The integrated use of in silico methods for the hepatotoxicity potential of Piper methysticum.

Herbal products as supplements and therapeutic intervention have been used for centuries. However, their toxicities are not completely evaluated and the mechanisms are not clearly understood. Dried rhizome of the plant kava (Piper methysticum) is used for its anxiolytic, and sedative effects. The drug is also known for its hepatotoxicity potential. Major constituents of the plant were identified as kavalactones, alkaloids and chalcones in previous studies. Kava hepatotoxicity mechanism and the constituent that causes the toxicity have been debated for decades. In this paper, we illustrated the use of computational tools for the hepatotoxicity of kava constituents. The proposed mechanisms and major constituents that are most probably responsible for the toxicity have been scrutinized. According to the experimental and prediction results, the kava constituents play a substantial role in hepatotoxicity by some means or other via glutathione depletion, CYP inhibition, reactive metabolite formation, mitochondrial toxicity and cyclooxygenase activity. Some of the constituents, which have not been tested yet, were predicted to involve mitochondrial membrane potential, caspase-3 stimulation, and AhR activity. Since Nrf2 activation could be favorable for prevention of hepatotoxicity, we also suggest that these compounds should undergo testing given that they were predicted not to be activating Nrf2. Among the major constituents, alkaloids appear to be the least studied and the least toxic group in general. The outcomes of the study could help to appreciate the mechanisms and to prioritize the kava constituents for further testing.

Indomethacin functionalised poly(glycerol adipate) nanospheres as promising candidates for modified drug release.

The linear polyester poly(glycerol adipate) (PGA) with its free pendant hydroxyl groups was covalently grafted with indomethacin which yields polymeric prodrugs. It was possible to produce nanospheres with narrow particle size distribution of these polymer-drug conjugates with an optimized interfacial deposition method. Nanospheres were characterized by zeta potential measurements, dynamic light scattering, electron microscopy and nanoparticle tracking analysis. Moreover, cell viability studies and cytotoxicity tests in three different cell lines were carried out showing low toxicity for three different degrees of grafting. In addition, the nanospheres had (in contrast to the free drug) low hemolytic activity in vitro. Release studies of nanodispersions are challenging. The use of a specially developed setup with highly porous aluminum oxide membranes enabled us to overcome problems associated with other setups (e.g. dialysis membranes). A slow and controlled release profile without any burst was observed over 15 days. The results indicate that indomethacin-PGA conjugates can be formulated successfully as nanospheres with the desired characteristics of small size with narrow distribution, controlled drug release and low toxicity. The newly developed particles have the potential to improve the therapy of inflammation and associated diseases.

Effects and possible mechanisms of Alpinia officinarum ethanol extract on indomethacin-induced gastric injury in rats.

CONTEXT: Alpinia officinarum Hance (Zingiberoside) has a long history in treating gastrointestinal diseases, but its mechanisms of action are not yet known. OBJECTIVE: To investigate the effects and underlying mechanisms of the ethanol extract of A. officinarum rhizomes in an indomethacin-induced gastric injury rat model. MATERIAL AND METHODS: Indomethacin (0.3 g/kg) was orally administered to Sprague-Dawley rats to induce gastric damage; after 7 h, the rats were treated with 0.03, 0.09, or 0.18 g/kg of the plant extract, galangin (0.2 g/kg), or bismuth potassium citrate (0.08 g/kg), once a day for 6 days. Rats in the control group received an equivalent volume of vehicle solution for 6 days. Gastric damage was evaluated by gross ulcer and histological indexes. Cyclooxygenase and non-cyclooxygenase pathway proteins were quantified by western blotting and ELISA. RESULTS: Alpinia officinarum extract ameliorated gastric injury in a dose-dependent manner, and 0.18 g/kg dose exhibited the best performance by reducing the gross ulcer (from 20.23 ± 1.38 to 1.66 ± 0.37) and histological (from 4.67 ± 1.03 to 0.33 ± 0.51) indexes, decreasing serum TNF-α level (14.17%), increasing serum VEGF level (1.58 times), increasing cyclooxygenase-1 level (1.25 times, p < 0.001) in the gastric mucosa, and reversing indomethacin-induced changes in the expression of non-cyclooxygenase pathway proteins (p < 0.05). Galangin was less effective as an antiulcer agent than the whole extract, indicating that other components also contributed to the protective effect. CONCLUSIONS: Alpinia officinarum extract and galangin exert antiulcer effects through cyclooxygenase and non-cyclooxygenase pathways validating use of galangin as a treatment for gastric damage.

In silico prediction of prostaglandin D2 synthase inhibitors from herbal constituents for the treatment of hair loss.

ETHNOPHARMACOLOGICAL RELEVANCE: Many herbal topical formulations have been marketed worldwide to prevent hair loss or promote hair growth. Certain in vivo studies have shown promising results among them; however, the effectiveness of their bioactive constituents remains unknown. AIM OF THE STUDY: Recently, prostaglandin D2 (PGD2) inhibition has been discovered as a pharmacological mechanism for treating androgenic alopecia (AGA). This present study was aimed to identify prostaglandin D2 synthase (PTGDS) inhibitors in traditional Chinese medicines (TCMs) for treating AGA. MATERIALS AND METHODS: In this study, 389 constituents of 12 selected herbs were docked into 6 different crystal structures of PTGDS. The accuracy of the docking methods was successfully validated with experimental data from the ZINC In Man (Zim) database using receiver operating characteristic (ROC) studies. Seven essential drug properties were predicted for topical formulation: skin permeability, sensitisation, irritation, corrosion, mutagenicity, tumorigenicity and reproductive effects. RESULTS: Many constituents of the twelve herbs were found to have more advanced binding energies than the experimentally proved PTGDS inhibitors, but many of them were indicative of at least one type of skin adverse reactions, and exhibited poor skin permeability. CONCLUSIONS: Overall, ricinoleic acid, acteoside, amentoflavone, quercetin-3-O-rutinoside and hinokiflavone were predicted to be PTGDS inhibitors with good pharmacokinetic properties and minimal adverse skin reactions. These compounds have the highest potential for further in vitro and in vivo investigation with the aim of developing safe and high-efficacy hair loss treatment.

Reproductive and Developmental Toxicity of Orally Administered Botanical Composition, UP446-Part I: Effects on Embryo-Fetal Development in New Zealand White Rabbits and Sprague Dawley Rats.

The pharmacotoxicology impacts of dietary supplements taken at the time of pregnancy have remained alarming since women are the frequent herbal medicine users in many countries as a complement to the conventional pregnancy management. The use of herbal medicines and diet supplements in expectant mothers linked closely to the health of the childbearing mothers and the fetuses where the lack of developmental safety data imposes a challenge to make the right choices. Here, we describe the potential adverse effects of UP446, a standardized bioflavonoid composition from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu, on embryo-fetal development following maternal exposure during the critical period of major organogenesis in rabbits and rats. Pregnant dams were treated orally with UP446 at doses of 250, 500, and 1000 mg/kg/day during gestation. The number of resorptions, implantations, litter size, body weights, and skeletal development was evaluated. Maternal food intake and body, tissue, and placenta weight were also assessed. There were no statistically significant differences in implantation, congenital malformation, embryo-fetal mortalities, and fetuses sex ratios in all dosing groups of both species. Therefore, the no observed adverse effect level of UP446 was considered to be greater than 1000 mg/kg in both the maternal and fetus in both species.

Reproductive and Developmental Toxicity of Orally Administered Botanical Composition, UP446-Part III: Effects on Fertility and Early Embryonic Development to Implantation in Sprague Dawley Rats.

In recent years, high prevalence of adverse effects associated to the use of traditional medicines during pregnancy is becoming alarming due to the self-medication of oral supplements by expecting mothers without supervision. Many expectant mothers use alternative and complementary medicines as a supplement to conventional pregnancy management with an inherent belief of considering herbal remedies as harmless. To the contrary, herbal remedies could incur a potential teratogenic risk both to the child bearing mother and the developing fetuses when consumed before or at the time of gestation. Here, we describe the potential adverse effects of orally administered UP446, a standardized bioflavonoid composition from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu, on fertility and early embryonic development to implantation in Sprague Dawley rats at doses of 250, 500, and 1000 mg/kg. Besides body weight and food consumption, reproductive functions, sperm motility and morphology, estrus cycle, and fertility rate were monitored. There were no statistically significant differences in reproductive function in all UP446 treated groups in both genders. Test substance impacts on reproductive parameters were very minimal. Neither sperm motility nor morphology was affected as a result of oral UP446 administrations in males. There were no treatment-related effects on estrus cycle stages in females. No significant changes in necropsy or histopathology were observed for all the groups. Therefore, the no observed adverse effect level (NOAEL) of UP446 was considered to be 1000 mg/kg, the highest dose tested, in both genders.

Reproductive and Developmental Toxicity of Orally Administered Botanical Composition, UP446-Part II: Effects on Prenatal and Postnatal Development, Including Maternal Function in Sprague-Dawley Rats.

Almost all herbal remedies could be therapeutic at one dose and toxic at another. These facts become more troubling and a double threat when uncharacterized medicinal herbs are blended together and used by expectant mothers as a supplement to conventional pregnancy management with an inherent belief of considering herbal remedies as harmless. Here we describe the potential adverse effects of UP446, a standardized bioflavonoid composition from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu, on the maternal and their first filial generation (F1) developmental and functional toxicity following exposure at doses of 250, 500, and 1000 mg/kg/day. Maternal gestation, viability index, sex ratio, body weight, and food consumption were evaluated. F1 growth and development, sexual function including mating index, fertility, implantation, and embryo mortality were also assessed. Test substance impacts on the maternal (F0) or F1 reproductive parameters were very minimal. There were no statistically significant differences in implantation, parturition, viability, and neonates' sex ratios. There were no significant changes in maturation, behavioral, or functional developments between groups. No treatment-related prenatal or postnatal in-life or necropsy abnormalities were observed. Therefore, the no observed adverse effect level in the prenatal and postnatal developments, including maternal function study was considered to be greater than 1000 mg/kg.

Effect of mucoprotective plant-derived therapies on damage to colonic mucosa caused by carprofen and robenacoxib administered to healthy dogs for 21 days.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) may cause gastrointestinal damage in dogs. HYPOTHESIS/OBJECTIVES: To determine the extent to which lansoprazole, liquorice extract, and a herbal solution exhibit protective effects on colonic mucosa when administered to dogs concurrently with the NSAIDs carprofen or robenacoxib. ANIMALS AND METHODS: Thirty-five healthy beagle dogs (15 male and 20 female) aged 13-14 weeks and weighing 4.3-5.5 kg at the beginning of the experiment were included. Endoscopy and biopsy of the caudal gastrointestinal tract were performed pretreatment and on the last day of a 21-day treatment period with (1) oral carprofen; (2) carprofen and the proton-pump inhibitor lansoprazole; (3) carprofen, liquorice extract, and a herbal solution that contained extracts of thyme, icelandic lichen, hyssop, and saponariae root; (4) robenacoxib; (5) robenacoxib and lansoprazole; (6) robenacoxib, liquorice extract, and herbal solution; or (7) an empty gelatin capsule. Statistical analyses were performed with the Kruskal-Wallis, Cochran's Q, and chi-squared test with p < 0.05 considered significant. RESULTS: Both carprofen and robenacoxib tested damaged the colonic mucosa with most severe microscopic lesions following administration of robenacoxib with lansoprazole. The risk of histopathological lesions in the colon increased most rapidly in robenacoxib with lansoprazole (absolute risk increase -0.85) similar to robenacoxib only (-0.75), whereas the best result was recorded following the plant remedies together with carprofen (-0.15) and the plant remedies together with robenacoxib (-0.2). CONCLUSIONS AND CLINICAL IMPORTANCE: Concurrent administration of liquorice extract and an herbal solution with robenacoxib was associated with decreased severity of the NSAID-induced mucosal lesions.

Ethnopharmacological study of plants from Pondoland used against diarrhoea.

ETHNOPHARMACOLOGICAL RELEVANCE: Waterborne diseases such as diarrhoea are common world wide, including in Bizana, South Africa where the majority of rural dwellers depend largely on water from unprotected sources. The people from Bizana use medicinal plants as their first line of health care to cure and prevent diarrhoea. AIM OF THE STUDY: To record and document plants used for the treatment of diarrhoea in Bizana, to evaluate antibacterial and anti-inflammatory activities of selected plant extracts as well as to perform genotoxicity testing of evaluated plants. MATERIALS AND METHODS: An ethnobotanical approach was used to select plants used for treating diarrhoea in Bizana for pharmacological assays using questionnaires. Nine plants were selected for bioassays based on their frequency index and the fact that they have never been evaluated against diarrhoea causing-microorganisms. The petroleum ether (PE), dichloromethane (DCM), 70% ethanol (EtOH), and water extracts were evaluated for antibacterial (Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli and Shigella flexneri) activity using the microdilution technique, their ability to inhibit COX-1 and COX-2 enzymes. Genotoxicity was evaluated using the Salmonella microsome assay. RESULTS: This study revealed that 34 plant species belonging to 27 families are used for the treatment of diarrhoea in Bizana. The extracts showed good inhibitory activity with MIC values ranging from 0.39 to 12.5mg/ml. The best activity was exhibited by DCM extracts of Rapanea melanophloeos, and EtOH extracts of Ficus craterostoma and Maesa lanceolata with MIC values of 0.098mg/ml. The inhibitory activity against COX-1 enzyme was higher than COX-2, with 19 plant extracts for the former and 7 for the latter. All the tested plant extracts were not mutagenic at all concentrations tested against all tester strains of bacteria. CONCLUSION: In view of the fact that the plants were selected based on their ethnobotanical usage for treating diarrhoea, the activities reported here goes a long way in validating the plants for traditional use.

Nitric oxide release is not required to decrease the ulcerogenic profile of nonsteroidal anti-inflammatory drugs.

The objective of this work was to evaluate the biological properties of a new series of nitric oxide-releasing nonsteroidal anti-inflammatory drugs (NO-NSAIDs) possessing a tyrosol linker between the NSAID and the NO-releasing moiety (PROLI/NO); however, initial screening of ester intermediates without the PROLI/NO group showed the required (desirable) efficacy/safety ratio, which questioned the need for NO in the design. In this regard, NSAID ester intermediates were potent and selective COX-2 inhibitors in vitro, showed equipotent anti-inflammatory activity compared to the corresponding parent NSAID, but showed a markedly reduced gastric toxicity when administered orally. These results provide complementary evidence to challenge the currently accepted notion that hybrid NO-NSAIDs exert their cytoprotective effects by releasing NO. Results obtained in this work constitute a good body of evidence to initiate a debate about the future replacement of NSAID prodrugs for unprotected NSAIDs (possessing a free carboxylic acid group) currently in clinical use.

Comparison of acute toxicity of ketoprofen to juvenile and embryonic stages of Danio rerio.

OBJECTIVES: Ketoprofen is a common human medicine from a class of non-steroidal anti-inflammatory drugs (NSAIDs), which is provably detected in surface waters in concentrations ordinarily in µg.L-1. The aim of this study was to compare the acute toxicity of ketoprofen to embryonic and juvenile stages of aquarium fish - zebrafish (Danio rerio). METHODS: Tests were performed according to the methods of the Organisation for Economic Co-operation and Development (OECD) No. 203 (Fish, acute toxicity test) and OECD No. 212 (Fish, short-term toxicity test on embryo and sac-fry stages). RESULTS: The results showed (mean ± SD) LC50 value of ketoprofen to be 632.30 ± 10.10 mg.L-1 in juvenile zebrafish and 6.44 ± 2.22 mg.L-1 in embryonic stages of zebrafish. The results revealed statistically significantly higher sensitivity (p<0.01) of the embryonic stages of zebrafish to ketoprofen compared to its juveniles. The susceptibility of embryos depends on many factors, especially yet improperly developed enzymatic system in embryos, different ways of the absorption of the substance into the organism or differences in metabolism pathways. CONCLUSIONS: The acute toxicity of ketoprofen for juvenile stages of zebrafish is low, but the substance seems to be toxic for embryonic stages.

Plant composition, pharmacological properties and mutagenic evaluation of a commercial Zulu herbal mixture: Imbiza ephuzwato.

ETHNOPHARMACOLOGY RELEVANCE: Imbiza ephuzwato is a traditional herbal tonic made from a mixture of extracts of roots, bulbs, rhizomes and leaves of 21 medicinal plants and is used in traditional medicine as a multipurpose remedy. AIM OF THE STUDY: To compile and investigate the bioactivity and mutagenic effects of extracts of the 21 plant species used in the preparation of Imbiza ephuzwato herbal tonic. MATERIALS AND METHODS: The 21 plant species used to make Imbiza ephuzwato herbal mixture were each investigated for their pharmacological properties. Petroleum ether (PE), dichloromethane (DCM), 80% ethanol (EtOH) and water extracts of the 21 plants were evaluated against two gram-positive, two gram-negative bacteria and a fungus Candida albicans. The extracts were also evaluated for their inhibitory effects against cyclooxygenase (COX-1 and -2) and acetylcholinesterase AChE enzymes. Mutagenic effects of the water extracts were evaluated using the Ames test. RESULTS: Gunnera perpensa and Rubia cordifolia were the only plant species used to manufacture Imbiza ephuzwato that had water extracts which showed good antibacterial activity. The extracts of G. perpensa (EtOH), Hypericum aethiopicum (DCM) and Urginea physodes (EtOH) showed the best antifungal activity. The water extracts of H. aethiopicum, G. perpensa, Drimia robusta, Vitellariopsis marginata, Scadoxus puniceus and Momordica balsamina showed percentage inhibition of COX-1 that was over 70%. For COX-2 enzyme, the water extracts of G. perpensa, Cyrtanthus obliquus, M. balsamina and Tetradenia riparia exhibited inhibitory activity above 70%. Water extracts of G. perpensa, C. obliquus, V. marginata, Asclepias fruticosa and Watsonia densiflora showed good AChE inhibitory activity (>80%). The Ames test results revealed that all the water extracts of the 21 plant species used to make Imbiza ephuzwato were non-mutagenic towards the Salmonella typhimurium TA98 strain for the assay with and without S9 metabolic activation. In contrast, Imbiza ephuzwato showed mutagenic effects after exposure to S9 enzyme mixture. CONCLUSION: The observed activities of some plant extracts, if supported by other confirmatory tests, may justify their inclusion in the makeup of Imbiza ephuzwato herbal mixture as well as their use in traditional medicine. Further studies aimed at investigating possible synergistic effects as a result of mixing plant extracts are necessary. The reported mutagenicity in Imbiza ephuzwato could be as a result of interaction of biomolecules in the heterogeneous mixture, yielding compounds that are converted to mutagenic agents by xenobiotic metabolizing enzymes. It is therefore important to carry out further studies aimed at identifying and eliminating the sources of the mutagenic compounds in the heterogeneous mixture.

Oral bioavailability, efficacy and gastric tolerability of P2026, a novel nitric oxide-releasing diclofenac in rat.

The present study was designed to evaluate, P2026 [(2-((2-(nitrooxy)ethyl)disulfanyl)ethyl 2-(2-(2,6-dichlorophenylamino)phenyl)acetate)], a novel NO (nitric oxide) donor prodrug of diclofenac for its ability to release NO and diclofenac, and whether P2026 provides advantage of improved activity/gastric tolerability over diclofenac. Oral bioavailability of P2026 was estimated from plasma concentration of diclofenac and nitrate/nitrite (NOx). Anti-inflammatory activity was evaluated in three different models of inflammation: acute (carrageenan-induced paw oedema), chronic (adjuvant-induced arthritis), and systemic (lipopolysaccharide-induced endotoxic shock). Gastric tolerability was evaluated from compound's propensity to cause gastric ulcers. P2026 exhibited dose-dependent diclofenac and NOx release. Similar to diclofenac, P2026 showed potent anti-inflammatory activity in acute and chronic model, whereas it improved activity in systemic model. Both diclofenac and P2026 inhibited gastric prostaglandin, but only diclofenac produced dose-dependent haemorrhagic ulcers. Thus, the results suggest that coupling of NO and diclofenac contribute to improved gastric tolerability while retaining the anti-inflammatory properties of diclofenac.

Naproxen-PC: a GI safe and highly effective anti-inflammatory.

UNLABELLED: We have been developing a family of phosphatidylcholine (PC)-associated NSAIDs, which appear to have improved GI safety and therapeutic efficacy in both rodent model systems and pilot clinical trials. As naproxen has been demonstrated to be associated with the lowest cardiovascular adverse events in comparison with both COX-2 selective inhibitors and conventional NSAIDs, we have been developing a Naproxen-PC formulation for evaluation in animal models and clinical trials. We have determined that an oil-based formulation of naproxen and triple strength soy lecithin provides excellent GI protection in both: 1) an acute NSAID-induced intestinal bleeding model in rats pretreated with L-NAME that are intragastrically administered a single dose of naproxen (at a dose of 50 mg/kg) vs the equivalent dose of Naproxen-PC; and 2) a more chronic model (at a naproxen dose of 25 mg/kg BID) in rats that have pre-existing hindpaw inflammation (induced with a intradermal injection of Complete Freund's Adjuvant/CFA). Both models demonstrate the superior GI safety of Naproxen-PC vs naproxen while this novel formulation had significant anti-inflammatory efficacy to reduce hindpaw edema and the generation of PGE(2) in the collected joint synovial fluid. CONCLUSION: Naproxen-PC appears to induce significantly less GI injury and bleeding in two rodent model systems while maintaining anti-inflammatory and COX-inhibitory activity.

Cochlear NMDA receptor blockade prevents salicylate-induced tinnitus.

Large doses of aspirin produce reversible hearing loss and tinnitus. These effects have been attributed to the salicylate ion, the active component of aspirin. Salicylate acts as a competitive antagonist at the anion-binding site of prestin, the motor protein of sensory outer hair cells. This provides an explanation for the hearing loss induced by aspirin. However, the molecular mechanism of salicylate-induced tinnitus remains obscure. One physiological explanation is that salicylate ototoxicity is likely to originate in an alteration to arachidonic acid metabolism. Arachidonic acid potentiates NMDA receptor currents. We therefore tested the involvement of cochlear NMDA receptors in the occurrence of tinnitus. Tinnitus was assessed with a behavioural test based on an active avoidance paradigm. Results showed that the tinnitus induced by salicylate may be suppressed by the introduction of NMDA antagonists into the cochlear fluids. To determine if the activation of NMDA receptors was linked to cyclooxygenase inhibition, we investigated the effect of mefenamate (a potent cyclooxygenase inhibitor). Since NMDA antagonists also blocked mefenamate-induced tinnitus, we suggest that salicylate-induced tinnitus is mediated by cochlear NMDA receptors through the inhibition of cyclooxygenase activity. Target cochlear NMDA receptors may therefore present a therapeutic strategy for the treatment of tinnitus.

Can the aqueous decoction of mango flowers be used as an antiulcer agent?

This study was designed to determine the effect of Mangifera indica flowers decoction, on the acute and subacute models of induced ulcer in mice and rats. A single oral administration of the aqueous decoction (AD) from M. indica up to a dose of 5 g/kg, p.o. did not produce any signs or symptom of toxicity in the treated animals. The oral pre-treatment with AD (250, 500 and 1000 mg/kg) in rats with gastric lesions induced by ethanol, decreased the gastric lesions from 89.0+/-6.71 (control group) to 9.25+/-2.75, 4.50+/-3.30 and 0, respectively. Pretreatment with AD (250, 500 and 1000 mg/kg) to mice with HCl/ethanol- or stress-induced gastric lesions resulted in a dose-dependent significant decrease of lesion index. In the piroxicam-induced gastric lesions, the gastroprotective effect of AD was reducing with the increase of the AD dose. In the pylorus-ligature, AD (p.o.) significantly decreased the acid output indicating the antisecretory property involved in the gastroprotective effect of M. indica. Treatment with AD during 14 consecutive days significantly accelerated the healing process in subacute gastric ulcer induced by acetic acid in rats. Pretreatment with N-nitro-l-arginine methyl ester (l-NAME), an inhibitor of NO-synthase, did not abolish the gastroprotective effects (99% with saline versus 80% with l-NAME) of AD against ethanol-induced gastric lesions. Pretreatment with N-ethylmaleimide (NEM), a blocker of endogenous sulphydryl group, significantly abolished the protective effects of AD against ethanol-induced gastric ulcers (95% with saline versus 47% with NEM). Phytochemical screening showed the presence of steroids, triterpenes, phenolic compounds and flavonoids. Estimation of the global polyphenol content in the AD was performed by Folin-Ciocalteu method and showed approximately 53% of total phenolic on this extract. These findings indicate the potential gastroprotective and ulcer-healing properties of aqueous decoction of M. indica flowers and further support its popular use in gastrointestinal disorders in Caribbean.

In vitro structure-activity relationship and in vivo studies for a novel class of cyclooxygenase-2 inhibitors: 5-aryl-2,2-dialkyl-4-phenyl-3(2H)furanone derivatives.

5-Aryl-2,2-dialkyl-4-phenyl-3(2H)furanone derivatives were studied as a novel class of selective cyclooxygenase-2 inhibitors with regard to synthesis, in vitro SAR, antiinflammatory activities, pharmacokinetic considerations, and gastric safety. 1f, a representative compound for methyl sulfone derivatives, showed a COX-2 IC(50) comparable to that of rofecoxib. In case of 20b, a representative compound for sulfonamide derivatives, a potent antiinflammatory ED(50) of 0.1 mg kg(-1) day(-1) was observed against adjuvant-induced arthritis by a preventive model, positioning 20b as one of the most potent COX-2 inhibitors ever reported. Furthermore, 20b showed strong analgesic activity as indicated by its ED(50) of 0.25 mg/kg against carrageenan-induced thermal hyperalgesia in the Sprague-Dawley rat. 3(2H)Furanone derivatives showed due gastric safety profiles as selective COX-2 inhibitors upon 7-day repeat dosing. A highly potent COX-2 inhibitor of the 3(2H)furanone scaffold could be considered suitable for a future generation COX-2 selective arthritis medication with improved safety profiles.

Pharmacological screening of six Amaryllidaceae species.

Dichloromethane and 90% methanol extracts of different parts of 6 Amaryllidaceae species were investigated for anti-inflammatory (COX-1 and COX-2), antibacterial and mutagenic (Salmonella/microsome test strain TA98) activities. Antibacterial activity was carried out using disc diffusion assay against three Gram-positive (Bacillus subtilis, Staphylococcus aureus and Microccus luteus) and two Gram-negative (Escherichia coli, Klebsiella pneumoniae) bacteria. With the exception of the leaf of Cyrtanthus mackenii, all CH(2)Cl(2) extracts of different parts of Cyrtanthus species inhibited the growth of at least one bacterium, with the CH(2)Cl(2) bulb/root extracts of Cyrtanthus suaveolens showing broad-spectrum antibacterial activity. In the anti-inflammatory assay, CH(2)Cl(2) extracts, resuspended at 500 microg/ml, from different parts of all species under investigation, inhibited activity of both COX-1 and COX-2 by at least 70%. The most active, 90% methanolic extracts (resuspended at 500 microg/ml) were from the leaves (78%) and roots (76%) of Cyrtanthus falcatus and the leaves of Gethyllis ciliaris (70%). Only CH(2)Cl(2) extracts of Cyrtanthus falcatus (leaf and root) and Cyrtanthus suaveolens (bulb/root and leaf) had a mutagenic effect in the Salmonella/microsome assay strain TA98.

Eugenol suppresses cyclooxygenase-2 expression in lipopolysaccharide-stimulated mouse macrophage RAW264.7 cells.

Inducible cyclooxygenase (COX-2) has been implicated in the processes of inflammation and carcinogenesis. Thus, the potential COX-2 inhibitors have been considered as anti-inflammatory or cancer chemopreventive agents. In this study, the methanolic extract of the cortex of Eugenia caryophyllata Thunberg (Myrtaceae) was found to potently inhibit the prostaglandin E(2) production in lipopolysaccharide (LPS)-activated mouse macrophage RAW264.7 cells (98.3% inhibition at the test concentration of 10 microg/ml). Further, hexane-soluble layer was the most active partition compared to ethyl acetate, n-butanol, and water-soluble parts. By bioassay-guided fractionation of hexane-soluble partition, eugenol was isolated and exhibited a significant inhibition of PGE(2) production (IC(50) = 0.37 microM). In addition, eugenol suppressed the cyclooxygenase-2 (COX-2) gene expression in LPS-stimulated mouse macrophage cells. On the line of COX-2 playing an important role in colon carcinogenesis further study was designed to investigate the effect of eugenol on the growth and COX-2 expression in HT-29 human colon cancer cells. Eugenol inhibited the proliferation of HT-29 cells and the mRNA expression of COX-2, but not COX-1. This result suggests that eugenol might be a plausible lead candidate for further developing the COX-2 inhibitor as an anti-inflammatory or cancer chemopreventive agent.

Ulcerogenic influence of selective cyclooxygenase-2 inhibitors in the rat stomach with adjuvant-induced arthritis.

Cyclooxygenase (COX)-2 inhibitors have been developed as new gastric sparing anti-inflammatory drugs. We previously reported that the ulcerogenic response to conventional nonselective COX inhibitors, such as indomethacin and aspirin, was markedly increased in arthritic rats. The ulcerogenic effect of selective COX-2 inhibitors in arthritic animals, however, remains unknown. The present study was designed to examine the influence of selective COX-2 inhibitors, such as rofecoxib and celecoxib, on gastric mucosal integrity in rats with adjuvant-induced arthritis. Arthritis was induced in male dark Agouti rats by injection of Freund's complete adjuvant into the right hind paw. Two weeks after the injection, the animals were fasted for 18 h, various COX inhibitors were administered orally, and the mucosa was examined for lesions 4 h later. Oral administration of indomethacin caused hemorrhagic gastric lesions in both normal and arthritic rats, although the severity of lesions was significantly greater in the latter group. In contrast, neither rofecoxib nor celecoxib caused any gastric damage in normal rats, but both drugs provoked hemorrhagic gastric lesions in arthritic rats. The expression of COX-2 mRNA and immuno-positive cells was observed in the gastric mucosa of arthritic but not normal rats. The gastric mucosal prostaglandin (PG) E(2) content was significantly elevated in arthritic rats in a rofecoxib-sensitive manner. In conclusion, COX-2 inhibitors produce gastric lesions in arthritic rats, similar to the nonselective COX-inhibitors. COX-2 is up-regulated in the stomach of arthritic rats, and PGs produced by COX-2 play a role in maintaining the integrity of the gastric mucosa.