COX-2 Assays Research Articles

Semisynthesis and pharmacological investigation of lipo-alkaloids prepared from aconitine

Abstract Processed aconite drugs are widely used in Eastern medicine as painkillers and antirheumatic agents. It is known that the traditional processing of aconite drugs increases the amount of lipo-alkaloids. In order to obtain information about the pharmacological potential of these compounds, semisynthesis of 9 aconitine-derived lipo-alkaloids was carried out and their COX-1, COX-2 and LTB4 formation inhibitory activities were investigated. It was found that compounds esterified with unsaturated fatty acids demonstrated significant COX-2 inhibitory effects, while in the COX-1 assay only 14-benzoylaconine-8-O-eicosapentaenoate exerted remarkable activity. The inhibition of LTB4 formation was pronounced in cases of long chain fatty acid derivatives.

Antimicrobial, anti-inflammatory and mutagenic investigation of the South African tree aloe ( Aloe barberae)

Ethnopharmacology relevance In recent times, many products ranging from aloe drinks to aloe gels, powders, capsules, and creams have appeared on the commercial market prepared from different aloe species including Aloe barberae. These products are used in ethnomedicine to treat various conditions including gastrointestinal disorders, insect bites, skin burns and other skin injuries by traditional communities. Aim of the study This study was aimed at evaluating the antibacterial, antifungal and anti-inflammatory activities as well as genotoxic effects of different extracts of Aloe barberae. Materials and methods Organic and water extracts of the upper stem, young bark, mature bark, leaves and roots of the South African tree aloe ( Aloe barberae) were evaluated for their antimicrobial [Gram-positive ( Bacillus subtilis and Staphylococcus aureus), Gram-negative ( Escherichia coli and Klebsiella pneumoniae) bacteria as well as the fungus Candida albicans], anti-inflammatory (COX-1 and COX-2) and mutagenic properties (Ames test). Thin layer chromatography (TLC) was used to compare the phytochemical profiles of different extracts of Aloe barberae. Results The petroleum ether (PE) and dichloromethane (DCM) extracts of the mature bark, leaves and roots exhibited good activity against all the bacteria and fungus Candida albicans with minimum inhibitory concentrations (MIC) ranging from 0.195 to 1.56 mg/ml. All the PE extracts evaluated showed a high activity (>70%) in both COX-1 and COX-2 assays. Apart from the organic extracts of the root with consistently good activity (>70%), all the remaining extracts showed moderate activity (40–69%) in COX-1 assay. The PE extracts also showed a dose dependent increase in activity. Ultraviolet (UV) spectrum of the leaves and root EtOH extracts indicated the presence of compounds that could absorb UV light (wavelength: 190–820 nm). None of the extracts had a mutagenic effect in the Salmonella/microsome assay against a tester strain, TA98. Conclusion Activity observed in the bark, leaves and roots of Aloe barberae validates its use in commercial herbal products, ethnobotany and ethnoveterinary medicine by South African communities and small scale farmers to treat various conditions.

T2043 Usefulness of Fecal COX-2, MMP-7 and Snail mRNAs Assay Using Quantitative RT-PCR for Detecting Colorectal Cancer

Background: Cross-sectional studies have reported an increase in annual colonoscopy volume associated with changes in Medicare reimbursement policies for colon cancer screening and surveillance. It is not known how much of the increment reflected initial versus follow up procedures and if the increase was associated with significant changes in polyp removal. Methods: Using a 5% sample of 1991-2002 Medicare claims data from cancer-free, fee-forservice beneficiaries aged 65 and older, the annual rate of first time colonoscopy procedures under Medicare was calculated. Procedures were divided into those that were diagnostic or included biopsy only (diagnostic), and those that included a code for snare polypectomy, hot biopsy or ablation (polypectomy). We compared the rates of diagnostic and polypectomy procedures by calendar year as well as between periods of Medicare reimbursement for screening: none (1991-1997), increased risk only (1998-6/01), and universal (7/01-2002). The proportion of all examinations with polypectomy was also compared between time periods in a multivariable model adjusting for demographic factors. Results: Annual rates for initial diagnostic colonoscopy and polypectomy are shown in the Table. The average annual rate of diagnostic procedures increased from 1.25% (1991-1997) to 1.42% (19982000) to 2.03% (2001-2002) and the annual rates of polypectomy increased from 0.17% to 0.20% to 0.32%, respectively. In multivariable analysis, there was a significant increase in the proportion of procedures associated with polypectomy in both 1998-6/01 (OR 1.07, 95% CI 1.02-1.14) and 7/01-2002 (OR 1.18, 95% CI 1.11-1.26). Conclusions: In this population-based sample, changes in colonoscopy reimbursement under Medicare were associated with increments in the volume of first-time colonoscopies and polypectomies. The increase in the proportion of procedures with polypectomy suggests that these policies may account in part for observed declines in colon cancer incidence and mortality in the U.S.

Evaluation of Antimicrobial and Anti-Inflammatory Activities of Seed Extracts from SixNigellaSpecies

Seed extracts from six species of the genus Nigella (Family Ranunculaceae)-Nigella arvensis, Nigella damascena, Nigella hispanica, Nigella nigellastrum, Nigella orientalis, and Nigella sativa-obtained by successive extraction with n-hexane, chloroform, and methanol, were tested for their antimicrobial activity against 10 strains of pathogenic bacteria and yeast using the microdilution method as well as for anti-inflammatory properties by in vitro cyclooxygenase (COX)-1 and COX-2 assay. Chemical characterization of active extracts was carried out including free and fixed fatty acid analysis. Comparison of antimicrobial activity showed that N. arvensis chloroform extract was the most potent among all species tested, inhibiting Gram-positive bacterial and yeast strains with minimum inhibitory concentration (MIC) values ranging from 0.25 to 1 mg/mL. With the exception of selective inhibitory action of n-hexane extract of N. orientalis on growth of Bacteroides fragilis (MIC = 0.5 mg/mL), we observed no antimicrobial activity for other Nigella species. Anti-inflammatory screening revealed that N. sativa, N. orientalis, N. hispanica, N. arvensis n-hexane, and N. hispanica chloroform extracts had strong inhibitory activity (more than 80%) on COX-1 and N. orientalis, N. arvensis, and N. hispanica n-hexane extracts were most effective against COX-2, when the concentration of extracts was 100 microg/mL in both COX assays. In conclusion, N. arvensis, N. orientalis, and N. hispanica seeds, for the first time examined for antimicrobial and anti-inflammatory effects, revealed their significant activity in one or both assays.

Efficacy of curcumin in lung cancer hamster model

Curcumin, the polyphenolic pigment from the rhizome Curcuma longa, is known for its antioxidant, anti‐inflammatory, antibacterial, and recently, anticarcinogenic properties. The aim of this study was to investigate efficacy of curcumin in lung cancer induced hamster model. 32 male Golden Syrian hamsters were divided into test (TO, T2 n= 10 each) and control (CO, C2 n=6 each) groups. Test groups received BOP (N‐nitrosobis (2‐oxopropyl) amine; 10mg/kg), a carcinogen, for 12 weeks, while the control animals received saline injections. Effect of curcumin was examined by providing 0 (C0, T0) or 2% (C2, T2) dietary curcumin. After 24 weeks tissues were harvested and lungs fixed for H&E and AE1/AE3 immunohistochemistry staining. COX‐2 and COMET assays were performed to determine the degree of inflammation and DNA damage in the tissues respectively. Histology showed significant differences in cancer development between the treatment groups with (T2) and without (T0) curcumin intervention. Cancer incidence (11.1% (T2) vs 45.5 %(T0)) and survival rate (72% (T2) vs. 33% (T0)) were significantly different. Loss in body weight, increase in Cox‐2 levels and DNA damage reinforced the beneficial role of curcumin in decreasing lung cancer in the hamster model. Overall, the study shows the chemopreventive effect of curcumin. Further investigations are needed to test curcumin as a therapeutic agent in the human population.Grant Funding SourceWayne State University

Differential effects of immunosuppressive drugs on COX-2 activity in vitro and in kidney transplant patients in vivo

It was hypothesized that calcineurin inhibitors suppress vascular cyclooxygenase (COX)-2 and exert a reciprocal influence on in vivo prostacyclin and thromboxane. This could contribute to cardiovascular morbidity in transplanted patients. The ability of immunosuppressives to suppress vascular COX-2 expression in vitro was studied in cultured human vascular smooth muscle cells. Blood and urine samples were collected from 28 renal transplant patients before and 2, 4 and 6 h after intake of immunosuppressives and from 11 controls. ELISA was used to measure (1) plasma 6-keto-PGF1alpha and TxB2; (2) urine excretion of PGI-M and TxB(2); (3) 6-keto-PGF1alpha in the whole-blood COX-2 assay; and (4) TxB2 in the whole-blood COX-1 assay. Platelet aggregation was measured optically. COX-2 in cultured vascular smooth muscle cells was suppressed by cyclosporine A (CsA); tacrolimus and rapamycin had no effect. Human renal arteries and vascular smooth muscle expressed calcineurin Abeta and Agamma isoforms. CsA had no effect on plasma 6-keto-PGF1alpha, whole-blood COX-2 activity or PGI-M urine excretion; after rapamycin intake, the former two increased. Plasma TxB2 did not change after drug intake. TxB2 in the COX-1 assay and urine excretion of TxB2 was significantly lower in tacrolimus- and rapamycin-treated patients compared to the CsA group. Platelet aggregation was increased significantly in the CsA group. Although CsA suppressed COX-2 in cultured vascular smooth muscle cells, systemic prostacyclin was not suppressed by either CsA or tacrolimus in vivo. Rapamycin and tacrolimus may actively suppress platelet and renal thromboxane formation. Differential changes in prostanoids may have implications for long-term cardiovascular hazard in patients treated with immunosuppressives.

In vitro pharmacological evaluation of three Barleria species

Ethnopharmacological relevance Various parts of Barleria prionitis L. (Acanthaceae) are used in traditional medicine to treat infection-related ailments. A comparison of their activities and knowledge of their mechanisms of action are important for drug development and conservation. Aims of the study This study investigated the antibacterial effects and underlying mechanisms of action of the anti-inflammatory activities of different parts of three Barleria species of South African origin. Materials and methods Crude extracts of different parts of three Barleria species were investigated in vitro for their biological activity. Antibacterial activity was evaluated using the micro-dilution assay against two Gram-positive and two Gram-negative bacteria. Anti-inflammatory activity was evaluated using the cyclooxygenase COX-1 and COX-2 assays. Results All the extracts showed broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.059 to 6.25 mg/ml. Twelve out of 21 crude extracts evaluated showed good activity (>70%) in the COX-1 assay while 10 extracts showed good activity in the COX-2 assay. All the petroleum ether extracts (except B. prionitis stem) exhibited good inhibition of prostaglandin synthesis in COX-1. Conclusion The results demonstrated the therapeutic potential of these plants as antibacterial and anti-inflammatory agents. Their anti-inflammatory properties are mediated by the inhibition of the cyclooxygenase enzymes.

Antibacterial, antifungal and anti-inflammatory properties of Burchellia bubalina

Extracts obtained from stems, leaves, roots and bark of Burchellia bubalina were evaluated for antibacterial, antifungal and anti-inflammatory (COX-1 and COX-2) activities. Antibacterial and antifungal activities were evaluated using micro-dilution assays against two Gram-positive ( Bacillus subtilis, Staphylococcus aureus) and two Gram-negative bacteria ( Escherichia coli, Klebsiella pneumoniae) and the fungus Candida albicans. The bark dichloromethane (DCM) extract showed the lowest minimum inhibitory concentrations (MIC) of 0.098 mg/ml against E. coli and 0.39 mg/ml against both Gram-positive bacteria. The DCM extracts of the leaf and stem showed MIC values of 0.15 mg/ml and 0.39 mg/ml respectively against the fungus. The DCM extract of the leaf showed the best fungicidal activity at a concentration of 0.20 mg/ml. The petroleum ether and DCM extracts of both the leaf and stem exhibited good inhibition (> 70%) of prostaglandin synthesis in both COX-1 and COX-2 assays.

In vitro pharmacological evaluation of three Barleria species

Abstract Ethnopharmacological relevance Various parts of Barleria prionitis L. (Acanthaceae) are used in traditional medicine to treat infection-related ailments. A comparison of their activities and knowledge of their mechanisms of action are important for drug development and conservation. Aims of the study This study investigated the antibacterial effects and underlying mechanisms of action of the anti-inflammatory activities of different parts of three Barleria species of South African origin. Materials and methods Crude extracts of different parts of three Barleria species were investigated in vitro for their biological activity. Antibacterial activity was evaluated using the micro-dilution assay against two Gram-positive and two Gram-negative bacteria. Anti-inflammatory activity was evaluated using the cyclooxygenase COX-1 and COX-2 assays. Results All the extracts showed broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.059 to 6.25 mg/ml. Twelve out of 21 crude extracts evaluated showed good activity (>70%) in the COX-1 assay while 10 extracts showed good activity in the COX-2 assay. All the petroleum ether extracts (except B. prionitis stem) exhibited good inhibition of prostaglandin synthesis in COX-1. Conclusion The results demonstrated the therapeutic potential of these plants as antibacterial and anti-inflammatory agents. Their anti-inflammatory properties are mediated by the inhibition of the cyclooxygenase enzymes.

S1124 Potential Usefulness of Predicting Stage of Colorectal Cancer By Fecal RNA Test

Background and Aims: We reported that fecal RNA test (FRT), detecting mRNA of COX2 and/or MMP-7 and/or Snail in feces, was superior to a single fecal immunochemical test (FIT) in term of sensitivity and specificity for colorectal cancer (CRC). (Gastroenterology 132(4): A-623, 2007). FIT is an excellent screening method of CRC, however, it is hard to make a qualitative diagnosis such as a rough stage of CRC. It is very interesting to examine whether FRT can predict a rough stage of CRC. Methods: Standard histological techniques were used to classify at 0 (TNM 0 is carcinoma in situ) to IV stage according to TNM classification, yielding stage 0 (n = 2), I (n = 12), II (n = 30), III (n = 14), and IV (n = 12). We purified RNA from routinely collected stool samples and screened mRNA using COX2, MMP-7 and Snail specific nested RT-PCR, which expression level was clarified in fifth grades (0: negative, 1-4: weakly to strongly positive). Results: Stool samples from 70 patients with CRC and 34 control patients without neoplastic or inflammatory disease were studied. By optimizing PCR conditions, the specificity of FRT was 100% [95% confidence interval (CI), 91.6%-100%]. The sensitivity of fecal COX-2 assay was 85.3% (95% CI; 75.3%-92.9%), 64.2% (95% CI, 51.9%-75.4%) for fecal MMP-7 assay and 51.4% (95% CI, 39.2%-63.6%) for fecal Snail assay, respectively. Consequently, FRT had 90% sensitivity (95% CI, 80.5%95.9%). The sensitivity of FRT was 78.6% (95% CI, 49.2%-95.3%) of stage 0 or I, 96.7% (95% CI, 82.8%-99.9%) of stage II, and 88.5% (95% CI, 69.8%-97.5%) of stage III or IV. Among patients with stage 0, I, or II, who are often cured by endoscopic or surgical resection, FRT had 90.9% sensitivity (95% CI, 78.3%-97.5%). FRT had 87.5% sensitivity (95% CI, 67.6%-91.3%) for detection of tumors proximal to the splenic flexure, and 91.3% sensitivity (95% CI, 79.2%-97.6%) for detection of tumors distal to the splenic flexure. Median expression level of each assay was 1 vs. 1 for COX-2, 0 vs. 3 for MMP-7, 0 vs. 1 for Snail (early cancer Vs. advanced cancer), respectively. Expression level of fecal COX-2 assay for advanced cancer was significantly higher than that of early cancer (P < 0.05, Mann-Whitney test). When expression level of each assay was more than 2, the positive predictive value for advanced cancer was 89.7% for COX-2, 85.7% for MMP-7, and 91.7% for Snail, respectively. Conclusions: Fecal RNA test had high sensitivity and high specificity for CRC. FRT may predict CRC whether it is advanced cancer or not. These results suggest that FRT would be a screening method of CRC with a potential of predicting rough stage.

Cyclooxygenase inhibition and antimycobacterial effects of extracts from Sudanese medicinal plants

Fifty one dichloromethane, ethyl acetate and ethanol extracts obtained from seven tree species used in Sudanese traditional medicine were screened for in vitro anti-inflammatory activity using COX-1 and COX-2 assays and for antimycobacterial activity using the broth micro-dilution methods against Mycobacterium aurum A+. In the cyclooxygenase assays, all ethyl acetate (leaf, bark, root) and ethanol root extracts of Acacia seyal, ethyl acetate twig extracts of Capparis decidua, dichloromethane bark extracts of Combretum hartmannianum and ethanol bark extracts of Ziziphus spina-christi showed inhibitory effect against prostaglandin synthesis by COX-2 ranging from 58 to 97% and weak (<50%) or no activity against COX-1 induced prostaglandin production. In the antimycobacterial assays, ethanol extracts of A. seyal (bark), C. hartmannianum (leaf, bark), Kigelia africana (bark) and Z. spina-christi (bark) inhibited growth of M. aurum A+ with MIC values ranging between 0.19 and 1.56 mg/ml. The in vitro anti-inflammatory activity observed in this study support the utilization of these plants in Sudanese traditional medicine as crude anti-inflammatory agents. The inhibition of COX-1 and COX-2 and the antimycobacterial effects of these plants have not been reported previously. Isolation of bioactive compounds from A. seyal and Erythrina latissima are in progress in our laboratory.

Comparative structure–activity relationship studies of 1-(5-methylsulfonylpyrid-2-yl)-5-alkyl and (hetero)aryl triazoles and pyrazoles in canine COX inhibition

Structure-activity relationship (SAR) studies of novel 5-alkyl and 5-aryl/heteroaryl substituted 1,2,4-triazoles are described. The in vitro activity is compared to the pyrazole class of compounds with analogous side chains to delineate the contribution of the triazole ring nitrogen in binding to the active site. Both series are quite potent and selective in the canine whole blood (CWB) COX-2 assay, suggesting the increased binding contribution of the hydrophobic side chains.

5-Heteroatom-substituted pyrazoles as canine COX-2 inhibitors: Part 2. Structure–activity relationship studies of 5-alkylethers and 5-thioethers

Structure–activity relationship (SAR) studies of novel 2-[3-trifluoromethyl-5-alkyl(thio)ether pyrazo-1-yl]-5-methanesulfonyl pyridine derivatives for canine COX enzymes are described. The 4-cyano-5-alkyl ethers were found to have excellent potency and selectivity, whereas the 5-thioethers were potent but less selective than the ether analogs in a canine whole blood (CWB) COX-2 assay.

Diterpenoid Alkaloids from Aconitum tanguticum

AbstractFor Abstract see ChemInform Abstract in Full Text.

Development of in vitro assays for the evaluation of cyclooxygenase inhibitors and predicting selectivity of nonsteroidal anti-inflammatory drugs in cats

To develop and validate in cats suitable in vitro assays for screening and ranking nonsteroidal antiinflammatory drugs (NSAIDs) on the basis of their inhibitory potencies for cyclooxygenase (COX)-1 and COX-2. 10 cats. COX-1 and COX-2 activities in heparinized whole blood samples were induced with calcium ionophore and lipopolysaccharide, respectively. For the COX-2 assay, blood was pretreated with aspirin. The COX-1 and COX-2 assays were standardized, such that time courses of incubation with the test compounds and conditions of COX expression were as similar as possible in the 2 assays. Inhibition of thromboxane B2 production, measured by use of a radioimmunoassay, was taken as a marker of COX-1 and COX-2 activities. These assays were used to test 10 to 12 concentrations of a COX-1 selective drug (SC-560) and of 2 NSAIDs currently used in feline practice, meloxicam and carprofen. Selectivities of these drugs were compared by use of classic 50% and 80% inhibitory concentration (ie, IC50 and IC80) ratios but also with alternative indices that are more clinically relevant. These assay conditions provide a convenient and robust method for the determination of NSAID selectivity. The S(+) enantiomeric form of carprofen was found to be COX-2 selective in cats, but meloxicam was only slightly preferential for this isoenzyme. In vitro pharmacodynamic and in vivo pharmacokinetic data predict that the COX-2 selectivity of both drugs for cats will be limited when used at the recommended doses. This study provides new approaches to the selection of COX inhibitors for subsequent clinical testing.

Characterization of Etoricoxib, a Novel, Selective COX‐2 Inhibitor

Etoricoxib is a potent selective COX-2 inhibitor in man. Ex vivo whole-blood assays assessed COX-2 inhibition after oral administration of etoricoxib in single (5-500 mg) and multiple (25-150 mg) once-daily doses to healthy human subjects. A separate study examined ex vivo gastric mucosal PGE2 synthesis after etoricoxib (120 mg qd), naproxen (500 mg bid), or placebo for 5 days. The effect of etoricoxib 120 mg qd on the COX-1-mediated antiplatelet effects of low-dose aspirin (ASA) was also assessed. The mean (time)-weighted average inhibition (WAI) of lipopolysaccharide (LPS)-stimulated PGE2 (COX-2 assay) vcrsus placebo was dose related after single (range: 3.1%-99.1%) and multiple doses (range: 52.5%-96.7%). PGE2 remained significantly inhibited 24 hours postdose at steady state. Inhibition of LPS-stimulated PGE2 showed a strong relationship with etoricoxib plasma concentrations; ex vivo, IC50 was almost identical to in vitro. Multiple dosing of etoricoxib (up to 150 mg qd) showed no important effects on serum TXB2, bleeding time, or platelet aggregation (COX-1-mediated effects). The nonselective nonsteroidal anti-inflammatory (NSAID) naproxen significantly inhibited (approximately 78%) ex vivo prostaglandin synthesis in gastric mucosa; etoricoxib had no effect. Etoricoxib did not interfere with the antiplatelet effects of low-dose ASA, as assessed by serum TXB2 and platelet aggregation. Etoricoxib was generally well tolerated, even at doses above the clinical dose range. Based on these results, etoricoxib is a potent selective inhibitor of COX-2 after single and multiple dosing regimens and does not inhibit prostaglandin synthesis in the gastric mucosa, even at doses above the clinical dose range of 60 to 120 mg.

Screening of Cenchrus ciliaris L. for biological activity

Cenchrus ciliaris L. (Poaceae) is a commonly occurring perennial grass in South Africa. The underground runners are used in Zulu traditional medicine for ailments including 'body pain', menstrual disorders and urinary infections. Water, ethanol and ethyl acetate extracts were prepared from the underground and leaf material of C. ciliaris plants. The extracts were screened for anti-inflammatory activity, antibacterial, anthelmintic and antischistosomial activity. Anti-inflammatory activity was confirmed as shown by the inhibition of prostaglandin synthesis by the ethanol and ethyl acetate extracts in both COX-1 and COX-2 assays. Some antibacterial activity was observed against the Gram-positive bacteria ( Bacillus subtilis, Staphylococcus aureus ) at minimal inhibitory concentrations ranging from 0.20-0.78mgml −1 , and against the Gram-negative bacteria ( Escherichia coli, Klebsiella pneumoniae ) at minimal concentrations ranging from 3.13-6.25mgml −1 for the ethanol and ethyl acetate extracts. Low levels of anthelmintic activity were observed against the test organism Caenorhabditis elegans. No activity was detected in the antischistosomial assay. These results provide evidence for the moderate biological activity of this plant, and could substantiate the use of C. ciliaris in traditional medicine.

Potential Cancer-Chemopreventive Activities of Wine Stilbenoids and Flavans Extracted From Grape (Vitis vinifera) Cell Cultures

Moderate consumption of wine is associated with a reduced risk of cancer. Grape plant cell cultures were used to purify 12 phenols: the stilbenoids trans-astringin, trans-piceid (2), trans-resveratroloside, trans-resveratrol, trans-piceatannol, cis-resveratroloside, cis-piceid, and cis-resveratrol; the flavans (+)-catechin, (-)-epicatechin, and epicatechin 3′-O-gallate; and the flavan dimer procyanidin B'2 3′-O-gallate. These compounds were evaluated for potential to inhibit cyclooxygenases and preneoplastic lesion formation in carcinogen-treated mouse mammary glands in organ culture. At 10 μg/ml, trans-astringin and trans-piceatannol inhibited development of 7,12-dimethylbenz[a]anthracene-induced preneoplastic lesions in mouse mammary glands with 68.8% and 76.9% inhibition, respectively, compared with untreated glands. The latter compound was the most potent of the 12 compounds tested in this assay, with the exception of trans-resveratrol (87.5% inhibition). In the cyclooxygenase (COX)-1 assay, trans isomers of the stilbenoids appear to be more active than cis isomers: trans-resveratrol [50% inhibitory concentration (IC5050) = 14.9 μM, 96%] vs. cis-resveratrol (IC50 = 55.4 μM). In the COX-2 assay, among the compounds tested, only trans- and cis-resveratrol exhibited significant inhibitory activity (IC50 = 32.2 and 50.2 μM, respectively). This is the first report showing the potential cancer-chemopreventive activity of trans-astringin, a plant stilbenoid recently found in wine. trans-Astringin and its aglycone trans-piceatannol were active in the mouse mammary gland organ culture assay but did not exhibit activity in COX-1 and COX-2 assays. trans-Resveratrol was active in all three of the bioassays used in this investigation. These findings suggest that trans-astringin and trans-piceatannol may function as potential cancer-chemopreventive agents by a mechanism different from that of trans-resveratrol.

THE EFFECT OF AGE, SEASON AND GROWTH CONDITIONS ON ANTI INFLAMMATORY ACTIVITY IN EUCOMIS AUTUMNALIS (MILL.) CHITT. PLANT EXTRACTS.

Eucomis (Family Hyacinthaceae) bulbs are greatly valued in traditionalmedicine for the treatment of a variety of ailments, predominantly thoseinvolving pain, fever and inflammation. The COX-1 assay was used to screenethanolic extracts prepared from the dried leaves, bulbs and roots of E. autumnalis (subspecies autumnalis) to determine the variation ofanti-inflammatory activity with age and season of harvest. Young plantswere found to have large amounts of COX-1 inhibitory activity, particularlyin the leaves. As the plant matured, greater activity was associated with thebulb and root extracts. The anti-inflammatory activity of the leaf, bulb androot extracts varied slightly throughout the year, with the greatest levelsdetected towards the end of the growing season, shortly before the onsetof dormancy. A seaweed application (Kelpak) decreased the anti-inflammatory activity of the leaf, bulb and root extracts, while increasedtemperature/increased light intensity had no significant effect on theCOX-1 inhibitory activity of the leaf extracts. The bulb extracts fromtreated plants harvested towards the end of the growing season showed asignificant decrease in anti-inflammatory activity, while the anti-inflammatory activity of the corresponding not root extracts increased.

A New Cyclooxygenase‐2 Inhibitor, Rofecoxib (VIOXX®), Did Not Alter the Antiplatelet Effects of Low‐Dose Aspirin in Healthy Volunteers

The present study examined whether rofecoxib (VIOXX), a new specific inhibitor of cyclooxygenase-2 (COX-2), would interfere with the desired antiplatelet effects of aspirin. Thus, the effects of rofecoxib on inhibition of ex vivo serum-generated thromboxane B2 (TXB2) and platelet aggregation by low doses (81 mg) of aspirin were examined in healthy volunteers. This was a double-blind, randomized, placebo-controlled, parallel study of two treatment groups (n = 12 per group) in which subjects received 50 mg of rofecoxib or placebo for 10 days in a blinded fashion. Subjects also received 81 mg aspirin once on each of days 4 through 10 in an open-label fashion. Blood for measurement of serum TXB2 production and platelet aggregation studies was collected on day 1 (prior to rofecoxib/placebo), on day 4 (prior to aspirin), and on day 10 (before and 4 hours following the seventh dose of aspirin). Platelet-derived serum TXB2 (COX-1 assay) was measured in blood clotted for 1 hour at 37 degrees C. Platelet aggregation was independently induced employing 1 mM arachidonic acid and 1 microgram/mL collagen as agonists. Rofecoxib administered alone had no significant effect on serum TXB2 production or platelet aggregation (day 4). TXB2 production was inhibited 98.4% by aspirin coadministered with either rofecoxib or placebo (day 10). Similarly, platelet aggregation induced by arachidonic acid was inhibited 93.7% and 93.5% by aspirin coadministered with either rofecoxib or placebo, respectively (day 10). The comparable values for inhibition of collagen-induced platelet aggregation were 86.8% and 90.8%, respectively. No important clinical or laboratory adverse experiences were observed. In conclusion, rofecoxib alone (50 mg QD for 4 days) did not inhibit serum TXB2 production or platelet aggregation. In addition, rofecoxib (50 mg QD for 10 days) did not alter the antiplatelet effects of low-dose aspirin (inhibition of platelet aggregation and TXB2 production). Rofecoxib was generally well tolerated when administered alone or in combination with low-dose aspirin.