Pharmacological properties of Myrtacine® and its potential value in acne treatment

This study aimed at evaluating the antiproliferative, antibacterial, and anti-inflammatory properties of an ethanolic myrtle extract (Myrtacine®) in vitro, characterising its potential active compounds (myrtucommulones A and B') by structural analysis, and evaluating their biological activity. Antiproliferative activity was assessed by the BrdU incorporation assay in HaCat keratinocytes and inhibitory and bactericidal activities against P. ACNES strains by measuring the minimal inhibitory concentration (MIC) and D value. Anti-inflammatory effect was evaluated by measuring 6-keto-prostaglandin F1 α and [³H]-arachidonic acid metabolite production in keratinocytes stimulated for inflammation. Myrtacine® inhibited keratinocyte proliferation by 27 % and 76 % at 1 and 3 µg/mL, respectively (p < 0.001). A comparable effect, though less marked, was observed with 5 µg/mL myrtucommulones A and B' (-36 % and -28 %, respectively). Myrtacine® inhibited erythromycin-sensible and -resistant P. ACNES strains growth with MICs of 4.9 µg/mL and 2.4 µg/mL, respectively. Myrtucommulone B' and myrtucommulone A displayed a similar inhibitory activity against both strains (for both strains, MIC = 1.2 µg/mL and about 0.5 µg/mL, respectively). At 3 and 10 µg/mL, Myrtacine® significantly decreased all metabolite production from cyclooxygenase (81 % and 107 %, p < 0.0001) and lipoxygenase (52 % and 95 %, p < 0.001) pathways. Finally, Myrtacine® exhibited a concentration-dependent anti-lipase activity at 100 µg/mL and 1 mg/mL, as it decreased lipase activity by respectively 53 % and 100 % (p < 0.01 for both). In conclusion, in vitro, Myrtacine® demonstrated antiproliferative, antibacterial, and anti-inflammatory properties that may be of value to exert a global action in the treatment of acne lesions.

Inhibition of 5-lipoxygenase and cyclooxygenase-2 pathways by pain-relieving plaster in macrophages

CONTEXT

Pain-relieving plaster (PRP) is a traditional Chinese medicine (TCM) that has been widely used with satisfactory results in the treatment of some diseases related to inflammation, such as bruises, chronic arthritis.

OBJECTIVE

The mechanisms underlying the anti-inflammatory actions of PRP are investigated in this study for the first time.

MATERIALS AND METHODS

The anti-inflammatory effects of PRP extracts were evaluated in lipopolysaccharide (LPS) or calcium ionophore A23187-treated murine peritoneal macrophages (PMs). Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), prostaglandin E₂ (PGE₂), and leukotrienes B₄ (LTB₄) were evaluated by ELISA assays. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis were used to detect the expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). Nuclear factor-kappa B (NF-κB)-DNA-binding activity was determined by gel mobility shift assay.

RESULTS

PRP extracts were found to inhibit the production of TNF-α, IL-1β, and PGE(2), reduce the expressions of COX-2 at the mRNA and protein levels induced by LPS, and reduced the production of LTB₄ induced by A23187. Furthermore, PRP extracts significantly attenuated LPS-induced NF-κB-DNA-binding activity.

DISCUSSION AND CONCLUSION

The anti-inflammatory effects of PRP possibly are related to reduction of inflammatory cytokines (TNF-α and IL-1β), inducible inflammatory enzyme (COX-2), and its metabolite PGE₂ via NF-κB signal pathway. Moreover, PRP extracts also notably inhibited the production of LTB₄, indicating that PRP inhibited the 5-LOX pathway, which may be the other mechanism for its anti-inflammatory action.

Cancer chemopreventive activity of maslinic acid: suppression of COX-2 expression and inhibition of NF-κB and AP-1 activation in Raji cells

Chronic inflammation is one of the predisposing factors for neoplastic transformation. Targeting inflammation through suppression of the pro-inflammatory pathway by dietary phytochemicals provides an important strategy for cancer prevention. Maslinic acid is a novel natural triterpenoid known to inhibit proliferation and induce apoptosis in some tumor cell lines. Although maslinic acid has cytotoxic and pro-apoptotic effects on cancer cells, the underlying mechanisms of its effects on the inflammatory pathway have yet to be elucidated. It has been reported that abnormal expression of pro-inflammatory enzyme cyclooxygenase-2 (COX-2) causes promotion of cellular proliferation, suppression of apoptosis, enhancement of angiogenesis and invasiveness. In the present study, the suppressive effect of maslinic acid on COX-2 expression and the binding activity of upstream transcription factors NF- κB and AP-1, which are known to regulate COX-2 transcriptional activation, were assessed using Raji cells. The anti-inflammatory action of maslinic acid was benchmarked against oleanolic acid and other standard drugs. Western blot analysis and electrophoretic mobility shift assay (EMSA) were employed to analyze COX-2 expression as well as NF- κB and AP-1 binding activity. Our results showed that maslinic acid suppresses COX-2 expression in a concentration-dependent manner. Likewise, the constitutive nuclear NF- κB (p65) activity as well as phorbol 12-myristate 13-acetate (PMA)- and sodium N-butyrate (SnB)-induced AP-1 binding activity in Raji cells were significantly reduced following treatment with maslinic acid. Since maslinic acid suppresses COX-2 expression in Raji cells at concentrations that also lowered the NF- κB (p65) and AP-1 binding activity, it is possible that the suppression of COX-2 by this natural triterpenoid might be achieved, at least in part, via the NF- κB and AP-1 signaling pathways.

Curcumin, but not Prima-1, decreased tumor cell proliferation in the syngeneic murine orthotopic bladder tumor model

OBJECTIVE

Cigarette smoking is the main risk factor for bladder cancer development. Among the mediators of this effect of smoking is nuclear factor-kappa B. Curcumin suppresses cellular transformation by downregulating the activity of nuclear factor-kappa B. Prima-1 is a compound that induces apoptosis in human tumor cells, restoring the function of mutant p53. Our study aimed to evaluate the effects of curcumin and prima-1 in an animal model of bladder cancer.

METHODS

Tumor implantation was achieved in six- to eight-week-old female C57BL/6 mice by introducing MB49 bladder cancer cells into the bladder. Intravesical treatment with curcumin and Prima-1 was performed on days 2, 6, 10, and 14. On day 15, the animals were sacrificed. Immunohistochemistry was used to determine the expression of cyclin D1, Cox-2, and p21. Cell proliferation was examined using PCNA.

RESULTS

Animals treated with curcumin exhibited a higher degree of necrosis than animals in other groups. Immunohistochemistry showed reduced expression of cyclin D1 in the curcumin-treated group. All of the cells in mice treated with curcumin were p21 positive, suggesting that the p53 pathway is induced by this compound. Prima-1 did not induce any change in tumor size, necrosis, cell proliferation, or the expression of proteins related to the p53 pathway in this animal model.

CONCLUSION

Curcumin showed activity in this animal bladder cancer model and probably acted via the regulation of nuclear factor-kappa B and p53. Therefore, curcumin is a good choice for the use in clinical trials to treat superficial bladder cancer as an alternative to bacillus Calmette-Guerin. In contrast, Prima-1 does not seem to have an effect on bladder cancer.

The effect of ellagic acid on platelet activation as measured by the quantification of P-selectin using flow cytometry

The purpose of this study was to investigate the effects of ellagic acid on platelet expression via the cyclooxygenase (COX) pathway by examining its effects on platelet activation and comparing them with known COX inhibitors in male Sprague-Dawley rats. Ellagic acid is a major compound found in certain fruits and nuts. It has been attributed as having anti-inflammatory, free radical scavenging, and coagulation properties as well as effects on tumor genesis in multiple forms of cancer. We assessed the similarities of ellagic acid to known COX-2 specific and nonspecific COX inhibitors by examining their effects on platelet activation via use of P-selectin flow cytometry. Compared with the vehicle group, both the ellagic acid (P = .035) and the ketorolac (P = .038) groups demonstrated a significant decrease in platelet activation (P = .026). Furthermore, compared with all other groups, ellagic acid plus ketorolac group showed a significant decrease in platelet activation (P = .01). Our findings suggest that ellagic acid is likely a nonspecific COX inhibitor. It also suggests that combining ellagic acid with a known nonspecific COX inhibitor such as ketorolac may cause a significant decrease in platelet activity and an increase in blood loss.

Ipomotaosides A-D, resin glycosides from the aerial parts of Ipomoea batatas and their inhibitory activity against COX-1 and COX-2

Four new resin glycosides, namely, ipomotaosides A-D (1-4), were isolated from the dried aerial parts of Ipomoea batatas. The structures of 1-4 were elucidated by analysis of their spectroscopic data and by chemical derivatization and were tested for their anti-inflammatory activity against cyclooxygenase (COX)-1 and -2.

Suppression of homodimerization of toll-like receptor 4 by isoliquiritigenin

Toll-like receptors (TLRs) play important inductive roles in innate immune responses for host defense against invading microbial pathogens. Activation of TLR4 by lipopolysaccharide (LPS) induces dimerization of TLR4 and, subsequently, activation of downstream signaling pathways including nuclear factor-kappa B and interferon regulatory factor 3. TLR4 dimerization may be an early regulatory event in activating signaling pathways induced by LPS. Here, biochemical evidence is reported that isoliquiritigenin, one of the major ingredients derived from licorice root, inhibits LPS-induced TLR4 dimerization resulting in inhibition of nuclear factor-kappa B and interferon regulatory factor 3 activation, and cyclooxygenase-2 and inducible nitric oxide synthase expression. These results suggest that isoliquiritigenin modulates TLR-mediated signaling pathways at the receptor level. Furthermore, these results suggest that TLRs themselves may be important targets for the prevention of chronic inflammatory diseases.

Modulation of acute and chronic inflammatory processes by a traditional medicine preparation GCSB-5 both in vitro and in vivo animal models

AIM OF THIS STUDY

GCSB-5 is a traditional medicine preparation composed with six oriental herbs which have been widely used for the inflammatory diseases in Asia. In the present study, we have demonstrated the anti-inflammatory effects of GCSB-5 in vivo and in vitro along with its underlying mechanism of action.

METHODS

The acute and chronic inflammation models in animals were applied to investigate the anti-inflammatory effects of GCSB-5. To further investigate the mechanism of the anti-inflammatory activity, lipopolysaccharide (LPS)-induced murine macrophage RAW264.7 cells were also employed.

RESULTS

In in vivo animal model, oral administration of GCSB-5 significantly inhibited TPA- and carrageenan-induced acute edema and adjuvant-induced arthritis. The vascular permeability, leukocyte migration, and granuloma formation were also inhibited by GCSB-5. In accordance, GCSB-5 suppressed the LPS-induced nitric oxide (NO) production by the downregulation of mRNA and protein expressions of inducible nitric oxide synthase (iNOS). GCSB-5 also suppressed the expressions of cyclooxygenase-2 (COX-2) and inflammatory cytokines such as interleukin-1beta and interferon-beta. The activation of NF-kappaB by LPS was also alleviated by GCSB-5, which correlated with its inhibitory effect on IkB degradation. The signaling pathway with the activation of Akt was also attenuated by the treatment by GCSB-5.

CONCLUSIONS

Taken together, our results demonstrate that GCSB-5 reduces the development of acute and chronic inflammation and its anti-inflammatory property might in part be a function of the inhibition of iNOS and COX-2 expression via down-regulation of the Akt signal pathway and inhibition of NF-kappaB activation. These findings suggest that GCSB-5 might be an applicable therapeutic traditional medicine in the regulation of the inflammatory response.

Atrovirinone inhibits proinflammatory mediator synthesis through disruption of NF-kappaB nuclear translocation and MAPK phosphorylation in the murine monocytic macrophage RAW 264.7

In a previous communication we showed that atrovirinone, a 1,4-benzoquinone isolated from the roots of Garcinia atroviridis, was able to inhibit several major proinflammatory mediators of inflammation. In this report we show that atrovirinone inhibits NO and PGE(2) synthesis through inhibition of iNOS and COX-2 expression. We also show that atrovirinone inhibits the secretion of IL-1beta and IL-6 in a dose dependent fashion whereas the secretion of IL-10, the anti-inflammatory cytokine, was enhanced. Subsequently we determined that the inhibition of proinflammatory cytokine synthesis and inducible enzyme expression was due to a dose-dependent inhibition of phosphorylation of p38 and ERK1/2. We also showed that atrovirinone prevented phosphorylation of I-kappaBalpha, which resulted in a reduction of p65NF-kappaB nuclear translocation as demonstrated by expression analysis. We conclude that atrovirinone is a potential anti-inflammatory drug lead that targets both the MAPK and NF-kappaB pathway.

Triterpene saponins from Clematis chinensis and their potential anti-inflammatory activity

Seven new triterpene saponins, clematochinenosides A-G (1-7), together with 17 known saponins (8-24), were isolated from the roots and rhizomes of Clematis chinensis. Their structures were elucidated on the basis of spectroscopic evidence and hydrolysis products. Compounds 1, 3-7, and 20-24 showed inhibitory activities against COX-1 and COX-2 enzymes.

Expression of the inflammatory marker cyclooxygenase-2 in dental pulp cells cultured with mineral trioxide aggregate or calcium silicate cements

INTRODUCTION

Mineral trioxide aggregate (MTA) and calcium silicate (CS) cements exhibit acceptable physical and chemical properties. The aim of the present study was to evaluate the effects of MTA and CS cements on inflammatory reactions in primary cultured human dental pulp cells.

METHODS

The mitochondrial colorimetric assay was used to evaluate pulp cell survival rates. Fluorescent immunohistochemistry was used to observe focal adhesion kinase (FAK) and cyclooxygenase-2 (COX-2) distributions in the cells. Reverse transcription-polymerase chain reaction was used to assess COX-2 expression.

RESULTS

The results showed that MTA and CS are biocompatible with pulp cells (P>.05). FAK was well-distributed in pulp cells in contact with both cements. Both MTA and CS cements induced pulp cell inflammation as evidenced by increased COX-2 expression.

CONCLUSIONS

The present study demonstrated that MTA and CS cements are biocompatible with primary cultured pulp cells. Both cements can induce inflammatory COX-2 expression in the pulp cells.

Cyclooxygenase-2 contributes to functional changes seen on experimental hemorrhagic cystitis induced by ifosfamide in rat urinary bladder

PURPOSE

Ifosfamide (IFS) is often involved in the occurrence of hemorrhagic cystitis due to direct contact of its metabolite acrolein with uroepithelium. It has been shown that COX-2 is involved in this pathogenesis. Thus, we aimed to study the functional changes on the urinary bladder in the putative modifications induced by IFS, as well as the COX-2 role in this process.

MATERIALS AND METHODS

IFS-treated rats were evaluated by cystometrography in absence or presence of COX inhibitors indomethacin or etoricoxib or in the presence of mesna. Experiments with isolated strips of urinary bladder obtained from animals with IFS-induced cystitis, either treated or not treated with COX inhibitors or mesna, were performed. Histological analyses, immunohistochemistry for COX-2, and measurement of plasma PGE(2) were also performed.

RESULTS

IFS treatment caused severe inflammation of the bladder tissue. Cystometrography recordings of IFS-treated rats revealed bladder with increased micturition frequency and enhanced filling intravesical pressure. Contractility of the isolated smooth muscle from the rat's bladder with IFS-induced cystitis showed decreased force development in response to KCl and CCh. Almost all effects induced by IFS were ameliorated by the use of COX inhibitors or mesna. Enzyme expression in the urinary bladder tissue was positive, and plasma concentration of PGE(2) was increased in IFS-treated animals and decreased significantly in etoricoxib-treated animals.

CONCLUSIONS

IFS causes important changes in the micturition physiology in rats, and the inhibition of the isoenzyme COX-2 could be an important event that could prevent the detrimental effects elicited by IFS-induced hemorrhagic cystitis.

Flavocoxid, an anti-inflammatory agent of botanical origin, does not affect coagulation or interact with anticoagulation therapies

INTRODUCTION

Flavocoxid, a botanical, anti-inflammatory agent, nonspecifically inhibits the peroxidase activity of cyclooxygenase (COX-1 and COX-2) enzymes and 5-lipooxygenase (5-LOX). Due to the concomitant use of aspirin or warfarin in many osteoarthritis (OA) patients with increased cardiovascular risk, we felt it necessary to assess the anticoagulation properties of flavocoxid.

METHODS

Three different studies were used: 1) a mouse model to assess effects on bleeding times when combined with aspirin; 2) the effect on platelet function as evaluated by platelet aggregation and bleed times in healthy human subjects; and 3) the effect on international normalized ratio in previously warfarinized patients with OA.

RESULTS

Flavocoxid at a human equivalent dose (HED) of 569 mg (within the standard human dosing range of 500 mg) produced no significant increases in bleeding time in mice. There was also no inhibition or synergistic increase in bleed times when flavocoxid was combined with aspirin (370 mg HED). Flavocoxid did not significantly inhibit thromboxane production or platelet aggregation, and did not increase bleeding times in healthy volunteers. Finally, flavocoxid did not inhibit or potentiate the anticoagulant effect of warfarin.

CONCLUSION

These results suggest that flavocoxid does not affect the primary or extrinsic pathways of secondary hemostasis and, by not inhibiting the anticoagulation effects of aspirin, may have utility in cardiovascular patients with OA.

Enhancement of 5-fluorouracil efficacy on high COX-2 expressing HCA-7 cells by low dose indomethacin and NS-398 but not on low COX-2 expressing HT-29 cells

The antiproliferative effect of 5-fluorouracil (5-FU) in the presence of low dose non-steroidal anti-inflammatory drugs (NSAIDs) on high cyclooxygenase-2 (COX-2)-expressing HCA-7 and low COX-2-expressing HT-29 colon carcinoma cell lines was investigated. Pharmacogenetic parameters were studied to characterize the 5-FU sensitivity of the two cell lines. Thymidylate synthase (TS) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms were determined by PCR analysis. Cell proliferation was measured by SRB assay, cell cycle distribution and apoptosis by FACS analysis. Cyclooxygenase expression was detected by Western blot and also by fluorescence microscopy. Prostaglandin E(2) (PGE(2)) levels were investigated with ELISA kit. The HT-29 cell line was found to be homozygous for TS 2R and 1494ins6 and T homozygous for MTHFR 677 polymorphisms predicting high 5-FU sensitivity (IC(50): 10 microM). TS 3R homozygosity, TS 1496del6 and MTHFR 677CT heterozygosity may explain the modest 5-FU sensitivity (IC(50): 1.1 mM) of the HCA-7 cell line. Indomethacin and NS-398 (10 microM and 1.77 microM, respectively) reduced the PGE(2) level in HCA-7 cells (>90%). Low concentrations of NSAIDs without antiproliferative potency increased the S-phase arrest and enhanced the cytotoxic action of 5-FU only in HCA-7 cells after 48-hours treatment. The presented data suggested that the enhancement of 5-FU cytotoxicity by indomethacin or NS-398 applied in low dose is related to the potency of NSAIDs to modulate the cell-cycle distribution and the apoptosis; however, it seems that this effect might be dependent on cell phenotype, namely on the COX-2 expression.

Effect of a cyclooxygenase-2 inhibitor on postexercise muscle protein synthesis in humans

Nonselective blockade of the cyclooxygenase (COX) enzymes in skeletal muscle eliminates the normal increase in muscle protein synthesis following resistance exercise. The current study tested the hypothesis that this COX-mediated increase in postexercise muscle protein synthesis is regulated specifically by the COX-2 isoform. Sixteen males (23 +/- 1 yr) were randomly assigned to one of two groups that received three doses of either a selective COX-2 inhibitor (celecoxib; 200 mg/dose, 600 mg total) or a placebo in double-blind fashion during the 24 h following a single bout of knee extensor resistance exercise. At rest and 24 h postexercise, skeletal muscle protein fractional synthesis rate (FSR) was measured using a primed constant infusion of [(2)H(5)]phenylalanine coupled with muscle biopsies of the vastus lateralis, and measurements were made of mRNA and protein expression of COX-1 and COX-2. Mixed muscle protein FSR in response to exercise (P < 0.05) was not suppressed by the COX-2 inhibitor (0.056 +/- 0.004 to 0.108 +/- 0.014%/h) compared with placebo (0.074 +/- 0.004 to 0.091 +/- 0.005%/h), nor was there any difference (P > 0.05) between the placebo and COX-2 inhibitor postexercise when controlling for resting FSR. The COX-2 inhibitor did not influence COX-1 mRNA, COX-1 protein, or COX-2 protein levels, whereas it did increase (P < 0.05) COX-2 mRNA (3.0 +/- 0.9-fold) compared with placebo (1.3 +/- 0.3-fold). It appears that the elimination of the postexercise muscle protein synthesis response by nonselective COX inhibitors is not solely due to COX-2 isoform blockade. Furthermore, the current data suggest that the COX-1 enzyme is likely the main isoform responsible for the COX-mediated increase in muscle protein synthesis following resistance exercise in humans.

Topical treatment of actinic keratoses with piroxicam 1% gel: a preliminary open-label study utilizing a new clinical score

BACKGROUND

The cyclo-oxygenase enzymes 1 and 2 (COX-1 and COX-2) are both involved in skin tumorigenesis, causing inhibition of apoptosis, angiogenesis, invasiveness, recruitment of growth factors, immunosuppression, and production of carcinogens. Piroxicam is a nonselective nonsteroidal anti-inflammatory drug that blocks the activity of COX-1 and COX-2.

OBJECTIVE

To evaluate the efficacy and tolerability of piroxicam 1% gel in the treatment of actinic keratoses.

METHODS

Piroxicam 1% gel was applied twice daily for 12 weeks to 31 actinic keratoses. The lesions were evaluated clinically and by means of dermoscopy at an initial baseline visit, at intermediate visits, and after 90 days. Changes were evaluated using a new scoring system (AKESA), based on the clinical presence of erythema, scale, and atrophy on a target lesion. In our experience, the use of piroxicam 1% gel for 90 days induced complete regression in 48% of evaluated actinic keratoses, corresponding to keratotic and verrucous clinical variants. In these lesions, the AKESA score was markedly reduced after treatment. Adverse effects were pruritus, mild erythema, dry skin, and, rarely, rash. Our preliminary trial shows that piroxicam exerts anti-tumorigenic effects and may play a useful role in the chemoprevention of skin cancers.

Novel role of Pin1 induction in type II collagen-mediated rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation in joints and subsequent destruction of cartilage and bone. Inflammatory mediators such as PGs and proinflammatory cytokines contribute to RA progress. Pin1, a peptidyl prolyl isomerase, plays important pathophysiological roles in several diseases, including cancer and neurodegeneration. We found that both Pin1 and cyclooxygenase-2 (COX-2) were highly expressed in ankle tissues of type II collagen-induced RA mice. HTB-94 cells overexpressing Pin1 and primary cultured human chondrocytes showed increased basal expression of proinflammatory proteins (COX-2, inducible NO synthase, TNF-alpha, and IL-1beta). Site-directed mutagenesis revealed that Pin1-mediated transcriptional activation of COX-2 was coordinately regulated by NF-kappaB, CREB, and C/EBP. Gel shift, reporter gene, and Western blot analyses confirmed that NF-kappaB, CREB, and C/EBP were consistently activated in chondrocytes overexpressing Pin1. Treatment of RA mice with juglone, a chemical inhibitor of Pin1, significantly reduced RA progress and COX-2 expression in the ankle tissues. Moreover, juglone dose dependently decreased the basal COX-2 expression in primary cultured chondrocytes from RA patients. These results demonstrate that Pin1 induction during RA progress stimulates proinflammatory protein expression by activating NF-kappaB, CREB, and C/EBP, and suggest that Pin1 is a potential therapeutic target of RA.

Synergistic anticancer effects of combined gamma-tocotrienol and celecoxib treatment are associated with suppression in Akt and NFkappaB signaling

The selective cyclooxygenase (COX)-2 inhibitor, celecoxib, and the vitamin E isoform, gamma-tocotrienol, both display potent anticancer activity. However, high dose clinical use of selective COX-2 inhibitors has been limited by gastrointestinal and cardiovascular toxicity, whereas limited absorption and transport of gamma-tocotrienol by the body has made it difficult to obtain and sustain therapeutic levels in the blood and target tissues. Studies were conducted to characterize the synergistic anticancer antiproliferative effects of combined low dose celecoxib and gamma-tocotrienol treatment on mammary tumor cells in culture. The highly malignant mouse +SA mammary epithelial cells were maintained in culture on serum-free defined control or treatment media. Treatment effects on COX-1, COX-2, Akt, NFkappaB and prostaglandin E(2) (PGE(2)) synthesis were assessed following a 3- or 4-day culture period. Treatment with 3-4 microM gamma-tocotrienol or 7.5-10 microM celecoxib alone significantly inhibited +SA cell growth in a dose-responsive manner. However, combined treatment with subeffective doses of gamma-tocotrienol (0.25 microM) and celecoxib (2.5 microM) resulted in a synergistic antiproliferative effect, as determined by isobologram analysis, and this growth inhibitory effect was associated with a reduction in PGE(2) synthesis, and decrease in COX-2, phospho-Akt (active), and phospho-NFkappaB (active) levels. These results demonstrate that the synergistic anticancer effects of combined celecoxib and gamma-tocotrienol therapy are mediated by COX-2 dependent and independent mechanisms. These findings also suggest that combination therapy with these agents may provide enhanced therapeutic response in breast cancer patients, while avoiding the toxicity associated with high-dose COX-2 inhibitor monotherapy.

Crotonkinensins A and B, diterpenoids from the Vietnamese medicinal plant Croton tonkinensis

Two new diterpenoids, crotonkinensins A (1) and B (2), were isolated from the leaves of the Vietnamese endemic medicinal plant Croton tonkinensis. Their structures were determined to be 7alpha,10alpha-epoxy-14beta-hydroxygrayanane-1(5),16(17)-dien-2,15-dione (1) and 7alpha,10alpha-epoxy-14beta-hydroxygrayanane-1(2),16(17)-dien-15-one (2) by spectroscopic analysis. Compounds 1 and 2 showed strong anti-inflammatory effects on the LPS-induced COX-2 promoter activity and COX-2 expression in Raw 264.7 cells.

Effect of Sasa senanensis Rehder extract on NO and PGE2 production by activated mouse macrophage-like RAW264.7 cells

Alkaline extract of Sasa senanensis Rehder (SE) has shown diverse biological activity. As an extension, whether SE affects the function of activated macrophages was investigated. SE inhibited the nitric oxide (NO) production by lipopolysaccharide (LPS)-activated mouse macrophage-like RAW264.7 cells. Western blot and RT-PCR analyses demonstrated that this was due to the inhibition of inducible NO synthase (iNOS) expression at both protein and mRNA levels. ESR spectroscopy shows that SE dose-dependently scavenged the NO radical produced by NOC-7. In order to confirm the anti-inflammatory potency, possible effects on prostaglandin (PG) E(2) production and expression of enzymes involved in the arachidonic acid pathway were next investigated. It was found that SE effectively inhibited the PGE(2) production by LPS-stimulated RAW264.7 cells, although the extent of inhibition of PGE(2) was slightly less than that of NO production. SE inhibited cyclooxygenase (COX)-2 expression at both protein and mRNA levels, but to much lesser extents as compared with those for iNOS expression. SE contained much lower concentration of arginine, precursor of NO, as compared with the culture medium. These data suggest that SE exerts a weak anti-inflammatory activity.

Anti-inflammatory and phytochemical properties of twelve medicinal plants used for treating gastro-intestinal ailments in South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

The investigated medicinal plants are commonly used for the treatment of pains and cramps related to gastro-intestinal tract infections in South African traditional medicine.

AIMS OF THE STUDY

This study aimed to evaluate the ability of the plant extracts to inhibit cyclooxygenase enzymes. Phytochemical analysis was also carried out in the quest to determine some plant metabolites that may be responsible for the observed anti-inflammatory activity.

MATERIALS AND METHODS

The cyclooxygenase assay was used to test for the anti-inflammatory activity of the plant extracts using cyclooxygenase-1 and -2 (COX-1 and COX-2) enzymes. Total phenolic compounds including condensed tannins, gallotannins and flavonoids were quantitatively determined using spectrophotometric methods. Qualitative tests for alkaloids and saponins were also carried out.

RESULTS

Most of the plant extracts evaluated showed dose dependent activity against COX-1 and/or COX-2 enzymes. Agapanthus campanulatus root dichloromethane extract showed the highest COX-2 inhibitory activity (83.7%) at 62.5 microg/ml. The presence and/or amounts of phenolics, condensed tannins, gallotannins, flavonoids, alkaloids and saponins varied with plant parts and species.

CONCLUSION

The results support the use of the investigated plant in treating pain and cramp related to gastro-intestinal tract infections. To some extent, the observed anti-inflammatory activity could be attributed to the various plant secondary metabolites detected in the plant materials.

Cannabinoid signaling in inhibitory autaptic hippocampal neurons

Depolarization-induced suppression of excitation and inhibition (DSE/DSI) appears to be an important form of short-term retrograde neuronal plasticity involving endocannabinoids (eCBs), the activation of presynaptic cannabinoid CB1 receptors, and the suppression of neurotransmitter release. Using murine autaptic hippocampal cultures, we have distinguished five populations of autaptic inhibitory neurons that exhibit differential cannabinoid responses, including three temporally distinct forms of DSI. One remaining population responded to cannabinoids but did not have DSI while a fifth had neither DSI nor cannabinoid responses. Of the two chief candidate eCBs, 2-AG reversibly inhibited inhibitory post synaptic currents (IPSCs) while anandamide did so irreversibly, the latter's action inconsistent with a role as a bona fide eCB mediator of DSI. The duration of depolarization necessary to elicit the two most prominent forms of DSI (effective dose (ED-50) approximately 210, approximately 280 ms) was far less than for autaptic DSE. However the nearly identical concentration response for 2-AG to inhibit excitatory postsynaptic currents (EPSCs) and IPSCs indicates that this difference is not due to differential cannabinoid receptor sensitivity. Interestingly, of the two populations exhibiting prominent DSI, one had a substantially faster recovery time course both after DSI and 2-AG, this despite being cultured under identical conditions. Several enzymes have been proposed to play a role in 2-AG breakdown, presumably determining the time course of DSI: fatty acid amide hydrolase (FAAH), cyclooxygenase-2 (COX-2), monoacyl glycerol lipase (MGL), and alpha/beta-hydrolase domains 6 and 12 (ABHD6 and ABHD12). We tested the impact on DSI duration by blockers of FAAH, COX-2, MGL and ABHD6. Notably, the population with slow DSI was regulated only by MGL, whereas the fast DSI population was regulated by both MGL and COX-2. This suggests that the faster DSI time course may occur as a result of the concerted action of multiple enzymes, which may represent a more general mechanism for regulation of the duration of different forms of DSI and DSE.

Differentiation of human osteosarcoma cells by isolated phlorotannins is subtly linked to COX-2, iNOS, MMPs, and MAPK signaling: implication for chronic articular disease

Arthritis is one of the most prevalent chronic inflammatory diseases, and it is characterized by structural and biochemical changes in major tissues of the joint, including degradation of the cartilage matrix, insufficient synthesis of extracellular matrix (ECM). Ecklonia cava (EC) is a member of the family of Laminariaceae, which is an edible marine brown alga with various bioactivities. In this study of the methanol extract of brown alga EC, the dieckol (1) and 1-(3',5'-dihydroxyphenoxy)-7-(2'',4'',6''-trihydroxyphenoxy) 2,4,9-trihydroxydibenzo-1,4,-dioxin (2) were isolated and characterized by NMR techniques with high yield. Phlorotannin derivatives (1, 2) promoted osteosarcoma differentiation by increasing alkaline phosphatase (ALP) activity, mineralization, total protein and collagen synthesis in human osteosarcoma cell (MG-63 cells), respectively. Furthermore, these phlorotannin derivatives (1, 2) inhibited mRNA gene and protein levels of matrix metalloproteinase (MMP-1, MMP-3, and MMP-13), iNOS and COX-2 in casein zymography, Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR) assays. In addition, it was observed that the phlorotannins inhibited phosphorylation of JNK and p38 MAPK in human osteosarcoma cell. These results suggested the phlorotannin derivatives (1, 2) could promote cell differentiation, attenuate MMP-1, MMP-3, MMP-13 expressions, and inflammatory response via MAPK pathway in chronic articular diseases.

Neoplasms escape selective COX-2 inhibition in an animal model of breast cancer

BACKGROUND

Cyclo-oxygenase-2 (COX-2) is up-regulated in malignant tumours rendering it an attractive target for cancer therapeutics. However, whether long-term antagonism maintains its initial efficacy on established tumours is unclear.

METHODS

4T1 cells were injected into the mammary fat pad of BALB/c mice (n = 8). Once tumour deposits were established, animals were randomized into two equal groups to receive either a selective COX-2 inhibitor (SC-236) or a drug vehicle. Further animals similarly treated (n = 7) were studied in diuresis cages allowing urine capture and analysis by mass spectrometry to determine Prostaglandin F-1 levels (PGF-1). In addition, both wild-type receiving SC-236 and COX-2 knockout mice receiving either SC 236 or vehicle were subjected to the same studies to determine whether tumour-derived or host-derived (stromal) COX-2 was the critical element. Finally, BALB/c mice with 4T1 tumours (n = 7) were treated with a combination of COX-2 and lipoxygenase (LOX) inhibition to attenuate this escape phenomenon.

RESULTS

While selective COX-2 inhibition initially retarded tumour growth, a rapid increase in tumour growth rate occurred later (day 9). This escape phenomenon correlated with an increase in urinary PGF-1 levels. An identical trend was also observed whether COX-2 knockout mice received SC-236 or not, suggesting that this effect is due to increased tumour-derived COX-2 production rather than recovery of host COX-2 functional capacity. Finally, dual inhibition of COX and LOX pathways attenuated this escape process.

CONCLUSION

The anti-neoplastic effects of selective COX-2 inhibition may not be sustained as tumours demonstrate an escape capacity. However, this phenomenon maybe attenuated by a combination of COX/LOX inhibitors.