Suppressive Effect of Natural Sesquiterpenoids on Inducible Cyclooxygenase (COX-2) and Nitric Oxide Synthase (iNOS) Activity in Mouse Macrophage Cells

Xanthorrhizol, a potential anticancer agent, from Curcuma xanthorrhiza Roxb

BACKGROUND

Xanthorrhizol (XTZ), a bisabolene sesquiterpenoid, is abundantly found in the plant Curcuma xanthorrhiza Roxb. Traditionally, C. xanthorrhiza is widely used for the treatment of different health conditions, including common fever, infection, lack of appetite, fatigue, liver complaints, and gastrointestinal disorders. XTZ exhibits wide-ranging pharmacological activities, including anticancer, antioxidative, anti-inflammatory, antimicrobial, and antidiabetic activities, in addition to a protective effect on multiple organs. The present review provides detailed findings on the anticancer activities of XTZ and the underlying cellular and molecular mechanisms.

METHODS

Literature was searched systematically in main databases following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, with keywords "tumor AND xanthorrhizol" or "cancer AND xanthorrhizol".

RESULTS

Studies show that XTZ has preventive and therapeutic activities against different types of cancer, including breast, cervical, colon, liver, lung, oral and esophageal, and skin cancers. XTZ regulates multiple signaling pathways that block carcinogenesis and proliferation. In vitro and in vivo studies showed that XTZ targets different kinases, inflammatory cytokines, apoptosis proteins, and transcription factors, leading to the suppression of angiogenesis, metastasis, and the activation of apoptosis and cell cycle arrest.

CONCLUSION

The potential anticancer benefits of XTZ recommend further in vivo studies against different types of cancer. Further, XTZ needs to be confirmed for its toxicity, bioavailability, protective, antifatigue, and energy booster activities. Future studies for the therapeutic development of XTZ may be directed to cancer-related fatigue.

Anti-Inflammatory and Antioxidant Chinese Herbal Medicines: Links between Traditional Characters and the Skin Lipoperoxidation “Western” Model

The relationship between lipid peroxidation and inflammation has been accepted as a paradigm in the field of topical inflammation. The underlying biochemical mechanisms may be summarised as unspecific oxidative damage followed by specific oxidative processes as the physio pathological response in skin tissues. In this experimental review we hypothesise that the characteristics attributed by Traditional Chinese Medicine (TCM) to herbal drugs can be linked to their biomolecular activities within the framework of the above paradigm. To this end, we review and collect experimental data from several TCM herbal drugs to create 2D-3D pharmacological and biochemical spaces that are further reduced to a bidimensional combined space. When multivariate analysis is applied to the latter, it unveils a series of links between TCM herbal characters and the skin lipoperoxidation “Western” model. With the help of these patterns and a focused review on their chemical, pharmacological and antioxidant properties we show that cleansing herbs of bitter and cold nature acting through removal of toxins—including P. amurense, Coptis chinensis, S. baicalensis and F. suspensa—are highly correlated with strong inhibition of both lipid peroxidation and eicosanoids production. Sweet drugs—such as A. membranaceus, A. sinensis and P. cocos—act through a specific inhibition of the eicosanoids production. The therapeutic value of the remaining drugs—with low antioxidant or anti-inflammatory activity—seems to be based on their actions on the Qi with the exception of furanocoumarin containing herbs—A. dahurica and A. pubescens—which “expel wind”. A further observation from our results is that the drugs present in the highly active “Cleansing herbs” cluster are commonly used and may be interchangeable. Our work may pave the way to a translation between two medical systems with radically different philosophies and help the prioritisation of active ingredients with specific biomolecular activities of interest for the treatment of skin conditions.

In Vitro Replication Inhibitory Activity of Xanthorrhizol against Severe Acute Respiratory Syndrome Coronavirus 2

In spite of the large number of repositioned drugs and direct-acting antivirals in clinical trials for the management of the ongoing COVID-19 pandemic, there are few cost-effective therapeutic options for severe acute respiratory syndrome (SARS) coronavirus 2 (SCoV2) infection. In this paper, we show that xanthorrhizol (XNT), a bisabolane-type sesquiterpenoid compound isolated from the Curcuma xanthorrhizza Roxb., a ginger-line plant of the family Zingiberaceae, displays a potent antiviral efficacy in vitro against SCoV2 and other related coronaviruses, including SARS-CoV-1 (SCoV1) and a common cold-causing human coronavirus. XNT reduced infectious SCoV2 titer by ~3-log₁₀ at 20 μM and interfered with the replication of the SCoV1 subgenomic replicon, while it had no significant antiviral effects against hepatitis C virus and noroviruses. Further, XNT exerted similar antiviral functions against SCoV2 variants, such as a GH clade strain and a delta strain currently predominant worldwide. Neither SCoV2 entry into cells nor the enzymatic activity of viral RNA polymerase (Nsp12), RNA helicase (Nsp13), or the 3CL main protease (Nsp5) was inhibited by XNT. While its CoV replication inhibitory mechanism remains elusive, our results demonstrate that the traditional folk medicine XNT could be a promising antiviral candidate that inhibits a broad range of SCoV2 variants of concern and other related CoVs.

Javanese Turmeric (Curcuma xanthorrhiza Roxb.): Ethnobotany, Phytochemistry, Biotechnology, and Pharmacological Activities

Curcuma xanthorrhiza Roxb., locally famed as Temulawak, has been extensively utilized in Indonesia as medicinal and nutritional plants since immemorial time. The rhizome of this plant is an important ingredient for jamu formulation (Indonesian traditional medicine). C. xanthorrhiza is traditionally used to treat several ailments such as lack of appetite, stomach disorder, liver illness, constipation, bloody diarrhea, dysentery, arthritis, children's fevers, hypotriglyceridaemia, hemorrhoids, vaginal discharge, rheumatism, and skin eruptions. To date, over 40 active compounds, including terpenoids, curcuminoids, and other phenolic compounds, have been isolated and identified from C. xanthorrhiza Roxb. Some pharmacological tests reported that C. xanthorrhiza Roxb. has antioxidant, antimicrobial, anti-inflammatory, anticancer and antitumor, antidiabetic, and skincare and hepatoprotective properties. Efforts for biotechnologically production of C. xanthorrhiza have also been conducted, resulting in some micropropagation protocols of this plant. The current review focuses on the botanical description and distribution, ethnomedicinal uses, production and conservation status, phytochemical properties, and pharmacological activities of C. xanthorrhiza Roxb. to provide accurate and reliable data for future researches and commercialization purposes.

Comprehensive computational target fishing approach to identify Xanthorrhizol putative targets

Xanthorrhizol (XNT), is a bioactive compound found in Curcuma xanthorrhiza Roxb. This study aimed to determine the potential targets of the XNT via computational target fishing method. This compound obeyed Lipinski's and Veber's rules where it has a molecular weight (MW) of 218.37 gmol^-1, TPSA of 20.23, rotatable bonds (RBN) of 4, hydrogen acceptor and donor ability is 1 respectively. Besides, it also has half-life (HL) values 3.5 h, drug-likeness (DL) value of 0.07, oral bioavailability (OB) of 32.10, and blood-brain barrier permeability (BBB) value of 1.64 indicating its potential as therapeutic drug. Further, 20 potential targets were screened out through PharmMapper and DRAR-CPI servers. Co-expression results derived from GeneMANIA revealed that these targets made connection with a total of 40 genes and have 744 different links. Four genes which were RXRA, RBP4, HSD11B1 and AKR1C1 showed remarkable co-expression and predominantly involved in steroid metabolic process. Furthermore, among these 20 genes, 13 highly expressed genes associated with xenobiotics by cytochrome P450, chemical carcinogenesis and steroid metabolic pathways were identified through gene ontology (GO) and KEGG pathway analysis. In conclusion, XNT is targeting multiple proteins and pathways which may be exploited to shape a network that exerts systematic pharmacological effects.

Herbal and Natural Dietary Products: Upcoming Therapeutic Approach for Prevention and Treatment of Hepatocellular Carcinoma

The most common tumor linked with elevated death rates is considered the hepatocellular carcinoma (HCC), sometimes called the malignant hepatoma. The initiation and progression of HCC are triggered by multiple factors like long term alcohol consumption, metabolic disorders, fatty liver disease, hepatitis B and C infection, age, and oxidative stress. Sorafenib is the merely US Food and Drug Administration (FDA)-approved drug used to treat HCC. Several treatment methods are available for HCC therapy such as chemotherapy, immunotherapy and adjuvant therapy but they often lead to several side effects. Yet these treatment methods are not entirely adequate due to the increasing resistance to the drug and their toxicity. Many natural products help to prevent and treat HCC. A variety of pathways are associated with the prevention and treatment of HCC with herbal products and their active components. Accumulating research shows that certain natural dietary compounds are possible source of hepatic cancer prevention and treatments, such as black currant, strawberries, plum, grapes, pomegranate, cruciferous crops, tomatoes, French beans, turmeric, garlic, ginger, asparagus, and many more. Such a dietary natural products and their active constituents may prevent the production and advancement of liver cancer in many ways such as guarding against liver carcinogens, improving the effectiveness of chemotherapeutic medications, inhibiting the growth, metastasis of tumor cells, reducing oxidative stress, and chronic inflammation. The present review article represents hepatic carcinoma etiology, role of herbal products, their active constituents, and dietary natural products for the prevention and treatment of HCC along with their possible mechanisms of action.

Anti-cancer properties of specific Chinese herbal medicines for hepatocellular carcinoma treatment

AIMS

This essay explores the anti-cancer activity of specific Chinese herbal medicines to clarify how effective Chinese herbal medicine is used for handling hepatocellular carcinoma.

METHODS

Literature form publica domain were studied and an analysis of anti-cancer activity of specific Chinese herbal medicines is presented in this review.

RESULTS

Hepatocellular carcinoma is one of the most dangerous malignant tumors in the world. The operative diagnosis of liver cancer remains a significant challenge. Although surgery tissue resection is encouraging, a high risk of recurrence and metastasis, illustrating disease-related mortality is desperately required to enhance postoperative preventive and therapeutic clinical procedures. The almost only effective clinical intervention seems to be developing advanced targeted therapies such as sorafenib for hepatocellular carcinoma patients, but there is little research in this field. Because their preventative/therapeutic properties strengthen Chinese herbal medicinal compounds, they are deemed relevant to the treatment of hepatocellular carcinoma. Conclusion: Chinese herbal medicine derivates provide multifaceted, orientated and orchestrated therapy, making it an ideal candidate for inhibiting hepatocellular tumor production and metastasis.

The Chemopreventive Activity of Indonesia Medicinal Plants Targeting on Hallmarks of Cancer

Cancer remains a complex disease with increasing global mortality and morbidity. Numerous theories have been established to understand the biological mechanism underlying cancer. One of the most renowned frameworks is the hallmark of cancer proposed by Hanahan and Weinberg that covers ten eminent characteristics of cancer: (i) genome instability and mutation, (ii) sustaining proliferative signaling, (iii) evading growth suppressor, (iv) enabling replicative immortality, (v) resisting cell death, (vi) inducing angiogenesis, (vii) activating invasion and metastasis, (viii) avoiding immune destruction, (ix) tumor-promoting inflammation, and (x) deregulating cellular energetics. These hallmarks provide a rational approach to design an anticancer therapy. In the current review, we summarized specific target molecules on each hallmark of cancer. Further, we evaluated the biological activity of several Indonesia medicinal plants against those specific targets. We explicated the anticancer and chemopreventive activities of some medicinal plants that have been used for centuries by local communities in Indonesia, including Curcuma genus, Brucea javanica, Boesenbergia pandurata, Caesalpinia sappan, and Nigella sativa. Interestingly, these medicinal plants target several hallmarks of cancer, and even Curcuma genus exhibited biological activities that target all hallmarks of cancer. Further, we also discuss several strategies to develop those medicinal plants and/or their active compounds as anticancer and chemopreventive agents.

Chemical composition and biological activity of the essential oil from the root of Jatropha pelargoniifolia Courb. native to Saudi Arabia

The chemical composition of the essential oil from Jatropha pelargoniifolia roots was determined via GC-FID. There were 80 compounds, representing 99.99% of the total oil constituents. Among these, 77.31% were sesquiterpenes, 14.62% were fatty acids, 7.21% were other components (i.e., phenolics, hydrocarbons, etc.), and 0.85% were monoterpenes. The major compounds in the oil were γ-eudesmol (35.31%), 5-guaien-11-ol (14.43%), epi-cedrol (8.19%), oleic acid (5.23%), bulnesol (4.45%), α-linoleic acid (4.20%), 3,4-dimethoxycinnamic acid (3.83%), palmitic acid (2.69%), isolongifolanone (2.68%), eicosane (1.41%), and cedrol (1.14%). Oxygenated sesquiterpenes were found to represent more than 50% percent of the total oil content. Moreover, the essential oil was evaluated for anti-inflammatory, antioxidant, antipyretic, and antinociceptive activities using in vivo and in vitro models. Additionally, the antioxidant potential of the oil was evaluated using various in vitro antioxidant tests, including DPPH•, ABTS•+ and FRAP. At a dose of 240 µl/kg, the oil showed anti-inflammatory (59.12%), antipyretic (37.00 ± 0.11), and antinociceptive (47.58%) activities and showed significant (p < 0.001) effect as compared to a standard drug (phenylbutazone and indomethacin). These findings demonstrated that the essential oil of Jatropha pelargoniifolia root could be used as a natural source for their anti-inflammatory, antinociceptive, antipyretic, and antioxidant effects.

Inhibitory effect of the compounds from the water extract of Curcuma longa on the production of PGE2 and NO in a macrophage cell line stimulated by LPS

We wished to search for the compounds contributing to the anti-inflammatory effects of the water extract of Curcuma longa (WEC). WEC was fractioned and the fractions were evaluated with regard to their inhibitory effect on the production of nitric oxide (NO) from the macrophage cell line stimulated by lipopolysaccharide. Compounds in the active fractions were isolated and identified. One isolated compound was identified as new: (6S)-2-methyl-5-hydroxy-6-(3-hydroxy-4-methylphenyl)-2-heptene-4-one (1). Four isolated compounds were identified as known: (6S)-2-methyl-6-(4-hydroxyphenyl)-2-heptene-4-one (4), bisabolone-4-one (5), curcumenone (6), and turmeronol A (8). Three isolated compounds were not identified their stereostructures but their planar structures: 2-methyl-6-(4-hydroxymethyl-phenyl)-2-heptene-4-one (2), 2-methyl-6-(2,3-epoxy-4-methyl-4-cyclohexene)-2-heptene (3), and 4-methylene-5-hydroxybisabola-2,10-diene-9-one (7). Compounds 1, 4, 7 and 8 inhibited production of prostaglandin E2 and NO. Others inhibited NO production only. These results (at least in part) show the active compounds contributing to the anti-inflammatory effects of WEC, and may be useful for elucidating its various beneficial physiologic effects.

Chemical Composition and Biological Activities of Essential Oils of Curcuma Species

Members of the genus Curcuma L. have been used in traditional medicine for centuries for treating gastrointestinal disorders, pain, inflammatory conditions, wounds, and for cancer prevention and antiaging, among others. Many of the biological activities of Curcuma species can be attributed to nonvolatile curcuminoids, but these plants also produce volatile chemicals. Essential oils, in general, have shown numerous beneficial effects for health maintenance and treatment of diseases. Essential oils from Curcuma spp., particularly C. longa, have demonstrated various health-related biological activities and several essential oil companies have recently marketed Curcuma oils. This review summarizes the volatile components of various Curcuma species, the biological activities of Curcuma essential oils, and potential safety concerns of Curcuma essential oils and their components.

Herbal management of hepatocellular carcinoma through cutting the pathways of the common risk factors

Hepatocellular carcinoma (HCC) is considered the most frequent tumor that associated with high mortality rate. Several risk factors contribute to the pathogenesis of HCC, such as chronic persistent infection with hepatitis C virus or hepatitis B virus, chronic untreated inflammation of liver with different etiology, oxidative stress and fatty liver disease. Several treatment protocols are used in the treatment of HCC but they also associated with diverse side effects. Many natural products are helpful in the co-treatment and prevention of HCC. Several mechanisms are involved in the action of these herbal products and their bioactive compounds in the prevention and co-treatment of HCC. They can inhibit the liver cancer development and progression in several ways as protecting against liver carcinogens, enhancing effects of chemotherapeutic drugs, inhibiting tumor cell growth and metastasis, and suppression of oxidative stress and chronic inflammation. In this review, we will discuss the utility of diverse natural products in the prevention and co-treatment of HCC, through its capturing of the common risk factors known to lead to HCC and shed the light on their possible mechanisms of action. Our theory assumes that shutting down the risk factor to cancer development pathways is a critical strategy in cancer prevention and management. We recommend the use of these plants side by side to recent chemical medications and after stopping these chemicals, as a maintenance therapy to avoid HCC progression and decrease its global incidence.

Chemical constituents and biological research on plants in the genus Curcuma

Curcuma, a valuable genus in the family Zingiberaceae, includes approximately 110 species. These plants are native to Southeast Asia and are extensively cultivated in India, China, Sri Lanka, Indonesia, Peru, Australia, and the West Indies. The plants have long been used in folk medicine to treat stomach ailments, stimulate digestion, and protect the digestive organs, including the intestines, stomach, and liver. In recent years, substantial progress has been achieved in investigations regarding the chemical and pharmacological properties, as well as in clinical trials of certain Curcuma species. This review comprehensively summarizes the current knowledge on the chemistry and briefly discusses the biological activities of Curcuma species. A total of 720 compounds, including 102 diphenylalkanoids, 19 phenylpropene derivatives, 529 terpenoids, 15 flavonoids, 7 steroids, 3 alkaloids, and 44 compounds of other types isolated or identified from 32 species, have been phytochemically investigated. The biological activities of plant extracts and pure compounds are classified into 15 groups in detail, with emphasis on anti-inflammatory and antitumor activities.

Degranulation Inhibitors from Medicinal Plants in Antigen-Stimulated Rat Basophilic Leukemia (RBL-2H3) Cells

Mast cells and basophils play important roles in both immediate- and late-phase reactions of type 1 allergy. Histamine, which is released from mast cells and basophils stimulated by an antigen or degranulation inducers, is usually determined as a degranulation marker in experiments on immediate allergic reactions in vitro. β-Hexosaminidase is also stored in secretory granules of the cells and is released concomitantly with histamine when the cells are immunologically activated, and recently this enzyme activity in the medium has been used as a marker of the degranulation. In this paper, we review our studies on the search for degranulation inhibitors, such as flavonoids, stilbenes, and curcuminoids, from medicinal plants using rat basophilic leukemia (RBL-2H3) cells.

Hepatic protection and anticancer activity of curcuma: a potential chemopreventive strategy against hepatocellular carcinoma

Malignant transformation of hepatocellular carcinoma (HCC) occurs through repetitive liver injury in a context of inflammation and oxidative DNA damage. A spectrum of natural sesquiterpenoids from curcuma oil has displayed anti-oxidant, anti-inflammatory and anti-carcinogenic properties. The aim of the study was to investigate the hepatoprotective and anti-HCC effects of curcuma oil in vivo and in vitro. Mice were pretreated with curcuma oil (100 mg/kg) for 3 days, then treated with Concanavalin A (30 mg/kg). The hepatic tissue was evaluated for histology, CD4⁺ cell, interferon-γ, apoptosis, lipid peroxidation, 8-hydroxy-deoxyguanosine and MnSOD. C57L/J mice were treated with curcuma oil and 10⁷ Hepa1-6 cells directly inoculated into liver lobes. The effects of curcuma oil on cell growth and cell death were evaluated. In addition, MnSOD, HSP60, catalase, NF-κB and caspase-3 were also investigated in the Hepa1-6 cells treated with curcuma oil. Pretreatment with curcuma oil significantly attenuates inflammation and oxidative damage by Concanavalin A. Treatment with curcuma oil can decrease the incidence of HCC. Curcuma oil inhibits cell growth and induces cell death in Hepa1-6 cells. Curcuma protected mice with hepatic injury from inflammatory and oxidative stress. Curcuma oil can inhibit hepatoma cell growth in vivo and in vitro.

Facilitated cellular uptake and suppression of inducible nitric oxide synthase by a metabolite of maritime pine bark extract (Pycnogenol)

Many natural products exhibit anti-inflammatory activity by suppressing excessive nitric oxide (NO) production by inducible NO synthase (iNOS). The maritime pine bark extract Pycnogenol has been formerly shown to decrease nitrite generation, taken as an index for NO, but so far it was not clear which constituent of the complex flavonoid mixture mediated this effect. The purpose of this study was to elucidate whether the in vivo generated Pycnogenol metabolite M1 (δ-(3,4-dihydroxyphenyl)-γ-valerolactone) displayed any activity in the context of induction of iNOS expression and excessive NO production. For the first time we show that M1 inhibited nitrite production (IC(50) 1.3 μg/ml, 95% CI 0.96-1.70) and iNOS expression (IC(50) 3.8 μg/ml, 95% CI 0.99-14.35) in a concentration-dependent fashion. This exemplifies bioactivation by metabolism because the M1 precursor molecule catechin is only weakly active. However, these effects required application of M1 in the low-micromolar range, which was not consistent with concentrations previously detected in human plasma samples after ingestion of maritime pine bark extract. Thus, we investigated a possible accumulation of M1 in cells and indeed observed high-capacity binding of this flavonoid metabolite to macrophages, monocytes, and endothelial cells. This binding was distinctly decreased in the presence of the influx inhibitor phloretin, suggesting the contribution of a facilitated M1 transport into cells. In fact, intracellular accumulation of M1 could explain why in vivo bioactivity can be observed with nanomolar plasma concentrations that typically fail to exhibit measurable activity in vitro.

Rosmarinus officinalis L. essential oil inhibits in vivo and in vitro leukocyte migration

Rosmarinus officinalis L. (Lamiaceae), popularly known as rosemary, is used for food flavoring and in folk medicine as an antispasmodic, analgesic, antirheumatic, diuretic, and antiepileptic agent. Few studies have shown the anti-inflammatory effects of rosemary essential oil (REO). This study evaluated the effects of REO on leukocyte migration through in vivo leukocyte migration and in vitro chemotaxis assay. REO was analyzed by using gas chromatography-mass spectometry, and the main components identified were camphor (27.59%), 1,8-cineole (15.74%), α-pinene (16.58%), and β-myrcene (10.02%). In rats, administration of REO reduced the number of leukocytes that rolled, adhered, and migrated to the scrotal chamber after carrageenan injection. All doses of REO tested significantly inhibited leukocyte chemotaxis induced by casein. The effects of REO on leukocyte migration highlight an important mechanism of the anti-inflammatory action of rosemary.

Xanthorrhizol attenuates dextran sulfate sodium-induced colitis via the modulation of the expression of inflammatory genes in mice

AIMS

The aim of this study was to investigate the effects of xanthorrhizol (5-(1,5-dimethyl-4-hexenyl)-2-methylphenol, XA) in a mouse model of dextran sulfate sodium (DSS)-induced colitis.

MAIN METHODS

Experimental colitis was induced by exposing male BALB/c mice to 5% DSS in drinking water for 7days. XA (10 or 100mg/kg) was administered orally once a day, together with the DSS. We evaluated body weight, colon length, histological changes, and myeloperoxidase (MPO) activity. A cDNA microarray was used to assess the gene expression profiles that were affected by XA and DSS treatment and a co-citation analysis was used to examine the biological relationship between XA-responsive genes and colitis.

KEY FINDINGS

Decreased body weight, shortened colon length, and damaged colon were observed in the group that was exposed to DSS. Oral administration of XA (10 or 100mg/kg) rescued these symptomatic and histopathological features. The DSS-induced increase in MPO activity, which was used as an index of neutrophil infiltration, was significantly decreased after treatment with XA. Microarray analysis revealed that XA treatment regulated the expression of 34 genes that were altered by exposure to DSS, and that these XA-responsive genes were associated with colonic inflammation. Furthermore, co-citation analysis and graphing of XA-responsive genes revealed a network associated with the gene that encodes for MPO.

SIGNIFICANCE

These results suggest that XA attenuates acute DSS-induced colitis, possibly by modulating the expression of genes mostly associated with colonic inflammation.

Targeting COX-2 expression by natural compounds: a promising alternative strategy to synthetic COX-2 inhibitors for cancer chemoprevention and therapy

Cyclooxygenase (COX)-2 is a pro-inflammatory immediate early response protein, chronically up-regulated in many pathological conditions. In autoimmune diseases, it is responsible for degenerative effects whereas in cancer, it correlates with poor prognosis. A constitutive expression of COX-2 is triggered since the earliest steps of carcinogenesis. Consequently, strategies aimed at inhibiting COX-2 enzymatic activity have been clinically applied for the treatment of autoimmune disorders; in addition, the same approaches are currently investigated for anti-cancer purposes. However, COX-2 protein inhibitors (i.e., NSAIDs and COXIBs) are not amenable to prolonged administration since they may cause severe side effects, and efforts are underway to identify alternative approaches for chemoprevention/therapy. COX-2 expression is a multi-step process, highly regulated at transcriptional and post-transcriptional levels. Defects in the modulation of one or both of these steps may be found in pathological conditions. Targeting COX-2 expression may therefore represent a promising strategy, by which the same preventive and therapeutic benefits may be gained while avoiding the severe side effects of COX-2 enzymatic inhibition. Naturally occurring compounds derived from plants/organisms represent a huge source of biologically active molecules, that remains largely unexplored. Derived from plants/organisms used in traditional forms of medicine or as dietary supplements, these compounds have been experimentally investigated for their anti-inflammatory and anti-cancer potential. In this review, we will analyze how natural compounds may modulate the multistep regulation of COX-2 gene expression and discuss their potential as a new generation of COX-2 targeting agents alternative to the synthetic COX-2 inhibitors.

Modified secoiridoid from Acicarpha tribuloides and inhibition of nitric oxide production in LPS-activated macrophages

Bioassay-guided fractionation of Acicarpha tribuloides Juss. resulted in the isolation of an uncommon non-glycosylated secoiridoid, tribulolide (1), two known secoiridoid glycosides named secologanic acid (2) and vogeloside (3) as well as two natural chromones, 6,7-dimethoxychromone (4) and 7-hydroxy-6-methoxy-chromone (5). Compounds 1-3 showed inhibition of nitric oxide production in lipopolysaccharide-activated macrophages; their activity is comparable to that of aminoguanidine, a classic inhibitor.

Inhibitory effect of Curcuma comosa on NO production and cytokine expression in LPS-activated microglia

Curcuma comosa is an indigenous plant of Thailand, which has been traditionally and widely used as an anti-inflammatory agent for the treatment of postpartum uterine bleeding and uterine inflammation. However, the scientific investigation on its anti-inflammatory activity has not been reported. In the present study, we investigated the anti-inflammatory effect of the extract from C. comosa on the responses in microglia stimulated with lipopolysaccharide (LPS). Pretreatment of highly aggressively proliferating immortalized (HAPI) cells, a rat microglial cell line, with the hexane extract of C. comosa rhizome at 10(-9) to 10(-5) g/ml significantly suppressed the levels of NO released from these cells. The attenuation in iNOS protein and mRNA expression was also observed suggesting an interference at transcriptional level. In addition, C. comosa extract inhibited interferon regulatory factor-1 expression which is an essential transcription factor governing the iNOS expression. Moreover, the levels of mRNA expressions of MCP-1 and IL-6 induced by LPS were also prominently decreased in the presence of C. comosa extract. These results suggest that C. comosa extract possesses a strong anti-inflammatory activity and has a potential to be developed as a therapeutic compound for diverse neurological disorders associated with inflammation.

The effect of turmeric extracts on inflammatory mediator production

Major compounds of several commonly used botanicals, including turmeric, have been purported to have anti-inflammatory actions. In order to test the anti-inflammatory activity of compounds isolated from rhizomes of Curcuma longa L. (Zingiberaceae), we have established an in vitro test system. HL-60 cells were differentiated and exposed to lipopolysaccharide (LPS) from Escherichia coli (1 microg/ml) in the presence or absence of botanical compounds for 24 h. Supernatants were collected and analyzed for the production of tumor necrosis factor alpha (TNF-alpha) and prostaglandin E2 (PGE2) using standard ELISA assays. Water-soluble extracts were not cytotoxic and did not exhibit biological activity. Organic extracts of turmeric were cytotoxic only at concentrations above 50 microg/ml. Crude organic extracts of turmeric were capable of inhibiting LPS-induced TNF-alpha (IC50 value = 15.2 microg/ml) and PGE2 (IC50 value = 0.92 microg/ml) production. Purified curcumin was more active than either demethoxy- or bisdemethoxycurcumin. Fractions and subfractions of turmeric extracts collected via preparative HPLC had differing biological activity, ranging from no activity to IC50 values of < 1 microg/ml. For some fractions, subfractionation resulted in a loss of activity, indicating interaction of the compounds within the fraction to produce an anti-inflammatory effect. A combination of several of the fractions that contain the turmeric oils was more effective than the curcuminoids at inhibiting PGE2. While curcumin inhibited COX-2 expression, turmeric oils had no effect on levels of COX-2 mRNA.

Xanthorrhizol, a natural sesquiterpenoid from Curcuma xanthorrhiza, has an anti-metastatic potential in experimental mouse lung metastasis model

Xanthorrhizol is a sesquiterpenoid compound isolated from the rhizome of Curcuma xanthorrhiza. In this study, the anti-metastatic activity of xanthorrhizol was evaluated by using an in vivo mouse lung metastasis model and a tumor mass formation assay. Interestingly, xanthorrhizol dramatically inhibited the formation of tumor nodules in the lung tissue and the intra-abdominal tumor mass formation. Next, to examine the mechanism of the anti-metastatic action of xanthorrhizol in the mouse lung metastasis, expression patterns of the several intracellular signaling molecules were evaluated using the lung tissues with tumor nodules. Higher expression levels of cyclooxygenase-2 (COX-2), matrix metalloproteinase-9 (MMP-9), and phosphorylated extracellular signal-regulated kinase (ERK) were observed in the metastatic group compared with control, but these were attenuated by the treatment of xanthorrhizol. In conclusion, xanthorrhizol exerts anti-metastatic activity in vivo and this effect could be highly linked to the metastasis-related multiplex signal pathway including ERK, COX-2, and MMP-9.

Chlorella dichloromethane extract ameliorates NO production and iNOS expression through the down-regulation of NFκB activity mediated by suppressed oxidative stress in RAW 264.7 macrophages

BACKGROUND

It has been proposed that chlorella extracts have antioxidative and anti-inflammatory effects.

METHODS

RAW 264.7 murine macrophage cell line was preincubated with various concentrations (0-100 mug/ml) of chlorella dichloromethane extract (CDE) and stimulated with lipopolysaccharide (LPS) to induce oxidative stress and inflammation.

RESULTS

Treatments of CDE reduced thiobarbituric acid-reactive substances (TBARS) accumulation, enhancing glutathione level and activities of antioxidative enzymes including superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-px), and glutathione reductase in LPS-stimulated macrophages than LPS-only treated cells. Nitric oxide (NO) production was significantly suppressed in a dose-dependent manner (p<0.05) with an IC(50) of 30.5 microg/ml. Treatment of CDE at 50 microg/ml suppressed NO production to 6% of LPS-control. Treatment with CDE suppressed the levels of inducible nitric oxide synthase (iNOS) protein and mRNA expressions. The specific DNA binding activities of nuclear factor kappa B (NF kappa B) on nuclear extracts from CDE treatments were significantly suppressed with an IC(50) of 62.7 mug/ml in a dose-dependent manner.

CONCLUSIONS

CDE ameliorates NO production and iNOS expression through the down-regulation of NF kappa B activity, which may be mediated by attenuated oxidative stress in RAW 264.7 macrophages.