the assembly of FtsZ protofilaments and also increased the GTPase activity of FtsZ. Electron microscopic analysis showed that curcumin reduced the bundling of FtsZ protofilaments in vitro. Further, curcumin was found to bind to FtsZ in vitro with a dissociation constant of 7.3±1.8 μM and the agent also perturbed the secondary structure of FtsZ. The results indicate that the perturbation of the GTPase activity of FtsZ assembly is lethal to bacteria and suggest that curcumin inhibits bacterial cell proliferation by inhibiting the assembly dynamics of FtsZ in the Z-ring.

Changing trends in gastrointestinal disease in the Asia-Pacific region

The new millennium has seen distinct changes in the pattern of gastrointestinal disease in the Asia-Pacific region. These changes are important as more than half of the world's population come from the region and therefore impact significantly on the global disease burden. The highest incidence of gastric cancer (GCA) has been reported from Asia and GCA remains a very important cancer. However time-trend studies have shown a decrease in GCA incidence in several countries in Asia. A rise in cardio-esophageal cancers as seen in the West has not been reported. On the other hand, colorectal cancer has been steadily increasing in Asia with age-standardized incidence rates of some countries approaching that of the West. The pattern of acid-related diseases has also changed. Gastroesophageal reflux disease is a fast emerging disease with an increasing prevalence of reflux esophagitis and reflux symptoms. The prevalence of peptic ulcer disease has at the same time declined in step with a decrease in H. pylori infection. Many of the changes taking place mirror the Western experience of several decades ago. Astute observation of the epidemiology of emerging diseases combined with good scientific work will allow a clearer understanding of the key processes underlying these changes. With rapid modernization, lifestyle changes have been blamed for an increase in several diseases including gastroesophageal reflux disease, nonalcoholic fatty liver disease and colorectal cancer. A worrying trend has been the increase in obesity among Asians, which has been associated with an increase in metabolic diseases and various gastrointestinal cancers. Conversely, an improvement in living conditions has been closely linked to the decrease in GCA and H. pylori prevalence.

Antimutagenic potential of curcumin on chromosomal aberrations in Allium cepa

Turmeric has long been used as a spice and food colouring agent in Asia. In the present investigation, the antimutagenic potential of curcumin was evaluated in Allium cepa root meristem cells. So far there is no report on the biological properties of curcumin in plant test systems. The root tip cells were treated with sodium azide at 200 and 300 microg/ml for 3 h and curcumin was given at 5, 10 and 20 microg/ml for 16 h, prior to sodium azide treatment. The tips were squashed after colchicine treatment and the cells were analyzed for chromosome aberration and mitotic index. Curcumin induces chromosomal aberration in Allium cepa root tip cells in an insignificant manner, when compared with untreated control. Sodium azide alone induces chromosomal aberrations significantly with increasing concentrations. The total number of aberrations was significantly reduced in root tip cells pretreated with curcumin. The study reveals that curcumin has antimutagenic potential against sodium azide induced chromosomal aberrations in Allium cepa root meristem cells. In addition, it showed mild cytotoxicity by reducing the percentage of mitotic index in all curcumin treated groups, but the mechanism of action remains unknown. The antimutagenic potential of curcumin is effective at 5 microg/ml in Allium cepa root meristem cells.

CURCUMIN: THE INDIAN SOLID GOLD

Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal "Spice for Life".

Ethnicity and H. pylori as risk factors for gastric cancer in Malaysia: A prospective case control study

OBJECTIVE

To determine the risk factors for gastric cancer (GCA), with particular emphasis on ethnicity in our multiracial population.

METHODS

A prospective case control study with ratio of cancer:controls of 1:2. Diagnosis of H. pylori was made by serology using the ELISA technique. Dietary intake was assessed by dietary recall over the preceding 6 months.

RESULTS

Eighty-seven cases of GCA were enrolled. The cancers were predominantly distal in location and of the intestinal type. Risk factors identified following multiple logistic regression analysis were: Chinese race (OR 10.23 [2.87-36.47]), H. pylori (OR 2.54 [1.16-5.58]), low level of education (OR 9.81 [2.03-47.46]), smoking (OR 2.52 [1.23-5.15]), and high intake of salted fish and vegetables (OR 5.18 [1.35-20.00]) were identified as significant independent risk factors for GCA, while high intake of fresh fruits and vegetables was protective for GCA (OR 0.15 [0.04-0.64]). Chili intake was not a significant protective factor following multivariate analysis.

CONCLUSIONS

Chinese race was a strong independent predictor of GCA. H. pylori was an important predictor of GCA with a 2.5-fold greater risk in our patients. Despite a high prevalence of H. pylori, the prevalence of GCA among Indians was low and this paradox can be appropriately called the "Indian enigma."

Curcumin-induced apoptosis in human leukemia cell HL-60 is associated with inhibition of telomerase activity

Curcumin (diferuloylmethane), a natural cancer chemopreventive compound, has been tested for its action in acute myeloblastic leukemia cell line HL-60. The results clearly show that curcumin induces apoptosis in these cells as evidenced by the release of cytochrome c from mitochondria to the cytosol and increase in the DNA content in sub G1 region as observed in FACS analysis. Apoptosis is apparently mediated by up-regulation of apoptotic gene bax and simultaneous down-regulation of anti-apoptotic gene bcl-2 followed by activation of caspases 3 and 8 and degradation of PARP. Telomerase, a reverse transcriptase, has been found to be activated in more than 80% of human cancers and, therefore, can be considered as a potential marker for tumorigenesis. Certain natural compounds have the potential of inhibiting telomerase activity leading to suppression of cell viability and induction of apoptosis. The present study shows that curcumin-induced apoptosis coincides with the inhibition of telomerase activity in a dose dependent manner.

Inhibition of telomerase activity and induction of apoptosis by curcumin in K-562 cells

Telomerase, a reverse transcriptase that maintains telomere length, is highly activated in tumor cells and practically absent in somatic cells and hence considered a potential marker for tumorigenesis. A connection between telomerase activity and resistance to apoptosis has been established. Telomerase, therefore, has been proposed to represent a novel and potentially selective target for cancer therapy. Several synthetic compounds have been developed in recent years with a view to inhibit telomerase activity with telomere shortening below a critical length resulting in apoptosis. Such compounds are always highly toxic. Many plant-derived products act through the induction of apoptosis as a mechanism to suppress carcinogenesis. Curcumin, a phenolic compound isolated from the rhizome of the plant Curcuma longa Linn., has been reported to possess anti-tumor, apoptotic and anti-angiogenic properties. Apoptosis has emerged as the major mechanism by which anti-tumor agents eliminate pre-neoplastic cells or cells progressed to malignancy. The present study was undertaken to examine the mechanism of curcumin-induced apoptosis in human leukemia cell line K-562 with particular emphasis on the role of curcumin on telomerase activity. Induction of apoptosis by curcumin is initiated by the release of cytochrome c from mitochondria into the cytosol, and evidenced by the increase in DNA content in the sub-G1 region as obtained from FACS analysis. Apoptosis is mediated by the activation of caspases 3 and 8, up-regulation of the apoptotic gene bax with concomitant down-regulation of the anti-apoptotic gene bcl-2. Using TRAP assay it has been observed that curcumin inhibits telomerase activity in a dose and time-dependent manner, the inhibition being due to suppression of translocation of telomerase reverse transcriptase (TERT), a catalytic subunit, from cytosol to nucleus. Most significantly, the inhibition of telomerase activity by curcumin correlates with several parameters of apoptosis. The results suggest that telomerase status plays an important role in the induction of apoptosis in K-562 cells by curcumin.

Cancer chemopreventive effect of phenothiazines and related tri-heterocyclic analogues in the 12-O-tetradecanoylphorbol-13-acetate promoted Epstein-Barr virus early antigen activation and the mouse skin two-stage carcinogenesis models

In continuation of our search for novel agents, we have investigated 29 phenothiazines and related tri-heterocyclic compounds as potential cancer chemopreventive agents in a short-term in vitro assay of Epstein-Barr virus early antigen (EBV-EA) activation induced by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). Among the evaluated compounds, chlorpromazine, phenoxazine, ethylpropazine, 9-oxo-9H-thioxanthene-3-carbonitrile-10,10-dioxide, thiothixene and phenothiazine showed profound inhibition of EBV-EA in the in vitro assay. This activity was influenced by a modification of the phenothiazine ring. Replacement of nitrogen in the phenothiazine ring with sulfur atoms decreased the anti-tumor activity. Overall analysis showed that the simple tri-cyclic compound phenoxazine was the most active anti-tumor promoting compound in the test system. Therefore, we assessed the anti-tumor promoting effect of phenoxazine in vivo in two different chemical carcinogen-induced-promotion experimental models in mice namely the 7,12-dimethylbenz(a)anthracene (DMBA) initiated and TPA-promoted ICR mouse skin two-stage carcinogenesis protocol and the peroxynitrite (PN)-induced and TPA-promoted skin carcinogenesis in HOS:HR-1 mouse. Following tumor initiation with DMBA, topical application of 0.0025% phenoxazine to the dorsal initiated mouse skin resulted in a highly significant inhibition of TPA tumor promotion. The compound exhibited remarkable inhibitory effects on the mouse skin tumor promotion in terms of a reduction in tumor multiplicity (>50%) and incidence, accompanied by an extension of the tumor latency. In the PN-induced and TPA-promoted two-stage mouse skin carcinogenesis, oral administration of phenoxazine (0.0025%) for 2 weeks showed profound decrease in both the tumor incidence and burden by more than 20 and 80%, respectively, at 10 weeks of treatment. This was also accompanied by a 20% delay in the tumor latency period. In all the treatment groups, there was no toxicity due to phenoxazine in the treatment groups as compared to the control animals. These significant anti-tumor potentials of phenoxazine either via topical or oral administration might be due to the inherent cytotoxicity of these classes of compounds, which can be utilized in the prevention of development of overt tumors, immunopotentiation, induction of differentiation and apoptosis. In addition, since phenoxazine derivatives and other related phenothiazine compounds in use, as anti-psychotic agents without any reported adverse effect are known to pass the blood-brain barrier, they represent a new class of cancer chemopreventive agents with greater implication in the prevention of brain cancers.

Suppression of altered hepatic foci development by curcumin in wistar rats

Curcumin, a yellow pigment of turmeric (Curcuma longa), is a commonly used spice and a coloring agent in foods, drugs, and cosmetics. Curcumin is known to possess chemopreventive properties in various animal tumor models. In the present study the effect of curcumin on the development of altered hepatic foci (AHF), by using a medium term liver bioassay, has been evaluated. AHF were analyzed by quantitative stereology using the Leica Qwin Image Analysis system from frozen liver sections stained for g-glutamyl transferase, adenosine triphosphatase, glucose-6-phosphatase, alkaline phosphatase, and placental isozyme of glutathione S-transferase. A significant protection on diethylnitrosamine (DEN) initiated and 2-acetylaminofluorene (AAF) promoted AHF by curcumin was observed on these biological markers. The curcumin administration was found to restore the normal levels of the enzymes glutathione S-transferase and g-glutamyl transferase in rat liver following DEN-AAF exposure. Similarly, a significant protection was provided by curcumin in the enzyme-deficient foci for the adenosine triphosphatase-, alkaline phosphatase-, and glucose-6-phosphatase-treated groups in comparison to the DEN-AAF-treated group. These results show that curcumin can effectively suppress the DEN-induced development of AHF in rat liver.

Antigenotoxic potential of certain dietary constituents

The human diet contains a variety of compounds that exhibit chemopreventive effects towards an array of xenobiotics. In the present study, the antigenotoxic potential of selected dietary constituents including Diallyl sulfide (DAS), Indole-3-carbinol (I3C), Curcumin (CUR), and Black tea polyphenols (BTP) has been evaluated in the Salmonella typhimurium reverse mutation and mammalian in vivo cytogenetic assays. In addition, the anticlastogenic effect of the above dietary constituents was identified towards Benzo(a)pyrene (BaP) and cyclophosphamide- (CP) induced cytogenetic damage in mouse bone marrow cells. The induction of BaP and CP induced chromosomal aberrations, micronuclei formation, and sister chromatid exchanges (SCEs) were found to be inhibited in a dose-dependent manner by DAS, I3C, CUR, and BTP. Thus the study reveals the antimutagenic potential of these dietary compounds towards BaP- and CP-induced genotoxicity in microbial and mammalian test systems.

Antimutagenic potential of curcumin on chromosomal aberrations in Wistar rats

Curcumin, a yellow pigment commonly used as a spice and food coloring agent is obtained from rhizomes of Curcuma longa and is a major chemopreventive component of turmeric. In the present set of investigations the antimutagenic potential of curcumin has been evaluated using in vivo chromosomal aberration assay in Wistar rats. Cyclophosphamide (CP), a well-known mutagen was given by intraperitoneal (i.p.) injection at the dose of 40 mg/kg body weight (b.w.). Curcumin was given at the dose of 100 and 200 mg/kg b.w. through gastric intubation for seven consecutive days prior to CP treatment. The animals were sacrificed at the sampling time of 24 h after treatment and their bone marrow tissue was analyzed for chromosomal damage and mitotic index. In CP treated animals a significant induction of chromosomal aberration was recorded with decrease in mitotic index. However, in curcumin-supplemented animals, no significant induction in chromosomal damage or change in mitotic index was recorded. In different curcumin-supplemented groups, a dose dependent significant decrease in CP induced clastogenicity was recorded. The incidence of aberrant cells was found to be reduced by both the doses of curcumin when compared to CP treated group. The anticytotoxic potential of curcumin towards CP was also evident as the status of mitotic index was found to show increment. The study revealed the antigenotoxic potential of curcumin against CP induced chromosomal mutations.

Inhibition of epstein-barr virus early antigen activation promoted by 12-O-tetradecanoylphorbol-13-acetate by the non-steroidal anti-inflammatory drugs

As part of our screening program for cancer inhibitory agents effective specifically in the promotion stage of cancer development, we have evaluated the possible inhibitory effects of 36 non-steroidal anti-inflammatory drugs (NSAIDs) on the Epstein-Barr virus early antigen (EBV-EA) activation which was induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. All the drugs were observed to inhibit the EBV-EA activation at low doses with low toxicity. The two most active anti-tumor promoting agents were the arylacetic acid derivatives, etodolac and sulindac. We also report for the first time the activities of 14 new NSAIDs belonging to different classes as potential cancer chemopreventive agents. A structure-activity relationship study showed that among the salicylic acid derivative tested, the oxidation of the thiol group to dithiol derivatives results in the reduction of the activity. Introduction of amino group on the salicylic acid molecules also results in the reduction of activity in the EBV-EA assay. The results are of great interest in the development of NSAIDs as cancer chemopreventive agents, which halt cancer progression in multistage carcinogenesis, where successive activities are required to evolve into fully-fledged and metastatic cancer.

An investigation on the antimutagenic properties of South African herbal teas

The antimutagenic properties of South African herbal teas were investigated using the Salmonella typhimurium mutagenicity assay. Aqueous extracts of fermented and unfermented rooibos tea (Aspalathus linearis) and honeybush tea (Cyclopia intermedia) both possess antimutagenic activity against 2-acetylaminofluorene (2-AAF) and aflatoxin B(1) (AFB(1))-induced mutagenesis using tester strains TA98 and TA100 in the presence of metabolic activation. A far less inhibitory effect was noticed against the direct acting mutagens, methyl methanesulfonate (MMS), cumolhydroperoxide (CHP), and hydrogen peroxide (H(2)O(2)) using TA102, a strain designed to detect oxidative mutagens and carcinogens. Depending on the mutagen used, the unfermented tea exhibited the highest protective effect. A similar response regarding the protection against mutagenesis was obtained when utilising different variations of the double layer Salmonella assay. The double layer technique proved to be more effective to detect the protective effect of the different tea preparations against the direct acting mutagens. With respect to indirect mutagens, the highest protection was noticed when the carcinogen was metabolically activated in the presence of the tea extract as compared with when the tea extract was incubated in a separate layer with the bacteria. The current data suggest that two mechanisms seem to be involved in the antimutagenicity of the tea extracts towards carcinogens that require metabolic activation: (i) the tea components may interfere with cytochrome P450-mediated metabolism of these mutagens and (ii) the direct interaction between the tea constituents, presumably the polyphenolic compounds, with the promutagens and/or the active mutagenic metabolites. However, the mild and/or lack of protection and in some cases even enhancement of mutagenesis induced by direct acting or oxidative mutagens, provide new perspectives regarding the role of the polyphenolic compounds known to exhibit antioxidant properties, in the protection against mutagenesis in the Salmonella assay. The present study provides the first evidence on the antimutagenic activity of honeybush tea and further evidence on the antimutagenicity of rooibos tea.

Review on some plants of Indian traditional medicine with antioxidant activity

A lot of medicinal plants, traditionally used for thousands of years, are present in a group of herbal preparations of the Indian traditional health care system (Ayurveda) named Rasayana proposed for their interesting antioxidant activities. Among the medicinal plants used in ayurvedic Rasayana for their therapeutic action, some of these have been throughly investigated. In the present paper seven plants (Emblica officinalis L., Curcuma longa L., Mangifera indica L., Momordica charantia L., Santalum album L., Swertia chirata Buch-Ham, Withania somnifera (L.) Dunal) are viewed for their historical, etymological, morphological, phytochemical and pharmacological aspects. The plants described contain antioxidant principles, that can explain and justify their use in traditional medicine in the past as well as the present. In order to identify the plants with antioxidant activity in Ayurveda, a formulation of some rasayanas with well defined antioxidant properties has been examinated. For this purpose, we have considered Sharma's work on the preparation MAK4, MAK5, MA631, MA 471, MA Raja's Cup, MA Student Rasayana, MA Ladies Rasayana.

The application of in vitro data in the derivation of the acceptable daily intake of food additives

The acceptable daily intake (ADI) for food additives is commonly derived from the NOAEL (no-observed-adverse-effect level) in long-term animal in vivo studies. To derive an ADI a safety or uncertainty factor (commonly 100) is applied to the NOAEL in the most sensitive test species. The 100-fold safety factor is considered to be the product of both species and inter-individual differences in toxicokinetics and toxicodynamics. Although in vitro data have previously been considered during the risk assessment of food additives, they have generally had no direct influence on the calculation of ADI values. In this review 18 food additives are evaluated for the availability of in vitro toxicity data which might be used for the derivation of a specific data-derived uncertainty factor. For the majority of the food additives reviewed, additional in vitro tests have been conducted which supplement and support the short- and long-term in vivo toxicity studies. However, it was recognized that these in vitro studies could not be used in isolation to derive an ADI; only when sufficient in vivo mechanistic data are available can such information be used in a regulatory context. Additional short-term studies are proposed for the food additives which, if conducted, would provide data that could then be used for the calculation of data-derived uncertainty factors.

Protective effects of fruits and vegetables against in vivo clastogenicity of cyclosphosphamide or benzo[a]pyrene in mice

Seven fruits and 10 vegetables commonly consumed in Germany were investigated for their anticlastogenic potencies against cyclophosphamide (CP) and benzo[a]pyrene (BaP) in the in vivo mouse bone marrow micronucleus assay. We detected protective effects in 76.5% and 70.6% of the samples, respectively, and more or less distinct quantitative differences between the various plant materials and the two clastogens investigated. With respect to CP, moderate activities were exerted by sweet cherries, strawberries, cucumber, radish and tomatoes, average activities by bananas, oranges, peaches, asparagus and red beets and strong activities by yellow red peppers and especially spinach. Apples (cultivar Jona Gold), brussels sprouts, cauliflower and onions were inactive. With respect to BaP, we found moderate activities in strawberries, brussels sprouts and radish, average activities in sweet cherries, oranges, peaches, asparagus, red beets, cucumber and spinach and strong activities in bananas and kiwi. Apples, cauliflower, onions, tomatoes and yellow-red peppers were inactive. When oranges were fractionated according to previously described schemes (Edenharder et al., 1995), anticlastogenic activities against CP were exerted by materials extracted with n-hexane, acetone and 2-propanol and in the terminal residue, but not in the dichloromethane and water phases. With respect to BaP, materials extracted with acetone showed strong anticlastogenicity while the 2-propanol fraction, the aqueous phase and the terminal residue were less potent. The n-hexane and the dichloromethane fractions were inactive. In red beets, all fractions showed anticlastogenicity against CP and BaP as well. However, the n-hexane and dichloromethane fractions were most potent with respect to CP, while for BaP the aqueous phase and the terminal residue were most effective. These result suggest the presence of various (groups of) anticlastogenic compounds with different chemical structure.

In vivo inhibition of nitric oxide synthase gene expression by curcumin, a cancer preventive natural product with anti-inflammatory properties

Curcumin is a naturally occurring, dietary polyphenolic phytochemical that is under preclinical trial evaluation for cancer preventive drug development and whose working pharmacological actions include anti-inflammation. With respect to inflammation, in vitro, it inhibits the activation of free radical-activated transcription factors, such as nuclear factor kappaB (NFkappaB) and AP-1, and reduces the production of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF alpha), interleukin-1beta (IL-1beta), and interleukin-8. Inducible nitric oxide synthase (iNOS) is an inflammation-induced enzyme that catalyzes the production of nitric oxide (NO), a molecule that may lead to carcinogenesis. Here, we report that in ex vivo cultured BALB/c mouse peritoneal macrophages, 1-20 microM of curcumin reduced the production of iNOS mRNA in a concentration-dependent manner. Furthermore, we demonstrated that, in vivo, two oral treatments of 0.5 mL of a 10-microM solution of curcumin (92 ng/g of body weight) reduced iNOS mRNA expression in the livers of lipopolysaccharide(LPS)-injected mice by 50-70%. Although many hold that curcumin needs to be given at dosages that are unattainable through diet to produce an in vivo effect, we were able to obtain potency at nanomoles per gram of body weight. This efficacy is associated with two modifications in our preparation and feeding regimen: 1) an aqueous solution of curcumin was prepared by initially dissolving the compound in 0.5 N NaOH and then immediately diluting it in PBS; and 2) mice were fed curcumin at dusk after fasting. Inhibition was not observed in mice that were fed ad lib., suggesting that food intake may interfere with the absorption of curcumin.

Retardation of experimental tumorigenesis and reduction in DNA adducts by turmeric and curcumin

Turmeric and its active principle curcumin have been extensively investigated for their antimutagenic and antioxidant effects in bacterial and animal systems. Because oral cancers are common in India, an experimental model of 7,12-dimethylbenzanthracene-induced buccal pouch tumors in Syrian Golden hamsters was used to evaluate the tumor retardation effects of turmeric and curcumin. Turmeric and/or curcumin was administered in the diet and/or applied locally for 14 weeks along with 7,12-dimethylbenzanthracene. After the experimental period, the animals were sacrificed and oral pouches were examined for tumor number and size. DNA adducts were estimated by 32P postlabel assay in the cheek pouches. Neoplastic changes were graded by histopathology. The results of the study suggest that turmeric or curcumin in the diet and/or applied locally significantly reduced DNA adducts at the target site. Tumor number and tumor burden were significantly lower (p < 0.05) in the animals that received turmeric in the diet and applied locally. The histopathological examinations suggested that the neoplastic grading was least in the animals fed or painted with curcumin (p < 0.05). The current study demonstrates that turmeric or curcumin administered in the diet or applied as paint may have a plausible chemopreventive effect on oral precancerous lesions.

Chemopreventive efficacy of curcumin-free aqueous turmeric extract in 7,12-dimethylbenz[a]anthracene-induced rat mammary tumorigenesis

The modulating effects of turmeric (T), ethanolic turmeric extract (ETE) and curcumin-free aqueous turmeric extract (CFATE) on the initiation or post-initiation phases of DMBA-induced mammary tumorigenesis were investigated in female Sprague-Dawley rats. Dietary administration of 1% T/0.05% ETE 2 weeks before, on the day of DMBA treatment (day 55) and 2 weeks after the single dose (15 mg/animal) of DMBA (during the initiation period) resulted in significant suppression of DMBA-induced mammary tumorigenesis as seen by a reduction in tumor multiplicity, tumor burden and tumor incidence. However, simultaneous administration of 1% T-derived CFATE as the sole source of drinking water during the initiation phase did not suppress DMBA-induced mammary tumorigenesis. Dietary administration of 1% T/0.05% ETE or 1% T-derived CFATE as the sole source of drinking water starting 48 h after DMBA treatment and continuing until the end of the experiment (during the post-initiation period) resulted in significant suppression of DMBA-induced mammary tumorigenesis as seen by reduction in the tumor multiplicity and/or tumor burden although tumor incidence was unaffected. The present data clearly indicate that dietary administration of T/ETE showed strong chemopreventive activity during initiation as well as post-initiation phases of DMBA-induced rat mammary tumorigenesis while CFATE was found to be weakly active only when it was administered during the post-initiation phase.

Inhibitory effects of phytopolyphenols on TPA-induced transformation, PKC activation, and c-jun expression in mouse fibroblast cells

The effects of 12 phytopolyphenols, including 3 catechin derivatives, 8 flavanols, and curcumin, on 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced transformation in mouse fibroblast cells are described. The location of hydroxyl functional groups at 2', 3', or 4' site(s), especially at the 4' site, as in apigenin, fisetin, morin, myricetin, and quercetin, seems essential for anti-TPA-induced transformation, anti-protein kinase C (PKC) activation, and anti-TPA-induced c-jun expression activities. Among the catechin derivatives, those with a cis form structure and with an additional hydroxyl group at the R1 site and galloyl groups at the R2 site, such as epigallocatechin gallate, have stronger inhibitory effects on the above-mentioned biochemical activities. Considering their polarities and chemical structures, these compounds have different oxygen radical absorbance capacity in the in vitro assay. In addition, curcumin also has these inhibitory effects on the above-mentioned biochemical activities and antioxidant activities for peroxyl radical but not hydroxyl radical. In addition to PKC activation, active oxygen species production, and c-jun induction, our data suggest that TPA treatment induces cellular transformation by other unknown routes, because some tested compounds have an inhibitory effect on TPA-induced transformation but have no or a slight inhibitory effect on PKC activation, active oxygen species production, and c-jun induction.

Inhibitory effects of curcumin-free aqueous turmeric extract on benzo[a]pyrene-induced forestomach papillomas in mice

The modulating effects of curcumin-free aqueous turmeric extract (CFATE), ethanolic turmeric extract (ETE) and turmeric (T) powder on the benzo(a)pyrene (B(a)P)-induced forestomach tumors were investigated in Swiss female albino mice receiving oral administration of B(a)P at a dose of 1 mg twice weekly for 4 weeks. Administration of 0.2%/1.0%/5.0% turmeric-derived CFATE as sole source of drinking water or 0.01%/0.05%/0.25% ETE in diet or 0.2%/1.0%/5.0% T in diet, 2 weeks before, during and 2 weeks after the last dose of B(a)P (during initiation period) resulted in significant suppression of B(a)P-induced tumorigenesis when compared with the group receiving B(a)P and control diet/drinking water. Among different fractions tested, CFATE appears to be more powerful as not only did it reduce the tumor multiplicity to the lowest levels but it also significantly reduced the tumor incidence. Administration of 5.0% turmeric-derived CFATE as the sole source of drinking water or 0.25% ETE/5.0% T in diet starting from 48 h after the last dose of B(a)P (during the post-initiation period) until the termination of the experiment, also inhibited the formation of multiple gastric tumors by B(a)P, although the suppression of tumor multiplicity was appreciably more in the groups that received 5.0% turmeric-derived CFATE/0.25% ETE treatment during initiation with carcinogen, i.e. 2 weeks before, during and 2 weeks after the last dose of B(a)P. The present data clearly indicate the potential of turmeric-derived CFATE as a powerful chemopreventive fraction and also demonstrate the efficacy of lower, i.e. 1/25th and/or 1/5th of the reported, chemopreventive doses of T/ETE (essentially curcumins) in inhibiting B(a)P-induced forestomach tumors in mice.