Potentiation by turmeric and curcumin of gamma-radiation-induced chromosome aberrations in Chinese hamster ovary cells

Phytochemicals: A potential next generation agent for radioprotection

BACKGROUND

Radiation hazards are accountable for extensive damage in the biological system and acts as a public health burden. Owing to the rapid increasing in radiation technology, both Ionizing radiation (IR) from natural and man made source poses detrimental outcome to public health. IR releases free radicals which induces oxidative stress and deleterious biological damage by modulating radiation induced signalling intermediates. The efficacy of existing therapeutic approach and treatment strategy are limited owing to their toxicity and associated side effects. Indian system of traditional medicine is enriched with prospective phytochemicals with potential radioprotection ability.

PURPOSE

The present review elucidated and summarized the potential role of plant derived novel chemical compound with prospective radioprotective potential.

METHOD

So far as the traditional system of Indian medicine is concerned, plant kingdom is enriched with potential bioactive molecules with diverse pharmacological activities. We reviewed several compounds mostly secondary metabolites from plant origin using various search engines.

RESULTS

Both compounds from land plants and marine source exhibited antioxidant antiinflammatory, free radical scavenging ability. These compounds have tremendous potential in fine-tuning of several signalling intermediates, which are actively participated in the progression and development of a pathological condition associated with radiation stress.

CONCLUSION

Development and explore of an operational radioprotective agent from originated from plant source that can be used as a novel molecular tool to eliminate the widespread damage caused by space exploration, ionizing radiation, nuclear war and radiotherapy has been significantly appreciated. Through extensive literature search we highlighted several compounds from both land plant and marine origin can be implemented for a better therapeutic potential against radiation induced injury. Furthermore, extensive clinical trials must be carried out in near future for better therapeutic modality and clinical efficacy.

Comparative Toxicity of Vegan Red, E124, and E120 Food Dyes on Three Rapidly Proliferating Model Systems

The abuse of artificial food dyes and the evidence that they harm human health recently prompted a significant effort to introduce vegan substitutes prepared from fruits and vegetables. Not much information, however, has been collected on their possible effects on aquatic and terrestrial ecosystems once released as waste in surface waters. For this purpose, we analyzed the effects of a vegan red (VEG) preparation (concentration 1.2 g/L) on three rapidly proliferating models for terrestrial and aquatic ecosystem contamination. In particular, in vitro cells cultures (exposure for 24 h), Artemia salina nauplii and Cucumis sativus seedlings (exposure 5 days). A comparison was made with the effects exerted by the two dyes that vegan red is intended to replace: an animal dye, cochineal E120 and an artificial dye E124. The analyses of conventional endpoints, indicative of cell proliferation, differentiation, and growth rate, demonstrate that the three dyes affect development and that the vegan substitute is as unsafe as the E124 and E120. Vegan red in fact impairs cell growth in in vitro cells, delays naupliar hatching and early growth in Artemia, and reduces shoot/root biomass in Cucumis. Marked hyperplasia and hypertrophy of mesophyll are also observed in Cucumis leaves. Substitution in food and beverages, therefore, should be carefully reconsidered to avoid unnecessary environmental contamination.

Pleiotropic nature of curcumin in targeting multiple apoptotic-mediated factors and related strategies to treat gastric cancer: A review

Gastric cancer (GC) is one of the major reasons for cancer-associated death and exhibits the second-highest mortality rate worldwide. Several advanced approaches have been designed to treat GC; however, these strategies possess many innate complications. In view of this, the upcoming research relying on natural products could result in designing potential anticancer agents with fewer side effects. Curcumin, isolated from the rhizomes of Curcuma longa L. has several medicinal properties like antiinflammatory, antioxidant, antiapoptotic, antitumor, and antimetastatic. Such pleiotropic nature of curcumin impedes the invasion and proliferation of GC by targeting several oncogenic factors like p23, human epidermal factor receptor2 including Helicobacter pylori. The side effect of chemotherapy, that is, chemotherapeutic resistance and radiotherapy could be reduced combination therapy of curcumin. Moreover, the photodynamic therapy of curcumin destroys the cancer cells without affecting normal cells. However, further more potential studies are required to establish the potent efficacy of curcumin in the treatment of GC. The current review details the anticancer activities of curcumin and related strategies which could be employed to treat GC with additional focus on its inhibitory properties against viability, proliferation, and migration of GC cells through cell cycle arrest and stimulation by apoptosis-mediated factors.

Antioxidant activity of curcumin protects against the radiation-induced micronuclei formation in cultured human peripheral blood lymphocytes exposed to various doses of γ-Radiation

PURPOSE

Ionizing radiations trigger the formation of free radicals that damage DNA and cause cell death. DNA damage may be simply evaluated by micronucleus assay and the pharmacophores that impede free radicals could effectively reduce the DNA damage initiated by irradiation. Therefore, it was desired to determine the capacity of curcumin to alleviate micronuclei formation in human peripheral blood lymphocytes (HPBLs) exposed to 0-4 Gy of γ-radiation.

MATERIALS AND METHODS

HPBLs were exposed to 3 Gy after 30 minutes of 0.125, 0.25, 0.5, 1, 2, 5, 10, 20 or 50 µg/mL curcumin treatment or with 0.5 μg/mL curcumin 30 minutes early to 0, 0.5, 1, 2, 3 or 4 Gy 60Co γ-irradiation. Cytokinesis of HPBLs was blocked by cytochalasin B and micronuclei scored. The ability of curcumin to suppress free radical induction in vitro was determined by standard methods.

RESULTS

HPBLs treated with different concentrations of curcumin before 3 Gy irradiation alleviated the micronuclei formation depending on curcumin concentration and the lowest micronuclei were detected at 0.5 µg/mL curcumin when compared to 3 Gy irradiation alone. Increasing curcumin concentration caused a gradual rise in micronuclei, and the significant increases were detected at 10-50 µg/mL curcumin than 3 Gy irradiation alone. Irradiation of HPBLs to different doses of γ-rays caused a significant rise in micronuclei depending on radiation dose, whereas HPBLs treated with 0.5 µg/mL curcumin 30 minutes before irradiation to different doses of γ-rays significantly reduced frequencies of HPBLs with one, two, or more micronuclei. Curcumin treatment inhibited the formation of hydroxyl (OH), 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH), and (nitric oxide) NO free radicals in a concentration-related way.

CONCLUSIONS

Curcumin when treated at a dose of 0.5 μg/mL attenuated micronuclei formation after γ-irradiation by inhibiting the formation of radiation-induced free radicals.

18F-FDG-induced DNA damage, chromosomal aberrations, and toxicity in V79 lung fibroblast cells

¹⁸F-FDG PET/CT imaging is used in the diagnosis of diseases, including cancers. The principal photons used for imaging are 511 ke V gamma photons resulting from positron annihilation. The absorbed dose varies among body organs, depending on administered radioactivity and biological clearance. We have attempted to evaluate DNA double-strand breaks (DSB) and toxicity induced in V79 lung fibroblast cells in vitro by ¹⁸F-FDG, at doses which might result from PET procedures. Cells were irradiated by ¹⁸F-FDG at doses (14.51 and 26.86 mGy), comparable to absorbed doses received by critical organs during PET procedures. The biological endpoints measured were formation of γ-H2AX foci, mitochondrial stress, chromosomal aberrations, and cell cycle perturbation. Irradiation induced DSB (γH2AX assay), mitochondrial depolarization, and both chromosome and chromatid types of aberrations. At higher radiation doses, increased aneuploidy and reduced mitotic activity were also seen. Thus, significant biological effects were observed at the doses delivered by the ¹⁸F-FDG exposure and the effects increased with dose.

Benefits of curcumin in brain disorders

Curcumin is widely consumed in Asia either as turmeric directly or as one of the culinary ingredients in food recipes. The benefits of curcumin in different organ systems have been reported extensively in several neurological diseases and cancer. Curcumin has got its global recognition because of its strong antioxidant, anti-inflammatory, anti-cancer, and antimicrobial activities. Additionally, it is used in diabetes and arthritis as well as in hepatic, renal, and cardiovascular diseases. Recently, there is growing attention on usage of curcumin to prevent or delay the onset of neurodegenerative diseases. This review summarizes available data from several recent studies on curcumin in various neurological diseases such as Alzheimer's disease, Parkinson's disease, Multiple Sclerosis, Huntington's disease, Prions disease, stroke, Down's syndrome, autism, Amyotrophic lateral sclerosis, anxiety, depression, and aging. Recent advancements toward increasing the therapeutic efficacy of curcuma/curcumin formulation and the novel delivery strategies employed to overcome its minimal bioavailability and toxicity studies have also been discussed. This review also summarizes the ongoing clinical trials on curcumin for different neurodegenerative diseases and patent details of curcuma/curcumin in India.

An Evaluation of the Genotoxicity and Subchronic Oral Toxicity of Synthetic Curcumin

A battery of toxicological studies was conducted in accordance with international guidelines to investigate the genotoxicity and repeated-dose oral toxicity in rats of synthetic curcumin (VEAMIN 99, >99% purity). There was no evidence of mutagenicity in a bacterial reverse mutation test, whereas an in vitro mammalian chromosomal aberration test was positive for induction of chromosomal aberrations which is in line with results reported for natural curcumin. There was no evidence of genotoxicity in an in vivo mammalian micronucleus test. Synthetic curcumin did not cause mortality or toxic effects in a 90-day repeated-dose oral toxicity study at daily doses of 250, 500, or 1000 mg/kg body weight (bw)/day (administered by gavage in a split dose). The no observed adverse effect level (NOAEL) determined from the 90-day study was 1000 mg/kg bw/day for both male and female Wistar rats.

A Toxicological Evaluation of a Standardized Hydrogenated Extract of Curcumin (CuroWhite™)

A series of toxicological investigations were conducted in order to evaluate the genotoxic potential and repeated-dose oral toxicity of CuroWhite, a proprietary extract of curcumin that has been hydrogenated and standardized to not less than 25% hydrogenated curcuminoid content. All tests were conducted in general accordance with internationally accepted standards. The test item was not mutagenic in the bacterial reverse mutation test or in vitro mammalian chromosomal aberration test, and no in vivo genotoxic activity was observed in rat bone marrow in the micronucleus test. A 90-day repeated-dose study was conducted in male and female Sprague-Dawley rats. Two mortalities occurred in the main and satellite high-dose groups and were determined due to gavage error. No organ specific or other toxic effects of the test item were observed up to the maximum dose of 800 mg/kg bw/day, administered by gavage. NOAEL was, therefore, estimated as 800 mg/kg bw/day.

Curcumin: A new radio-sensitizer of squamous cell carcinoma cells

PURPOSE: Curcumin, a potential chemopreventive agent, was found to inhibit cancer cells in S/G2M phases of the cell cycle, when radiation is more effective. The purpose of the current study was to investigate whether curcumin can sensitize squamous cell carcinoma (SCC) cells to the ionizing effects of irradiation.

METHODS: Curcumin (3.5 μM) was added for 48 hours to an SCC cell line prior to irradiation. Cell growth (counts) and colony-formation (colonogenic assay) were examined after radiation.

RESULTS: Incubation with curcumin only (3.75 μM) for 48 hours did not decrease the number of cells or the ability to form colonies in the absence of radiation. However, in plates that were exposed to 1–5 Gy of radiation, cell counts dropped significantly if pretreated with curcumin with a maximal effect at 2.5 Gy (where the cell counts dropped from 1240 to 1017, P < 0.001). The colonogenic assay revealed a significant decrease in the ability to form colonies following pretreatment with curcumin in all radiation doses ( P < 0.05).

CONCLUSIONS: Given the appropriate doses, curcumin exhibits radio-sensitizing effects on SCC cells in vitro.

Quantitative Measurement of Histone Tail Acetylation Reveals Stage-Specific Regulation and Response to Environmental Changes during Drosophila Development

Histone modification plays a major role in regulating gene transcription and ensuring the healthy development of an organism. Numerous studies have suggested that histones are dynamically modified during developmental events to control gene expression levels in a temporal and spatial manner. However, the study of histone acetylation dynamics using currently available techniques is hindered by the difficulty of simultaneously measuring acetylation of the numerous potential sites of modification present in histones. Here, we present a methodology that allows us to combine mass spectrometry-based histone analysis with Drosophila developmental genetics. Using this system, we characterized histone acetylation patterns during multiple developmental stages of the fly. Additionally, we utilized this analysis to characterize how treatments with pharmacological agents or environmental changes such as γ-irradiation altered histone acetylation patterns. Strikingly, γ-irradiation dramatically increased the level of acetylation at H3K18, a site linked to DNA repair via nonhomologous end joining. In mutant fly strains deficient in DNA repair proteins, however, this increase in the level of H3K18 acetylation was lost. These results demonstrate the efficacy of our combined mass spectrometry system with a Drosophila model system and provide interesting insight into the changes in histone acetylation during development, as well as the effects of both pharmacological and environmental agents on global histone acetylation.

Utilization of cytogenetic biomarkers as a tool for assessment of radiation injury and evaluation of radiomodulatory effects of various medicinal plants - a review

Systematic biological measurement of “cytogenetic endpoints” has helped phenomenally in assessment of risks associated with radiation exposure. There has been a surge in recent times for the usage of radioactive materials in health care, agriculture, industrial, and nuclear power sectors. The likelihood of radiation exposure from accidental or occupational means is always higher in an overburdened ecosystem that is continuously challenged to meet the population demands. Risks associated with radiation exposure in this era of modern industrial growth are minimal as international regulations for maintaining the safety standards are stringent and strictly adhered to, however, a recent disaster like “Fukushima” impels us to think beyond. The major objective of radiobiology is the development of an orally effective radio-modifier that provides protection from radiation exposure. Once available for mass usage, these compounds will not only be useful for providing selective protection against accidental and occupational radiation exposure but also help to permit use of higher doses of radiation during treatment of various malignancies curtailing unwarranted adverse effects imposed on normal tissues. Bio-active compounds isolated from natural sources enriched with antioxidants possess unique immune-modulating properties, thus providing a double edged benefit over synthetic radioprotectors. We aim to provide here a comprehensive overview of the various agents originating from plant sources that portrayed promising radioprotection in various experimental models with special emphasis on studies that used cytogenetic biomarkers. The agents will include crude extracts of various medicinal plants, purified fractions, and herbal preparations.

Protective effect of dietary curcumin in Anabas testudineus (Bloch) with a special note on DNA fragmentation assay on hepatocytes and micronucleus assay on erythrocytes in vivo

The present study was conducted to evaluate the safety of long-term dietary curcumin at doses 0.5 and 1% in Anabas testudineus employing hematological and cytological techniques. The fish were fed with curcumin-supplemented feed for 6 months. Fine blood smears were prepared and subjected to three different staining techniques. The erythrocyte micronucleus frequency (MN) and the cytometric measurements of erythrocytes were determined. Blood from the control and treated fish was subjected to the assessment of several hematological parameters. Also, DNA fragmentation assay on hepatocytes was conducted. The results showed that hemoglobin content, RBC count and hematocrit increased in the curcumin-fed fish compared to control, whereas WBC count, platelet count, mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were unaffected. WBC/RBC ratio was lower in the case of curcumin-treated fish. The cytometric measurements revealed no change in the erythrocytes and their nuclei after curcumin treatment. DNA fragmentation assay revealed intact DNA in curcumin-fed group, ruling out the possibility of curcumin-induced DNA damage. The positive control group showed a significant increase in MN frequency compared to negative control and curcumin-fed groups. In fact, the MN frequency decreased in 1% curcumin-fed group compared to the negative control and 0.5% curcumin groups. All these indicated a state of well-being of the curcumin-treated fish. Therefore, it is concluded that curcumin could be used as a safe feed ingredient to improve the growth of finfish in aquaculture.

In vivo protective effect of dietary curcumin in fish Anabas testudineus (Bloch)

The present study describes, for the first time, the protective effect of natural curcumin in vivo in a lower vertebrate, a teleost, Anabas testudineus (Bloch). Two doses of curcumin 0.5 and 1% were supplemented in the 40% protein feed and fed to fish for the periods, 2 and 8 weeks. The antioxidant status, protein content, and the tissue structure in experimental fish were examined after the short-term and long-term feeding. In all the curcumin fed groups, the lipid peroxidation product, thiobarbituric acid reactive substances content either decreased or unaffected. The glutathione content increased while the antioxidant enzyme activity pattern varied with time and dose. The histological analysis also confirmed the safety of curcumin retaining the normal arrangement of hepatocytes, hepatopancreas, macrophage-melanocyte centers in Anabas. The improved antioxidant status and protein content suggest a favorable effect for curcumin in cultured fish.

Extract of Lillium candidum L. can modulate the genotoxicity of the antibiotic zeocin

Lilium candidum L. extract (LE) is well known in folk medicine for the treatment of burns, ulcers, inflammations and for healing wounds. This work aims to clarify whether the genotoxic potential of the radiomimetic antibiotic zeocin (Zeo) could be modulated by LE. Our results indicate that LE exerts no cytotoxic, DNA-damaging and clastogenic activity in in Chlamydomonas reinhardtii, Pisum sativum L. and Hordeum vulgare L. test systems over a broad concentration range. Weak but statistically significant clastogenic effects due to the induction of micronuclei and chromosome aberrations have been observed in H. vulgare L. after treatment with 200 and 300 μg/mL LE. To discriminate protective from adverse action of LE different experimental designs have been used. Our results demonstrate that the treatment with mixtures of LE and Zeo causes an increase in the level of DNA damage, micronuclei and "metaphases with chromatid aberrations" (MwA). Clear evidence has been also obtained indicating that pretreatment with LE given 4 h before the treatment with Zeo accelerates the rejoining kinetics of Zeo-induced DNA damage in P. sativum L. and C. reinhardtii, and can decrease clastogenic effect of Zeo measured as frequencies of micronuclei and MwA in H. vulgare L. Here, we show for the first time that LE can modulate the genotoxic effects of zeocin. The molecular mode of action strongly depends on the experimental design and varies from synergistic to protective effect (adaptive response-AR). Our results also revealed that LE-induced AR to zeocin involves up-regulation of DSB rejoining in C. reinhardtii and P. sativum L. cells.

Phenylpropanoids in radioregulation: double edged sword

Radiotherapy, frequently used for treatment of solid tumors, carries two main obstacles including acquired radioresistance in cancer cells during radiotherapy and normal tissue injury. Phenylpropanoids, which are naturally occurring phytochemicals found in plants, have been identified as potential radiotherapeutic agents due to their anti-cancer activity and relatively safe levels of cytotoxicity. Various studies have proposed that these compounds could not only sensitize cancer cells to radiation resulting in inhibition of growth and cell death but also protect normal cells against radiation-induced damage. This review is intended to provide an overview of recent investigations on the usage of phenylpropanoids in combination with radiotherapy in cancer treatment.

Evaluation of curcumin and cisplatin-induced DNA damage in PC12 cells by the alkaline comet assay

A very appropriate method for antigenotoxicity evaluation of antioxidants is the comet assay, since this analytical method detects initial DNA lesions that are still subject to repair; in other words, lesions that are very associated to damages resulting from the generation and subsequent action of reactive species. However, a solid evaluation should be developed in order to avoid inexact interpretations. In our study, besides the association of curcumin with cisplatin, curcumin and cisplatin agents were also tested separately. Classical genotoxic compounds, when tested by the comet assay, present an increase in the nucleoid tail; however, the cisplatin treatment has resulted in a decrease of DNA migration. This was an expected effect, as the cross-links between cisplatin and DNA decrease the DNA electrophoretic mobility. A similar effect was observed with the curcumin treatment, which decreased the nucleoid tail. Such effect was not expected and reinforced the necessity of including in the study, separate treatment groups with potentially antigenotoxic substances. The comet assay results have been analyzed using specific software for image analysis, as well as the classical visual analysis, and we have observed that the effect of decrease in DNA electrophoretic mobility was more easily observed when the data were analyzed by the software.

Can the therapeutic gain of radiotherapy be increased by concurrent administration of Asian botanicals?

Therapeutic gain by radiotherapy can be achieved through improved targeting, selectively sensitizing malignant cells, or protecting normal tissue. The majority of synthetic chemical radiation sensitizers and normal tissue protectors have proved to be too toxic at effective clinical doses. However, Asian botanicals (from both Chinese and Ayurvedic medicine) are being evaluated for their ability to improve therapeutic gain through the modulation of reactive oxygen species. An increase in the efficacy of radiotherapy on tumor tissue allows a reduction in the dose applied to normal tissues. In addition, some botanicals may selectively protect normal tissue or increase its repair following radiation therapy. The results are promising enough to consider clinical trials.

Curcumin, resveratrol and flavonoids as anti-inflammatory, cyto- and DNA-protective dietary compounds

Numerous dietary compounds, ubiquitous in fruits, vegetables and spices have been isolated and evaluated during recent years for their therapeutic potential. These compounds include flavonoid and non-flavonoid polyphenols, which describe beneficial effects against a variety of ailments. The notion that these plant products have health promoting effects emerged because their intake was related to a reduced incidence of cancer, cardiovascular, neurological, respiratory, and age-related diseases. Exposure of the body to a stressful environment challenges cell survival and increases the risk of chronic disease developing. The polyphenols afford protection against various stress-induced toxicities through modulating intercellular cascades which inhibit inflammatory molecule synthesis, the formation of free radicals, nuclear damage and induce antioxidant enzyme expression. These responses have the potential to increase life expectancy. The present review article focuses on curcumin, resveratrol, and flavonoids and seeks to summarize their anti-inflammatory, cytoprotective and DNA-protective properties.

Curcumin: a potential radio-enhancer in head and neck cancer

OBJECTIVES/HYPOTHESIS

To investigate whether curcumin enhances the cytotoxic effect of radiotherapy in head and neck squamous cell carcinoma (HNSCC).

METHODS

HNSCC cell lines SCC-1, SCC-9, KB, as well as A431 cell line were treated with curcumin, irradiation, or their combination. Cell viability was evaluated by XTT assay. Cyclooxygenase-2 (COX-2), epithelial growth factor receptor (EGFR), and p-Erk1/2 were measured by Western blot analysis. CD-1 athymic nude mice with orthotopic implanted SCC-1 cells, were treated with control diet, curcumin containing diet, local single-dose radiation, or combination.

RESULTS

Curcumin (IC50 range, 15-22 microM) and radiation inhibited cell viability in all cell lines were tested. The combination of curcumin and radiation resulted in additive effect. Curcumin decreased COX-2 expression and inhibited phosphorylation of EGFR in SCC-1 cells. In tumor-bearing mice the combination regimen showed a decrease in both tumor weight (25%, P = .09) and tumor size (15%, P = .23) compared to the nontreated mice.

CONCLUSIONS

: Curcumin inhibited HNSCC cell growth and augmented the effect of radiation in vitro and in vivo. A possible mechanism is inhibition of COX-2 expression and EGFR phosphorylation.

Anticancer and carcinogenic properties of curcumin: considerations for its clinical development as a cancer chemopreventive and chemotherapeutic agent

A growing body of research suggests that curcumin, the major active constituent of the dietary spice turmeric, has potential for the prevention and therapy of cancer. Preclinical data have shown that curcumin can both inhibit the formation of tumors in animal models of carcinogenesis and act on a variety of molecular targets involved in cancer development. In vitro studies have demonstrated that curcumin is an efficient inducer of apoptosis and some degree of selectivity for cancer cells has been observed. Clinical trials have revealed that curcumin is well tolerated and may produce antitumor effects in people with precancerous lesions or who are at a high risk for developing cancer. This seems to indicate that curcumin is a pharmacologically safe agent that may be used in cancer chemoprevention and therapy. Both in vitro and in vivo studies have shown, however, that curcumin may produce toxic and carcinogenic effects under specific conditions. Curcumin may also alter the effectiveness of radiotherapy and chemotherapy. This review article analyzes the in vitro and in vivo cancer-related activities of curcumin and discusses that they are linked to its known antioxidant and pro-oxidant properties. Several considerations that may help develop curcumin as an anticancer agent are also discussed.

Protective in vivo effect of curcumin on copper genotoxicity evaluated by comet and micronucleus assays

Curcumin is a phytochemical with antiinflammatory, antioxidant and anticarcinogenic activities. Apparently, curcumin is not genotoxic in vivo, but in vitro copper and curcumin interactions induce genetic damage. The aim of this study was to test if in vivo copper excess induces DNA damage measured by comet and micronucleus assays in the presence of curcumin. We tested 0.2% curcumin in Balb-C mice at normal (13 ppm) and high (65, 130 and 390 ppm) copper ion concentrations. The comet and micronucleus assays were performed 48 hr after chemical application. Comet tail length in animals treated with 0.2% curcumin was not significantly different from the control. Animals exposed to copper cations (up to 390 ppm) exhibited higher oxidative DNA damage. Curcumin reduced the DNA damage induced by 390 ppm copper. We observed statistically significant increase in damage in individuals exposed to 390 ppm copper versus the control or curcumin groups, which was lowered by the presence of curcumin. Qualitative data on comets evidenced that cells from individuals exposed to 390 ppm copper had longer tails (categories 3 and 4) than in 390 ppm copper + curcumin. A statistically significant increase in frequency of micronucleated erythrocytes (MNE/10000TE) was observed only in 390 ppm copper versus the control and curcumin alone. Also cytotoxicity measured as the frequency of polychromatic erythrocytes (PE/1000TE) was attributable to 390 ppm copper. The lowest cytotoxic effect observed was attributed to curcumin. In vivo exposure to 0.2% curcumin for 48 hr did not cause genomic damage, while 390 ppm copper was genotoxic, but DNA damage induced by 390 ppm copper was diminished by curcumin. Curcumin seems to exert a genoprotective effect against DNA damage induced by high concentrations of copper cations. The comet and micronucleus assays prove to be suitable tools to detect DNA damage by copper in the presence of curcumin.

Curcumin protects against cytotoxic and inflammatory effects of quartz particles but causes oxidative DNA damage in a rat lung epithelial cell line

Chronic inhalation of high concentrations of respirable quartz particles has been implicated in various lung diseases including lung fibrosis and cancer. Generation of reactive oxygen species (ROS) and oxidative stress is considered a major mechanism of quartz toxicity. Curcumin, a yellow pigment from Curcuma longa, has been considered as nutraceutical because of its strong anti-inflammatory, antitumour and antioxidant properties. The aim of our present study was to investigate whether curcumin can protect lung epithelial cells from the cytotoxic, genotoxic and inflammatory effects associated with quartz (DQ12) exposure. Electron paramagnetic resonance (EPR) measurements using the spin-trap DMPO demonstrated that curcumin reduces hydrogen peroxide-dependent hydroxyl-radical formation by quartz. Curcumin was also found to reduce quartz-induced cytotoxicity and cyclooxygenase 2 (COX-2) mRNA expression in RLE-6TN rat lung epithelial cells (RLE). Curcumin also inhibited the release of macrophage inflammatory protein-2 (MIP-2) from RLE cells as observed upon treatment with interleukin-1 beta (IL-1beta) and tumour necrosis factor-alpha (TNFalpha). However, curcumin failed to protect the RLE cells from oxidative DNA damage induced by quartz, as shown by formamidopyrimidine glycosylase (FPG)-modified comet assay and by immunocytochemistry for 8-hydroxydeoxyguanosine. In contrast, curcumin was found to be a strong inducer of oxidative DNA damage itself at non-cytotoxic and anti-inflammatory concentrations. In line with this, curcumin also enhanced the mRNA expression of the oxidative stress response gene heme oxygenase-1 (ho-1). Curcumin also caused oxidative DNA damage in NR8383 rat alveolar macrophages and A549 human lung epithelial cells. Taken together, these observations indicate that one should be cautious in considering the potential use of curcumin in the prevention or treatment of lung diseases associated with quartz exposure.

Radioprotection and radiosensitization by curcumin

This chapter gives an overview of the radioprotective and radiosensitizing effect of curcumin. Ionizing radiations interact with biological molecules inducing radiolytic products like e(aq), *OH, *H, -OH, +H, O2, and peroxides. These free radicals damage important biomolecules and subsequently inflict deleterious effects in the organism. Whole-body exposure to ionizing radiations results in central nervous system, gastrointestinal tract, and bone marrow syndromes, whereas chronic irradiation causes cancer, birth anomalies, erythema, and dysfunctions to almost all organ of the body depending on the total dose and site of irradiation. Curcumin (diferuloyl methane), a yellow pigment present in the rhizomes of turmeric, has been used in Southeast Asia to give yellow color and flavor to curries. Turmeric has been used to treat various ailments in the Ayurvedic system of medicine in India. Recently, it has been evaluated for its radioprotective and radiosensitizing activities. Curcumin has been found to exert a dual mode of action after irradiation depending on its dose. It has been reported to protect various study systems against the deleterious effects induced by ionizing radiation and to enhance the effect of radiation. Therefore, curcumin can be very useful during radiotherapy of cancer. Administration of curcumin in patients will be able to kill the tumor cells effectively by enhancing the effect of radiation and, at the same time, protect normal cells against the harmful effects of radiation. The available information on curcumin suggests that the radioprotective effect might be mainly due to its ability to reduce oxidative stress and inhibit transcription of genes related to oxidative stress and inflammatory responses, whereas the radiosensitive activity might be due the upregulation of genes responsible for cell death.

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".

Curcumin-induced genotoxicity and antigenotoxicity in HepG2 cells

Curcumin, a polyphenolic yellow pigment found in turmeric, is commonly used as a coloring agent in foods, drugs, and cosmetics. In our previous study, we found that low levels of curcumin did not increase the reactive oxygen species (ROS) formation and caused no damage to DNA in human hepatoma G2 (HepG2) cells, but at high doses, curcumin imposed oxidative stress and damaged DNA. In the present study, we are determined to investigate the genotoxic and antigenotoxic effects of curcumin using HepG2 cell line, a relevant in vitro model to detect the cytoprotective, antigenotoxic, and cogenotoxic agents. The results of micronucleus (MN) assays showed that, on one hand, curcumin at the high tested concentrations (8 and 16 microg/ml) displayed a small but significant increase in the frequency of MN, and on the other hand, it was observed that the low tested concentration (2 microg/ml) significantly reduced the MN formation induced by the chemotherapeutic agent cyclophosphamide. The present results indicate that curcumin shows both genotoxicity and antigenotoxicity depending on its concentration.

DNA damage in mouse lymphocytes exposed to curcumin and copper

Dietary polyphenolics, such as curcumin, have shown antioxidant and anti-inflammatory effects. Some antioxidants cause DNA strand breaks in excess of transition metal ions, such as copper. The aim of this study was to evaluate the in vitro effect of curcumin in the presence of increasing concentrations of copper to induce DNA damage in murine leukocytes by the comet assay. Balb-C mouse lymphocytes were exposed to 50 microM curcumin and various concentrations of copper (10 microM, 100 microM and 200 microM). Cellular DNA damage was detected by means of the alkaline comet assay. Our results show that 50 microM curcumin in the presence of 100-200 microM copper induced DNA damage in murine lymphocytes. Curcumin did not inhibit the oxidative DNA damage caused by 50 microM H2O2 in mouse lymphocytes. Moreover, 50 microM curcumin alone was capable of inducing DNA strand breaks under the tested conditions. The increased DNA damage by 50 mM curcumin was observed in the presence of various concentrations of copper, as detected by the alkaline comet assay.

Curcumin treatment enhances the repair and regeneration of wounds in mice exposed to hemibody gamma-irradiation

Hemibody irradiation in multiple fractionated doses is frequently used for the treatment of various neoplastic disorders. It produces both acute and late effects on the skin and subcutaneous tissues that have profound implications in the healing of surgical wounds. Because of the crucial practical importance of hemibody radiation exposure associated with skin wounds, it is imperative to investigate the efficacy of cost-effective herbal products in the reconstruction of irradiated wounds. Therefore, the effect of pretreatment of curcumin was studied on the healing of excision wound in mice exposed to 2, 4, 6, or 8 Gy of hemibody gamma-radiation. A full-thickness skin wound was created by removing the skin flap of the dorsum of 8- to 10-week-old Swiss albino mice partially (lower half, below the rib cage) exposed to 2, 4, 6, or 8 Gy of gamma-radiation. The progression of wound contraction was monitored periodically by capturing video images of the wound, where the first image of each wound from different groups was obtained 1 day after wounding and that day was considered as day 0. Eight animals were used in each group at each exposure dose for wound contraction studies. Furthermore, the effect of curcumin on mean healing time after exposure of mice to 2, 4, 6, or 8Gy of hemibody gamma-radiation was also evaluated, where eight animals were used in each group at each exposure dose. Collagen, hexosamine, DNA, nitric oxide, and histologic profiles were also evaluated during the course of healing of excision wounds at days 4, 8, and 12 after irradiation treated or not with curcumin before exposure to 0 or 6 Gy of gamma-radiation. Six animals were used in each group at each interval for each biochemical parameter studied, except for histologic evaluations, where four animals were used in each group at each interval. Exposure of mice to different doses of gamma-radiation resulted in a dose-dependent delay in contraction and wound-healing time of excision wound, whereas curcumin pretreatment caused a significant elevation in the rate of wound contraction and a decrease in the mean wound-healing time. Treatment with curcumin before irradiation enhanced the synthesis of collagen, hexosamine, DNA, nitrite, and nitrate, and histologic assessment of wound biopsy specimens revealed improved collagen deposition and an increase in fibroblast and vascular densities. The authors' study demonstrates that curcumin pretreatment has a conducive effect on the irradiated wound and could be a substantial therapeutic strategy for ameliorating radiation-induced delay in wound repair in cases of radiation-induced skin injuries.

Biological properties of curcumin-cellular and molecular mechanisms of action

Curcuminoids, a group of phenolic compounds isolated from the roots of Curcuma longa (Zingiberaceae), exhibit a variety of beneficial effects on health and on events that help in preventing certain diseases. A vast majority of these studies were carried out with curcumin (diferuloyl methane), which is a major curcuminoid. The most detailed studies using curcumin include anti-inflammatory, antioxidant, anticarcinogenic, antiviral, and antiinfectious activities. In addition, the wound healing and detoxifying properties of curcumin have also received considerable attention. As a result of extensive research on the therapeutic properties of curcumin, some understanding on the cellular, molecular, and biochemical mechanism of action of curcumin is emerging. These findings are summarized in this review.

Role of curcumin, a naturally occurring phenolic compound of turmeric in accelerating the repair of excision wound, in mice whole-body exposed to various doses of γ-radiation

The healing of irradiated wounds has always been a central consideration in medical practice because radiation disrupts normal response to injury, leading to a protracted recovery period. The quest for clinically effective wound healing agents is important in the medical management of irradiated wounds. Therefore, the present study was conceptualized to investigate the effect of curcumin (natural yellow, diferuloylmethane), a major yellow pigment and an active component of turmeric on wound healing in mice exposed to whole-body gamma-radiation. A full-thickness wound was created on the dorsum of mice whole-body irradiated to 2, 4, 6, or 8 Gy. The progression of wound contraction was monitored periodically by capturing video images of the wound. The collagen, hexosamine, DNA, nitric oxide, and histological profiles were evaluated at various postirradiation days in mice treated and not treated with curcumin before exposure to 0 or 6 Gy. The whole-body exposure resulted in a dose-dependent delay in wound contraction and prolongation of wound healing time. Irradiation caused a significant reduction in collagen, hexosamine, DNA, and nitric oxide synthesis. Pretreatment with curcumin significantly enhanced the rate of wound contraction, decreased mean wound healing time, increased synthesis of collagen, hexosamine, DNA, and nitric oxide and improved fibroblast and vascular densities. This study demonstrates that curcumin pretreatment has a conducive effect on the irradiated wound and could be a substantial therapeutic strategy in initiating and supporting the cascade of tissue repair processes in irradiated wounds.

Effect of curcumin on radiation-impaired healing of excisional wounds in mice

OBJECTIVE

To study the effect on wound contraction of pretreatment with various doses of curcumin (the most important active ingredient of the spice turmeric) in mice exposed to 6 Gy whole-body gamma radiation.

METHOD

A full-thickness skin wound was produced on the dorsum of Swiss albino mice treated with and without 25, 50, 100, 150 or 200 mg/kg body weight of curcumin before exposure to 6 Gy gamma radiation. Progression of wound contraction was monitored using video images of the wound at various days post-irradiation until full healing occurred. Mean wound healing times were also calculated.

RESULTS

Irradiation caused significant delay in wound contraction and healing times. However, treatment with curcumin resulted in a dose-dependent increase in contraction when compared with a control. Greatest contraction was observed for 100 mg/kg curcumin, with statistically significant results at days three (p < 0.009), six (p < 0.05) and nine (p < 0.05) post-irradiation for this dose. Complete healing was achieved by day 23 post-irradiation in the curcumin-treated irradiation group.

CONCLUSION

Pretreatment with curcumin has a conductive effect on irradiated wounds. It could be a substantial therapeutic agent for ameliorating radiation-induced delay in wound repair in cases of combined injuries.

Protection against ionizing radiation by antioxidant nutrients and phytochemicals

The potential of antioxidants to reduce the cellular damage induced by ionizing radiation has been studied in animal models for more than 50 years. The application of antioxidant radioprotectors to various human exposure situations has not been extensive although it is generally accepted that endogenous antioxidants, such as cellular non-protein thiols and antioxidant enzymes, provide some degree of protection. This review focuses on the radioprotective efficacy of naturally occurring antioxidants, specifically antioxidant nutrients and phytochemicals, and how they might influence various endpoints of radiation damage. Results from animal experiments indicate that antioxidant nutrients, such as vitamin E and selenium compounds, are protective against lethality and other radiation effects but to a lesser degree than most synthetic protectors. Some antioxidant nutrients and phytochemicals have the advantage of low toxicity although they are generally protective when administered at pharmacological doses. Naturally occurring antioxidants also may provide an extended window of protection against low-dose, low-dose-rate irradiation, including therapeutic potential when administered after irradiation. A number of phytochemicals, including caffeine, genistein, and melatonin, have multiple physiological effects, as well as antioxidant activity, which result in radioprotection in vivo. Many antioxidant nutrients and phytochemicals have antimutagenic properties, and their modulation of long-term radiation effects, such as cancer, needs further examination. In addition, further studies are required to determine the potential value of specific antioxidant nutrients and phytochemicals during radiotherapy for cancer.

Curcumin disrupts mitotic spindle structure and induces micronucleation in MCF-7 breast cancer cells

The dietary phytochemical curcumin possesses anti-inflammatory, -oxidant, and cytostatic properties, and exhibits significant potential as a chemopreventative agent in humans. Although many cell types are arrested in the G2/M-phase of the cell cycle after curcumin treatment, the mechanisms by which this occurs are not well understood. The purpose of this study was to examine the effects of curcumin on the cell cycle of MCF-7 breast cancer cells to determine whether growth arrest is associated with structural changes in cellular organization during mitosis. For this purpose, MCF-7 breast cancer cells were treated with 10-20 microM curcumin, and the effects on cell proliferation and mitosis studied. Structural changes were monitored by immunolabeling cells with antibodies to a number of cytoplasmic and nuclear proteins, including beta-tubulin, NuMA, lamins A/C and B1, lamin B receptor, and centromere antigens. At the concentrations used, a single dose of curcumin does not induce significant apoptosis, but is highly effective in inhibiting cell proliferation for over 6 days. During the first 24-48 h of treatment, many cells are arrested in M-phase, and DNA synthesis is almost completely inhibited. Remarkably, arrested mitotic cells exhibit monopolar spindles, and chromosomes do not undergo normal anaphase movements. After 48 h, most cells eventually leave M-phase, and many form multiple micronuclei instead of individual daughter nuclei. These observations indicate that the curcumin-induced G2/M arrest previously described for MCF-7 cells is due to the assembly of aberrant, monopolar mitotic spindles that are impaired in their ability to segregate chromosomes. The production of cells with extensive micronucleation after curcumin treatment suggests that at least some of the cytostatic effects of this phytochemical are due to its ability to disrupt normal mitosis, and raises the possibility that curcumin may promote genetic instability under some circumstances.

Protective effect of thiourea, a hydroxyl-radical scavenger, on curcumin-induced chromosomal aberrations in an in vitro mammalian cell system

Natural dietary antioxidants are extensively studied for their ability to protect cells from damage to DNA, protein, and lipids induced by antitumor agents or radiation that leads to the generation of free radical in normal cells in vivo and in vitro. Curcumin is a natural antioxidant known to possess therapeutic properties and has been reported to scavenge free radicals and to inhibit clastogenesis in mammalian cells. However, curcumin has been reported to induce a significant increase in the frequency of chromosomal aberrations in Chinese hamster ovary (CHO) cells. To investigate whether the clastogenic activity of curcumin in CHO cells in culture can be ascribed to a pro-oxidant behavior, mediated by free radical generation, experiments were carried out with the combination of curcumin (15 microg/ml) and thiourea (10, 20, or 40 microg/ml), a potent hydroxyl radical scavenger. The results showed that the clastogenic action of curcumin was statistically decreased in a dose-dependent manner in the presence of thiourea. These data have shown that curcumin-induced chromosomal damage in CHO cells can be mediated by hydroxyl radical generation in the present experimental conditions. Teratogenesis Carcinog. Mutagen. 21:175-180, 2001.

Mutagenicidade e antimutagenicidade dos principais corantes para alimentos

Muitos compostos presentes nos alimentos, tanto naturalmente, como adicionados ou produzidos durante o processamento, já foram testados quanto à mutagenicidade ou antimutagenicidade em diferentes sistemas experimentais. O grande número de corantes para alimentos, naturais ou sintéticos, tem levado os pesquisadores a avaliar a mutagenicidade e/ou antimutagenicidade desses compostos. Alguns corantes sintéticos apresentaram potencial mutagênico e seu uso foi proibido em alguns países. Muitos corantes naturais testados apresentaram potencial antimutagênico em pelo menos um sistema-teste, entretanto, isto não quer dizer que os corantes naturais são inócuos. O corante natural curcumina, por exemplo, apresentou potencial antimutagênico nos testes in vivo e foi mutagênico nos testes in vitro. Este paradoxo ressalta a importância de uma avaliação criteriosa e ampla na avaliação da possível atividade mutagênica e/ou antimutagênica dos corantes.

Effects of turmeric and its active principle, curcumin, on bleomycin-induced chromosome aberrations in Chinese hamster ovary cells

Naturally occurring antioxidants have been extensively studied for their capacity to protect organisms and cells from oxidative damage. Many plant constituents including turmeric and curcumin appear to be potent antimutagens and antioxidants. The effects of turmeric and curcumin on chromosomal aberration frequencies induced by the radiomimetic agent bleomycin (BLM) were investigated in Chinese hamster ovary (CHO) cells. Three concentrations of each drug, turmeric (100, 250 and 500 <FONT FACE="Symbol">m</FONT>g/ml) and curcumin (2.5, 5 and 10 <FONT FACE="Symbol">m</FONT>g/ml), were combined with BLM (10 <FONT FACE="Symbol">m</FONT>g/ml) in CHO cells treated during the G1/S, S or G2/S phases of the cell cycle. Neither turmeric nor curcumin prevented BLM-induced chromosomal damage in any phases of the cell cycle. Conversely, a potentiation of the clastogenicity of BLM by curcumin was clearly observed in cells treated during the S and G2/S phases. Curcumin was also clastogenic by itself at 10 µg/ml in two protocols used. However, the exact mechanism by which curcumin produced clastogenic and potentiating effects remains unknown.