Curcumin induces caspase-3-dependent apoptotic pathway but inhibits DNA fragmentation factor 40/caspase-activated DNase endonuclease in human Jurkat cells

The Bright Side of Curcumin: A Narrative Review of Its Therapeutic Potential in Cancer Management

Curcumin, a polyphenolic compound derived from Curcuma longa, exhibits significant therapeutic potential in cancer management. This review explores curcumin's mechanisms of action, the challenges related to its bioavailability, and its enhancement through modern technology and approaches. Curcumin demonstrates strong antioxidant and anti-inflammatory properties, contributing to its ability to neutralize free radicals and inhibit inflammatory mediators. Its anticancer effects are mediated by inducing apoptosis, inhibiting cell proliferation, and interfering with tumor growth pathways in various colon, pancreatic, and breast cancers. However, its clinical application is limited by its poor bioavailability due to its rapid metabolism and low absorption. Novel delivery systems, such as curcumin-loaded hydrogels and nanoparticles, have shown promise in improving curcumin bioavailability and therapeutic efficacy. Additionally, photodynamic therapy has emerged as a complementary approach, where light exposure enhances curcumin's anticancer effects by modulating molecular pathways crucial for tumor cell growth and survival. Studies highlight that combining low concentrations of curcumin with visible light irradiation significantly boosts its antitumor efficacy compared to curcumin alone. The interaction of curcumin with cytochromes or drug transporters may play a crucial role in altering the pharmacokinetics of conventional medications, which necessitates careful consideration in clinical settings. Future research should focus on optimizing delivery mechanisms and understanding curcumin's pharmacokinetics to fully harness its therapeutic potential in cancer treatment.

Intracellular Pathways and Mechanisms of Colored Secondary Metabolites in Cancer Therapy

Despite the great advancements made in cancer treatment, there are still many unsatisfied aspects, such as the wide palette of side effects and the drug resistance. There is an obvious increasing scientific attention towards nature and what it can offer the human race. Natural products can be used to treat many diseases, of which some plant products are currently used to treat cancer. Plants produce secondary metabolites for their signaling mechanisms and natural defense. A variety of plant-derived products have shown promising anticancer properties in vitro and in vivo. Rather than recreating the natural production environment, ongoing studies are currently setting various strategies to significantly manipulate the quantity of anticancer molecules in plants. This review focuses on the recently studied secondary metabolite agents that have shown promising anticancer activity, outlining their potential mechanisms of action and pathways.

Evaluation of Antileukemic and Antimalarial Potential of Zanthoxylum rhetsa DC (Rutaceae): A Well-Known Spice

Introduction:

Zanthoxylum rhetsa fruits, a common spice in many cuisines, have proven to have a good therapeutic potential and are routinely used in food, medicine, and commerce. The present study was conducted to screen the in vitro antileukemic and antimalarial activities of the methanolic extract of Z. rhetsa fruits and conduct mechanistic studies for antileukemic activity.

Methods:

Methanol extract was prepared by maceration process and standardised with lupeol as a marker using HPLC. MTT and SRB assays were used to establish the cytotoxicity of the extract against L929 and leukemic cell lines (Jurkat, K562, and HL-60). Amount of ROS in cell lines was detected by flow cytometry using 2',7'-dichlorodihydrofluorescin diacetate. Apoptosis on HL-60 was detected by Annexin-V/PI dual staining assay through cell cycle analysis and gel electrophoresis. In vitro antimalarial activity was conducted on Plasmodium falciparum CQ sensitive 3D7 strains according to the WHO 2001 guidelines.

Results:

The methanol extract contained 1.03% of lupeol. Potent antileukemic activity (IC50 <10 μg/mL) was observed against HL-60 in comparison to K562 and Jurkat cell lines. The extract induced apoptosis in cancer cells in the proliferative and mitotic phase without DNA fragmentation. Therefore, the antileukemic activity exhibited by the extract could be attributed to the increased oxidative stress generated in cancer cells. Fruits also exhibited good antioxidant activity against normal cells, thus proving beneficial as a cytoprotective agents. Promising antimalarial activity (IC50 = 16.21 μg/mL) with high selectivity against malarial parasites was exhibited by the fruits.

Conclusion:

Thus, the fruits of Z.rhetsa can be used as an adjuvant therapy to reduce the side effects and resistance associated with chemotherapy and can be a potential candidate for drug discovery research in the areas of cancer and parasitic infection.

Mechanism of enhancing the water-solubility and stability of curcumin by using self-assembled cod protein nanoparticles at an alkaline pH

Curcumin (Cur) is a bioactive phytochemical which is claimed to have several health-promoting benefits, whose applications are challenging due to its poor water-solubility, chemical instability, and low bioavailability. In this research, Cur was encapsulated in the cod protein (CP) using a pH-driven method to enhance its solubility and stability. The physicochemical and structural properties of cod protein-curcumin nanoparticles (CP-Cur) formed were characterized. Fluorescence spectroscopy (FL), ultraviolet spectroscopy (UV), circular dichroism (CD), and dynamic light scattering (DLS) results collectively suggest that the protein originally with a molten-globule state refolded into a more ordered structure after neutralization, during which Cur was incorporated. Fluorescence quenching and isothermal titration calorimetry (ITC) further showed that the CP/Cur binding was mainly driven by hydrophobic interactions, resulting in static fluorescence quenching and energy release. Up to 99.50% of Cur was loaded in the CP delivery system. Furthermore, the thermal stability and photostability of Cur were greatly improved due to the protection of the protein. The present study proved that cod protein could be a great potential edible carrier for encapsulating curcumin.

DFF40 deficiency in cancerous T cells is implicated in chemotherapy drug sensitivity and resistance through the regulation of the apoptotic pathway

The regulation of the apoptotic pathway is one of the most studied mechanisms regarding cancer cell resistance. Many mutations have been linked to drug resistance. The DNA fragmentation factor 40 (DFF40) has been gaining interest regarding cancer cell response to chemotherapy and patient outcomes. Glioblastomas and uterine leiomyosarcomas have been shown to have a downregulation of DFF40 expression, conferring a poor patient prognosis. In concordance with these observations, in this study, we showed that DFF40 gene is also downregulated in breast, endocervical, ovarian, lung, pancreas and glioblastomas. DFF40 is the endonuclease responsible of DNA fragmentation during apoptosis. In this study, we sought to determine if a DFF40 deficiency in Jurkat T cells could impact the sensitivity to conventional chemotherapy drugs. CRISPR-cas9 generated DFF40 knockout (DFF40 KO) stable Jurkat cells and wild-type (DFF40 WT) cells were treated with different antimetabolites and topoisomerase II (TOP2) inhibitors, and cell viability was subsequently assessed. DFF40 deficient cells show chemoresistance to antimetabolites (e.g. methotrexate, 6-mercaptopurine and cytarabine) and surprisingly, they are more sensitive to TOP2 inhibitors (e.g. etoposide and teniposide). DFF40 deficient cells exposed to cytarabine present lower phosphatidylserine translocation levels to the outer cell membrane layer. Etoposide exposure in DFF40 deficient cells induces higher mortality levels and downregulation of Bcl-xL cells compared to DFF40 expressing T cells. The abolition of DFF40 expression in Jurkat cells significantly impairs histone H2AX phosphorylation following etoposide and cytarabine treatments. Our findings suggest that DFF40 is a novel key target in cancer cell resistance that potentially regulates genomic stability.

Immunodetection of heat shock protein 70 and cell death in liver of a neotropical fish acutely and chronically exposed to acetaminophen and propranolol

The use of pharmaceutical drugs ends frequently in their inappropriate disposal and treatment at waste water treatment plants, which is the cause of their widespread presence in the environment. Yet, there is limited understanding or knowledge of their effects to non-target aquatic organisms. The drugs acetaminophen (analgesic and antipyretic) and propranolol (β-blocker) are widely found in the aquatic environment, where they can interact with non-target exposed organisms, causing adverse effects. Heat shock proteins (namely HSP70) are molecular chaperones which help to refold misfolded cellular proteins, and the increase in their in vivo levels indicates a change in the cell to counteract the proteotoxic effects of the triggered stress, namely which is consequent to exposure to toxicants. The objective of this study was to quantify the levels of liver HSP70 proteins in individuals of the neotropical fish species Phalloceros harpagos, acutely and chronically exposed to concentrations of acetaminophen and propranolol, in the range of those already determined to occur in the wild. Fish acutely exposed to acetaminophen (concentrations of 8, 80, 800, and 8000 μg L^-1) and to propranolol (levels of 1, 10, and 1000 μg L^-1) evidenced increased intensity of HSP70 immunolabeling in liver cells. Similarly, animals chronically exposed to propranolol, at concentrations of 0.0625, 0.125, 0.25, and 0.5 μg L^-1, showed a comparable trend. This finding suggests the triggering of a cytoprotective effect that was effective in preventing cell death in exposed groups in relation to the control group. In contrast, chronic exposure to acetaminophen caused a decrease in HSP70 labeling intensity in fish hepatocytes (animals exposed to 5, 10, 20, 40, and 80 μg L^-1), with no induction of DNA fragmentation in the nuclei of hepatocytes of these fish. Some of the hepatic HSP70 responses observed in this study were obtained at levels already reported to occur in the wild. Finally, this study showed how levels of acetaminophen at microliter concentration can exert side effects on non-target organisms after chronic exposure, suggesting that environmentally exposed organisms may be subjected to adverse conditions that modify the typical response pattern of HSP70 levels.

Co-delivery of rituximab targeted curcumin and imatinib nanostructured lipid carriers in non-Hodgkin lymphoma cells

The aim of the present study was production of nanostructured lipid carriers (NLCs) of curcumin and imatinib for co-administration in non-Hodgkin lymphoma cells. NLCs were prepared and conjugated to rituximab to target CD20 receptors of lymphoma cell lines. Oleic acid or Labrafac and glyceryl monostearate or lecithin were used for production of NLCs. The antibody coupling efficiency to NLCs and their physical characteristics were studied. The cytotoxicity of NLCs on Jurkat T cells (CD20 receptor negative) and Ramos B cells (CD20 receptor positive) was studied by MTT assay. The cellular uptake was determined by fluorescent microscopy. The results indicated both curcumin and imatinib targeted NLCs had a significant cytotoxic effect much higher than the free drugs and non-targeted NLCs on Ramos cells. In both cell lines, the cytotoxicity of the co-administrated drugs was significantly higher than each drug alone. In Ramos cells the co-administration of curcumin (15 μg/ml)/imatinib (5 μg/ml) decreased the free curcumin IC₅₀ from 8.3 ± 0.9 to 1.9 ± 0.2 μg/ml, and curcumin targeted NLCs from 6.7 ± 0.1 to 1.3 ± 0.2 μg/ml. In this case the IC₅₀ of imatinib was reduced from 11.1 ± 0.7 to 2.3 ± 0.1 μg/ml and imatinib targeted NLCs from 4.3 ± 0.1 to 1.4 ± 0.0 μg/ml. The co-administration of ritoximab conjugated NLCs of curcumin and imatinib may enhance cytotoxicity of imatinib in treatment of non-Hodgkin lymphoma.

Evaluating the Anti-cancer Efficacy of a Synthetic Curcumin Analog on Human Melanoma Cells and Its Interaction with Standard Chemotherapeutics

Melanoma is the leading cause of skin-cancer related deaths in North America. Metastatic melanoma is difficult to treat and chemotherapies have limited success. Furthermore, chemotherapies lead to toxic side effects due to nonselective targeting of normal cells. Curcumin is a natural product of Curcuma longa (turmeric) and has been shown to possess anti-cancer activity. However, due to its poor bioavailability and stability, natural curcumin is not an effective cancer treatment. We tested synthetic analogs of curcumin that are more stable. One of these derivatives, Compound A, has shown significant anti-cancer efficacy in colon, leukemia, and triple-negative inflammatory breast cancer cells. However, the effects of Compound A against melanoma cells have not been studied before. In this study, for the first time, we demonstrated the efficacy of Compound A for the selective induction of apoptosis in melanoma cells and its interaction with tamoxifen, taxol, and cisplatin. We found that Compound A induced apoptosis selectively in human melanoma cells by increasing oxidative stress. The anti-cancer activity of Compound A was enhanced when combined with tamoxifen and the combination treatment did not result in significant toxicity to noncancerous cells. Additionally, Compound A did not interact negatively with the anti-cancer activity of taxol and cisplatin. These results indicate that Compound A could be developed as a selective and effective melanoma treatment either alone or in combination with other non-toxic agents like tamoxifen.

Demethoxycurcumin: A naturally occurring curcumin analogue for treating non-cancerous diseases

Turmeric extracts contain three primary compounds, which are commonly referred to as curcuminoids. They are curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin. While curcumin has been the most extensively studied of the curcuminoids, it suffers from low overall oral bioavailability due to extremely low absorption as a result of low water solubility and instability at acidic pH, as well as rapid metabolism and clearance from the body. However, DMC, which lacks the methoxy group on the benzene ring of the parent structure, has much greater chemical stability at physiological pH and has been recently reported to exhibit antitumor properties. However, the treatment of noncancerous diseases with DMC has not been comprehensively reviewed. Therefore, here we evaluate published scientific literature on the therapeutic properties of DMC. The beneficial pharmacological actions of DMC include anti-inflammatory, neuroprotective, antihypertensive, antimalarial, antimicrobial, antifungal, and vasodilatory properties. In addition, DMC's ability to ameliorate the effects of free radicals and an environment characterized by oxidative stress caused by the accumulation of advanced glycation end-products associated with diabetic nephropathy, as well as DMC's capacity to inhibit the migration and proliferation of vascular smooth muscle cells following balloon angioplasty are also addressed. This review collates the available literature regarding the therapeutic possibilities of DMC in noncancerous conditions.

The Role of Curcumin in the Modulation of Ageing

It is believed that postponing ageing is more effective and less expensive than the treatment of particular age-related diseases. Compounds which could delay symptoms of ageing, especially natural products present in a daily diet, are intensively studied. One of them is curcumin. It causes the elongation of the lifespan of model organisms, alleviates ageing symptoms and postpones the progression of age-related diseases in which cellular senescence is directly involved. It has been demonstrated that the elimination of senescent cells significantly improves the quality of life of mice. There is a continuous search for compounds, named senolytic drugs, that selectively eliminate senescent cells from organisms. In this paper, we endeavor to review the current knowledge about the anti-ageing role of curcumin and discuss its senolytic potential.

Mitochondrial separation protein inhibitor inhibits cell apoptosis in rat lungs during intermittent hypoxia

Obstructive sleep apnoea (OSA) is a very common sleep and breathing disorder that occurs in worldwide. It is important to develop a more effective treatment for OSA to overcome lung cell apoptosis during intermittent hypoxia (IH). A mitochondrial separation protein inhibitor (Mdivi-1) has been demonstrated to be a powerful tool for inhibiting apoptosis. In the present study, the protective effect and possible mechanism of apoptosis in lung cells during IH was investigated using in vivo and in vitro experiments. Following IH exposure for 4 weeks, the lung tissues of Sprague Dawley rats exhibited interstitial lesions, while Mdivi-1 reduced these pulmonary interstitial lesions. B-cell lymphoma (Bcl)-2 mRNA and protein expression levels were decreased however caspase-3, caspase-9 and dynamin-related protein 1 (Drp-1) mRNA and protein expression levels were increased. Following Mdivi-1 intervention, Bcl-2 mRNA and protein expression levels were increased while caspase-3, caspase-9 and Drp-1 mRNA and protein expression levels were decreased (P<0.05). After exposure to IH for 12 h, the apoptosis rate of WTRL1 cells in rats increased gradually with the IH time (P<0.05). Bcl-2 mRNA and protein expression levels were decreased, whereas caspase-3, caspase-9, cytochrome C (Cyt-C) and Drp-1 mRNA levels were increased, and caspase-3, caspase-9 and Drp-1 protein expression levels were increased. After Mdivi-1 intervention, Bcl-2 mRNA and protein expression levels were increased but caspase-3, caspase-9, Cyt-C and Drp-1 mRNA levels were decreased along with caspase-9, Cyt-C and Drp-1 protein expression levels which were decreased (P<0.05). The results of the present study suggest that Mdivi-1 may be a potential agent for treating OSA because it inhibits the mitochondrial pathway and reduces apoptosis.

Vicenin-2: a potential radiosensitizer of non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is a major form of cancer and is resistant to chemo- and radio-therapy. Vicenin-2 (VCN-2) is a flavonoid obtained from Ocimum sanctum L. and it has been reported to have radioprotective and anti-cancer properties. This study was conducted to check for the radiosensitizing potential of VCN-2 in the NSCLC cell line, NCI-H23. NCI-H23 cells were exposed to VCN-2 singularly, and to X-rays with and without prior VCN-2 treatment. Cytotoxicity assay, cell proliferation assay, caspase-3 activity assay, DNA fragmentation assay and Western blotting for Rad50, MMP-2 and p21 were performed to investigate the radiosensitizing properties of VCN-2. Fibroblast survival assay was performed using HEK293T cells to check for any adverse effects of VCN-2 on normal fibroblast cell line. VCN-2 singularly and in combination with radiation reduced the surviving cancer cells, increased caspase-3 activity, increased DNA fragmentation, increased the levels of Rad50 and lowered levels of MMP-2 and p21 proteins while being non-toxic and radioprotective to the fibroblast cells. VCN-2 showed a potent radiosensitizing property while also showing a chemotherapeutic property against NSCLC cell line NCI-H23.

Demethoxycurcumin: A naturally occurring curcumin analogue with antitumor properties

The eradication of cancer in a patient remains an elusive challenge despite advances in early detection and diagnosis, chemo- and immunotherapy, pinpoint radiation treatments, and expert surgical intervention. Although significant gains have been made in our understanding of cancer cell biology, a definite cure for most cancers does not exist at present. Thus, it is not surprising that the research and medical communities continue to explore the importance and therapeutic potential of natural products in their multimodality cancer treatment approach. Curcuminoids found in turmeric are one such class of natural products that have been extensively investigated for their potential to halt the progression of cancer cell proliferation and, more important, to stop metastasis from occurring. In this review, we examine one curcuminoid (demethoxycurcumin [DMC]) largely because of its increased stability and better aqueous solubility at physiological pH, unlike the more well-known curcuminoid (curcumin), which is largely unabsorbed after oral ingestion. The present review will focus on the signaling pathways that DMC utilizes to modulate the growth, invasion, and metastasis of cancer cells in an effort to provide enhanced mechanistic insight into DMC's action as it pertains to brain, ovarian, breast, lung, skin, and prostate cancer. Additionally, this review will attempt to provide an overview of DMC's mechanism of action by modulating apoptosis, cell cycle, angiogenesis, metastasis, and chemosensitivity. Lastly, it is hoped that increased understanding will be gained concerning DMC's interactive role with microRNA-551a, 5' adenosine monophosphate-activated protein kinase, nuclear factor-κB, Wnt inhibitory factor-1, and heat shock protein 70 to affect the progression of cancer.

Binding analysis of antioxidant polyphenols with PAMAM nanoparticles

Dietary polyphenols are abundant micronutrients in our diet and paly major role in prevention of degenerative diseases. The binding efficacy of antioxidant polyphenols resveratrol, genistein, and curcumin with PAMAM-G3 and PAMAM-G4 nanoparticles was investigated in aqueous solution at physiological conditions, using multiple spectroscopic methods, TEM images, and docking studies. The polyphenol bindings are via hydrophilic, hydrophobic, and H-bonding contacts with resveratrol forming more stable conjugates. As PAMAM size increased the loading efficacy and the stability of polyphenol-polymer conjugates were increased. Polyphenol binding induced major alterations of dendrimer morphology. PAMAM nanoparticles are capable of delivery of polyphenols in vitro.

Promising anti-tumor properties of bisdemethoxycurcumin: A naturally occurring curcumin analogue

Curcuminoids are turmeric-extracted phytochemicals with documented chemopreventive and anti-tumor activities against several types of malignancies. Curcuminoids can modulate several molecular pathways and cellular targets involved in different stages of tumor initiation, growth, and metastasis. Bisdemethoxycurcumin (BDMC) is a minor constituent (approximately 3%) of curcuminoids that has been shown to be more stable than the other two main curcuminoids, that is, curcumin and demthoxycurcumin. Recent studies have revealed that BDMC has anti-tumor effects exerted through a multimechanistic mode of action involving inhibition of cell proliferation, invasion and migration, metastasis and tumour growth, and induction of apoptotic death in cancer cells. The present review discusses the findings on the anti-tumor effects of BDMC, underlying mechanisms, and the relevance of finding for translational studies in human.

Selective Targeting of Cancer Cells by Oxidative Vulnerabilities with Novel Curcumin Analogs

Recently, research has focused on targeting the oxidative and metabolic vulnerabilities in cancer cells. Natural compounds like curcumin that target such susceptibilities have failed further clinical advancements due to the poor stability and bioavailability as well as the need of high effective doses. We have synthesized and evaluated the anti-cancer activity of several monocarbonyl analogs of curcumin. Interestingly, two novel analogs (Compound A and I) in comparison to curcumin, have increased chemical stability and have greater anti-cancer activity in a variety of human cancer cells, including triple-negative, inflammatory breast cancer cells. In particular, the generation of reactive oxygen species was selective to cancer cells and occurred upstream of mitochondrial collapse and execution of apoptosis. Furthermore, Compound A in combination with another cancer-selective/pro-oxidant, piperlongumine, caused an enhanced anti-cancer effect. Most importantly, Compound A was well tolerated by mice and was effective in inhibiting the growth of human triple-negative breast cancer and leukemia xenografts in vivo when administered intraperitoneally. Thus, exploiting oxidative vulnerabilities in cancer cells could be a selective and efficacious means to eradicate malignant cells as demonstrated by the curcumin analogs presented in this report with high therapeutic potential.

Immunosuppressive Effects of Natural α,β-Unsaturated Carbonyl-Based Compounds, and Their Analogs and Derivatives, on Immune Cells: A Review

The immune system is complex and pervasive as it functions to prevent or limit infections in the human body. In a healthy organism, the immune system and the redox balance of immune cells maintain homeostasis within the body. The failure to maintain the balance may lead to impaired immune response and either over activity or abnormally low activity of the immune cells resulting in autoimmune or immune deficiency diseases. Compounds containing α,β-unsaturated carbonyl-based moieties are often reactive. The reactivity of these groups is responsible for their diverse pharmacological activities, and the most important and widely studied include the natural compounds curcumin, chalcone, and zerumbone. Numerous studies have revealed the mainly immunosuppressive and anti-inflammatory activities of the aforesaid compounds. This review highlights the specific immunosuppressive effects of these natural α,β-unsaturated carbonyl-based compounds, and their analogs and derivatives on different types of immune cells of the innate (granulocytes, monocytes, macrophages, and dendritic cells) and adaptive (T cells, B cells, and natural killer cells) immune systems. The inhibitory effects of these compounds have been comprehensively studied on neutrophils, monocytes and macrophages but their effects on T cells, B cells, natural killer cells, and dendritic cells have not been well investigated. It is of paramount importance to continue generating experimental data on the mechanisms of action of α,β-unsaturated carbonyl-based compounds on immune cells to provide useful information for ensuing research to discover new immunomodulating agents.

Curcumin and Osteosarcoma: Can Invertible Polymeric Micelles Help?

Systematic review of experimental and clinical data on the use of curcumin in the treatment of osteosarcoma is presented. The current status of curcumin's therapeutic potential against bone cancer is analyzed in regard to using polymeric micelles (including recently developed invertible, responsive, micelles) as a platform for curcumin delivery to treat osteosarcoma. The potential of micellar assemblies from responsive macromolecules in a controlled delivery of curcumin to osteosarcoma cells, and the release using a new inversion mechanism is revealed.

Curcumin hampers the antitumor effect of vinblastine via the inhibition of microtubule dynamics and mitochondrial membrane potential in HeLa cervical cancer cells

BACKGROUND

Curcumin, a major component of curry powder, which is a natural polyphenol product extracted from rhizoma curcumae longae, interacts with a specific binding site on microtubules. Vinblastine is an antitumor drug that induces microtubule depolymerization.

PURPOSE

We investigated whether curcumin influences the antitumor effect of vinblastine in HeLa human cervical cancer cells.

STUDY DESIGN

Changes in microtubule filaments were visualized by immuno-staining. Cell death was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) or water-soluble tetrazolium(WST) assay. Apoptotic cell formation was assessed by flow cytometry after staining cells with propidium iodide(PI) and/or Annexin V or with 6-diamidino-2-phenylindole(DAPI). Reactive oxygen species(ROS) were also measured by flow cytometry using dichloro-dihydro-fluorescein diacetate(DCF-DA). JC-1 was used to determine mitochondrial membrane potential (MMP).

RESULTS

When cells were pretreated with curcumin, microtubule filaments were disordered. Vinblastine-induced microtubule depolymerization and cell death were reduced in HeLa human cervical cancer cells pretreated with curcumin compared to the control. The decrease in cell death was much greater in cells pretreated with curcumin compared to cotreatment or post-treatment. DNA condensation by vinblastine was also decreased in curcumin-pretreated cells. Curcumin reduced ROS production by vinblastine. However, no changes in vinblastine-mediated microtubule depolymerization were detected upon N-acetylcysteine(NAC) treatment. In contrast, vinblastine-induced MMP collapse was inhibited by pretreatment with curcumin or NAC. These findings suggest that vinblastine-induced tumor cell death might be inhibited by curcumin via ROS-independent microtubule dynamics and ROS-dependent MMP collapse. It also suggests that microtubule dynamics could be necessary for the optimal antitumor activity of vinblastine. Our results suggest that patients treated with vinblastine should not consume curcumin.

Curcumin-treated cancer cells show mitotic disturbances leading to growth arrest and induction of senescence phenotype

Cellular senescence is recognized as a potent anticancer mechanism that inhibits carcinogenesis. Cancer cells can also undergo senescence upon chemo- or radiotherapy. Curcumin, a natural polyphenol derived from the rhizome of Curcuma longa, shows anticancer properties both in vitro and in vivo. Previously, we have shown that treatment with curcumin leads to senescence of human cancer cells. Now we identified the molecular mechanism underlying this phenomenon. We observed a time-dependent accumulation of mitotic cells upon curcumin treatment. The time-lapse analysis proved that those cells progressed through mitosis for a significantly longer period of time. A fraction of cells managed to divide or undergo mitotic slippage and then enter the next phase of the cell cycle. Cells arrested in mitosis had an improperly formed mitotic spindle and were positive for γH2AX, which shows that they acquired DNA damage during prolonged mitosis. Moreover, the DNA damage response pathway was activated upon curcumin treatment and the components of this pathway remained upregulated while cells were undergoing senescence. Inhibition of the DNA damage response decreased the number of senescent cells. Thus, our studies revealed that the induction of cell senescence upon curcumin treatment resulted from aberrant progression through the cell cycle. Moreover, the DNA damage acquired by cancer cells, due to mitotic disturbances, activates an important molecular mechanism that determines the potential anticancer activity of curcumin.

Pharmacological inhibition of lipid droplet formation enhances the effectiveness of curcumin in glioblastoma

Increased lipid droplet number and fatty acid synthesis allow glioblastoma multiforme, the most common and aggressive type of brain cancer, to withstand accelerated metabolic rates and resist therapeutic treatments. Lipid droplets are postulated to sequester hydrophobic therapeutic agents, thereby reducing drug effectiveness. We hypothesized that the inhibition of lipid droplet accumulation in glioblastoma cells using pyrrolidine-2, a cytoplasmic phospholipase A2 alpha inhibitor, can sensitize cancer cells to the killing effect of curcumin, a promising anticancer agent isolated from the turmeric spice. We observed that curcumin localized in the lipid droplets of human U251N glioblastoma cells. Reduction of lipid droplet number using pyrrolidine-2 drastically enhanced the therapeutic effect of curcumin in both 2D and 3D glioblastoma cell models. The mode of cell death involved was found to be mediated by caspase-3. Comparatively, the current clinical chemotherapeutic standard, temozolomide, was significantly less effective in inducing glioblastoma cell death. Together, our results suggest that the inhibition of lipid droplet accumulation is an effective way to enhance the chemotherapeutic effect of curcumin against glioblastoma multiforme.

Curcumin loaded pH-sensitive hybrid lipid/block copolymer nanosized drug delivery systems

Curcumin is a perspective drug candidate with pleiotropic antineoplastic activity, whose exceptionally low aqueous solubility and poor pharmacokinetic properties have hampered its development beyond the preclinical level. A possible approach to overcome these limitations is the encapsulation of curcumin into nano-carriers, incl. liposomes. The present contribution is focused on feasibility of using hybrid pH-sensitive liposomes, whereby curcumin is entrapped as a free drug and as a water soluble inclusion complex with PEGylated tert-butylcalix[4]arene, which allows the drug to occupy both the phospholipid membranes and the aqueous core of liposomes. The inclusion complexes were encapsulated in dipalmithoylphosphathydilcholine:cholesterol liposomes, whose membranes were grafted with a poly(isoprene-b-acrylic acid) diblock copolymer to confer pH-sensitivity. The liposomes were characterized by DLS, ζ-potential measurements, cryo-TEM, curcumin encapsulation efficacy, loading capacity, and in vitro release as a function of pH. Free and formulated curcumin were further investigated for cytotoxicity, apoptosis-induction and caspase-8, and 9 activation in chemosensitive HL-60 and its resistant sublines HL-60/Dox and HL-60/CDDP. Formulated curcumin was superior cytotoxic and apoptogenic agent vs. the free drug. The mechanistic assay demonstrated that the potent proapoptotic effects of pH-sensitive liposomal curcumin presumably mediated via recruitment of both extrinsic and intrinsic apoptotic pathways in both HL-60 and HL-60/CDDP cells.

Locating the binding sites of antioxidants resveratrol, genistein and curcumin with tRNA

We located the binding sites of antioxidants resveratrol, genistein and curcumin on tRNA in aqueous solution at physiological conditions using constant tRNA concentration and various polyphenol contents. FTIR, UV-visible, CD spectroscopic methods and molecular modeling were used to determine polyphenol binding sites, the binding constant and the effects of polyphenol complexation on tRNA conformation and particle formation. Structural analysis showed that polyphenols bind tRNA via G-C and A-U base pairs through hydrophilic, hydrophobic and H-bonding contacts with overall binding constants of K(res-tRNA)=8.95(±0.80)×10(3) M(-1), K(gen-tRNA)=3.07(±0.5)×10(3) M(-1) and K(cur-tRNA)=1.55(±0.3)×10(4) M(-1). Molecular modeling showed the participation of several nucleobases in polyphenol-tRNA adduct formation with free binding energy of -4.43 for resveratrol, -4.26 kcal/mol for genistein and -4.84 kcal/mol for curcumin, indicating that the interaction process is spontaneous at room temperature. While tRNA remains in A-family structure, major biopolymer aggregation and particle formation occurred at high polyphenol contents.

Caspase-dependent cell death-associated release of nucleosome and damage-associated molecular patterns

Apoptosis, which is anti-inflammatory, and necrosis, which is pro-inflammatory, represent the extremes of the cell death spectrum. Cell death is complex and both apoptosis and necrosis can be observed in the same cells or tissues. Here, we introduce a novel combined mode of cellular demise--caspase-dependent regulated necrosis. Most importantly, it is mainly characterized with release of marked amount of oligo- or poly-nucleosomes and their attached damage-associated molecular patterns (DAMPs) and initiated by caspase activation. Caspase-activated DNase has dual roles in nucleosomal release as it can degrade extracellularly released chromatin into poly- or oligo-nucleosomes although it prohibits release of nucleosomes. In addition, osmotically triggered water movement following Cl(-) influx and subsequent Na(+) influx appears to be the major driving force for nucleosomal and DAMPs release. Finally, Ca(2+)-activated cysteine protease, calpain, is an another essential factor in nucleosomal and DAMPs release because of complete reversion to apoptotic morphology from necrotic one and blockade of nucleosomal and DAMPs release by its inhibition.

Deoxyribonuclease inhibitors

Deoxyribonucleases (DNases) are a class of enzymes able to catalyze DNA hydrolysis. DNases play important roles in cell function, while DNase inhibitors control or modify their activities. This review focuses on DNase inhibitors. Some DNase inhibitors have been isolated from various natural sources, such as humans, animals (beef, calf, rabbit and rat), plants (Nicotiana tabacum), and microorganisms (some Streptomyces and Adenovirus species, Micromonospora echinospora and Escherichia coli), while others have been obtained by chemical synthesis. They differ in chemical structure (various proteins, nucleotides, anthracycline and aminoglycoside antibiotics, synthetic organic and inorganic compounds) and mechanism of action (forming complexes with DNases or DNA). Some of the inhibitors are specific toward only one type of DNase, while others are active towards two or more. Physico-chemical properties of DNase inhibitors are calculated using the Molinspiration tool and most of them meet all criteria for good solubility and permeability. DNase inhibitors may be used as pharmaceuticals for preventing, monitoring and treating various diseases.

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.

Synthesis and biological evaluation of halogenated curcumin analogs as potential nuclear receptor selective agonists

This report describes the synthesis of analogs of curcumin, and their analysis in acting as nuclear receptor specific agonists. Curcumin (CM), a turmeric-derived bioactive polyphenol found in curry, has recently been identified as a ligand for the vitamin D receptor (VDR), and it is possible that CM exerts some of its bioeffects via direct binding to VDR and/or other proteins in the nuclear receptor superfamily. Using mammalian-two-hybrid (M2H) and vitamin D responsive element (VDRE) biological assay systems, we tested CM and 11 CM synthetic analogs for their ability to activate VDR signaling. The M2H assay revealed that RXR and VDR association was induced by CM and several of its analogs. VDRE-based assays demonstrated that pure curcumin and eight CM analogs activated transcription of a luciferase plasmid at levels approaching that of the endocrine 1,25 dihydroxyvitamin D(3) (1,25D) ligand in human colon cancer cells (HCT-116). Additional experiments were performed in HCT-116 utilizing various nuclear receptors and hormone responsive elements to determine the receptor specificity of curcumin binding. CM did not appear to activate transcription in a glucocorticoid responsive system. However, CM along with several analogs elicited transcriptional activation in retinoic acid and retinoid X receptor (RXR) responsive systems. M2H assays using RXR-RXR, VDR-SRC1 and VDR-DRIP revealed that CM and select analogs stimulate RXR homodimerization and VDR-coactivator interactions. These studies may lead to the discovery of novel curcumin analogs that activate nuclear receptors, including RXR, RAR and VDR, resulting in similar health benefits as those for vitamins A and D, such as lowering the risk of epithelial and colon cancers.

Curcuminoid binding to embryonal carcinoma cells: reductive metabolism, induction of apoptosis, senescence, and inhibition of cell proliferation

Curcumin preparations typically contain a mixture of polyphenols, collectively referred to as curcuminoids. In addition to the primary component curcumin, they also contain smaller amounts of the co-extracted derivatives demethoxycurcumin and bisdemethoxycurcumin. Curcuminoids can be differentially solubilized in serum, which allows for the systematic analysis of concentration-dependent cellular binding, biological effects, and metabolism. Technical grade curcumin was solubilized in fetal calf serum by two alternative methods yielding saturated preparations containing either predominantly curcumin (60%) or bisdemethoxycurcumin (55%). Continual exposure of NT2/D1 cells for 4–6 days to either preparation in cell culture media reduced cell division (1–5 µM), induced senescence (6–7 µM) or comprehensive cell death (8–10 µM) in a concentration-dependent manner. Some of these effects could also be elicited in cells transiently exposed to higher concentrations of curcuminoids (47 µM) for 0.5–4 h. Curcuminoids induced apoptosis by generalized activation of caspases but without nucleosomal fragmentation. The equilibrium binding of serum-solubilized curcuminoids to NT2/D1 cells incubated with increasing amounts of curcuminoid-saturated serum occurred with apparent overall dissociation constants in the 6–10 µM range. However, the presence of excess free serum decreased cellular binding in a hyperbolic manner. Cellular binding was overwhelmingly associated with membrane fractions and bound curcuminoids were metabolized in NT2/D1 cells via a previously unidentified reduction pathway. Both the binding affinities for curcuminoids and their reductive metabolic pathways varied in other cell lines. These results suggest that curcuminoids interact with cellular binding sites, thereby activating signal transduction pathways that initiate a variety of biological responses. The dose-dependent effects of these responses further imply that distinct cellular pathways are sequentially activated and that this activation is dependent on the affinity of curcuminoids for the respective binding sites. Defined serum-solubilized curcuminoids used in cell culture media are thus suitable for further investigating the differential activation of signal transduction pathways.

Curcumin induces permanent growth arrest of human colon cancer cells: link between senescence and autophagy

Curcumin, a natural polyphenol derived from the rhizome of Curcuma longa, is a potent anticancer agent, which restricts tumor cell growth both in vitro and in vivo. Thus far curcumin was shown to induce death of cancer cells. This study reports the induction of cellular senescence of human colon cancer cells HCT116 upon curcumin treatment. The SA-β-galactosidase activation was observed both in p53+/+ and p53-/- cells, however the latter ones were less sensitive to the prosenescent activity of curcumin. Upregulation of p53 and p21 proteins was observed in p53+/+ HCT116, while p53-independent induction of p21 was noticed in p53-/- HCT116. Moreover, the senescence of HCT116 cells was accompanied by autophagy, that was confirmed by electron microscopy observations of autophagosomes in the curcumin-treated cells as well as LC3-II expression, punctue staining of LC3 and increased content of acidic vacuoles. Inhibition of autophagy, due to the diminished expression of ATG5 by RNAi decreased the number of senescent cells induced by curcumin, but did not lead to increased cell death. Altogether, we demonstrated a new antitumor activity of curcumin leading to cancer cell senescence and revealed the presence of a functional link between senescence and autophagy in curcumin-treated cells.

Curcumin-induced autophagy contributes to the decreased survival of oral cancer cells

Curcumin, a major active component of turmeric Curcuma longa, has been shown to have inhibitory effects on cancers. In vitro studies suggest that curcumin inhibits cancer cell growth by activating apoptosis, but the mechanism underlying the anticancer effects of curcumin is unclear. Recently, it has been suggested that autophagy may play an important role in cancer therapy. However, little data are available regarding the role of autophagy in oral cancers. In this study, we have shown that curcumin has anticancer activity against oral squamous cell carcinoma (OSCC). Induction of autophagy, marked by autophagic vacuoles formation, was detected by acridine orange staining and monodansylcadaverine (MDC) dye after exposure to curcumin. Conversion of LC3-I to LC3-II, a marker of active autophagosome formation, was also detectable by Western blot following curcumin treatment. We have also observed that curcumin induced reactive oxygen species (ROS) production and autophagic vacuoles formation by curcumin was almost completely blocked in the presence of N-acetylcystein (NAC), an antioxidant. Rescue experiments using an autophagy inhibitor suppressed curcumin-induced cell death in OSCC, confirming that autophagy acts as a pro-death signal. Furthermore, curcumin shows anticancer activity against OSCC via both autophagy and apoptosis. These findings suggest that curcumin may potentially contribute to oral cancer treatment and provide useful information for the development of a new therapeutic agent.

Demethoxycurcumin Retards Cell Growth and Induces Apoptosis in Human Brain Malignant Glioma GBM 8401 Cells

Demethoxycurcumin (DMC; a curcumin-related demethoxy compound) has been recently shown to display antioxidant and antitumor activities. It has also produced a potent chemopreventive action against cancer. In the present study, the antiproliferation (using the MTT assay, DMC was found to have cytotoxic activities against GBM 8401 cell with IC₅₀ values at 22.71 μM) and induced apoptosis effects of DMC have been investigated in human brain malignant glioma GBM 8401 cells. We have studied the mitochondrial membrane potential (MMP), DNA fragmentation, caspase activation, and NF-κB transcriptional factor activity. By these approaches, our results indicated that DMC has produced an inhibition of cell proliferation as well as the activation of apoptosis in GBM 8401 cells. Both effects were observed to increase in proportion with the dosage of DMC treatment, and the apoptosis was induced by DMC in human brain malignant glioma GBM 8401 cells via mitochondria- and caspase-dependent pathways.

Curcumin potentiates antitumor activity of L-asparaginase via inhibition of the AKT signaling pathway in acute lymphoblastic leukemia

L-asparaginase (L-ASP) is a universal component of therapy for acute lymphoblastic leukemia (ALL). Curcumin is a naturally occurring yellow pigment that is derived from the rhizome of Curcuma longa. In this study, we evaluated the cytotoxicity of the combined treatment of L-ASP and curcumin in three ALL cell lines. Synergistic cytotoxicity was observed in all three cell lines following the combined treatment of curcumin and L-ASP. Our results revealed that curcumin significantly enhanced the antitumor effect of L-ASP in the three ALL cell lines compared to that for L-ASP alone ( p < 0.05). Curcumin and L-ASP co-treatments induced apoptosis, via activation and cleavage of caspase-8 and BID cleavage accompanied by release of cytochrome c and activation of caspase-9/3, compared to the group treated with only L-ASP and the control group. Furthermore, the combination of curcumin and L-ASP led to significant reductions in phosphorylated AKT and expression of AKT-regulated gene products (FoxO1, GSK3β, IKKα, NF-κB, XIAP) compared with the group treated with only L-ASP and the control group. Overall, our findings suggest that curcumin potentiates the antitumor effects of L-ASP in acute lymphoblastic leukemia by constitutively inhibiting AKT and AKT-regulated gene products.

Antiproliferative activity and standardization of Tecomella undulata bark extract on K562 cells

ETHNOPHARMACOLOGICAL RELEVANCE

The bark of Tecomella undulata is primarily used in the treatment of syphilis, painful swellings and cancer by traditional healers. Also, it is claimed to be useful in treating urinary discharges, enlargement of spleen, leucorrhoea, leukoderma, tumors, liver disorders, gonorrhea, gout and promotes wound healing in Indian traditional system of medicine.

AIM

To establish a scientific validation for the antitumor effects of Tecomella undulata bark and explore the mechanistic pathway in chronic myeloid leukemia cell line, K562. The study was further extended to standardize the extract using quercetin as biomarker.

METHODS

Induction of apoptosis by chloroform extract of Tecomella undulata bark (CTUB) was determined by MTT, Annexin V and caspase activation assays. The cell cycle analysis was done by flow cytometer and nuclear staining by DAPI. The standardization of the extract was performed through reverse phase-HPLC method under PDA detection.

RESULT

Results clearly showed the induction of apoptosis by CTUB in K562 cells. The effect was found to be dose dependent, having IC(50) of 30 μg/ml with activation of FAS, FADD, caspase 8, caspase 3/7 and fragmentation of DNA. The bioactive CTUB was determined to possess 0.03% (w/w) of quercetin.

CONCLUSION

The investigation clearly demonstrated the potential antitumor effect of CTUB, thereby validating the traditional claim. Quercetin, known to have anticancer activity is being reported and quantified for the first time from the bark of Tecomella undulata.

Curcuminoids suppress the growth and induce apoptosis through caspase-3-dependent pathways in glioblastoma multiforme (GBM) 8401 cells

Curcuminoids, natural plant components, have been recently shown to display antioxidant and anti-inflammatory activities. They also produce potent chemo-preventive action against several types of cancer. In the present study, the anti-proliferative and induced apoptosis effects of curcuminoids have been investigated in human brain glioblastoma multiforme (GBM) 8401 cells. Results indicated that curcuminoids have produced an inhibition of cell proliferation in a dose-dependent manner as dosage increased from 12.5 to 100 μM (n = 6) via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay as well as activation of apoptosis in GBM 8401 cells. Both effects were observed to increase in proportion with the dose of curcuminoids. We have studied the mitochondrial membrane potential (ΔΨm), DNA fragmentation, caspase-3, caspase-8, and caspase-9 activation, and nuclear factor κB (NF-κB) transcriptional factor activity to analyze apoptosis in GBM 8401 cells. From these approaches, apoptosis was induced by curcuminoids in human brain GBM 8401 cells via mitochondria and a caspase-dependent pathway. The results observed with proliferation inhibition (y = 94.694e(-0.025x), R(2) = 0.9901, and n = 6) and apoptosis (y = 0.9789e(-0.0102x), R(2) = 0.99854, and n = 3) depend upon the amount of curcuminoid treatment in the cancer cells.

Immunomodulatory and therapeutic activity of curcumin

Inflammation is a disease of vigorous uncontrolled activated immune responses. Overwhelming reports have suggested that the modulation of immune responses by curcumin plays a dominant role in the treatment of inflammation and metabolic diseases. Observations from both in-vitro and in-vivo studies have provided strong evidence towards the therapeutic potential of curcumin. These studies have also identified a plethora of biological targets and intricate mechanisms of action that characterize curcumin as a potent 'drug' for numerous ailments. During inflammation the functional influence of lymphocytes and the related cross-talk can be modulated by curcumin to achieve the desired immune status against diseases. This review describes the regulation of immune responses by curcumin and effectiveness of curcumin in treatment of diseases of diverse nature.

Curcumin causes superoxide anion production and p53-independent apoptosis in human colon cancer cells

Curcumin from the rhizome of theCurcuma longa plant has chemopreventative activity and inhibits the growth of neoplastic cells. Since p53 has been suggested to be important for anticancer activity by curcumin, we investigated curcumin-induced cytotoxicity in cultures of p53(+/+) and p53(-/-) HCT-116 colon cancer cells, as well as mutant p53 HT-29 colon cancer cells. Curcumin killed wild-type p53 HCT-116 cells and mutant p53 HT-29 cells in a dose- and time-dependent manner. In addition, curcumin-treated p53(+/+) HCT-116 cells and mutant p53 HT-29 cells showed upregulation of total and activated p53, as well as increased expression of p53-regulated p21, PUMA (p53 upregulated modulator of apoptosis), and Bax; however, an equivalent cytotoxic effect by curcumin was observed in p53(+/+) and p53(-/-) HCT-116 cells, demonstrating that curcumin-induced cytotoxicity was independent of p53 status. Similar results were obtained when the cytotoxic effect of curcumin was assessed in wild-type p53 HCT-116 cells after siRNA-mediated p53 knockdown. Chromatin condensation, poly (ADP-ribose) polymerase-1 cleavage and reduced pro-caspase-3 levels in curcumin-treated p53(+/+) and p53(-/-) HCT-116 cells suggested that curcumin caused apoptosis. In addition, exposure to curcumin resulted in superoxide anion production and phosphorylation of oxidative stress proteins in p53(+/+) and p53(-/-) HCT-116 cells. Collectively, our results indicate that, despite p53 upregulation and activation, curcumin-induced apoptosis in colon cancer cells was independent of p53 status and involved oxidative stress. Curcumin may therefore have therapeutic potential in the management of colon cancer, especially in tumorsthatare resistant to conventional chemotherapydue todefects inp53 expression or function.

Structure-activity relationship of C5-curcuminoids and synthesis of their molecular probes thereof

A series of novel analogues of 1,5-bis(4-hydroxy-3-methoxyphenyl)-penta-(1E,4E)-1,4-dien-3-one (C(5)-curcumin), which is a natural analogue of curcumin isolated from the rhizomes of Curcuma domestica Val. (Zingiberacea), were synthesized and evaluated for their cytotoxicities against human colon cancer cell line HCT-116 to conclude the SAR of C(5)-curcuminoids for further development of their use in cancer chemotherapy: (1) Bis(arylmethylidene)acetone serves as a promising skeleton for eliciting cytotoxicity. (2) The 3-oxo-1,4-pentadiene structure is essential for eliciting cytotoxicity. (3) As for the extent of the aromatic substituents, hexasubstituted compounds exhibit strong activities, in which 3,4,5-hexasubstitution results in the highest potency. (5) The symmetry between two aryl rings is not an essential requirement for bis(arylmethylidene)acetones to elicit cytotoxicity. (6) para-Positions allows the installation of additional functional groups for use as molecular probes. By taking advantage of the SAR diagram, we have elaborated several advanced derivatives having GI(50) of single-digit micromolar potencies that will function as molecular probes to target and/or report key biomolecules interacting with curcumin and C(5)-curcumin.