Low Concentrations Of Curcumin Research Articles

WITHDRAWN: Curcumin reduces the cytotoxicity and osteogenesis inhibition induced by oxidative stress via inhibited the NF-κB and MAPK signaling

// Qihua Qi 1, 2, * , Liangping Li 3, * , Ze min Ling 1, 2 , Yan Chen 1, 2 , Junxuan Ma 2 , Wei Guo 1, 2 , Manman Gao 1, 2 , Zhiyu Zhou 2 , R. Geoff Richards 4 and Xuenong Zou 1, 2 1 Department of Spine Surgery, Orthopedic Research Institute, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China 2 Guangdong Provincial Key Laboratory of Orthopaedics and Traumatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China 3 Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Medical College of Zhejiang University, Hangzhou, 310016, China 4 AO Research Institute Davos, Davos, 7270, Switzerland * These authors contributed equally to this work Correspondence to: Xuenong Zou, email: zxnong@hotmail.com Keywords: oxidative stress; osteogenesis; reactive oxygen species; curcumin; bone fusion Received: October 30, 2017 Accepted: December 05, 2017 Published: January 02, 2018 ABSTRACT Excessive oxidative stress is considered a significant pathogenic factor leading to the failure of bony fusion at the interface between implanted materials and the host. Curcumin has demonstrated anti-inflammatory and antioxidant properties. However, there were few studies investigating the effects of curcumin on osteogenesis, as well as the underlying mechanism involved in pre-osteoblastic MC3T3-E1 cells. We established an oxidative damage model by exposing MC3T3-E1 cells to hydrogen peroxide (H 2 O 2 ) for 24 h before osteogenic induction with curcumin. We discovered that oxidative stress diminished the viability of MC3T3-E1 cells, inhibited alkaline phosphatase (ALP) activity and calcium mineralization, and down-regulated osteogenesis-related gene expression; low concentrations of curcumin (1–10 μM) reversed the effects of oxidative stress during osteogenic induction, but high concentrations (20 μM) did not. Notably, curcumin exerted its protective effects in part by inhibiting the phosphorylation of JNK and p38 induced by H 2 O 2 and by blocking of the NF-κB signaling pathway. In vivo analysis indicated that curcumin alleviated the deterioration of the micro-architecture of trabecular bone and the reduction in bone mineral density (BMD) of the distal femur; the protective effects of curcumin were dose-dependent. Taken together, these results indicate that curcumin can exert protective effects on osteogenesis and bone remodeling via inhibition of the NF-κB and MAPK pathways. This study suggests that curcumin might be effective in preventing oxidative stress and facilitate osteogenesis.

Antimicrobial activity of curcumin in combination with light against Escherichia coli O157:H7 and Listeria innocua: Applications for fresh produce sanitation

Sanitation of fresh produce is critical for reducing microbial load and preventing the risk of foodborne illness. This study evaluated an alternative approach for the inactivation of bacteria in wash water and fresh produce using curcumin in combination with UV-A or visible light. This study characterized the inactivation of Escherichia coli O157:H7 and Listeria innocua under different experimental conditions, such as curcumin concentration, time of light exposure, incubation temperature, pH and chemical oxygen demand content (COD). The combination of UV-A light and curcumin was also evaluated to prevent cross-contamination of fresh produce from contaminated wash water during simulated spinach and tomato washing. It was observed that UV-A light in combination with low concentrations of curcumin (1–10mgL−1) was able to inactivate more than 5 log CFU mL−1 of E. coli O157:H7 and L. innocua in solution regardless of the incubation temperature. In addition, reduced pH increased the antimicrobial activity of curcumin in combination with light against both E. coli O157:H7 and L. innocua. This enhancement in antimicrobial activity reduced the time required for the inactivation of 5 log CFU mL−1 of E. coli O157:H7 from 10min to 2min of treatment. Combination of curcumin with UV-A light was more effective than its combination with visible light for achieving the same level of reduction in bacterial plate count. Although the presence of COD in simulated wash water decreased the antimicrobial photo-activity of curcumin, more than 5 log CFU mL−1 of bacteria could still be inactivated in the presence of high COD (1000mgL−1). Furthermore, the combination of UV-A light and curcumin was able to significantly inhibit bacterial cross-contamination from contaminated wash water to produce surfaces. In summary, the results demonstrate significant potential of curcumin in combination with light for the inactivation of bacteria in food systems including sanitation of wash water and fresh produce.

Photodynamic Treatment of Oral Squamous Cell Carcinoma Cells with Low Curcumin Concentrations.

Objective: Curcumin is known for its anti-oxidative, anti-inflammatory and anti-tumorigenic qualities at concentrations ranging from 3.7µg/ml to 55µg/ml. Therefore it is pre-destined for tumour therapy. Due to high oral doses that have to be administered and the low bioavailability of curcumin new therapy concepts have to be developed. One of these therapy concepts is the combination of low curcumin concentrations and UVA or visible light. Aim of our study was to investigate the influence of this treatment regime on oral squamous cell carcinoma cells.Materials and Methods: A human oral squamous cell carcinoma cell line (HN) was pre-incubated with low curcumin concentrations (0.01µg/ml to 1µg/ml). Thereafter cell cultures were either left un-irradiated or were irradiated either with 1J/cm2 UVA or for 5min with visible light. Quantitative analysis of proliferation, membrane integrity, oxidative potential and DNA fragmentation were done.Results: It could be shown that low curcumin concentrations neither influenced proliferation, nor cell morphology, nor cell integrity nor apoptosis. When combining these curcumin concentrations with UVA or visible light irradiation cell proliferation as well as development of reactive oxygen species was reduced whereas DNA fragmentation was increased. Concentration as well as light entity specific effects could be observed.Conclusions: The present findings substantiate the potential of the combination of low curcumin concentrations and light as a new therapeutic concept to increase the efficacy of curcumin in the treatment of cancer of the oral mucosa.

Composition and antimalarial activity of extracts of Curcuma longa L. obtained by a combination of extraction processes using supercritical CO2, ethanol and water as solvents

Rhizome of Curcuma longa L. is rich in curcumin which is also an important natural pigment and has important biological activity. In order to obtain curcumin concentrated extracts, one-step and two-step processes were employed. The one step process involves supercritical carbon dioxide (scCO2) at 60°C and 400bar, ethanol at 25°C and water at 60°C, both at atmospheric pressure. Ethanol and/or water were used as solvents. In the two-step process, sequential extraction, using scCO2, was performed followed by ethanol or water extraction. All the extracts obtained were analyzed and results were reported for global extraction yield, the total phenolic content, total flavonoids, curcumin, antimalarial activity and antioxidant activity. The two-step process showed the highest global yield (23.4%) when water is used as solvent in the second step. However, high concentrations of curcumin and high antioxidant activity were obtained when ethanol is used as solvent. The supercritical extract presents low concentration of curcumin and high antimalarial activity; which shows that extracts of different compositions and functionality can be obtained from a sequential extraction.

Curcumin and Extracellular Matrix Proteins Synergistically Act to Inhibit the Proliferation of Breast Cancer Cells

Aim: Natural substances have been gaining attention as they are accessible, cheap and associated with milder adverse effects as compared with conventional treatment. Curcumin is polyphenol derived from turmeric plant and is known to possess anti-inflammatory, antioxidant and antimetastatic effects. In the present work, the effect of curcumin individually and in combination with extracellular matrix proteins has been systematically studied on the breast cancer cell line, MCF-7. Materials & methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to screen the effect of various concentrations of curcumin on MCF-7 cells. Flow cytometry and caspase-3 assays were done to detect apoptosis. Nitric oxide and reactive oxygen species generation levels were also examined as both are known to play very important roles in cancer initiation and progression. Results: It was observed that at low concentrations curcumin exhibited significant antiproliferative activity which was supported with increased apoptosis and reduced levels of reactive oxygen species and nitric oxide. Moreover, the combined treatment of curcumin and proteins further boosted the antiproliferative effect of low concentrations of curcumin indicating that they act synergistically to inhibit the proliferation of breast cancer cells. Conclusion: This finding could be further investigated for development of novel anticancer therapies.

Abstract 5242: Differential, dose-dependent, effects of curcumin/analogs, on long (L) versus short (S) isoforms of a cancer stem cell marker, DCLK1, in colon and pancreatic cancer cells: biological impact

Abstract Curcumin, a dietary agent, has potent anti-inflammatory/anti-cancer activities, but is much less bioavailable, unlike some of its more potent synthetic analogs, such as EF24. In recent years, inhibitory effects of curcumin/analogs on DNMT1 have been described, resulting in de-methylation and re-expression of several genes, including tumor suppressor genes. Double-Cortin Like Kinase 1 (DCLK1) marks colon cancer stem cells, and is required for colon-carcinogenesis in mice. We recently reported a critical role of DCLK1 for maintaining tumorogenic/metastatic potential of human colon cancer (CRC) cells (Kantara et al, Can Res 2014). More recently we reported that the 5’α promoter of hDCLK1-gene is epigenetically silenced in CRCs due to hypermethylation, while a novel short (DCLK1-S) isoform is transcriptionally up-regulated in response to oncogenic pathways, including NFκB, from an alternate β promoter, located in intron V (O’Connell and Sarkar et al, Sci. Rep 2015). Since curcumin potently inhibits NFκB pathway, and can potentially de-methylate epigenetically silenced promoters, we examined possible re-expression/loss of expression of L/S isoforms, respectively, in colon/pancreatic cancer cells, in vitro and in vivo, in response to curcumin/EF24, using several molecular approaches and bioassays. Surprisingly, both agents had dose-dependent effects on demethylation. Low concentrations of curcumin (10μM) and EF24 (0.5μM) inhibited DNMT1, resulting in re-expression of DCLK1-L in both colon/pancreatic cancer cells in vitro. However, higher concentrations of curcumin (>20μM) and EF24 (>1.0μM) caused autophagic death of the cells, and re-expression of DCLK1-L was not measured. NFκB activation and DCLK1-S expression, on the other hand, were increasingly decreased in all cell lines in a dose-dependent manner, in response to curcumin/EF24. Low doses were equally effective against DNMT1/NFκB in vivo, resulting in re-expression of DCLK1-L and loss of DCLk1-S, in xenografts of colon/pancreatic cancer cells. However, the high doses used in this study continued to be effective against the two enzymes, suggesting that the high dose used was not enough for causing autophagic death in vivo, and may need to be increased to replicate cell-death effects observed in vitro. Even though DCLK1-L was re-expressed in the xenografts at both does, in vivo, the size and weight of the tumors was reduced in a dose-dependent manner, mimicking the loss of expression of DCLKL1-S. Our results thus show, for the first time, a dose-dependent epigenetic effect of curcumin/EF24 on cancer cells, which could significantly impact treatment decisions. Low to moderate doses of curcumin/EF24 may allow re-expression of normal/silenced genes, such as DCLK1-L, while reducing growth promoting pathways (such as NFκB/DCLK1-S). Citation Format: Shubhashish Sarkar, Malaney O. Connell, Pomila Singh. Differential, dose-dependent, effects of curcumin/analogs, on long (L) versus short (S) isoforms of a cancer stem cell marker, DCLK1, in colon and pancreatic cancer cells: biological impact. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5242.

Antibacterial Activity of Curcumin Against Periodontopathic Bacteria.

Curcumin is a polyphenol extracted from root of turmeric and known to possess multifunctional properties, including antibacterial activity. Although previous studies have investigated the effects of curcumin on microorganisms, available knowledge on the effects of curcumin on periodontopathic bacteria is still limited. In this study, the antibacterial effect of curcumin on periodontopathic bacteria is investigated, particularly Porphyromonas gingivalis. Representative periodontopathic bacteria were cultured in media with and without various curcumin concentrations, and the optical density at 600 nm was measured for 60 hours. The inhibitory effect of curcumin on P. gingivalis Arg- and Lys-specific proteinase (RGP and KGP, respectively) activities were assessed using spectrofluorophotometric assay. Analysis of biofilm formation by P. gingivalis with or without Streptococcus gordonii was conducted using confocal laser-scanning microscopy (CLSM). Curcumin inhibited the growth of P. gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Treponema denticola in a dose-dependent manner. Bacterial growth was suppressed almost completely at very low concentrations of curcumin. Conversely, 100 μg/mL curcumin did not suppress the growth of Aggregatibacter actinomycetemcomitans. It also demonstrated inhibitory effects against RGP and KGP activities in a dose-dependent manner. CLSM revealed that curcumin suppressed P. gingivalis homotypic and P. gingivalis-S. gordonii heterotypic biofilm formation in a dose-dependent manner. A concentration of 20 μg/mL curcumin inhibited these P. gingivalis biofilm formations by >80%. Curcumin possesses antibacterial activity against periodontopathic bacteria and may be a potent agent for preventing periodontal diseases.

Phytonutrients Differentially Stimulate NAD(P)H:Quinone Oxidoreductase, Inhibit Proliferation, and Trigger Mitotic Catastrophe in Hepa1c1c7 Cells.

quinone oxidoreductase (NQO1), a key enzyme in the hepatic neutralization of menadione, other biological oxidants, and some environmental carcinogens. Moreover, our findings demonstrate that relatively low concentrations of either sulforaphane or curcumin significantly (P < .05) increase NQO1 protein expression and activity without triggering G2/M cell cycle arrest or mitotic catastrophe. The minimal quercetin concentration inducing NQO1, however, was 100-fold higher than that which disrupted mitosis. Also, while resveratrol modestly stimulated NQO1, the minimally effective resveratrol concentration concomitantly induced evidence of cellular apoptosis. Taken together, these findings indicate that only particular phytonutrients are likely efficacious in upregulating NQO1 activity without also leading to hepatic cytotoxicity.

Red Light Combined with Blue Light Irradiation Regulates Proliferation and Apoptosis in Skin Keratinocytes in Combination with Low Concentrations of Curcumin.

Curcumin is a widely known natural phytochemical from plant Curcuma longa. In recent years, curcumin has received increasing attention because of its capability to induce apoptosis and inhibit cell proliferation as well as its anti-inflammatory properties in different cancer cells. However, the therapeutic benefits of curcumin are severely hampered due to its particularly low absorption via trans-dermal or oral bioavailability. Phototherapy with visible light is gaining more and more support in dermatological therapy. Red light is part of the visible light spectrum, which is able to deeply penetrate the skin to about 6 mm, and directly affect the fibroblast of the skin dermis. Blue light is UV-free irradiation which is fit for treating chronic inflammation diseases. In this study, we show that curcumin at low concentrations (1.25–3.12 μM) has a strong anti-proliferative effect on TNF-α-induced psoriasis-like inflammation when applied in combination with light-emitting-diode devices. The treatment was especially effective when LED blue light at 405 nm was combined with red light at 630 or 660 nm, which markedly amplified the anti-proliferative and apoptosis-inducing effects of curcumin. The experimental results demonstrated that this treatment reduced the viability of human skin keratinocytes, decreased cell proliferation, induced apoptosis, inhibited NF-κB activity and activated caspase-8 and caspase-9 while preserving the cell membrane integrity. Moreover, the combined treatment also down-regulated the phosphorylation level of Akt and ERK. Taken together, our results indicated that the combination of curcumin with LED blue light united red light irradiation can attain a higher efficiency of regulating proliferation and apoptosis in skin keratinocytes.

Can curcumin prevent the formation of Pseudomonas aeruginosa biofi lm on the surface of tympanostomy tubes?

Formation of bacterial biofilm on the surface of tympanostomy tubes are held responsible in the pathogenesis of post-tympanostomy tube otorrhea. To prevent the formation of biofilm, various methods were employed and varying degrees of success have been achieved. In some recent studies curcumin, which is the fenolic form of Curcuma longa (turmeric), has been pointed out to have inhibitory effects on virulence factors of Pseudomonas aeruginosa. The aim of this study was to investigate whether the administration of curcumin is able to prevent the formation of P.aeruginosa biofilm on the surface of silicone tympanostomy tubes in vitro conditions. For this purpose, qualitative and quantitative analysis of P.aeruginosa biofilm created on the surface of the tympanostomy tubes were performed following a period of 48 hours incubation in microplate wells that contained decreasing concentrations of curcumin. For qualitative analysis, specimens were evaluated with an environmental scanning electron microscope for the existence of biofilm. For the quantitative analysis, bacteria attached to the tube surface was detached using a combination of vortexing and sonication. Following serial dilutions, the obtained solution was then inoculated on the sheep blood agar plates using calibrated loop, incubated for 24 hours and the colony forming unit (CFU) per mL were recorded. Environmental scanning electron microscope analysis revealed that 100 µg/mL of curcumin could prevent formation of the biofilm. Lower concentrations of curcumin could not prevent the biofilm formation. Qualitative analysis also revealed that when the concentrations of curcumin in the wells were decreased, the number of CFU/mL was increased significantly. Mean number of CFU in 100 µg/mL and 12.5 µg/mL groups were 35±7.07 and 650±494, respectively. Curcumin could prevent formation of P.aeruginosa biofilm on the surface of tympanostomy tubes in vitro with concentrations lower than the MIC value. The results of the present study show that local administration of curcumin may prevent suppurative otitis media following tympanostomy tube insertion, keep the patency of the tube and decrease the rate of treatment failure. In vivo studies are needed to support the in vitro anti-biofilm action of curcumin on tympanostomy tubes.

Mechanism of Dose-Dependent Regulation of UBE1L by Polyphenols in Human Bronchial Epithelial Cells.

Ubiquitin activating enzyme E1-like (UBE1L) is the activating enzyme for ISG15ylation (ISG15, interferon stimulated gene 15). UBE1L is thought to be a candidate tumor suppressor gene and has positive activity against stress responses such as viral infections. Both type I interferon and retinoic acid are known to induce UBE1L expression. However, the molecular mechanism of UBE1L regulation is unclear. Here, the effect of several chemopreventive polyphenols on UBE1L expression in human bronchial epithelial cells (Beas-2B) was investigated. Lower concentrations of curcumin, (-)-epigallocatechin-3-gallate (EGCG) and resveratrol upregulated UBE1L, while high concentrations of curcumin, EGCG and resveratrol downregulated UBE1L levels. Interestingly, curcumin, EGCG and resveratrol diminished intracellular reactive oxygen species (ROS) at lower concentrations but generated ROS at higher concentrations. The antioxidant N-acetylcysteine (NAC) increased UBE1L protein levels, while pro-oxidants such as hydrogen peroxide and tert-butyl hydroperoxide (tBHP) decreased UBE1L protein levels, indicating that the intracellular redox status is associated with UBE1L expression. Kinase inhibitors were used to examine the contribution of mitogen-activated protein kinase (MAPK) activity to the polyphenol-regulated UBE1L. Only the inhibition of c-Jun N-terminal kinase (JNK) significantly reduced UBE1L expression. Knockdown of nuclear factor erythroid-2 related factor-2 (Nrf2) caused a concomitant decrease in UBE1L protein levels. It is concluded from the above mentioned results that JNK/Nrf2 signal pathway is involved in the regulation of UBE1L via intracellular ROS status when cells came in contact with polyphenols.

Curcumin-mediated decrease in the expression of nucleolar organizer regions in cervical cancer (HeLa) cells

Curcumin, the major yellow-orange pigment of turmeric derived from the rhizome of Curcuma longa, is a highly pleiotropic molecule with the potential to modulate inflammation, oxidative stress, cell survival, cell secretion, homeostasis and proliferation. Curcumin, at relatively high concentrations, was repeatedly reported to be a potent inducer of apoptosis in cancer cells and thus considered a promising anticancer agent. In the present paper, the effects of low concentrations of curcumin on human cervical cancer (HeLa) cells were studied. We found curcumin-mediated decrease in the cell number and viability, and increase in apoptotic events and superoxide level. In contrast to previously shown curcumin cytotoxicity toward different cervical cancer lines, we observed toxic effects when even as low as 1μM concentration of curcumin was used. Curcumin was not genotoxic to HeLa cells. Because argyrophilic nucleolar protein (AgNOR protein) expression is elevated in malignant cells compared to normal cells reflecting the rapidity of cancer cell proliferation, we evaluated curcumin-associated changes in size (area) and number of silver deposits. We showed curcumin-induced decrease in AgNOR protein pools, which may be mediated by global DNA hypermethylation observed after low concentration curcumin treatment. In summary, we have shown for the first time that curcumin at low micromolar range may be effective against HeLa cells, which may have implications for curcumin-based treatment of cervical cancer in humans.

Formulation and characterization of lyophilized curcumin solid dispersions for antimicrobial photodynamic therapy (aPDT): studies on curcumin and curcuminoids LII

Context: Bacterial resistance to antibiotics is increasing and alternative antibacterial treatments like antimicrobial photodynamic therapy (aPDT) are needed. Curcumin is under investigation as a potential photosensitizer in aPDT.Objective: The purpose of this study was to develop rapidly dissolving formulations of curcumin that could photoinactivate both Gram-positive and Gram-negative bacteria.Materials and methods: Curcumin solid dispersions with methyl-β-cyclodextrin and hyaluronic acid (HA), hydroxypropyl methylcellulose (HPMC) or both HA and HPMC were prepared through lyophilization. The lyophilizates were characterized by curcumin drug load [% (w/w)], differential scanning calorimetry, photostability, thermal stability, their ability to form supersaturated solutions and by in vitro photoinactivation of Enterococcus faecalis and Escherichia coli.Results and discussion: The lyophilizates were amorphous solid dispersions with a curcumin drug load in the range of 1.4–5.5% (w/w) depending on the included polymer and the ratio between curcumin and the cyclodextrin. The lyophilizates were photolabile, but thermally stable and dissolved rapidly in contact with water to form supersaturated solutions. Selected lyophilizates demonstrated >log 6 reduction of colony forming units/ml of both E. faecalis and E. coli after exposure to low curcumin concentrations (0.5–10 µM) and blue light dose (11–16 J/cm2). The high drug load of the lyophilizates, rapid dissolution, ability to form relatively stable supersaturated solutions and the very high phototoxicity towards both E. faecalis and E. coli make these lyophilizates suitable for in vivo aPDT.Conclusions: This treatment with optimized curcumin formulations should be explored as an alternative to topical antibiotics in the treatment of wound infections.

Curcumin influences semen quality parameters and reverses the di(2-ethylhexyl)phthalate (DEHP)-induced testicular damage in mice

BackgroundCurcumin is a phytochemical derived from rhizome of turmeric Curcuma longa, present in the curry spice. Recently, it has attracted the attention of researchers and clinicians as an anti-inflammatory and anti-oxidant agent with a potential use in therapy of many diseases with an inflammatory component. Interestingly, curcumin despite its very low bioavailability showed protective activity against many organ lesions. MethodsIn the present study we investigated the effects of curcumin treatment on mice semen quality parameters in vitro and on semen and testicular damage induced by di(2-ethylhexyl)phthalate in vivo. ResultsThe study demonstrated protective effects of low concentrations (1–50μM) of curcumin on mouse sperm motility in vitro and on DEHP-induced damage of seminiferous tubules in testes and its ability to diminish the decrease in sperm motility in vivo. In contrast, curcumin used in high concentration (100μM) decreased sperm motility and viability in vitro. ConclusionThe effects of curcumin were dependent on its concentration. In male germ cells in vivo the protective effect was seen despite the low bioavailability of curcumin. In contrast, high, unattainable in the organism, concentration of curcumin had a cytotoxic effect on male reproductive cells in vitro. Curcumin also had a protective effect against the harmful impact of DEHP on the male reproductive system.

Streptococcus MutansPhotoinactivation by Combination of Short Exposure of a Broad-Spectrum Visible Light and Low Concentrations of Photosensitizers

Investigate the photodynamic antimicrobial effect by the combination of a novel noncoherent broad spectrum visible light and low concentrations of curcumin and toluidine blue over suspensions of Streptococcus mutans. Long illumination times to activate photosensitizers (PS) and the use of high concentrations of these drugs in photodynamic antimicrobial chemotherapy (PACT) are limitations of its application as an antimicrobial technology in dental practice. Planktonic suspensions of S. mutans were standardized and submitted to PACT treatment at low concentrations of curcumin (C) (0.075; 0.75 and 7.5 μM) and toluidine blue (T) (0.25; 2.5 and 25 μM) exposed to 42 J/cm2 (12.2 sec; set power: 3.930 mW) of a white light (WL) (output wavelength range: 400-700 nm; beam diameter: 12 mm) (C+WL+ and T+WL+, PACT groups; incubation time, C: 60 sec; T: 5 min); isolated effect of both C (C+WL-) and T concentrations (T+WL-); effect of light source (C-WL+ and T-WL+) and suspensions neither submitted to PS nor to light-emitting diode (LED) illumination (control groups, C-WL- and T-WL-). Aliquots of each group were diluted and cultured on blood agar plates and the number of colony-forming units (CFU)/mL was recorded, transformed into log10 and analyzed by ANOVA and Tukey's test at a cutoff value at 0.05. The groups submitted to PACT presented a bacterial reduction value of>5-log10 to both tested PS in comparison with control groups (p<0.05). PS or light source used alone demonstrated no antimicrobial effect on the number of viable bacterial counts. The combination of a novel noncoherent light at short illumination exposure time with low concentrations of studied PS achieved a lethal photoinactivation of S. mutans, and can be considered an effective antimicrobial in vitro approach for reducing the number of micro-organisms involved with the dental caries process.

Effect of curcumin on radiosensitization of CNE-2 cells and its mechanism

To investigate the effect of curcumin (Cur) on radiosensitivity of nasopharyngeal carcinoma cell CNE-2 and its mechanism. The effect of curcumin on radiosensitivity was determined by the clone formation assay. The cell survival curve was fitted by Graph prism 6. 0. The changes in cell cycle were analyzed by flow cytometry (FCM). The differential expression of long non-coding RNA was detected by gene chip technology. Part of differentially expressed genes was verified by Real-time PCR. After 10 micro mol L-1 Cur had worked for 24 h, its sensitization enhancement ratio was 1. 03, indicating that low concentration of curcumin could increase the radiosensitivity of nasopharyngeal carcinoma cells; FCM displayed a significant increase of G2 phase cells and significant decrease of S phase cells in the Cur combined radiation group. In the Cur group, the GUCY2GP, H2BFXP, LINC00623 IncRNA were significantly up-regulated and ZRANB2-AS2 LOC100506835, FLJ36000 IncRNA were significantly down-regulated. Cur has radiosensitizing effect on human nasopharyngeal carcinoma CNE-2 cells. Its mechanism may be related to the changes in the cell cycle distribution and the expression of long non-coding IncRNA.

A simple reversed phase high-performance liquid chromatography (RP-HPLC) method for determination of curcumin in aqueous humor of rabbit.

This article describes a simple and rapid method for determination of curcumin (diferuloylmethane) in aqueous humor of rabbit using high-performance liquid chromatography (HPLC). Analysis was performed using a C-18 column (250 × 4.6 mm, 5 μ luna) by isocratic elution with a mobile phase containing 25 mM potassium dihydrogen orthophosphate (pH 3.5): Acetonitrile (40:60) and detection at 424 nm using a photodiode array (PDA) detector for curcumin. The regression data for curcumin showed a good linear relationship with r2> 0.998 over the concentration range of 0.1-10 μg ml−1. Relative standard deviations (RSD) for the intraday and interday coefficient of variations for the assay were less than 5.0 and 8.5, respectively. The recovery of the method was between 79.8-83.6%. The quantification limit of the method for curcumin was 0.01 μg ml−1. This method has good accuracy, precision, and quantitation limit. It is also concluded that the method is useful for measuring very low curcumin concentrations in aqueous humor.

Comparative antiulcer effect of curcumin and tetrahydrocurcumin in a gastric ulcer model system

It has been reported that curcumin, a yellow pigment found mainly in rhizomes of Curcuma longa, accelerates ulcer healing in a chronic gastric ulcer model in rats by a main mechanism involving its anti-inflammatory activity against iNOS and TNF-a production. The suppression of iNOS production in activated macrophages and endothelium, decrease the leukocyte infiltration, a COX-2 dependent production of inflammatory PGs, and a formation of cytotoxic oxidants. Despite the promising pharmacological effects of curcumin, its poor oral systemic bioavailability limits its clinical use. The absorbed curcumin is rapidly biotransformed to its major active metabolite: tetrahydrocurcumin (THC) which is reported to be an active principle of curcumin for its antioxidant effect. In contrast, THC showed less inhibitory effects than curcumin on the induction of iNOS and COX-2 in activated RAW 264.7 cells. However, the potential gastric ulcer healing activity of THC has not been systematically examined. To investigate the possibility that the antiulcer activity of curcumin may be mediated, in part, by its active metabolites, curcumin and THC were compared in terms of their ability to accelerate the ulcer healing and to inhibit iNOS and COX-2 mRNA expression in ulcerated gastric mucosa induced by acetic acid in rats. The obtained result indicated that curcumin itself directly inhibited the production of these pro-inflammatory cytokines in the ulcerated area. In contrast, its major metabolite (THC) had less ulcer healing capacity and had no significant inhibitory effect on the activity and expression level of iNOS and COX-2. Therefore, curcumin directly exerted its gastric ulcer healing capacity and a low blood concentration of curcumin is needed to obtain an in vivo antiulcer effect.

COMPARISON OF GENOTOXICITY PRODUCED BY HYDRO ALCOHOLIC EXTRACT OF CURCUMA AROMATICA SALISB, CURCUMA ZEDOARIA WITH CURCUMIN BY AMES TEST, COMET ASSAY AND MICRONUCLEUS TEST

This paper deals with the comparison of genotoxicity produced by the hydro alcoholic extract of Curcuma aromatica salisb and Curcuma zedoaria (christm) rosecoe with curcumin by Ames test, comet assay and Micronuc leus test. Curcuma aromatica and Curcuma Zedoaria belon gs to the family Zingiberaceae. In the presence of metabolic activation factor (S9), the revertant colonies were found to be more in the case of TA98 and TA 100 strains. When compared to positive control the numbers of revertant colonies were found to be m ore or less equivalent to negative control which confirmed the absence of genotoxic effect of test compounds. In the comet assay, a mong the three tested compounds, curcumin was found to be more genotoxic in nature when compared by Curcuma aromatica , Curcum a zedoaria . The damage of the cells was found to be more in the presence of metabolic activation factor than the absence of metabolic activation factor. This confirmed that the phytoconstituents are not genotoxic in nature but their metabolites that are f ormed in the presence o f metabolic activation factor is mainly responsible for their genotoxic effect. In the Micronucleus test, when compared to the positive control (Methyl metha ne sulfonate at the concentration of 50 µg/ml), all the test compounds such as hydro alcoholic extract of Curcuma aromatica , Curcuma zedoaria , and Curcumin at the concentration of 50μg/ml showed less toxicity to HEp - 2 cells. These results might either due to the presence of low concentration of curcumin in the extracts or due to the presence of other phytoconsituents that are present in the e xtract.

Curcumin Triggers p16-Dependent Senescence in Active Breast Cancer-Associated Fibroblasts and Suppresses Their Paracrine Procarcinogenic Effects

Activated cancer-associated fibroblasts (CAFs) or myofibroblasts not only facilitate tumor growth and spread but also affect tumor response to therapeutic agents. Therefore, it became clear that efficient therapeutic regimens should also take into account the presence of these supportive cells and inhibit their paracrine effects. To this end, we tested the effect of low concentrations of curcumin, a pharmacologically safe natural product, on patient-derived primary breast CAF cells. We have shown that curcumin treatment upregulates p16INK4A and other tumor suppressor proteins while inactivates the JAK2/STAT3 pathway. This reduced the level of alpha-smooth muscle actin (α-SMA) and the migration/invasion abilities of these cells. Furthermore, curcumin suppressed the expression/secretion of stromal cell-derived factor-1 (SDF-1), interleukin-6 (IL-6), matrix metalloproteinase-2 (MMP-2), MMP-9, and transforming growth factor-β, which impeded their paracrine procarcinogenic potential. Intriguingly, these effects were sustained even after curcumin withdrawal and cell splitting. Therefore, using different markers of senescence [senescence-associated β-galactosidase (SA-β-gal) activity, Ki-67 and Lamin B1 levels, and bromodeoxyuridine incorporation], we have shown that curcumin markedly suppresses Lamin B1 and triggers DNA damage-independent senescence in proliferating but not quiescent breast stromal fibroblasts. Importantly, this curcumin-related senescence was p16INK4A-dependent and occurred with no associated inflammatory secretory phenotype. These results indicate the possible inactivation of cancer-associated myofibroblasts and present the first indication that curcumin can trigger DNA damage-independent and safe senescence in stromal fibroblasts.