Curcumin at Low Doses Potentiates and at High Doses Inhibits ABT-737-Induced Platelet Apoptosis

Curcumin is a natural bioactive component derived from the turmeric plant Curcuma longa, which exhibits a range of beneficial activities on human cells. Previously, an inhibitory effect of curcumin on platelets was demonstrated. However, it is unknown whether this inhibitory effect is due to platelet apoptosis or procoagulant platelet formation. In this study, curcumin did not activate caspase 3-dependent apoptosis of human platelets, but rather induced the formation of procoagulant platelets. Interestingly, curcumin at low concentration (5 µM) potentiated, and at high concentration (50 µM) inhibited ABT-737-induced platelet apoptosis, which was accompanied by inhibition of ABT-737-mediated thrombin generation. Platelet viability was not affected by curcumin at low concentration and was reduced by 17% at high concentration. Furthermore, curcumin-induced autophagy in human platelets via increased translocation of LC3I to LC3II, which was associated with activation of adenosine monophosphate (AMP) kinase and inhibition of protein kinase B activity. Because curcumin inhibits P-glycoprotein (P-gp) in cancer cells and contributes to overcoming multidrug resistance, we showed that curcumin similarly inhibited platelet P-gp activity. Our results revealed that the platelet inhibitory effect of curcumin is mediated by complex processes, including procoagulant platelet formation. Thus, curcumin may protect against or enhance caspase-dependent apoptosis in platelets under certain conditions.     

Curcumin Suppresses TGF-β1-Induced Myofibroblast Differentiation and Attenuates Angiogenic Activity of Orbital Fibroblasts

Orbital fibrosis, a hallmark of tissue remodeling in Graves’ ophthalmopathy (GO), is a chronic, progressive orbitopathy with few effective treatments. Orbital fibroblasts are effector cells, and transforming growth factor β1 (TGF-β1) acts as a critical inducer to promote myofibroblast differentiation and subsequent tissue fibrosis. Curcumin is a natural compound with anti-fibrotic activity. This study aims to investigate the effects of curcumin on TGF-β1-induced myofibroblast differentiation and on the pro-angiogenic activities of orbital fibroblasts. Orbital fibroblasts from one healthy donor and three patients with GO were collected for primary cell culture and subjected to myofibroblast differentiation under the administration of 1 or 5 ng/mL TGF-β1 for 24 h. The effects of curcumin on TGF-β1-induced orbital fibroblasts were assessed by measuring the cellular viability and detecting the expression of myofibroblast differentiation markers, including connective tissue growth factor (CTGF) and α-smooth muscle actin (α-SMA). The pro-angiogenic potential of curcumin-treated orbital fibroblasts was evaluated by examining the transwell migration and tube-forming capacities of fibroblast-conditioned EA.hy926 and HMEC-1 endothelial cells. Treatment of orbital fibroblasts with curcumin inhibited the TGF-β1 signaling pathway and attenuated the expression of CTGF and α-SMA induced by TGF-β1. Curcumin, at the concentration of 5 μg/mL, suppressed 5 ng/mL TGF-β1-induced pro-angiogenic activities of orbital fibroblast-conditioned EA hy926 and HMEC-1 endothelial cells. Our findings suggest that curcumin reduces the TGF-β1-induced myofibroblast differentiation and pro-angiogenic activity in orbital fibroblasts. The results support the potential application of curcumin for the treatment of GO.     

姜黄素对转化生长因子-β1诱导的乳腺癌MDA-MB-231细胞基质金属蛋白酶-9表达及其侵袭能力的影响

目的研究姜黄素对转化生长因子-β1(Transforming growth factor-beta 1,TGF-β1)诱导的人乳腺癌MDA-MB-231细胞基质金属蛋白酶-9(Matrix metallopeptidase-9,MMP-9)表达及其侵袭能力的影响,探讨姜黄素在防治TGF-β1诱导的乳腺癌侵袭转移中可能的作用机制。方法采用CCK-8法检测姜黄素对MDA-MB-231细胞的细胞毒性作用。将MDA-MB-231细胞分为阴性对照组(无血清RPMI1640培养基/DMSO)、TGF-β1处理组(无血清RPMI1640培养基/DMSO+10 ng/ml TGF-β1),姜黄素+TGF-β1处理组(无血清RPMI1640培养基+5、7.5、10μmol/L姜黄素+10 ng/ml TGF-β1)。处理24 h后,采用侵袭小室试验观察细胞的侵袭能力;处理不同时间后,采用Western blot法检测细胞MMP-9、p-Smad2、p-ERK1/2以及p-p38的表达,明胶酶谱法检测各组细胞上清液中MMP-9的活性变化;以ERK特异性抑制剂PD98059、p38特异性抑制剂SB202580、姜黄素和/或TGF-β1处理细胞48 h,采用Western blot和明胶酶谱法检测MMP-9的表达。结果低浓度姜黄素(≤10μmol/L)对MDA-MB-231细胞无明显的细胞毒性作用;姜黄素呈剂量依赖性明显减少了TGF-β1诱导的细胞穿膜数量(P<0.001);姜黄素可显著抑制TGF-β1诱导的MDA-MB-231细胞MMP-9、p-Smad2、p-ERK1/2及p-p38蛋白的表达,且呈浓度、时间依赖性(P<0.05);姜黄素随浓度的增加,对TGF-β1诱导的MDA-MB-231细胞MMP-9活性的抑制作用明显增强(P<0.05);PD98059抑制MMP-9蛋白表达及活性的作用与姜黄素相似,而SB202580对MMP-9无明显影响。结论姜黄素可能通过TGF-β/Smad、TGF-β/ERK信号通路下调TGF-β1诱导的MMP-9的表达及其活性,从而抑制肿瘤的侵袭能力。     

姜黄素对HeLa细胞增殖和凋亡的影响

目的探讨姜黄素对HeLa细胞增殖和凋亡的影响及其机制。方法分别用10、20、40μmol/L姜黄素处理HeLa细胞24h后,MTT法检测细胞的增殖,光镜观察细胞形态,TUNEL技术检测细胞的凋亡,免疫细胞化学法检测Cytochrome C和Caspase-9蛋白的表达,Western blot法检测XIAP蛋白的表达。结果姜黄素对HeLa细胞的增殖有抑制作用,并呈剂量依赖性;部分细胞呈现典型的凋亡形态学改变;姜黄素作用后,Cytochrome C和Caspase-9蛋白的表达显著增强,XIAP蛋白的表达显著下降,且均呈剂量依赖性。结论姜黄素能抑制HeLa细胞增殖并诱导其凋亡,Cytochrome C和Caspase-9的表达上调及XIAP的表达下调可能参与凋亡过程。     

姜黄素对人喉癌Hep-2细胞的生长抑制及诱导凋亡作用

目的探讨姜黄素(Curcumin)对人喉癌Hep-2细胞的生长抑制及诱导凋亡作用。方法将Hep-2细胞用含不同浓度姜黄素(3、6、12.5、25μmol/L)的培养基分别培养24和48h,采用MTT法检测其对细胞增殖的影响;台盼蓝染色法检测其对细胞活力的影响;流式细胞术检测其对细胞周期分布及细胞凋亡的影响;DNA琼脂糖凝胶电泳检测其对细胞DNA的影响。结果姜黄素可明显抑制Hep-2细胞增殖,且呈时间-剂量依赖性;可明显降低细胞活力,且呈剂量依赖性;可使细胞阻滞在G2/M期,并诱导细胞出现典型的凋亡峰,凋亡率呈时间-剂量依赖性;能使细胞DNA形成典型的DNA-Ladder。结论姜黄素对人喉癌Hep-2细胞增殖及细胞活力具有显著的抑制作用,并能诱导Hep-2细胞发生凋亡。     

Growth,Proliferation and Metastasis of Prostate Cancer Cells Is Blocked by Low-Dose Curcumin in Combination with Light Irradiation

Although anti-cancer properties of the natural compound curcumin have been reported, low absorption and rapid metabolisation limit clinical use. The present study investigated whether irradiation with visible light may enhance the inhibitory effects of low-dosed curcumin on prostate cancer cell growth, proliferation, and metastasis in vitro. DU145 and PC3 cells were incubated with low-dosed curcumin (0.1–0.4 µg/mL) and subsequently irradiated with 1.65 J/cm² visible light for 5 min. Controls remained untreated and/or non-irradiated. Cell growth, proliferation, apoptosis, adhesion, and chemotaxis were evaluated, as was cell cycle regulating protein expression (CDK, Cyclins), and integrins of the α- and β-family. Curcumin or light alone did not cause any significant effects on tumor growth, proliferation, or metastasis. However, curcumin combined with light irradiation significantly suppressed tumor growth, adhesion, and migration. Phosphorylation of CDK1 decreased and expression of the counter-receptors cyclin A and B was diminished. Integrin α and β subtypes were also reduced, compared to controls. Irradiation distinctly enhances the anti-tumor potential of curcumin in vitro and may hold promise in treating prostate cancer.     

Curcumin‐Derived Pyrazoles and Isoxazoles: Swiss Army Knives or Blunt Tools for Alzheimer's Disease?

Curcumin binds to the amyloid beta peptide (Abeta) and inhibits or modulates amyloid precursor protein (APP) metabolism. Therefore, curcumin-derived isoxazoles and pyrazoles were synthesized to minimize the metal chelation properties of curcumin. The decreased rotational freedom and absence of stereoisomers was predicted to enhance affinity toward Abeta(42) aggregates. Accordingly, replacement of the 1,3-dicarbonyl moiety with isosteric heterocycles turned curcumin analogue isoxazoles and pyrazoles into potent ligands of fibrillar Abeta(42) aggregates. Additionally, several compounds are potent inhibitors of tau protein aggregation and depolymerized tau protein aggregates at low micromolar concentrations.     

Curcumin inhibits glutamate release from rat prefrontal nerve endings by affecting vesicle mobilization

Curcumin, one of the major constituents of Curcuma longa, has been shown to inhibit depolarization-evoked glutamate release from rat prefrontocortical nerve terminals by reducing voltage-dependent Ca(2+) entry. This study showed that curcumin inhibited ionomycin-induced glutamate release and KCl-evoked FM1-43 release, suggesting that some steps after Ca(2+) entry are regulated by curcumin. Furthermore, disrupting the cytoskeleton organization using cytochalasin D abolished the inhibitory action of curcumin on ionomycin-induced glutamate release. Mitogen-activated protein kinase kinase (MEK) inhibition also prevented the inhibitory effect of curcumin on ionomycin-induced glutamate release. Western blot analyses showed that curcumin decreased the ionomycin-induced phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and synaptic vesicle-associated protein synapsin I, the main presynaptic target of ERK. These results show that curcumin-mediated inhibition of glutamate release involves modulating downstream events by controlling synaptic vesicle recruitment and exocytosis, possibly through a decrease of MAPK/ERK activation and synapsin I phosphorylation, thereby decreasing synaptic vesicle availability for exocytosis.     

Enhanced Antimicrobial Activity of Biocompatible Bacterial Cellulose Films via Dual Synergistic Action of Curcumin and Triangular Silver Nanoplates

Curcumin and triangular silver nanoplates (TSNP)-incorporated bacterial cellulose (BC) films present an ideal antimicrobial material for biomedical applications as they afford a complete set of requirements, including a broad range of long-lasting potency and superior efficacy antimicrobial activity, combined with low toxicity. Here, BC was produced by Komagataeibacter medellinensis ID13488 strain in the presence of curcumin in the production medium (2 and 10%). TSNP were incorporated in the produced BC/curcumin films using ex situ method (21.34 ppm) and the antimicrobial activity was evaluated against Escherichia coli ATCC95922 and Staphylococcus aureus ATCC25923 bacterial strains. Biological activity of these natural products was assessed in cytotoxicity assay against lung fibroblasts and in vivo using Caenorhabditis elegans and Danio rerio as model organisms. Derived films have shown excellent antimicrobial performance with growth inhibition up to 67% for E. coli and 95% for S. aureus. In a highly positive synergistic interaction, BC films with 10% curcumin and incorporated TSNP have shown reduced toxicity with 80% MRC5 cells survival rate. It was shown that only 100% concentrations of film extracts induce low toxicity effect on model organisms’ development. The combined and synergistic advanced anti-infective functionalities of the curcumin and TSNP incorporated in BC have a high potential for development for application within the clinical setting.     

Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo

Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 ± 0.011) with a mean particle size of 27.3 ± 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 ± 1.02%, and drug loading of 12.95 ± 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t(1/2) and AUC of curcumin in vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesis in vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cells in vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg(-1) curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p < 0.01), and induced a stronger anticancer effect than that of free curcumin (p < 0.05). In conclusion, Cur/MPEG-PCL micelles are an excellent intravenously injectable aqueous formulation of curcumin; this formulation can inhibit the growth of colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.     

Antimicrobial activity of cotton fabrics treated with curcumin

Curcumin, a yellow pigment known to have various biological activities, was applied onto cotton as an antimicrobial agent. Curcumin could provide both color and antimicrobial activity to cotton and can be dyed using a batch or continuous process. However, curcumin and cotton have low affinity and therefore the ability of curcumin to impart durable antimicrobial activity on cotton needs to be studied. In this research, the ability of curcumin dyed onto cotton fabrics to inhibit the growth of Escherichia coli and Staphylococcus aureus was studied. Relationships that can predict the rate of inhibition based on the curcumin concentration or shade depth (K/S values) were developed without the need for an antimicrobial test. Durability of antimicrobial activity to laundering and to light was also studied. Curcumin was more effective in inhibiting S. aureus than E. coli. The reduction of bacteria and durability of antimicrobial activity of curcumin to laundering was inferior on cotton fabrics compared with wool. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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.     

姜黄素的生物学活性研究进展

姜黄素是一种从姜科植物姜黄等的根茎中提取得到的黄色色素,具有广泛的生物学活性。本文对姜黄素生物学活性等方面的研究进展做一综述,为姜黄素的进一步深入研究和开发利用提供参考。     

Inhibition of lipoxygenase 1 by phosphatidylcholine micelles-bound curcumin

Curcumin (diferuloyl methane) from rhizomes of Curcuma longa L. binds to phosphatidylcholine (PC) micelles. The binding of curcumin with PC micelles was followed by fluorescence measurements. Curcumin emits at 490 nm with an excitation wavelength of 451 nm after binding to PC-mixed micelles stabilized with deoxycholate. Curcumin in aqueous solution does not inhibit dioxygenation of fatty acids by Lipoxygenase 1 (LOX1). But, when bound to PC micelles, it inhibits the oxidation of fatty acids. The present study has shown that 8.6 μM of curcumin bound to the PC micelles is required for 50% inhibition of linoleic acid peroxidation. Lineweaver-Burk plot analysis has indicated that curcumin is a competitive inhibitor of LOX1 with K _l of 1.7 μM for linoleic and 4.3 μM for arachidonic acids, respectively. Based on spectroscopic measurements, we conclude that the inhibition of LOX1 activity by curcumin can be due to binding to active center iron and curcumin after binding to the PC micelles acts as an inhibitor of LOX1.     

Antitumor Activity of Curcumin in Glioblastoma

Current standard-of-care treatment for glioblastoma, the most common malignant primary central nervous system (CNS) tumor, consists of surgical resection followed by adjuvant chemotherapy and radiation (Stupp protocol), providing an overall median survival of 15 months. With additional treatment using tumor-treating fields (Optune^® therapy, Novocure Ltd., Haifa, Israel), survival can be extended up to 20 months. In spite of significant progress in our understanding of the molecular pathogenesis, the prognosis for patients with malignant gliomas remains poor and additional treatment modalities are critically needed. Curcumin is a bright yellow pigment found in the rhizome of the widely utilized spice, turmeric (Curcuma longa). It has long been used in South Asian traditional medicines and has been demonstrated to have in vitro antioxidant, anti-inflammatory, and antiproliferative effects. Curcumin has been demonstrated to induce multiple cytotoxic effects in tumor cells including cell cycle arrest, apoptosis, autophagy, changes in gene expression, and disruption of molecular signaling. Additionally, curcumin has been shown to potentiate the effect of radiation on cancer cells, while exhibiting a protective effect on normal tissue. Curcumin’s positive safety profile and widespread availability make it a promising compound for future clinical trials for high-grade gliomas.     

“Squalenoylcurcumin” Nanoassemblies as Water‐Dispersible Drug Candidates with Antileishmanial Activity

Curcumin, a natural polyphenolic compound, showed antiparasitic potential, including trypanocidal and leishmanicidal activity, in several in vitro and in vivo models. The molecule is well tolerated in humans. However, it is insoluble in water and displays poor oral bioavailability as a result of low absorption. New derivatives of curcumin were prepared by esterification of one or two of its phenolic groups with 1,1′,2‐tris‐norsqualenic acid. These “squalenoylcurcumins” were formulated as water‐dispersible nanoassemblies of homogeneous size, and they proved to be stable. Squalenoylcurcumins were inactive against Trypanosoma brucei brucei trypomastigotes, even as nanoassemblies, in contrast with curcumin. However, against Leishmania donovani promastigotes, the activities of the squalenoylcurcumins and their nanoassemblies were enhanced relative to that of curcumin. In L. donovani axenic and intramacrophagic amastigotes, they showed activity in the range of miltefosine, with good selectivity indexes. In regard to their dispersibility in water and to the safety of curcumin, these nanoassemblies are promising candidates for preclinical study toward the treatment of visceral leishmaniasis.     

Novel Chemically Modified Curcumin (CMC) Analogs Exhibit Anti-Melanogenic Activity in Primary Human Melanocytes

Hyperpigmentation is a dermatological condition characterized by the overaccumulation and/or oversecretion of melanin pigment. The efficacy of curcumin as an anti-melanogenic therapeutic has been recognized, but the poor stability and solubility that have limited its use have inspired the synthesis of novel curcumin analogs. We have previously reported on comparisons of the anti-melanogenic activity of four novel chemically modified curcumin (CMC) analogs, CMC2.14, CMC2.5, CMC2.23 and CMC2.24, with that of parent curcumin (PC), using a B16F10 mouse melanoma cell model, and we have investigated mechanisms of inhibition. In the current study, we have extended our findings using normal human melanocytes from a darkly pigmented donor (HEMn-DP) and we have begun to study aspects of melanosome export to human keratinocytes. Our results showed that all the CMCs downregulated the protein levels of melanogenic paracrine mediators, endothelin-1 (ET-1) and adrenomedullin (ADM) in HaCaT cells and suppressed the phagocytosis of FluoSphere beads that are considered to be melanosome mimics. All the three CMCs were similarly potent (except CMC2.14, which was highly cytotoxic) in inhibiting melanin production; furthermore, they suppressed dendricity in HEMn-DP cells. CMC2.24 and CMC2.23 robustly suppressed cellular tyrosinase activity but did not alter tyrosinase protein levels, while CMC2.5 did not suppress tyrosinase activity but significantly downregulated tyrosinase protein levels, indicative of a distinctive mode of action for the two structurally related CMCs. Moreover, HEMn-DP cells treated with CMC2.24 or CMC2.23 partially recovered their suppressed tyrosinase activity after cessation of the treatment. All the three CMCs were nontoxic to human dermal fibroblasts while PC was highly cytotoxic. Our results provide a proof-of-principle for the novel use of the CMCs for skin depigmentation, since at low concentrations, ranging from 5 to 25 µM, the CMCs (CMC2.24, CMC2.23 and CMC2.5) were more potent anti-melanogenic agents than PC and tetrahydrocurcumin (THC), both of which were ineffective at melanogenesis at similar doses, as tested in HEMn-DP cells (with PC being highly toxic in dermal fibroblasts and keratinocytes). Further studies to evaluate the efficacy of CMCs in human skin tissue and in vivo studies are warranted.