Zerumbone, an anti-inflammatory phytochemical, induces expression of proinflammatory cytokine genes in human colon adenocarcinoma cell lines

Anti-cancer potential of zerumbone in cancer and glioma: current trends and future perspectives

Plant-derived immunomodulators and antitumor factors have appealed lots of attention from natural product scientists for their efficiency and safety and their important contribution to well-designed targeted drug action and delivery mechanisms. Zerumbone (ZER), the chief component of Zingiber zerumbet rhizomes, has been examined for its wide-spectrum in the treatment of multi-targeted diseases. The rhizomes have been used as food flavoring agents in numerous cuisines and in flora medication. Numerous in vivo and in vitro experiments have prepared confirmation of ZER as a potent immunomodulator as well as a potential anti-tumor agent. This review is an interesting compilation of all the important results of the research carried out to date to investigate the immunomodulatory and anticancer properties of ZER. The ultimate goal of this comprehensive review is to supply updated information and a crucial evaluation on ZER, including its chemistry and immunomodulating and antitumour properties, which may be of principal importance to supply a novel pathway for subsequent investigation to discover new agents to treat cancers and immune-related sickness. In addition, updated information on the toxicology of ZER has been summarized to support its safety profile.

Zerumbone Sensitizes the Anti-Cancer Efficacy of Cisplatin in Hepatocellular Carcinoma Cells

BACKGROUND

Zerumbone (ZER) possesses potent antiproliferative, apoptotic, and antiangiogenic functions in a variety of cancer cells. Cisplatin (CIS), a well-known chemotherapeutic drug, is effective against different types of cancers. However, the combined effect of ZER and CIS on hepatocellular carcinoma remains unknown.

OBJECTIVE

The present study is attempted to examine the effectiveness of the combination of ZER and CIS in liver cancer in vitro using the hepatocellular carcinoma Huh-7 cell line.

METHODS

Effect of ZER, CIS, and their Combination therapy on cell viability and cytotoxicity was assessed by MTT and LDH leakage assays. Cell cycle and apoptosis analysis were performed by flow cytometry. Quantitative real-time PCR was used to examine the M RNA expression of genes involved in apoptosis, angiogenesis, and invasion. Caspase activities were performed by commercial kit methods in the Huh-7 cell line.

RESULTS

Cells exposed to ZER, CIS individually, and both together significantly inhibited cell proliferation with an IC50 values of 10 µM for ZER and 3µM for CIS. The combination treatment of ZER and CIS revealed a synergistic effect with CI value < 1. CIS treatment either alone or in combination with ZER caused cell cycle arrest at the S phase. More importantly, ZER combined with CIS exhibited synergistic effects by up-regulation of Bax/Bcl-2ratio, leading to caspase cascade activation.

CONCLUSION

In conclusion, the current study indicates that the treatment of ZER combined with CIS in human liver cancer cells exerts synergistic effects on cell growth inhibition, apoptosis induction, angiogenesis and invasion through modulating gene expression.

A promising effect of zerumbone with improved anti-tumor-promoting inflammation activity of miR-34a in colorectal cancer cell lines

Cross-talk among inflammation and colorectal cancer cells is chiefly reported through a complex of cytokines, chemokines, and growth factors. MicroRNA performs strategic roles in controlling a variety of signaling cascades. miR-34a is known as a master regulator of tumor suppression. Combined application of different miRNA-based agents and chemotherapeutic drugs has been used to augment drug sensitivity and may reinforce the antitumor effect. A lot of studies specify a substantial increase in the effectiveness of combination therapies. The anti-inflammatory activity of Zerumbone (ZER) was investigated in many cancers. In this study the level of the inflammatory cytokines including CXCL-12 (SDF-1), CCL-2 (MCP-1), TGF-β and IL-33 has been measured in pmiR-34a-5p transfected and pmiR-34a-5p +ZER treated CRC cell lines (HCT-116 and SW48) by QRT-PCR and ELISA methods, respectively. The results showed that miR-34a could significantly inhibit cytokine expression in both cell lines for 48 and 72 h except SDF-1 which no inhibition was observed in SW48 cells. ZER suppressed SDF-1 for all three time points in both cell lines, while in SW48 cells IL-33 and TGF-β were inhibited in 72 h and in HCT-116 cells MCP-1 diminished for only 24 h and TGF-β diminished for all three times. Combination of both miR-34a and ZER suppressed TGF-β, SDF-1 and MCP-1 in HCT-116 cells in all time points while in SW48 cells, suppression of most cytokines was observed in 48 and 72 h. Furthermore Colony formation assay and scratch test were employed to detect changes of proliferation and migration in CRC transfected and treated cells. Generally, we found that miR-34a could considerably decrease the expression of inflammatory cytokines and the combination of ZER+ miR-34 boosted this effect. Moreover the migration and proliferation decreased in treated and transfected cells and this reduction was more severe in miR-34a +ZER treatment. It is important to note that in the case of cell resistance to each of these therapeutic agents, inhibition of cytokines can be compensated by another one.

Formulation and Nanotechnology-Based Approaches for Solubility and Bioavailability Enhancement of Zerumbone

About 40–70% of drug molecules in the clinical development pipeline suffer from one of either low aqueous solubility, poor absorption, or extremely low bioavailability. Approximately 75% of the world population relies on traditional therapies and therefore there has been a growing interest in the utilization of natural compounds. Zerumbone is one such natural compound, classified as a sesquiterpenoid that is extracted from the essential volatile oils of rhizomes from Zingiber zerumbet. It possesses strong antitumor, antioxidant, antimicrobial, and anti-inflammatory activity. However, despite promising preclinical studies demonstrating the therapeutic utility of zerumbone, its clinical development has been limited due to its low aqueous solubility, poor absorption, or associated low bioavailability. Multiple reviews demonstrating the pharmacological effects of zerumbone for various diseases have been published. However, to our knowledge, no review demonstrates the various formulation strategies developed to overcome the biopharmaceutical challenges of zerumbone. The purpose of this review is to provide a comprehensive perspective on zerumbone as a molecule for formulation development. A section related to pharmacokinetics, toxicity, and patents of zerumbone is included. This review provides the importance of developing novel formulations of zerumbone to overcome its biopharmaceutical challenges thereby advance its potential in the treatment of various diseases.

Remarkable Potential of Zerumbone to Generate a Library with Six Natural Product-like Skeletons by Natural Material-Related Diversity-Oriented Synthesis

Diversity-oriented synthesis (DOS) is an effective strategy for the quick creation of diverse and high three-dimensional compounds from simple starting materials. The selection of a starting material is the key to constructing useful, chemically diverse compound libraries for the development of new drugs. Here, we report a novel, general, and facile strategy for the creation of diverse compounds with high structural diversity from readily available natural products, such as zerumbone, as the synthetic starting material. Zerumbone is the major component of the essential oil from wild ginger, Zingiber zerumbet Smith. It is noteworthy that zerumbone has a powerful latent reactivity, partly because of its three double bonds, two conjugated and one isolated, and a double conjugated carbonyl group in an 11-membered ring structure. In fact, zerumbone has been shown to be a successful example of natural material-related DOS (NMRDOS). We will report that zerumbone can be converted in one chemical step from four zerumbone derivatives into rare and markedly different scaffolds by transannulation.

Gingers and Their Purified Components as Cancer Chemopreventative Agents

Chemoprevention by ingested substituents is the process through which nutraceuticals and/or their bioactive components antagonize carcinogenesis. Carcinogenesis is the course of action whereby a normal cell is transformed into a neoplastic cell. This latter action involves several steps, starting with initiation and followed by promotion and progression. Driving these stages is continued oxidative stress and inflammation, which in turn, causes a myriad of aberrant gene expressions and mutations within the transforming cell population and abnormal gene expressions by the cells within the surrounding lesion. Chemoprevention of cancer with bioreactive foods or their extracted/purified components occurs primarily via normalizing these inappropriate gene activities. Various foods/agents have been shown to affect different gene expressions. In this review, we discuss how the chemoprevention activities of gingers antagonize cancer development.

Potential of Zerumbone as an Anti-Cancer Agent

Cancer is still a major risk factor to public health globally, causing approximately 9.8 million deaths worldwide in 2018. Despite advances in conventional treatment modalities for cancer treatment, there are still few effective therapies available due to the lack of selectivity, adverse side effects, non-specific toxicities, and tumour recurrence. Therefore, there is an immediate need for essential alternative therapeutics, which can prove to be beneficial and safe against cancer. Various phytochemicals from natural sources have been found to exhibit beneficial medicinal properties against various human diseases. Zerumbone is one such compound isolated from Zingiber zerumbet Smith that possesses diverse pharmacological properties including those of antioxidant, antibacterial, antipyretic, anti-inflammatory, immunomodulatory, as well as anti-neoplastic. Zerumbone has shown its anti-cancer effects by causing significant suppression of proliferation, survival, angiogenesis, invasion, and metastasis through the molecular modulation of different pathways such as NF-κB, Akt, and IL-6/JAK2/STAT3 (interleukin-6/janus kinase-2/signal transducer and activator of transcription 3) and their downstream target proteins. The current review briefly summarizes the modes of action and therapeutic potential of zerumbone against various cancers.

Zerumbone inhibits epithelial-mesenchymal transition and cancer stem cells properties by inhibiting the β-catenin pathway through miR-200c

Colorectal cancer (CRC) is one of the most lethal and rampant human malignancies in the world. Zerumbone, a sesquiterpene isolated from subtropical ginger, has been found to exhibit an antitumor effect in various cancer types. However, the effect of Zerumbone on the biological properties of CRC, including epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs) has not been fully elucidated. Here, we investigated the inhibitory action of Zerumbone on the EMT process, CSC markers, and the β-catenin signaling pathway in the presence or absence of miR-200c. The effect of Zerumbone on HCT-116 and SW-48 cells viability was examined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The effects of Zerumbone on EMT-related genes, CSCs markers, cell migration, invasion, sphere-forming, and β-catenin signaling pathway were explored. To evaluate the role of miR-200c in anticancer effects by Zerumbone, miR-200c was downregulated by LNA-anti-miR-200c. Zerumbone significantly inhibited cell viability, migration, invasion, and sphere-forming potential in HCT-116 and SW-48 cell lines. Zerumbone significantly suppressed the EMT and CSC properties as well as downregulated the β-catenin. Silencing of miR200c reduced the inhibitory effects of Zerumbone on EMT and CSCs in CRC cells. These data indicated that Zerumbone may be a promising candidate for reducing the risk of CRC progression by suppressing the β-catenin pathway via miR-200c.

A Review of the Biomedical Applications of Zerumbone and the Techniques for Its Extraction from Ginger Rhizomes

Zerumbone (ZER) is a phytochemical isolated from the subtropical Zingiberaceae family and as a natural compound it has different biomedical properties such as antioxidant, anti-inflammatory anti-proliferative activity. ZER also has effects on angiogenesis and acts as an antitumor drug in the treatment of cancer, showing selective toxicity toward various cancer cell lines. Several techniques also have been established for extraction of ZER from the rhizomes of ginger. This review paper is an overview of recent research about different extraction methods and their efficiencies, in vivo and vitro investigations of ZER and also its prominent chemopreventive properties and treatment mechanisms. Most of the studies mentioned in this review paper may be useful use as a knowledge summary to explain ZER extraction and anticancer activities, which will show a way for the development of strategies in the treatment of malignancies using ZER.

Bioproduction of α-humulene in metabolically engineered Escherichia coli and application in zerumbone synthesis

Zerumbone is a sesquiterpene ketone with potent anti-cancerogenic activities, produced in several ginger species of the Zingiberaceae familiy. We have investigated the biotechnological production of α-humulene, a precursor of zerumbone. By implementing a heterologous mevalonate pathway in combination with the α-humulene synthase expression, we effectively synthesized α-humulene from glucose in Escherichia coli. In this study, we developed a practical and efficient in situ separation method for α-humulene by comparison of extractive and adsorptive strategies. By the in situ adsorption of the product to the hydrophobic resin Amberlite® XAD4 we were able to increase α-humulene yield by 2310% to 60.2 mg/L. Furthermore we present an easy applicable, short subsequent chemical process for the conversion of α-humulene to zerumbone by using transition metal catalysis. To reduce process steps, the chemical reaction was carried out in the same solvent as the eluting solvent that was used to elute α-humulene from the adsorbent resin. By allylic oxidation of α-humulene with manganese^II chloride as a catalyst and tert.-butylhydroperoxide as an oxidizing agent we were able to synthetize zerumbone with a selectivity of 51.6%. Product and byproducts of the oxidation reaction were identified by GC-MS.

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.

Optimization of microwave-assisted extraction of zerumbone from Zingiber zerumbet L. rhizome and evaluation of antiproliferative activity of optimized extracts

Background

The extraction of bioactive compounds from herbal materials requires optimization in order to recover the highest active dose. Response surface methodology was used to optimize variables affecting the microwave extraction of zerumbone from Zingiber zerumbet using the Box–Behnken design. The influence of variables, such as ethanol concentration (X₁), microwave power (X₂), irradiation time (X₃), and liquid-to-solid ratio (X₄), on the extraction of zerumbone was modeled using a second-order regression equation. The antiproliferative activity of optimized and non-optimized extracts was evaluated against the HeLa cancer cell line using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay.

Results

Two linear parameters, X₁ and X₄, and their quadratic parameters were highly significant at the P < 0.01 level. Two interaction parameters, X₁X₄ and X₂X₃ were significant, whereas interactions of X₁X₂, X₁X₃, X₂X₄ and X₃X₄ were insignificant (P > 0.05). The optimum microwave extraction conditions were as follows: ethanol concentration, 44%; microwave power, 518 W; irradiation time, 38.5 s; and liquid-to-solid ratio, 38 mL/g. Under these conditions, the maximum zerumbone yield was 5.88 mg/g DM, which was similar to the predicted value (5.946 mg/g DM). Optimized and non-optimized Z. zerumbet rhizome extracts exhibited significant antiproliferative activity against HeLa cancer cells, with half-maximal inhibitory concentration (IC₅₀) values of 4.3 and 7.8 μg/mL, respectively, compared with 1.68 μg/mL for the anticancer drug cisplatin. When the extract concentration increased from 4.3 to 16.0 μg/mL, the inhibition of cancer cell growth increased from 50.0 to 79.5%.

Conclusions

In this study, the optimized microwave protocol developed for extracting zerumbone from Z. zerumbet was faster and consumed less solvent than previous methods, while improving and enhancing the antiproliferative activity.

Exploring the immunomodulatory and anticancer properties of zerumbone

Plant-derived immunomodulators and anti-cancer agents have attracted a lot of interest from natural product scientists for their efficacy and safety, and their significant contribution towards understanding targeted drug action and drug delivery mechanisms.

Synthesis and in vitro evaluation of zerumbone pendant derivatives: potent candidates for anti-diabetic and anti-proliferative activities

A series of zerumbone pendant derivatives were synthesized and evaluated for their α-glucosidase, α-amylase and glycation inhibition activities.

Terpenoids as anti-colon cancer agents - A comprehensive review on its mechanistic perspectives

Multistep model of colon carcinogenesis has provided the framework to advance our understanding of the molecular basis of colon cancer. This multistage process of carcinogenesis takes a long period to transform from a normal epithelial cell to invasive carcinoma. Thus, it provides enough time to intervene the process of carcinogenesis especially through dietary modification. In spite of the in-depth understanding of the colon cancer etiology and pathophysiology and its association with diet, colon cancer remains a major cause of cancer mortality worldwide. Phytochemicals and their derivatives are gaining attention in cancer prevention and treatment strategies because of cancer chemotherapy associated adverse effects. Being the largest group of phytochemicals traditionally used for medicinal purpose in India and China, terpenoids are recently being explored as anticancer agents. Anticancer properties of terpenoids are associated with various mechanisms like counteraction of oxidative stress, potentiating endogenous antioxidants, improving detoxification potential, disrupting cell survival pathways and inducing apoptosis. This review gives a comprehensive idea of naturally occurring terpenoids as useful agents for the prevention of colon cancer with reference to their classes, sources and molecular targets. Based on the explored molecular targets further research in colon cancer chemoprevention is warranted.

Chemotherapeutic effect of Zerumbone on melanoma cells through mitochondria-mediated pathways

BACKGROUND

Zerumbone (ZER) is a phytochemical that appears to regulate cell proliferation and apoptosis. It has been reported to have an anti-tumour effect in various malignant cells; however, the effect and the mechanism of ZER on melanoma cells needs to be clarified.

AIM

To explore whether ZER has an effect on human melanoma cells and to identify the mechanisms involved.

METHODS

We determined the chemotherapeutic action of ZER on the human malignant melanoma (MM) A375 cell line by CCK-8 immunohistochemistry, Hoechst 33342 staining and flow cytometry analysis. We also investigated the signalling pathways by which ZER induces apoptosis in A375 cells, using western blotting, reverse transcription PCR and caspase-3 activity analysis.

RESULTS

ZER induced significant cytotoxic action in A375 cells. Hoechst 33342 staining and flow cytometry apoptosis analysis further demonstrated that ZER induced apoptosis in A375 cells. Treatment with ZER downregulated Bcl-2 gene and protein levels, upregulated Bax and Cytochrome c gene and protein levels, and activated Caspase-3.

CONCLUSIONS

ZER might have a chemotherapeutic effect on human melanoma cells through mitochondria-mediated pathways.

Possible Contribution of Zerumbone-Induced Proteo-Stress to Its Anti-Inflammatory Functions via the Activation of Heat Shock Factor 1

Zerumbone is a sesquiterpene present in Zinger zerumbet. Many studies have demonstrated its marked anti-inflammatory and anti-carcinogenesis activities. Recently, we showed that zerumbone binds to numerous proteins with scant selectivity and induces the expression of heat shock proteins (HSPs) in hepatocytes. To dampen proteo-toxic stress, organisms have a stress-responsive molecular machinery, known as heat shock response. Heat shock factor 1 (HSF1) plays a key role in this protein quality control system by promoting activation of HSPs. In this study, we investigated whether zerumbone-induced HSF1 activation contributes to its anti-inflammatory functions in stimulated macrophages. Our findings showed that zerumbone increased cellular protein aggregates and promoted nuclear translocation of HSF1 for HSP expression. Interestingly, HSF1 down-regulation attenuated the suppressive effects of zerumbone on mRNA and protein expressions of pro-inflammatory genes, including inducible nitric oxide synthase and interlukin-1β. These results suggest that proteo-stress induced by zerumbone activates HSF1 for exhibiting its anti-inflammatory functions.

Acute toxicity study of zerumbone-loaded nanostructured lipid carrier on BALB/c mice model

Zerumbone- (ZER-) loaded nanostructure lipid carrier (NLC) (ZER-NLC) prepared for its antileukemia effect in vitro was evaluated for its toxicological effects by observing changes in the liver, kidney, spleen, lung, heart, and brain tissues, serum biochemical parameters, total haemogram, and bone marrow stem cells. The acute toxicity study for ZER-NLC was conducted by orally treating BALB/c mice with a single dose with either water, olive oil, ZER, NLC, or ZER-NLC for 14 days. The animals were observed for clinical and behavioral abnormalities, toxicological symptoms, feed consumption, and gross appearance. The liver, kidney, heart, lung, spleen, and brain tissues were assessed histologically. Total haemogram was counted by hemocytometry and microhematocrit reader. Bone marrow examination in terms of cellular morphology was done by Wright staining with bone marrow smear. Furthermore, serum biochemical parameters were determined spectrophotometrically. Grossly all treated mice, their investigated tissues, serum biochemical parameters, total haemogram, and bone marrow were normal. At oral doses of 100 and 200 mg/kg ZER-NLC there was no sign of toxicity or mortality in BALB/c mice. This study suggests that the 50% lethal dose (LD₅₀) of ZER-NLC is higher than 200 mg/kg, thus, safe by oral administration.

Biomedical properties of a natural dietary plant metabolite, zerumbone, in cancer therapy and chemoprevention trials

Zerumbone (ZER) is a naturally occurring dietary compound, present in many natural foods consumed today. The compound derived from several plant species of the Zingiberaceae family that has been found to possess multiple biomedical properties, such as antiproliferative, antioxidant, anti-inflammatory, and anticancer activities. However, evidence of efficacy is sparse, pointing to the need for a more systematic review for assessing scientific evidence to support therapeutic claims made for ZER and to identify future research needs. This review provides an updated overview of in vitro and in vivo investigations of ZER, its cancer chemopreventive properties, and mechanisms of action. Therapeutic effects of ZER were found to be scientifically plausible and could be explained partially by in vivo and in vitro pharmacological activities. Much of the research outlined in this paper will serve as a foundation to explain ZER anticancer bioactivity, which will open the door for the development of strategies in the treatment of malignancies using ZER.

Prevention and Treatment of Colorectal Cancer by Natural Agents From Mother Nature

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the United States after cancers of the lung and the breast/prostate. While the incidence of CRC in the United States is among the highest in the world (approximately 52/100,000), its incidence in countries in India is among the lowest (approximately 7/100,000), suggesting that lifestyle factors may play a role in development of the disease. Whereas obesity, excessive alcohol consumption, a high-calorie diet, and a lack of physical activity promote this cancer, evidence indicates that foods containing folates, selenium, Vitamin D, dietary fiber, garlic, milk, calcium, spices, vegetables, and fruits are protective against CRC in humans. Numerous agents from "mother nature" (also called "nutraceuticals,") that have potential to both prevent and treat CRC have been identified. The most significant discoveries relate to compounds such as cardamonin, celastrol, curcumin, deguelin, diosgenin, thymoquinone, tocotrienol, ursolic acid, and zerumbone. Unlike pharmaceutical drugs, these agents modulate multiple targets, including transcription factors, growth factors, tumor cell survival factors, inflammatory pathways, and invasion and angiogenesis linked closely to CRC. We describe the potential of these dietary agents to suppress the growth of human CRC cells in culture and to inhibit tumor growth in animal models. We also describe clinical trials in which these agents have been tested for efficacy in humans. Because of their safety and affordability, these nutraceuticals provide a novel opportunity for treatment of CRC, an "old age" disease with an "age old" solution.

Zerumbone attenuates the severity of acute necrotizing pancreatitis and pancreatitis-induced hepatic injury

This paper investigated the potential effects of zerumbone pretreatment on an acute necrotizing pancreatitis rat model induced by sodium taurocholate. The pancreatitis injury was evaluated by serum AMY, sPLA2, and pancreatic pathological score. Pancreatitis-induced hepatic injury was measured by ALT, AST, and hepatic histopathology. The expression of I-κBα and NF-κB protein was evaluated by western blot and immunohistochemistry assay while ICAM-1 and IL-1β mRNA were examined by RT-PCR. The results showed that AMY, sPLA2, ALT, and AST levels and histopathological assay of pancreatic and hepatic tissues were significantly reduced following administration of zerumbone. Applying zerumbone also has been shown to inhibit NF-κB protein and downregulation of ICAM-1 and IL-1β mRNA. The present paper suggests that treatment of zerumbone on rat attenuates the severity of acute necrotizing pancreatitis and pancreatitis-induced hepatic injury, via inhibiting NF-κB activation and downregulating the expression of ICAM-1 and IL-1β.

Potential chemoprevention of diethylnitrosamine-initiated and 2-acetylaminofluorene-promoted hepatocarcinogenesis by zerumbone from the rhizomes of the subtropical ginger (Zingiber zerumbet)

Zerumbone (ZER), a monosesquiterpene found in the subtropical ginger (Zingiber zerumbet Smith), possesses antiproliferative properties to several cancer cells lines, including the cervical, skin and colon cancers. In this study, the antitumourigenic effects of ZER were assessed in rats induced to develop liver cancer with a single intraperitoneal injection of diethylnitrosamine (DEN, 200 mg/kg) and dietary 2-acetylaminofluorene (AAF) (0.02%). The rats also received intraperitoneal ZER injections at 15, 30 or 60 mg/kg body wt. twice a week for 11 weeks, beginning week four post-DEN injection. The hepatocytes of positive control (DEN/AAF) rats were smaller with larger hyperchromatic nuclei than normal, showing cytoplasmic granulation and intracytoplasmic violaceous material, which were characteristics of hepatocarcinogenesis. Histopathological evaluations showed that ZER protects the rat liver from the carcinogenic effects of DEN and AAF. Serum alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (AP) and alpha-fetoprotein (AFP) were significantly lower (P<0.05) in ZER-treated than untreated rats with liver cancer. The liver malondialdehyde (MDA) concentrations significantly (P<0.05) increased in the untreated DEN/AAF rats indicating hepatic lipid peroxidation. There was also significant (P<0.05) reduction in the hepatic tissue glutathione (GSH) concentrations. The liver sections of untreated DEN/AAF rats also showed abundant proliferating cell nuclear antigen (PCNA), while in ZER-treated rats the expression of this antigen was significantly (P<0.05) lowered. By the TUNEL assay, there were significantly (P<0.05) higher numbers of apoptotic cells in DEN/AAF rats treated with ZER than those untreated. Zerumbone treatment had also increased Bax and decreased Bcl-2 protein expression in the livers of DEN/AAF rats, which suggested increased apoptosis. Even after 11 weeks of ZER treatment, there was no evidence of abnormality in the liver of normal rats. This study suggests that ZER reduces oxidative stress, inhibits proliferation, induces mitochondria-regulated apoptosis, thus minimising DEN/AAF-induced carcinogenesis in rat liver. Therefore, ZER has great potential in the treatment of liver cancers.

Anti-inflammatory effect of zerumbone on acute and chronic inflammation models in mice

The anti-inflammatory activity of zerumbone (1), a natural cyclic sesquiterpene isolated from Zingiber zerumbet Smith was investigated using carrageenan-induced paw edema and cotton pellet-induced granuloma tissue formation test in mice. It was demonstrated that intraperitoneal administration of 1 at a dose of 5, 10, 50 and 100 mg/kg produced significant dose-dependent inhibition of paw edema induced by carrageenan. It was also demonstrated that 1 at similar doses significantly suppressed granulomatous tissue formation in cotton pellet-induced granuloma test.

Antitumor and antimetastatic effects of licochalcone A in mouse models

Licochalcone A (LicA), a major phenolic constituent of licorice, has antiproliferative and anti-inflammatory properties in human and murine cell lines. We previously showed that LicA down-regulates the expression of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) via the modulation of nuclear factor-kappaB and activator protein-1 activation in cell culture. We therefore tested whether LicA inhibits carcinogenesis and metastasis in mouse models. To induce colon carcinogenesis, C57BL/6 mice were given a single intraperitoneal injection of azoxymethane (10 mg/kg body weight), followed by 1% dextran sulfate sodium in the drinking water. Additionally, we also assessed the effect of LicA on liver metastasis by intrasplenic injection of BALB/c mice with CT-26 cells. Feeding the mice with LicA (5, 15, and 30 mg/kg body weight) significantly reduced tumor formation as well as the number of cells expressing proliferating cell nuclear antigen, beta-catenin, COX-2, and iNOS in the colon. LicA also decreased colon levels of proinflammatory cytokines and chemokines. In addition, LicA significantly increases survival of animals and inhibited liver metastasis as well as the expression of matrix metalloproteinase-9 in the liver. These preclinical studies indicate that LicA has potent antitumor and antimetastatic activity, suggesting that LicA could increase efficacy and improve patient outcomes in colorectal cancer.

Zerumbone, a tropical ginger sesquiterpene, inhibits colon and lung carcinogenesis in mice

Zerumbone (ZER), present in subtropical ginger Zingiber zerumbet Smith, possesses anti-growth and anti-inflammatory properties in several human cancer cell lines. ZER also down-regulates the cyclooxygenase-2 and inducible nitric oxide synthase expression via modulation of nuclear factor (NF)-kappaB activation in cell culture systems. These findings led us to investigate whether ZER is able to inhibit carcinogenesis in the colon and lung, using 2 different preclinical mouse models. In Exp. 1, a total of 85 male ICR mice were initiated using a single intraperitoneal (i.p.) injection with azoxymethane (AOM, 10 mg/kg bw) and promoted by 1.5% dextran sulfate sodium (DSS) in drinking water for 7 days for rapid induction of colonic neoplasms. Animals were then fed the diet containing 100, 250 or 500 ppm ZER for 17 weeks. In Exp. 2, a total of 50 female A/J mice were given a single i.p. injection of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (10 micromol/mouse) to induce lung proliferative lesions. They were then fed the diet mixed with 100, 250 or 500 ppm ZER for 21 weeks. At the termination of the experiments (wk 20 of Exp. 1 and wk 22 of Exp. 2), all animals were subjected to complete necropsy examination to determine the pathological lesions in both tissues. Oral administration of ZER at 100, 250 and 500 ppm significantly inhibited the multiplicity of colonic adenocarcinomas. The treatment also suppressed colonic inflammation. In the lung carcinogenesis, ZER feeding at 250 and 500 ppm significantly inhibited the multiplicity of lung adenomas in a dose-dependent manner. Feeding with ZER resulted in inhibition of proliferation, induction of apoptosis, and suppression of NFkappaB and heme oxygenase (HO)-1 expression in tumors developed in both tissues. Our findings suggest that dietary administration of ZER effectively suppresses mouse colon and lung carcinogenesis through multiple modulatory mechanisms of growth, apoptosis, inflammation and expression of NFkappaB and HO-1 that are involved in carcinogenesis in the colon and lung.

Zerumbone down-regulates chemokine receptor CXCR4 expression leading to inhibition of CXCL12-induced invasion of breast and pancreatic tumor cells

CXC chemokine receptor 4 (CXCR4), initially linked with leukocyte trafficking, is now known to be expressed in various tumors including breast, ovary, prostate, gastrointestinal, head and neck, bladder, brain, and melanoma. This receptor mediates homing of tumor cells to specific organs that express the ligand CXCL12 for this receptor. Thus, agents that can down-regulate CXCR4 expression have potential against cancer metastasis. In this study, we report the identification of zerumbone, a component of subtropical ginger (Zingiber zerumbet), as a regulator of CXCR4 expression. This sesquiterpene down-regulated the expression of CXCR4 on HER2-overexpressing breast cancer cells in a dose- and time-dependent manner. The decrease in CXCR4 by zerumbone was found to be not cell type specific as its expression was abrogated in leukemic, skin, kidney, lung, and pancreatic cancer cell lines. The down-regulation of CXCR4 was not due to proteolytic degradation but rather to transcriptional regulation, as indicated by down-regulation of mRNA expression, inhibition of nuclear factor-kappaB activity, and suppression of chromatin immunoprecipitation activity. Suppression of CXCR4 expression by zerumbone correlated with the inhibition of CXCL12-induced invasion of both breast and pancreatic cancer cells. An analogue of zerumbone, alpha-humulene, which lacks the carbonyl group, was found to be inactive in inducing CXCR4 down-regulation. Overall, our results show that zerumbone is a novel inhibitor of CXCR4 expression and thus has a potential in the suppression of cancer metastasis.

Citrus nobiletin suppresses bone loss in ovariectomized ddY mice and collagen-induced arthritis in DBA/1J mice: possible involvement of receptor activator of NF-kappaB ligand (RANKL)-induced osteoclastogenesis regulation

Bone resorption is known to accelerate during the onset of several disorders, including osteoporosis (OP) and rheumatoid arthritis (RA). Some epidemiological surveys have suggested that a high intake of vegetables and fruits has an inverse relation to such disease incidence, though the number of active constituents elucidated thus far is limited. In the present study, we examined the efficacy of various food phytochemicals using two animal models. First, female ddY mice were ovariectomized (OVX) or sham-operated (sham), after which five different compounds (phenethyl isothiocyanate, zerumbone, auraptene, 1'-acetoxychavicol acetate, and nobiletin) were administered separately to OVX mice with a mini-osmotic pump at doses of 0.25 or 0.5 mg/day for 4 weeks, with 17beta-estradiol (E_{2}, 0.03 microg/day) used as a positive control. Nobiletin, in contrast to the other tested phytochemicals, significantly (P<0.05) suppressed the reduction of whole bone mineral density by 61%, which was comparable to or higher than the efficacy of E_{2}. Next, nobiletin given as an i.p. administration at 20 mg/kg of body weight, but not 2 mg/kg, to male DBA/1J mice every 2 days for 12 days led to a marked decrease in type II collagen-induced arthritis by 45% (P < 0.05). Furthermore, the flavonoid (4-50 microM) attenuated receptor activator of nuclear factor kappaB ligand (RANKL)-induced osteoclastogenesis of RAW264.7 cells, as detected by tartarate-resistant acid phosphatase activity and microscopic observations. Of note, nobiletin also suppressed RANKL-activated extracellular signal-regulated kinase1/2, c-Jun N-terminal kinase1/2, and p38 mitogen-activated protein kinase activities, and thereby regulated the promoter activation of nuclear factor kappaB (NFkappaB) and activator protein-1, key transcription factors for differentiation. Together, our results suggest that nobiletin is a promising phytochemical for the prevention or treatment of osteoclastogenesis-related disorders, including OP and RA, with reasonable action mechanisms.