Curcumin and genistein, plant natural products, show synergistic inhibitory effects on the growth of human breast cancer MCF-7 cells induced by estrogenic pesticides

COVID-19-Associated Sepsis: Potential Role of Phytochemicals as Functional Foods and Nutraceuticals

The acute manifestations of coronavirus disease 2019 (COVID-19) exhibit the hallmarks of sepsis-associated complications that reflect multiple organ failure. The inflammatory cytokine storm accompanied by an imbalance in the pro-inflammatory and anti-inflammatory host response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to severe and critical septic shock. The sepsis signature in severely afflicted COVID-19 patients includes cellular reprogramming and organ dysfunction that leads to high mortality rates, emphasizing the importance of improved clinical care and advanced therapeutic interventions for sepsis associated with COVID-19. Phytochemicals of functional foods and nutraceutical importance have an incredible impact on the healthcare system, which includes the prevention and/or treatment of chronic diseases. Hence, in the present review, we aim to explore the pathogenesis of sepsis associated with COVID-19 that disrupts the physiological homeostasis of the body, resulting in severe organ damage. Furthermore, we have summarized the diverse pharmacological properties of some potent phytochemicals, which can be used as functional foods as well as nutraceuticals against sepsis-associated complications of SARS-CoV-2 infection. The phytochemicals explored in this article include quercetin, curcumin, luteolin, apigenin, resveratrol, and naringenin, which are the major phytoconstituents of our daily food intake. We have compiled the findings from various studies, including clinical trials in humans, to explore more into the therapeutic potential of each phytochemical against sepsis and COVID-19, which highlights their possible importance in sepsis-associated COVID-19 pathogenesis. We conclude that our review will open a new research avenue for exploring phytochemical-derived therapeutic agents for preventing or treating the life-threatening complications of sepsis associated with COVID-19.

The Efficacy of Curcumin Application to Melanoma in Mice: A Systematic Review and Meta-analysis

OBJECTIVE

Melanoma is a skin tumor that poses a serious threat to human health. Our study explores the effectiveness and safety of curcumin in the treatment of melanoma based on animal models, and providing evidence-based medical evidence for curcumin in the treatment of malignant melanoma.

METHODS

The study collected all randomized controlled trial data from the establishment of the database to October 2023 of curcumin for the treatment of melanoma in mice by searching PubMed, Embase, and the Cochrane Library. According to inclusion and exclusion criteria, data were extracted and quality assessment of included studies was performed by using the SYRCLE (Systematic Review Center for Laboratory animal Experimentation) animal experiment bias risk assessment tool. RevMan 5.4 and Stata 15.1 software were used for meta-analysis.

RESULTS

Eighteen randomized controlled trials were included in this study with a total of 185 mouse models, including 93 mice in the experimental group and 92 in the control group. The results of meta-analysis showed that the IC50 (inhibitory concentrations of 50%) in the experimental group is lower than that of the control group [standardized mean difference (SMD) = -4.68, 95% confidence interval (CI) (-7.30, -2.06), P < 0.01]; the tumor volume is significantly smaller than the control group [SMD = -3.10, 95% CI (-4.45, -1.75), P < 0.01]; the tumor weight is smaller than the control group [SMD = -3.01, 95% CI (-4.81, -1.21), P < 0.01]. However, there was no significant statistical difference in the apoptosis rate between the experimental group and the control group [SMD = 2.27, 95% CI (-1.39, 5.92), P < 0.01].

CONCLUSION

Based on animal models for meta-analysis, curcumin can inhibit the growth and proliferation of melanoma in mice. Melanoma may be an effective method for treating melanoma. However, this result still requires further in-depth research.

Enhancing the Bioavailability and Bioactivity of Curcumin for Disease Prevention and Treatment

Curcumin, a natural polyphenolic component from Curcuma longa roots, is the main bioactive component of turmeric spice and has gained increasing interest due to its proposed anti-cancer, anti-obesity, anti-inflammatory, antioxidant, and lipid-lowering effects, in addition to its thermogenic capacity. While intake from dietary sources such as curry may be sufficient to affect the intestinal microbiome and thus may act indirectly, intact curcumin in the body may be too low (<1 microM) and not sufficient to affect signaling and gene expression, as observed in vitro with cultured cells (10-20 microM). Several strategies can be envisioned to increase curcumin levels in the body, such as decreasing its metabolism or increasing absorption through the formation of nanoparticles. However, since high curcumin levels could also lead to undesired regulatory effects on cellular signaling and gene expression, such studies may need to be carefully monitored. Here, we review the bioavailability of curcumin and to what extent increasing curcumin levels using nanoformulations may increase the bioavailability and bioactivity of curcumin and its metabolites. This enhancement could potentially amplify the disease-preventing effects of curcumin, often by leveraging its robust antioxidant properties.

Synergistic inhibitory actions of resveratrol, epigallocatechin-3-gallate, and diallyl trisulfide against skin cancer cell line A431 through mitochondrial caspase dependent pathway: a combinational drug approach

The harmful effect of chemotherapeutic side effects has paid a way to discover a novel with curative way for skin cancer treatment. Skin cancer prevention is more viable with the use of combination of bioactive agents than using of single bioactive compounds. Present work was demonstrated to evaluate the interaction of Resveratrol (Res), Epigallocatechin-3-gallate (EGCG), and diallyl trisulfide (DATS) with each other as a binary combination on A431 cells. Nuclear fragmentation analysis of combination of bioactive agents using DAPI analysis, detection of apoptosis, analysis of cell cycle, ROS assay, antimigration assays, and western blotting were implemented to study the combination of bioactive compounds on A431 cell line. Among the selected combination EGCG + DATS had a synergetic effect reducing cellular migration, increased intercellular reactive oxygen species generation, condensation, cell phagocytosis induced by phosphatidylserine externalization, rise in sub-G1 DNA content, and S-phase were cell cycle arrest. The combinations EGCG + DATS induced apoptotic proteins in A431 cells by upregulation of proapoptotic Bax and Bad proteins, a downmodulation of anti-apoptotic proteins Bcl2 and caspases (caspase-3, and -9) activity got triggered by intrinsic pathway. The combination of EGCG + DATS showed good anticancer potential against A431 skin cancer cell line via the mitochondrial caspase dependent pathway with very strong synergism. This finding will help to produce a novel combination/chemoprevention using dietary bioactive agents (EGCG + DATS) for the treatment of skin cancer after clinical trial.

Lead Optimization of BIBR1591 To Improve Its Telomerase Inhibitory Activity: Design and Synthesis of Novel Four Chemical Series with In Silico, In Vitro, and In Vivo Preclinical Assessments

Herein, modifications to the previously reported BIBR1591 were conducted to obtain bioisosteric candidates with improved activities. The % inhibition of the newly afforded candidates against the telomerase target was investigated. Notably, 6f achieved superior telomerase inhibition (63.14%) compared to BIBR1532 and BIBR1591 (69.64 and 51.58%, respectively). In addition, 8a and 8b showed comparable promising telomerase inhibition with 58.65 and 55.57%, respectively, which were recorded to be frontier to that of BIBR1591. 6f, 8a, and 8b were tested against five cancer cell lines related to the lung and liver subtypes. Moreover, 6f was examined on both cell cycle progression and apoptosis induction in HuH7 cancer cells. Furthermore, the in vivo antitumor activity of 6f was further assessed in female mice with solid Ehrlich carcinoma. In addition, molecular docking and molecular dynamics simulations were carried out. Collectively, 6f, 8a, and 8b could be considered potential new telomerase inhibitors to be subjected to further investigation and/or optimization.

The Synergistic Hepatoprotective Activity of Rosemary Essential Oil and Curcumin: The Role of the MEK/ERK Pathway

BACKGROUND

Curcumin is a natural product obtained from the rhizome of Curcuma longa. Rosemary (Rosmarinus officinalis) is a medicinal and aromatic plant that is widely spread in the Mediterranean region. Both Curcumin and rosemary essential oil are natural products of high medicinal and pharmacological significance. The hepatoprotective effect of both natural products is well-established; however, the mechanism of such action is not fully understood. Thus, this study is an attempt to explore the hepatoprotective mechanism of action of these remedies through their effect on MEK and ERK proteins. Furthermore, the effect of rosemary essential oil on the plasma concentration of curcumin has been scrutinized.

MATERIALS AND METHODS

The major constituents of REO were qualitatively and quantitatively determined by GC/MS and GC/FID, respectively. Curcumin and rosemary essential oil were given to mice in a pre-treatment model, followed by induction of liver injury through a high dose of paracetamol. Serum liver enzymes, lipid peroxidation, antioxidant activities, the inflammatory and apoptotic biomarkers, as well as the MEK and ERK portions, were verified. The plasma levels of curcumin were determined in the presence and absence of rosemary essential oil.

RESULTS

The major constituents of REO were 1,8-cineole (51.52%), camphor (10.52%), and α-pinene (8.41%). The results revealed a superior hepatoprotective activity of the combination when compared to each natural product alone, as demonstrated by the lowered liver enzymes, lipid peroxidation, mitigated inflammatory and apoptotic biomarkers, and enhanced antioxidant activities. Furthermore, the combination induced the overexpression of MEK and ERK proteins, providing evidence for the involvement of this cascade in the hepatoprotective activity of such natural products. The administration of rosemary essential oil with curcumin enhanced the curcuminoid plasma level.

CONCLUSION

The co-administration of both curcumin and rosemary essential oil together enhanced both their hepatoprotective activity and the level of curcumin in plasma, indicating a synergistic activity between both natural products.

Inhibitory effect of selected Indian honey on colon cancer cell growth by inducing apoptosis and targeting the β-catenin/Wnt pathway

Colon cancer is the most prevalent cause of death from cancer across the globe. Although chemotherapy drugs are predominantly used, their toxicity always remains a cause of concern. As an alternative to synthetic drugs, natural compounds or nutraceuticals are comparatively less toxic. Honey is widely used across different cultures as an alternative form of medicine. It represents a prominent source of plant-phenolic compounds and there is demonstrable evidence of its anti-oxidant and anti-microbial activities. The aim of the present work was to investigate the anti-proliferative effect of some Indian honeys and analyze their mechanism of action in colon cancer. In order to establish the composition-activity relationship, we evaluated the bioactive components present in selected honey samples by GC-MS and HPLC analysis. Indian honey samples showed a significant inhibitory impact on cell growth by restricting cell proliferation, causing apoptosis, and restricting the cell cycle in the G₂/M phase specifically for colon cancer cells. The apoptotic activities, as imparted by the honey samples, were established by Annexin V/PI staining, real-time PCR, and immunoblot analyses. The treated cells showed increased expressions of p53 and caspases 3, 8, and 9, thus indicating the involvement of both extrinsic and intrinsic apoptotic pathways. The honey samples were also found to inhibit the β-catenin/Wnt pathway. In the next phase of the study, the efficacy of these honey samples was evaluated in colon carcinoma induced SD-rats. Overall, these findings demonstrated that selected Indian honeys could be established as effective nutraceuticals for the prevention as well as cure of colon cancer.

The Cooperative Anti-Neoplastic Activity of Polyphenolic Phytochemicals on Human T-Cell Acute Lymphoblastic Leukemia Cell Line MOLT-4 In Vitro

Acute lymphoblastic leukemia (ALL) is the most common hematological malignancy affecting pediatric patients. ALL treatment regimens with cytostatics manifest substantial toxicity and have reached the maximum of well-tolerated doses. One potential approach for improving treatment efficiency could be supplementation of the current regimen with naturally occurring phytochemicals with anti-cancer properties. Nutraceuticals such as quercetin, curcumin, resveratrol, and genistein have been studied in anti-cancer therapy, but their application is limited by their low bioavailability. However, their cooperative activity could potentially increase their efficiency at low, bioavailable doses. We studied their cooperative effect on the viability of a human ALL MOLT-4 cell line in vitro at the concentration considered to be in the bioavailable range in vivo. To analyze their potential side effect on the viability of non-tumor cells, we evaluated their toxicity on a normal human foreskin fibroblast cell line (BJ). In both cell lines, we also measured specific indicators of cell death, changes in cell membrane permeability (CMP), and mitochondrial membrane potential (MMP). Even at a low bioavailable concentration, genistein and curcumin decreased MOLT-4 viability, and their combination had a significant interactive effect. While resveratrol and quercetin did not affect MOLT-4 viability, together they enhanced the effect of the genistein/curcumin mix, significantly inhibiting MOLT-4 population growth in vitro. Moreover, the analyzed phytochemicals and their combinations did not affect the BJ cell line. In both cell lines, they induced a decrease in MMP and correlating CMP changes, but in non-tumor cells, both metabolic activity and cell membrane continuity were restored in time. (4) Conclusions: The results indicate that the interactive activity of analyzed phytochemicals can induce an anti-cancer effect on ALL cells without a significant effect on non-tumor cells. It implies that the application of the combinations of phytochemicals an anti-cancer treatment supplement could be worth further investigation regardless of their low bioavailability.

Turmeric and its bioactive constituents trigger cell signaling mechanisms that protect against diabetes and cardiovascular diseases

Turmeric, the rhizome of Curcuma longa plant belonging to the ginger family Zingiberaceae, has a history in Ayurvedic and traditional Chinese medicine for treatment of chronic diseases, including metabolic and cardiovascular diseases (CVD). This parallels a prevalence of age- and lifestyle-related diseases, especially CVD and type 2 diabetes (T2D), and associated mortality which has occurred in recent decades. While the chemical composition of turmeric is complex, curcuminoids and essential oils are known as two major groups that display bioactive properties. Curcumin, the most predominant curcuminoid, can modulate several cell signaling pathways involved in the etiology and pathogenesis of CVD, T2D, and related morbidities. Lesser bioactivities have been reported from other curcuminoids and essential oils. This review examines the chemical compositions of turmeric, and related bioactive constituents. A focus was placed on the cellular and molecular mechanisms that underlie the protective effects of turmeric and turmeric-derived compounds against diabetes and CVD, compiled from the findings obtained with cell-based and animal models. Evidence from clinical trials is also presented to identify potential preventative and therapeutic efficacies. Clinical studies with longer intervention durations and specific endpoints for assessing health outcomes are warranted in order to fully evaluate the long-term protective efficacy of turmeric.

Synergistic effect of the anti-PD-1 antibody with blood stable and reduction sensitive curcumin micelles on colon cancer

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) is a potent anticancer drug with versatile biological activities, while the clinical translation of curcumin is severely limited due to its hydrophobicity, rapid elimination, and metabolism in the blood circulation. Herein, we aim to unravel the potential of curcumin as a synergistic agent with immunotherapy in the treatment of cancers. In an effort to minimize premature release and improve the systemic bioavailability, a superior blood stable and reduction sensitive curcumin micellar formulation, of which the release can be triggered by cancer cells, is rationally designed. We have synthesized a telodendrimer (mPEG-PLA-(LA)₄) capable of forming reversible disulfide crosslinked micelles (DCMs). The curcumin loaded DCMs (Cur/DCMs) are spherical with a uniform size of 24.6 nm. The in vitro release profile demonstrates that curcumin releases significantly slower from DCMs than that from non-crosslinked micelles (NCMs), while the release can be accelerated with the increasing concentration of reducing agent glutathione (GSH). Intravenous administration of Cur/DCMs stably retains curcumin in the bloodstream and efficiently improves the systemic bioavailability. Furthermore, Cur/DCMs exhibit synergistic anticancer efficacy when combined with the anti-PD-1 antibody in an MC-38 colon cancer xenograft model. Our results potentiate the integration of blood stable curcumin nanoformulation and immunotherapy for cancer treatment.

Design of New Improved Curcumin Derivatives to Multi-targets of Cancer and Inflammation

BACKGROUND

Curcumin is a major active principle of Curcuma longa. There are more than 1700 citations in the Medline, reflecting various biological effects of curcumin. Most of these biological activities are associated with the antioxidant, anti-inflammatory and antitumor activity of the molecule. Several reports suggest various targets of natural curcumin that include growth factors, growth factor receptor, cytokines, enzymes and gene regulators of apoptosis. This review focuses on the improved curcumin derivatives that target the cancer and inflammation.

METHODOLOGY

In this present review, we explored the anticancer drugs with curcumin-based drugs under pre-clinical and clinical studies with critical examination. Based on the strong scientific reports of patentable and non-patented literature survey, we have investigated the mode of the interactions of curcumin-based molecules with the target molecules.

RESULTS

Advanced studies have added new dimensions of the molecular response of cancer cells to curcumin at the genomic level. However, poor bioavailability of the molecule seems to be the major limitation of the curcumin. Several researchers have been involved to improve the curcumin derivatives to overcome this limitation. Sufficient data of clinical trials to various cancers that include multiple myeloma, pancreatic cancer and colon cancer, have also been discussed.

CONCLUSION

The detailed analysis of the structure-activity relationship (SAR) and common synthesis of curcumin-based derivatives have been discussed in the review. Utilising the predictions of in silico coupled with validation reports of in vitro and in vivo studies have concluded many targets for curcumin. Among them, cancer-related inflammation genes regulating curcumin-based molecules are a very promising target to overcome hurdles in the multimodality therapy of cancer.

Nutritional implications of ginger: chemistry, biological activities and signaling pathways

Ginger (Zingiber officinale Roscoe) has been used as a food, spice, supplement and flavoring agent and in traditional medicines due to its beneficial characteristics such as pungency, aroma, nutrients and pharmacological activity. Ginger and ginger extracts were reported to have numerous effects, such as those on diabetes and metabolic syndrome, cholesterol levels and lipid metabolism, and inflammation, revealed by epidemiological studies. To understand the beneficial characteristics of ginger, especially its physiological and pharmacological activities at the molecular level, the biological effects of ginger constituents, such as monoterpenes (cineole, citral, limonene and α/β-pinenes), sesquiterpenes (β-elemene, farnesene and zerumbone), phenolics (gingerols, [6]-shogaol, [6]-paradol and zingerone) and diarylheptanoids (curcumin), and the associated signaling pathways are summarized. Ginger constituents are involved in biological activities, such as apoptosis, cell cycle/DNA damage, chromatin/epigenetic regulation, cytoskeletal regulation and adhesion, immunology and inflammation, and neuroscience, and exert their effects through specific signaling pathways associated with cell functions/mechanisms such as autophagy, cellular metabolism, mitogen-activated protein kinase and other signaling, and development/differentiation. Estrogens, such as phytoestrogens, are one of the most important bioactive materials in nature, and the molecular mechanisms of estrogen actions and the assays to detect them have been discussed. The molecular mechanisms of estrogen actions induced by ginger constituents and related applications, such as the chemoprevention of cancers, and the improvement of menopausal syndromes, osteoporosis, endometriosis, prostatic hyperplasia, polycystic ovary syndrome and Alzheimer's disease, were summarized by a comprehensive search of references to understand more about their health benefits and associated health risks.

An Update on the Pharmacological Usage of Curcumin: Has it Failed in the Drug Discovery Pipeline?

The pharmacological propensities of curcumin have been reported in a plethora of pre-clinical and clinical studies. However, innate attributes account for extremely low oral bioavailability which impedes its development as a therapeutic agent. Regardless, these drawbacks have not deterred researchers from optimizing its potentials. This review discussed the pharmacokinetic properties of curcumin relative to its outlook as a lead compound in drug discovery. Also, we highlighted therapeutic strategies that have expedited improvements in curcumin oral bioavailability and delivery to target sites over the years. Recent implementations of these strategies were also covered. More research efforts should be directed towards investigating the pharmacokinetic impacts of these novel curcumin formulations in human clinical studies since inter-species disparities could limit the accuracies of animal studies. We envisaged that integrative-clinical research would help determine 'actual' improvements in curcumin pharmacokinetics coupled with suitable administrative routes, optimal dosing, and drug-enzyme or drug-drug interactions. In addition, this could help determine formulations for achieving higher systemic exposure of parent curcumin thereby providing a strong impetus towards the development of curcumin as a drug candidate in disease treatment.

The Power of Phytochemicals Combination in Cancer Chemoprevention

Conventional therapies for cancer treatment have posed many challenges, including toxicity, multidrug resistance and economic expenses. In contrast, complementary alternative medicine (CAM), employing phytochemicals have recently received increased attention owing to their capability to modulate a myriad of molecular mechanisms with a less toxic effect. Increasing evidence from preclinical and clinical studies suggest that phytochemicals can favorably modulate several signaling pathways involved in cancer development and progression. Combinations of phytochemicals promote cell death, inhibit cell proliferation and invasion, sensitize cancerous cells, and boost the immune system, thus making them striking alternatives in cancer therapy. We previously investigated the effect of six phytochemicals (Indol-3-Carbinol, Resveratrol, C-phycocyanin, Isoflavone, Curcumin and Quercetin), at their bioavailable levels on breast cancer cell lines and were compared to primary cell lines over a period of 6 days. This study showed the compounds had a synergestic effect in inhibiting cell proliferation, reducing cellular migration and invasion, inducing both cell cycle arrest and apoptosis. Despite the vast number of basic science and preclinical cancer studies involving phytochemicals, the number of CAM clinical trials in cancer treatment still remains nascent. In this review, we summarize findings from preclinical and clinical studies, including our work involving use of phytochemicals, individually as well as in combination and further discuss the potential of these phytochemicals to pave way to integrate CAM in primary health care.

Cytotoxic and Antibiotic Potential of Secondary Metabolites from the Lichen Umbilicaria muhlenbergii

OBJECTIVE

Lichens are emerging as a promising natural source of bioactivities of pharmaceutical interest. The present study aims to contribute to the knowledge of the lichen Umbilicaria muhlenbergii as a potential source of pharmaceutically relevant anticancer and antibiotic lichen chemicals.

METHODS

The crude acetone extract of U. muhlenbergii exhibited 13.3 μg mL-1 cytotoxic activity (EC50) against breast cancer cells (MCF-7), as compared to a cisplatin positive control with EC50 of 5.8 μg mL-1. The antibiotic activity of the crude extract against a gram-positive Staphylococcus aureus was 22.5 μg mL-1 as MIC. Using silica gel 60 (SG60) column chromatography, the crude extract was then separated into eight fractions, which were further evaluated for their anticancer activities against MCF-7 cells. By means of propidium iodide flow cytometry, two of the eight SG60 fractions were found to cause cell cycle arrest in MCF-7 cells (73.14% of cells) at the G2 phase, which is indicative of apoptosis and inhibition of cellular proliferation.

RESULTS

Identification of chemical constituents present in these two SG60 fractions was carried out with Thin-Layer Chromatography (TLC) and a lichen metabolite database (Wintabolites). The two fractions (SG60-5 and SG60-6) were found to contain compounds belonging to the chemical families depsides, depsidones, anthraquinones, and xanthones.

DISCUSSION

The SG60-5 and SG60-6 fractions were further fractionated with Sephadex LH-20. Over 15% of the 46 LH-20 fractions obtained from the SG60-5 fraction caused 100% cell death, whereas 32% of the LH-20 fractions derived from SG60 6 fraction reduced cell survival to below 20%.

CONCLUSION

This work extends the evaluation of the cytotoxic and antibiotic activities of lichen secondary metabolites to the species U. muhlenbergii. It presents encouraging results of pharmaceutical interest that set up lichens as an effective source of new bioactive natural products. Further investigations are underway to reveal the full biopharmaceutical potential of U. muhlenbergii.

Curcumin: a phytochemical modulator of estrogens and androgens in tumors of the reproductive system

Curcumin (Cur) is an active derivative extracted from turmeric which exerts a wide range of interactions with biomolecules through complex signaling pathways. Cur has been extensively shown to possess potential antitumor properties. In addition, there is growing body of evidence suggesting that Cur may exert potential anti-estrogen and anti-androgen activity. In vitro and in vivo studies suggest that anticancer properties of Cur against tumors affecting the reproductive system in females and males may be underlied by the Cur-mediated inhibition of androgen and estrogen signaling pathways. In this review we examine various studies assessing the crosstalk between Cur and both androgen and estrogen hormonal activity. Also, we discuss the potential chemopreventive and antitumor role of Cur in the most prevalent cancers affecting the reproductive system in females and males.

Synergistic immuno-modulatory activity in human macrophages of a medicinal mushroom formulation consisting of Reishi, Shiitake and Maitake

A key characteristic of mushroom polysaccharides that elicit an immunomodulatory response is that they are rich in β-glucans and low in α-glucans. In this study we analysed nine commercially available preparations from three mushroom species, Reishi (Ganoderma lucidum), Shiitake (Lentinula edodes) and Maitake (Grifola frondosa), for β- and α-glucan content. Based on β- and α-glucan content we selected three extracts to combine into a formula and evaluated the ability of the individual extracts and formula to impact on the expression of cytokines IL-1α, IL-6, IL-10 and TNF-α in human macrophages with and without LPS stimulation. The majority of mushroom extracts and the formula were found to be highly potent immuno-stimulators possessing EC50 values lower than 100 μg/mL. Interestingly the mushroom formula had lower EC50 values in TNF-α expression from LPS stimulated macrophages compared to the individual extracts, suggesting a potential synergistic effect of the mushroom formula. A response additivity graph and curve-shift analysis illustrated that indeed the mushroom formula exhibited an immuno-stimulatory synergistic effect on the expression of the majority of cytokines evaluated in both LPS stimulated and non-stimulated human macrophages, with IL-10 having an antagonistic response. This study represents the first report of a synergistic immuno-modulatory response in human macrophages elicited from a mushroom formula rationally derived from β- and α-glucan content.

Curcumin Mitigates Immune-Induced Epithelial Barrier Dysfunction by Campylobacter jejuni

Campylobacter jejuni (C. jejuni) is the most common cause of foodborne gastroenteritis worldwide. The bacteria induce diarrhea and inflammation by invading the intestinal epithelium. Curcumin is a natural polyphenol from turmeric rhizome of Curcuma longa, a medical plant, and is commonly used in curry powder. The aim of this study was the investigation of the protective effects of curcumin against immune-induced epithelial barrier dysfunction in C. jejuni infection. The indirect C. jejuni-induced barrier defects and its protection by curcumin were analyzed in co-cultures with HT-29/B6-GR/MR epithelial cells together with differentiated THP-1 immune cells. Electrophysiological measurements revealed a reduction in transepithelial electrical resistance (TER) in infected co-cultures. An increase in fluorescein (332 Da) permeability in co-cultures as well as in the germ-free IL-10^−/− mouse model after C. jejuni infection was shown. Curcumin treatment attenuated the C. jejuni-induced increase in fluorescein permeability in both models. Moreover, apoptosis induction, tight junction redistribution, and an increased inflammatory response—represented by TNF-α, IL-1β, and IL-6 secretion—was observed in co-cultures after infection and reversed by curcumin. In conclusion, curcumin protects against indirect C. jejuni-triggered immune-induced barrier defects and might be a therapeutic and protective agent in patients.

Curcumae Radix Extract Decreases Mammary Tumor-Derived Lung Metastasis via Suppression of C-C Chemokine Receptor Type 7 Expression

Curcumae radix is the dry root of Curcuma longa L. (turmeric) that can be used either as a spice or traditional medicine. The aim of this study was to investigate the survival benefits and the anti-metastatic activity of curcumae radix extract (CRE) in MCF7 cells and in MMTV-PyMT transgenic mice—a mouse model of breast cancer metastasis. In vitro wound scratch assay revealed that CRE treatment inhibited cell motility and cell migration in a dose-dependent manner. To investigate the effect of CRE in breast cancer metastasis, MMTV-PyMT transgenic female virgin mice were used and randomly divided into two groups. For survival curve analysis, CRE was administered in a dose of 50 mg/kg to 8–20-week-old mice. Interestingly, CRE treatment significantly increased the median and prolonged survival of MMTV-PyMT mice. Furthermore, CRE treatment decreased tumor burden and inhibited cell proliferation in primary breast tumor, and also suppressed mammary tumor-derived lung metastasis. The size of the lung metastases substantially decreased in the CRE-treated group compared with the ones in the control group. Curcumae radix extract showed anti-metastatic activity through regulating the expression of metastasis markers including C-C Chemokine Receptor Type 7, Matrix Metalloproteinase 9 and the proto-oncogenes c-fos and c-jun. We demonstrated that these metastatic regulators were decreased when CCR7 expression was suppressed in MCF7 cells transfected with CCR7 siRNA. The results of this study show that curcumae radix exerts antitumor and anti-metastatic activities, and we suggest that curcumae radix might be a potential supplement for the treatment and prevention of breast cancer metastasis.

Curcumin-Loaded Blood-Stable Polymeric Micelles for Enhancing Therapeutic Effect on Erythroleukemia

Curcumin has high potential in suppressing many types of cancer and overcoming multidrug resistance in a multifaceted manner by targeting diverse molecular targets. However, the rather low systemic bioavailability resulted from its poor solubility in water and fast metabolism/excretion in vivo has hampered its applications in cancer therapy. To increase the aqueous solubility of curcumin while retaining the stability in blood circulation, here we report curcumin-loaded copolymer micelles with excellent in vitro and in vivo stability and antitumor efficacy. The two copolymers used for comparison were methoxy-poly(ethylene glycol)-block-poly(ε-caprolactone) (mPEG-PCL) and N-(tert-butoxycarbonyl)-l-phenylalanine end-capped mPEG-PCL (mPEG-PCL-Phe(Boc)). In vitro cytotoxicity evaluation against human pancreatic SW1990 cell line showed that the delivery of curcumin in mPEG-PCL-Phe(Boc) micelles to cancer cells was efficient and dosage-dependent. The pharmacokinetics in ICR mice indicated that intravenous (i.v.) administration of curcumin/mPEG-PCL-Phe(Boc) micelles could retain curcumin in plasma much better than curcumin/mPEG-PCL micelles. Biodistribution results in Sprague-Dawley rats also showed higher uptake and slower elimination of curcumin into liver, lung, kidney, and brain, and lower uptake into heart and spleen of mPEG-PCL-Phe(Boc) micelles, as compared with mPEG-PCL micelles. Further in vivo efficacy evaluation in multidrug-resistant human erythroleukemia K562/ADR xenograft model revealed that i.v. administration of curcumin-loaded mPEG-PCL-Phe(Boc) micelles significantly delayed tumor growth, which was attributed to the improved stability of curcumin in the bloodstream and increased systemic bioavailability. The mPEG-PCL-Phe(Boc) micellar system is promising in overcoming the key challenge of curcumin's to promote its applications in cancer therapy.

Impact of Phytochemicals and Dietary Patterns on Epigenome and Cancer

Cancer remains one of the leading causes of death around the world. Initially it is recognized as a genetic disease, but now it is known to involve epigenetic abnormalities along with genetic alterations. Epigenetics refers to heritable changes that are not encoded in the DNA sequence itself, but play an important role in the control of gene expression. It includes changes in DNA methylation, histone modifications, and RNA interference. Although it is heritable, environmental factors such as diet could directly influence epigenetic mechanisms in humans. This article will focus on the role of dietary patterns and phytochemicals that have been demonstrated to influence the epigenome and more precisely histone and non-histone proteins modulation by acetylation that helps to induce apoptosis and phosphorylation inhibition, which counteracts with cells proliferation. Recent developments discussed here enhance our understanding of how dietary intervention could be beneficial in preventing or treating cancer and improving health outcomes.

Role of dietary bioactive natural products in estrogen receptor-positive breast cancer

Estrogen receptor (ER)-positive breast cancer, including luminal-A and -B, is the most common type of breast cancer. Extended exposure to estrogen is associated with an increased risk of breast cancer. Both ER-dependent and ER-independent mechanisms have been implicated in estrogen-mediated carcinogenesis. The ER-dependent pathway involves cell growth and proliferation triggered by the binding of estrogen to the ER. The ER-independent mechanisms depend on the metabolism of estrogen to generate genotoxic metabolites, free radicals and reactive oxygen species to induce breast cancer. A better understanding of the mechanisms that drive ER-positive breast cancer will help optimize targeted approaches to prevent or treat breast cancer. A growing emphasis is being placed on alternative medicine and dietary approaches toward the prevention and treatment of breast cancer. Many natural products and bioactive compounds found in foods have been shown to inhibit breast carcinogenesis via inhibition of estrogen induced oxidative stress as well as ER signaling. This review summarizes the role of bioactive natural products that are involved in the prevention and treatment of estrogen-related and ER-positive breast cancer.

The increased binding affinity of curcumin with human serum albumin in the presence of rutin and baicalin: A potential for drug delivery system

The impacts of rutin and baicalin on the interaction of curcumin (CU) with human serum albumin (HSA) were investigated by fluorescence and circular dichroism (CD) spectroscopies under imitated physiological conditions. The results showed that the fluorescence quenching of HSA by CU was a simultaneous static and dynamic quenching process, irrespective of the presence or absence of flavonoids. The binding constants between CU and HSA in the absence and presence of rutin and baicalin were 2.268×10(5)M(-1), 3.062×10(5)M(-1), and 3.271×10(5)M(-1), indicating that the binding affinity was increased in the case of two flavonoids. Furthermore, the binding distance determined according to Förster's theory was decreased in the presence of flavonoids. Combined with the fact that flavonoids and CU have the same binding site (site I), it can be concluded that they may simultaneously bind in different regions in site I, and formed a ternary complex of flavonoid-HSA-CU. Meanwhile, the results of fluorescence quenching, CD and three-dimensional fluorescence spectra revealed that flavonoids further strengthened the microenvironmental and conformational changes of HSA induced by CU binding. Therefore, it is possible to develop a novel complex involving CU, flavonoid and HSA for CU delivery. The work may provide some valuable information in terms of improving the poor bioavailabiliy of CU.

Phytochemicals as Innovative Therapeutic Tools against Cancer Stem Cells

The theory that several carcinogenetic processes are initiated and sustained by cancer stem cells (CSCs) has been validated, and specific methods to identify the CSCs in the entire population of cancer cells have also proven to be effective. This review aims to provide an overview of recently acquired scientific knowledge regarding phytochemicals and herbal extracts, which have been shown to be able to target and kill CSCs. Many genes and proteins that sustain the CSCs’ self-renewal capacity and drug resistance have been described and applications of phytochemicals able to interfere with these signaling systems have been shown to be operatively efficient both in vitro and in vivo. Identification of specific surface antigens, mammosphere formation assays, serial colony-forming unit assays, xenograft transplantation and label-retention assays coupled with Aldehyde dehydrogenase 1 (ALDH1) activity evaluation are the most frequently used techniques for measuring phytochemical efficiency in killing CSCs. Moreover, it has been demonstrated that EGCG, curcumin, piperine, sulforaphane, β-carotene, genistein and the whole extract of some plants are able to kill CSCs. Most of these phytochemicals act by interfering with the canonical Wnt (β-catenin/T cell factor-lymphoid enhancer factor (TCF-LEF)) pathway implicated in the pathogenesis of several cancers. Therefore, the use of phytochemicals may be a true therapeutic strategy for eradicating cancer through the elimination of CSCs.

Diet-based strategies for cancer chemoprevention: the role of combination regimens using dietary bioactive components

Chemopreventive agents that the general population can consume for prolonged periods of time with minimal risk of any side effects are of great interest to all in search of a solution to the pervasive incidence of cancer. Dietary bioactive components have been found to modulate many deregulated molecular pathways associated with the initiation and progression of different types of cancer. Combination regimens with dietary bioactive components are a promising strategy for cancer chemoprevention because they may offer enhanced protective effects against cancer development but cause little or no adverse effects. This article provides an overview of studies examining the combination of dietary bioactive components for the chemoprevention of major types of cancer. A better understanding of existing research on the combination of dietary bioactive components will provide an important basis for the rational design of future combination studies and the successful development of cancer chemoprevention strategies.

Phytochemicals perturb membranes and promiscuously alter protein function

A wide variety of phytochemicals are consumed for their perceived health benefits. Many of these phytochemicals have been found to alter numerous cell functions, but the mechanisms underlying their biological activity tend to be poorly understood. Phenolic phytochemicals are particularly promiscuous modifiers of membrane protein function, suggesting that some of their actions may be due to a common, membrane bilayer-mediated mechanism. To test whether bilayer perturbation may underlie this diversity of actions, we examined five bioactive phenols reported to have medicinal value: capsaicin from chili peppers, curcumin from turmeric, EGCG from green tea, genistein from soybeans, and resveratrol from grapes. We find that each of these widely consumed phytochemicals alters lipid bilayer properties and the function of diverse membrane proteins. Molecular dynamics simulations show that these phytochemicals modify bilayer properties by localizing to the bilayer/solution interface. Bilayer-modifying propensity was verified using a gramicidin-based assay, and indiscriminate modulation of membrane protein function was demonstrated using four proteins: membrane-anchored metalloproteases, mechanosensitive ion channels, and voltage-dependent potassium and sodium channels. Each protein exhibited similar responses to multiple phytochemicals, consistent with a common, bilayer-mediated mechanism. Our results suggest that many effects of amphiphilic phytochemicals are due to cell membrane perturbations, rather than specific protein binding.

Why it is necessary to translate curcumin into clinical practice for the prevention and treatment of metabolic syndrome?

Curcumin (diferuloylmethane) is the yellow-orange pigment of dried Curcuma longa L. rhizomes (turmeric). During the past two decades, there has been a large volume of published studies describing the biological and pharmacological properties of this phytochemical including anticancer, anti-inflammatory, antioxidant, antithrombotic, antiatherosclerotic, cardioprotective, neuroprotective, memory enhancing, antiparkinsonism, antirheumatic, anti-infectious, antiaging, antipsoriatic, and anticonvulsant activities. In addition, curcumin has been shown to be extremely safe and interact with multiple molecular targets that are involved in the pathogenesis of metabolic syndrome. Curcumin could favorably affect all leading components of metabolic syndrome including insulin resistance, obesity, hypertriglyceridemia, decreased HDL-C and hypertension, and prevent the deleterious complications of MetS including diabetes and cardiovascular disease. Owing to its antioxidant and anti-inflammatory properties, curcumin can also exert several pleiotropic effects and improve endothelial dysfunction, adipokine imbalances, and hyperuricemia which usually accompany MetS. Despite the potential tremendous benefit of this multifaceted phytopharmaceutical, no trial result has yet been publicized on this issue. This review seeks to briefly summarize the ample scientific evidence that supports the therapeutic efficacy of curcumin, at least as an adjunctive treatment, in patients with MetS.

DNA Repair and Cancer Therapy: Targeting APE1/Ref-1 Using Dietary Agents

Epidemiological studies have demonstrated the cancer protective effects of dietary agents and other natural compounds isolated from fruits, soybeans, and vegetables on neoplasia. Studies have also revealed the potential for these natural products to be combined with chemotherapy or radiotherapy for the more effective treatment of cancer. In this paper we discuss the potential for targeting the DNA base excision repair enzyme APE1/Ref-1 using dietary agents such as soy isoflavones, resveratrol, curcumin, and the vitamins ascorbate and α-tocopherol. We also discuss the potential role of soy isoflavones in sensitizing cancer cells to the effects of radiotherapy. A comprehensive review of the dual nature of APE1/Ref-1 in DNA repair and redox activation of cellular transcription factors, NF-κB and HIF-1α, is also discussed. Further research efforts dedicated to delineating the role of APE1/Ref-1 DNA repair versus redox activity in sensitizing cancer cells to conventional treatment are warranted.

Apoptotic effects of curcumin on human osteosarcoma U2OS cells

OBJECTIVE

 Curcumin, an active ingredient derived from the rhizome of the plant, Curcuma longa, has antioxidant, anti-inflammatory and anti-cancer activities. The aims of this study were to examine whether curcumin can induce apoptosis in an osteosarcoma cell line.

METHODS

Curcumin-induced apoptosis in human osteosarcoma U2OS cells was investigated using morphological analysis, marked nuclear condensation and fragmentation of chromatin, which were observed by Hoechst 33258 staining and DNA ladder formation. The U2OS cells were treated with or without curcumin. Cell viability was assessed by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium (MTT) method. Cell-cycle, apoptosis and apoptosis-related proteins in U2OS cells were evaluated by flow cytometry and western blotting.

RESULTS

Curcumin showed growth inhibitory effects on U2OS cells in a dose-and time-dependent manner, inducing significant G1 arrest and apoptosis in U2OS cells. This curcumin-induced apoptosis in U2OS cells was accompanied by up-regulation of Bax, Bak, and p-Bad and down-regulation of Bcl-2, but no effect on the levels of Bcl-X(L) or Bad proteins was noted. Moreover, curcumin treatment resulted in a significant reduction of mitochondrial membrane potential and increase in the concentrations of mitochondrial cytochrome C and caspase-3.

CONCLUSION

Multiple molecular pathways are involved in curcumin-induced apoptosis of human U2OS cells. These include pro-and anti-apoptotic Bcl-2 family proteins, mitochondrial membrane potential, mitochondrial cytochrome C and caspase-3.

Curcumin: an anti-inflammatory molecule from a curry spice on the path to cancer treatment

Oxidative damage and inflammation have been pointed out in preclinical studies as the root cause of cancer and other chronic diseases such as diabetes, hypertension, Alzheimer's disease, etc. Epidemiological and clinical studies have suggested that cancer could be prevented or significantly reduced by treatment with anti-oxidant and anti-inflammatory drugs, therefore, curcumin, a principal component of turmeric (a curry spice) showing strong anti-oxidant and anti-inflammatory activities, might be a potential candidate for the prevention and/or treatment of cancer and other chronic diseases. However, curcumin, a highly pleiotropic molecule with an excellent safety profile targeting multiple diseases with strong evidence on the molecular level, could not achieve its optimum therapeutic outcome in past clinical trials, largely due to its low solubility and poor bioavailability. Curcumin can be developed as a therapeutic drug through improvement in formulation properties or delivery systems, enabling its enhanced absorption and cellular uptake. This review mainly focuses on the anti-inflammatory potential of curcumin and recent developments in dosage form and nanoparticulate delivery systems with the possibilities of therapeutic application of curcumin for the prevention and/or treatment of cancer.

[Effect of curcumin on nitric oxide induced structural and functional modifications of high molecular weight cystatin from the goat brain]

Cystatins are thiol proteinase inhibitors ubiquitously present in the mammalian body. In brain, they prevent unwanted proteolysis and are involved in several neurodegenerative diseases. Under physiological conditions nitric oxide can be found in almost all the tissues, but under pathological conditions NO has damaging effects. Its increased concentration, under various neural diseases leads to cell damage through formation of highly reactive peroxynitrite. Our present study was designed to investigate the protective effect of curcumin against NO induced damage of HM-GBC. NO caused intensive structural and functional damage of HM-GBC, resulting in 89% loss of its antiproteolytic activity after 2 h of incubation. Structural damage occurs in the form of protein degradation. Curcumin significantly protected HM-GBC against this damage. This suggests that curcumin has a significant potential in the treatment of diseases caused by nitrogen free radicals and this potential must be further explored for the development of novel drugs.

Chemopreventive potential of natural compounds in head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is one of the most fatal cancers worldwide. Despite advances in the management of HNSCC, the overall survival for patients has not improved significantly due to advanced stages at diagnosis, high recurrence rate after surgical removal, and second primary tumor development, which underscore the importance of novel strategies for cancer prevention. Cancer chemoprevention, the use of natural or synthetic compounds to prevent, arrest, or reverse the process of carcinogenesis at its earliest stages, aims to reverse premalignancies and prevent second primary tumors. Genomics and proteomics information including initial mutation, cancer promotion, progression, and susceptibility has brought molecularly targeted therapies for drug development. The development of preventive approaches using specific natural or synthetic compounds, or both, requires a depth of understanding of the cross-talk between cancer signaling pathways and networks to retain or enhance chemopreventive activity while reducing known toxic effects. Many natural dietary compounds have been identified with multiple molecular targets, effective in the prevention and treatment of cancer. This review describes recent advances in the understanding of the complex signaling networks driving cancer progression and of molecularly targeted natural compounds under preclinical and clinical investigation.

Assessing combined toxicity of estrogen receptor agonists in a primary culture of rainbow trout (Oncorhynchus mykiss) hepatocytes

The presence of highly complex mixtures of chemicals in the environment challenges our ability to assess single chemical effects and the interaction that occurs with cellular receptor targets and regulation of endocrine processes. In this study concentration addition (CA) and independent action (IA) prediction models were used to assess the combined toxicity of mixtures of environmental relevant estrogen receptor (ER) agonists (hormones and anthropogenic pollutants) in a primary culture of rainbow trout (Oncorhynchus mykiss) hepatocytes using the ER-mediated production of vitellogenin (Vtg) as a biological marker (biomarker) for estrogenicity. Nine of the eleven tested chemicals induced the production of Vtg and the parameters from the fitted concentration-response curves were used to model four mixtures containing four (17β-estradiol, estrone, estriol and diethylstilbestrol), five (musk ketone, 4-tert-octylphenol, bisphenol A, o,p'-DDT and dibenzothiophene), seven (17β-estradiol, estrone, estriol, diethylstilbestrol, 4-tert-octylphenol, bisphenol A and o,p'-DDT) and nine compounds (17β-estradiol, estrone, estriol, diethylstilbestrol, musk ketone, 4-tert-octylphenol, bisphenol A, o,p'-DDT and dibenzothiophene). The CA and IA prediction model proved to be a good estimation for the combined effect of mixtures of ER agonists at low relative mixture concentration (e.g. relative to the maximum mixture concentrations used), but a deviation from the prediction models was observed when exposing hepatocytes to high relative mixture concentrations. The CA and IA prediction models' ability to predict the combined estrogenic effect of complex mixtures, especially in the low concentration-response range, is of ecological relevance since organisms in the environment generally encounter low concentrations of chemicals from a wide array of chemical groups that may not elicit estrogenic effects on their own.

Cancer prevention with natural compounds

Botanical and nutritional compounds have been used for the treatment of cancer throughout history. These compounds also may be useful in the prevention of cancer. Population studies suggest that a reduced risk of cancer is associated with high consumption of vegetables and fruits. Thus, the cancer chemopreventive potential of naturally occurring phytochemicals is of great interest. There are numerous reports of cancer chemopreventive activity of dietary botanicals, including cruciferous vegetables such as cabbage and broccoli, Allium vegetables such as garlic and onion, green tea, Citrus fruits, soybeans, tomatoes, berries, and ginger, as well as medicinal plants. Several lead compounds, such as genistein (from soybeans), lycopene (from tomatoes), brassinin (from cruciferous vegetables), sulforaphane (from asparagus), indole-3-carbinol (from broccoli), and resveratrol (from grapes and peanuts) are in preclinical or clinical trials for cancer chemoprevention. Phytochemicals have great potential in cancer prevention because of their safety, low cost, and oral bioavailability. In this review, we discuss potential natural cancer preventive compounds and their mechanisms of action.

Curcumin inhibits human lung large cell carcinoma cancer tumour growth in a murine xenograft model

Curcumin can decrease viable cells through the induction of apoptosis in human lung cancer NCI-H460 cells in vitro. However, there are no reports that curcumin can inhibit cancer cells in vivo. In this study, NCI-H460 lung tumour cells were implanted directly into nude mice and divided randomly into four groups to be treated with vehicle, curcumin (30 mg/kg of body weight), curcumin (45 mg/kg of body weight) and doxorubicin (8 mg/kg of body weight). Each agent was injected once every 4 days intraperitoneally (i.p.), with treatment starting 4 weeks after inoculation with the NCI-H460 cells. Treatment with 30 mg/kg and 45 mg/kg of curcumin or with 8 mg/kg of doxorubicin resulted in a reduction in tumour incidence, size and weight compared with the control group. The findings indicate that curcumin can inhibit tumour growth in a NCI-H460 xenograft animal model in vivo.

Curcumin-the paradigm of a multi-target natural compound with applications in cancer prevention and treatment

As cancer is a multifactor disease, it may require treatment with compounds able to target multiple intracellular components. We summarize here how curcumin is able to modulate many components of intracellular signaling pathways implicated in inflammation, cell proliferation and invasion and to induce genetic modulations eventually leading to tumor cell death. Clinical applications of this natural compound were initially limited by its low solubility and bioavailability in both plasma and tissues but combination with adjuvant and delivery vehicles was reported to largely improve bio-availability of curcumin. Moreover, curcumin was reported to act in synergism with several natural compounds or synthetic agents commonly used in chemotherapy. Based on this, curcumin could thus be considered as a good candidate for cancer prevention and treatment when used alone or in combination with other conventional treatments.

Mechanisms for the activity of heterocyclic cyclohexanone curcumin derivatives in estrogen receptor negative human breast cancer cell lines

Estrogen receptor (ER)-negative breast cancer is an aggressive form that currently requires more drug treatment options. Thus, we have further modified cyclohexanone derivatives of curcumin and examined them for cytotoxicity towards ER-negative human breast cancer cells. Two of the analogs screened elicited increased cytotoxic potency compared to curcumin and other previously studied derivatives. Specifically, 2,6-bis(pyridin-3-ylmethylene)-cyclohexanone (RL90) and 2,6-bis(pyridin-4-ylmethylene)-cyclohexanone (RL91) elicited EC(50) values of 1.54 and 1.10 µM, respectively, in MDA-MB-231 cells and EC(50) values of 0.51 and 0.23 in SKBr3 cells. All other new compounds examined were less potent than curcumin, which elicited EC(50) values of 7.6 and 2.4 µM in MDA-MB-231 and SKBr3 cells, respectively. Mechanistic analyses demonstrated that RL90 and RL91 significantly induced G(2)/M-phase cell cycle arrest and apoptosis. RL90 and RL91 also modulated the expression of key cell signaling proteins, specifically, in SKBr3 cells, protein levels of Her-2, Akt, and NFκB were decreased in a time-dependent manner, while activity of stress kinases JNK1/2 and P38 MAPK were increased. Signaling events in MDA-MB-231 cells were differently implicated, as EGFR protein levels were decreased and activity of GSK-3β transiently decreased, while β-catenin protein level and activity of P38 MAPK, Akt, and JNK1/2 were transiently increased. In conclusion replacement of the phenyl group of cyclohexanone derived curcumin derivatives with heterocyclic rings forms a class of second-generation analogs that are more potent than both curcumin and other derivatives. These new derivatives provide a platform for the further development of drugs for the treatment of ER-negative breast cancer.

Perspectives for cancer prevention with natural compounds

Cancer is the second leading cause of death in the United States. Despite the estimated 565,650 deaths in 2008 of Americans as a result of cancer, it is mostly a preventable disease. Simply by modification of diet, maintenance of optimum body weight, and regular physical activity, 30% to 40% of all instances of cancer could be prevented. Modification of diet alone by increasing vegetable and fruit intake could prevent 20% or more of all cases of cancer and may potentially prevent approximately 200,000 cancer-related deaths annually. Because of their safety, low toxicity, antioxidant properties, and general acceptance as dietary supplements, fruits, vegetables, and other dietary elements (phytochemicals and minerals) are being investigated for the prevention of cancer. Extensive research over the past several decades has identified numerous dietary and botanical natural compounds that have chemopreventive potential. In this review, we discuss promising natural chemopreventive compounds, their molecular targets, and their mechanisms, which may help the further design and conduct of preclinical and clinical trials.

New difluoro Knoevenagel condensates of curcumin, their Schiff bases and copper complexes as proteasome inhibitors and apoptosis inducers in cancer cells

PURPOSE

Emerging evidence clearly suggests the potential chemopreventive and anti-tumor activity of a well known "natural agent" curcumin. However, studies have shown that curcumin is not readily bioavailable, and thus the tissue bioavailability of curcumin is also poor except for gastrointestinal track. Because of the potential biological activity of curcumin, many studies have attempted for making a better analog of curcumin that is equally effective or better with increased bioavailability, which was the purpose of our current study.

METHODS

We have designed and synthesized new difluoro Knoevenagel condensates of curcumin and Schiff bases along with their copper (II) complexes and evaluated their biological activities with respect to the inhibitory effects on purified rabbit 26S proteasome, and growth inhibition and induction of apoptosis in colon and pancreatic cancer cell lines.

RESULTS

All copper complexes possess distorted square planar geometries with 1:1 metal to ligand stoichiometry with reversible copper redox couple. The difluoro compound CDF exhibited inhibitory effects on purified rabbit 20S proteasome or cellular 26S proteasome, and caused both growth inhibition of cancer cell lines and induced apoptotic cell death in our preliminary assessment.

CONCLUSION

Our results suggest that our newly synthesized classes of curcumin analogs could be useful as chemopreventive and/or therapeutic agents against cancers.