Ecotoxicological Impact of the Marine Toxin Palytoxin on the Micro-Crustacean Artemia franciscana.

Palytoxin (PLTX) is a highly toxic polyether identified in various marine organisms, such as Palythoa soft corals, Ostreopsis dinoflagellates, and Trichodesmium cyanobacteria. In addition to adverse effects in humans, negative impacts on different marine organisms have been often described during Ostreopsis blooms and the concomitant presence of PLTX and its analogues. Considering the increasing frequency of Ostreopsis blooms due to global warming, PLTX was investigated for its effects on Artemia franciscana, a crustacean commonly used as a model organism for ecotoxicological studies. At concentrations comparable to those detected in culture media of O. cf. ovata (1.0-10.0 nM), PLTX significantly reduced cysts hatching and induced significant mortality of the organisms, both at larval and adult stages. Adults appeared to be the most sensitive developmental stage to PLTX: significant mortality was recorded after only 12 h of exposure to PLTX concentrations > 1.0 nM, with a 50% lethal concentration (LC50) of 2.3 nM (95% confidence interval = 1.2-4.7 nM). The toxic effects of PLTX toward A. franciscana adults seem to involve oxidative stress induction. Indeed, the toxin significantly increased ROS levels and altered the activity of the major antioxidant enzymes, in particular catalase and peroxidase, and marginally glutathione-S-transferase and superoxide dismutase. On the whole, these results indicate that environmentally relevant concentrations of PLTX could have a negative effect on Artemia franciscana population, suggesting its potential ecotoxicological impact at the marine level.

In vivo anti-inflammatory activity of some naturally occurring O- and N-prenyl secondary metabolites.

A series of O- and N-prenyl secondary metabolites of insect, fungal, and plant origin have been evaluated for their topical anti-inflammatory activity using the Croton oil ear test in mice as a model of acute inflammation. Some of the tested compounds revealed an effect (ID50 = 0.31 divided by 0.56 micromol/cm2) comparable with that of the reference non-steroidal anti-inflammatory drug indomethacin (ID50 = 0.23 micromol/cm2).

Steroids with anti-inflammatory activity from Vernonia nigritiana Oliv. & Hiern.

The leaves of Vernonia nigritiana Oliv. & Hiern. (Asteraceae) were investigated for their in vivo topical anti-inflammatory properties, following a bioassay-oriented fractionation approach. Petroleum ether, chloroform and chloroform-methanol extracts inhibited the Croton oil-induced ear dermatitis in mice. The chloroform extract was only about half as active as the non steroidal anti-inflammatory drug indomethacin (ID50=237 and 93 µg/cm(2), respectively). Phytochemical investigation of this extract led to the isolation of nine polyhydroxylated stigmasterol glycosides and six polyhydroxylated stigmasterols. Their structures were elucidated by NMR, MS and chemical methods. Each compound exerted a significant anti-oedema activity, the most active being 1 (3ß-O-ß-D-glucopyranosyloxy-5α-stigmasta-7,9(11),24(28)Z-triene-6ß,16ß,26,29-tetrol) and 3 (3ß-O-ß-D-glucopyranosyloxy-5α-stigmasta-7,9(11),24(28)Z-triene-6ß,16ß,29-triol), only two and five fold less potent than the steroidal drug hydrocortisone (ID50=0.10, 0.21 and 0.04 µmol/cm(2), respectively). Compound 1 (50 µM) also completely inhibited the transcription factor NF-κB in vitro.

Comparative topical anti-inflammatory activity of cannabinoids and cannabivarins.

A selection of seven phytocannabinoids representative of the major structural types of classic cannabinoids and their corresponding cannabivarins was investigated for in vivo topical anti-inflammatory activity in the Croton oil mouse ear dermatitis assay. Differences in the terpenoid moiety were far more important for anti-inflammatory activity than those at the C-3 alkyl residue, suggesting the involvement not only of cannabinoid receptors, but also of other inflammatory end-points targeted by phytocannabinoids.

Topical anti-inflammatory activity of Eupatilin, a lipophilic flavonoid from mountain wormwood ( Artemisia umbelliformis Lam.).

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is the major lipophilic flavonoid from Artemisia umbelliformis Lam. and Artemisia genipi Weber, two mountain wormwoods used for the production of the celebrated alpine liqueur genepy. The topical anti-inflammatory activity of eupatilin was investigated using the inhibition of the Croton-oil-induced dermatitis in the mouse ear as the end point. The oedematous response and the leukocyte infiltration were evaluated up to 48 h after the induction of phlogosis, comparing eupatilin with hydrocortisone and indomethacin as representatives of steroid and non-steroid anti-inflammatory drugs, respectively. At maximum development, eupatilin significantly reduced edema in a dose-dependent manner (ID(50) = 0.28 micromol/cm(2)), showing an anti-inflammatory potency comparable to that of indomethacin (ID(50) = 0.26 micromol/cm(2)) and only 1 order of magnitude lower than that of hydrocortisone (ID(50) = 0.03 micromol/cm(2)). Within 48 h, eupatilin (0.30 micromol/cm(2)) caused a global inhibition of the oedematous response (42%) higher than that of an equimolar dose of indomethacin (18%) and fully comparable to that of 0.03 micromol/cm(2) of hydrocortisone (55%). Moreover, the effect of eupatilin on the granulocytes infiltrate (32% inhibition) was similar to that of indomethacin (35% inhibition) and comparable to that of hydrocortisone (42% reduction), as confirmed by histological analysis. When our results are taken together, they show that eupatilin is endowed with potent in vivo topical anti-inflammatory activity, qualitatively similar to that of hydrocortisone and intermediate in terms of potency between those of steroid and non-steroid drugs.

Topical anti-inflammatory activity of extracts and compounds from Hypericum perforatum L.

Three preparations of Hypericum perforatum L. (a hydroalcoholic extract, a lipophilic extract and an ethylacetic fraction) and the pure compounds hypericin, adhyperforin, amentoflavone, hyperoside, isoquercitrin, hyperforin dicyclohexylammonium (DHCA) salt and dicyclohexylamine were evaluated for their topical anti-inflammatory activity. H. perforatum preparations provoked a dose-dependent reduction of Croton-oil-induced ear oedema in mice, showing the following rank order of activity: lipophilic extract > ethylacetic fraction > hydroalcoholic extract (ID50 (dose that inhibited oedema by 50%) 220, 267 and >1000 microg cm(-2), respectively). Amentoflavone (ID50 0.16 micromol cm(-2)), hypericin (ID50 0.25 micromol cm(-2)), hyperforin DHCA salt (ID50 0.25 micromol cm(-2)) and adhyperofrin (ID50 0.30 micromol cm(-2)) had anti-inflammatory activity that was more potent or comparable to that of indometacin (ID50 0.26 micromol cm(-2)), whereas isoquercitrin and hyperoside were less active (ID50 about 1 micromol cm(-2)). As dicyclohexylamine alone was inactive, the effect of hyperforin DHCA salt can be attributed completely to the phloroglucinol moiety. The pharmacological activity and phytochemical profile of the tested extracts and fraction suggest that different constituents are involved in the topical antiphlogistic property of H. perforatum in-vivo.

Characterization of topical antiinflammatory compounds in Rosmarinus officinalis L.

The topical antiinflammatory activity of three extracts at increasing polarity (n-hexane, chloroform, and methanol) from the leaves of Rosmarinus officinalis L. (Labiatae) has been tested using the croton oil ear test in mice. Both the n-hexane and the chloroform (CE-1) extracts from the leaves showed a dose-dependent activity, the last one possessing an antiinflammatory potency similar to that of indomethacin, the nonsteroidal antiinflammatory drug used as a reference drug (ID50 = 83 and 93 microg/cm2, respectively). The bioassay-oriented fractionation of CE-1 led to the identification of tritepenes, ursolic acid, oleanolic acid, and micromeric acid as the main antiinflammatory principles. Furthermore, the CE-1 extract obtained from the residue of the steam distillation of the leaves (extract A) showed the same antiinflammatory potency of CE-1, suggesting this waste product as a source of antiinflammatory products.

Topical anti-inflammatory activity of flavonoids and a new xanthone from Santolina insularis.

Bioactivity-guided fractionation of the methanol extract from the leaves of Santolina insularis led to the isolation of one new xanthone, (E)-3-(6-[(E)-3-hydroxy-3-oxo-1-propenyl]-9-oxo-9H-xanthen-2-yl)-2-propenoic acid, together with six known flavonoids: hispidulin, nepetin, cirsimaritin, rhamnocitrin, luteolin and luteolin 7-O-beta-D-glucopyranoside. The structures were elucidated by means of 1D-, 2D-NMR spectroscopy and mass spectrometry. The topical anti-inflammatory activity of all isolated compounds and extracts was investigated employing the croton oil-induced dermatitis in mouse ear. The most active compound, luteolin, showed an ID50 of 0.3 micromol/cm(2) and prevented ear oedema more effectively than an equimolar dose of indomethacin within 24 h.

Improved anti-inflammatory activity of three new terpenoids derived, by systematic chemical modifications, from the abundant triterpenes of the flowery plant Calendula officinalis.

Rings A, D and E of faradiol (1), and ring E of both arnidiol (10) and calenduladiol (4) have been subjected to various selective chemical manipulations to modify polarity, water affinity, H-bonding, sterics, and number of aromatic groups of these anti-inflammatory natural compounds. A total of 15 new and four known pentacyclic triterpenoids have been obtained in this way. Some 13 terpenoids were evaluated for their topical anti-inflammatory activities with respect to inhibition of croton oil induced ear oedema in mouse. Three derivatives of 1, the C(16) benzyl ether 15, the C(30) aldehyde 24, and the C(30) primary alcohol 25 showed significantly improved anti-inflammatory potencies, which is relevant for (future) structure-activity-relationship (SAR) studies.

Anti-inflammatory activity of Leontopodium alpinum and its constituents.

The aerial parts and roots of Leontopodium alpinum Cass. (Asteraceae) were investigated for their in vivo topical anti-inflammatory activity using the inhibition of Croton oil-induced ear dermatitis in mice. For both of the plant parts, the dichloromethane extract induced a dose-dependent oedema reduction, being more active than the methanol and 70% aqueous methanol ex-tracts. Moreover, the dichloromethane extract of the aerial parts was more active than that of the roots (ID50 = 221 and 338 pg/cm2, respectively). Fatty acids make a significant contribution to the anti-oedema activity of the dichloromethane extract of the aerial parts, whereas bisabolane sesquiterpenes, tricyclic sesquiterpenes, coumarins and lignans are involved in the activity of the root extract. Two bisabolane derivatives reduced also the polymorphonuclear neutrophil leukocytes accumulation in the inflamed tissue, while a 7a-silphiperfol-5-ene type sesquiterpene and a coumarin derivative inhibited the in vitro chemotaxis of these inflammatory cells.

HET-CAM bioassay as in vitro alternative to the croton oil test for investigating steroidal and non-steroidal compounds.

In this study the irritation phenomena at the chorioallantoic membrane of incubated hen's eggs as an in vitro model (HET-CAM assay) were investigated in comparison to the in vivo croton oil test by including hydrocortisone, indomethacin, phenylbutazone, acetylsalicylic acid, rutin, quercetin, apigenin, and p-coumaric acid as steroidal and non-steroidal test substances. For the first time the two methods were compared in a valid way with the perspective of a realistic reduction of animal experiments. It should be investigated whether an in vitro-in vivo correlation exists and, if there is any possibility, to replace the in vivo model by an in vitro test system. Both bioassays were able to demonstrate the anti-inflammatory potency of the constituents tested. The determination of the anti-inflammatory activity of all compounds in the two test systems showed individual trends of inhibitory effects. However, the in vitro HET-CAM test was much more sensitive in comparison to the in vivo croton oil test. The croton oil test gave dose-effect correlations in the anti-inflammatory substances investigated. The modified HET-CAM assay did not provide clear dose-effect ratios. The HET-CAM assay is an inexpensive test being easy to manage after a short practical training. Because of its sensitivity the HET-CAM assay could be considered a suitable tool for qualitative testing of the anti-inflammatory activity of substances if no appropriate dose-effect curves are required. From these results it can be concluded that the different courses of the dose-effect curves may be primarily due to different mechanisms of action.

Studies on the anti-inflammatory activity of phytopharmaceuticals prepared from Arnica flowers.

Phytopharmaceuticals prepared from flowerheads of Arnica montana of Spanish origin and of the new type "Arbo", which can be easily and economically cultivated, were studied for their capability to impair activation of the transcription factors NF-kappa B and NF-AT. Both proteins are responsible for the transcription of genes encoding various inflammatory mediators. Additionally, their influence on the release of the cytokines IL-1 and TNF-alpha were examined. The inhibitory activities correlate with their quantitative and qualitative content of sesquiterpene lactones (Sls). Moreover, it was shown that the inhibitory potency of 11 alpha,13-dihydrohelenalin derivatives being the main Sls in the Spanish flowers depend on their esterfication. Compounds with unsaturated acyl moieties, such as methacrylate and tiglinate, exhibited a stronger activity in the NF-kappa B EMSA as well as in the croton oil ear test in mice than the acetate derivative.