Biomedical subjects

P Bermejo

Publications and source records attributed to P Bermejo.

At least 19 recordsLinked to original sources

PubMed2005

Anti-inflammatory activity of four Bolivian Baccharis species (Compositae).

Hexanic, dichloromethanic, ethanolic and aqueous extracts from Baccharis obtusifolia HBK, Baccharis latifolia (R. et P.) Pers., Baccharis pentlandii D.C. and Baccharis subulata Wedd., plants used in the traditional medicine of South America have been studied for their in vitro anti-inflammatory activity in cellular systems. Calcium ionophore A23187-stimulated mouse peritoneal macrophages were validated as a source of cyclooxygenase-1 (COX-1) (prostaglandin E2, PGE2) and 5-lipoxygenase (5-LOX) (leukotriene C4, LTC4), and mouse peritoneal macrophages stimulated with Escherichia coli lipopolysaccharide (LPS) were used for testing cyclooxygenase-2 (COX-2) (PGE2), nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha) activity. Most of the extracts tested were active in all assays.

Animals↗

PubMed2004

Enzymolysis approach to compare cu availability from human milk and infant formulas.

The purpose of the present paper is to develop an easy and quick in vitro method to compare copper availability from breast milk and infant formulas. This study focuses on the differences caused by the use of pH 2.0 (adult gastric pH) or pH 5.0 (newborn gastric pH) in the first stage of the enzymolysis. pH affects Cu solubility, a possible estimator of the availability. Selection of a digestor, times of enzymolysis, centrifugation parameters, and Cu determination by ETAAS were discussed as well. Percentage of Cu solubility was larger from breast milk (gastric pH 2.0, 65.3 +/- 14.0 vs 40.0 +/- 13.9%; gastric pH 5.0, 61.2 +/- 16.5 vs 26.6 +/- 10.3%), but the soluble content was larger from infant formulas for both pHs (gastric pH 2.0, 245.3 +/- 82.1 vs 113.0 +/- 103.4 ng mL(-1); gastric pH 2.0, 169.3 +/- 76.9 vs 75.3 +/- 21.9 vs ng mL(-1)).

Biological Availability↗

PubMed2002

Screening of selected plant extracts for in vitro inhibitory activity on human immunodeficiency virus.

As part of our screening of anti-AIDS agents from natural sources, extracts of 15 medicinal plants widely used in the folk medicines of North America and Europe were evaluated in vitro. Most of the extracts tested were relatively nontoxic to human lymphocytic MT-2 cells, but only the extracts of Hysopp officinalis and Dittrichia viscosa exhibited anti-HIV activity in an in vitro MTT assay. The 50% hydroalcohol extract of Hysopp officinalis and the aqueous extract of Dittrichia viscosa showed inhibitory effects against HIV-1 induced infections in MT-2 cells at concentrations ranging from 50 to 100 microg/mL and 25 to 400 microg/mL, respectively. Both extracts showed no appreciable cytotoxicity at these concentrations.

Anti-HIV Agents↗

PubMed2001

Effects of six diterpenes on macrophage eicosanoid biosynthesis.

Six diterpenes (three clerodanes, two abietanes and one rosane) were tested for interactions with the cyclooxygenase and 5-lipoxygenase pathways of arachidonate metabolism and for effects of nitric oxide production. Two abietane diterpenes, aethiopinone and 11,12-dihydroxy-6-oxo-8,11,13-abietatriene and the rosane lagascatriol showed a remarkable effect on COX-1 pathway of PGE2 release in calcium ionophore A23187-stimulated peritoneal macrophages. Only the two latter diterpenes showed inhibition on COX-2 pathway of PGE2 release in E. coli LPS-stimulated peritoneal macrophages. In addition, all compounds assayed were inhibitors of LTC4 release with IC50 < or = 10 microM. Clerodane diterpenes were inactive in COX assay. None of the diterpenes assayed, except 11,12-dihydroxy-6-oxo-8,11,13-abietatriene, affected NO production. The results obtained suggest that the cellular mechanisms of action of some of these substances may involve inhibition of cyclooxygenase/lipoxygenase pathways and nitric oxide production.

Animals↗

PubMed2001

Modulated release of cyclosporine from soluble vinyl pyrrolidone--hydroxyethyl methacrylate copolymer hydrogels. A correlation of 'in vitro' and 'in vivo' experiments.

Soluble, uncrosslinked and high molecular weight copolymers of vinylpyrrolidone, VP, with 2-hydroxyethyl methacrylate, HEMA, prepared by free radical copolymerization, are proposed as supports for the modulated release of the immunosuppressor cyclosporine. Two copolymeric systems with copolymer compositions f(VP)=0.52 (namely VP--HEMA 60--40) and 0.42 (VP--HEMA 40--60) have been prepared and tested in vitro and in vivo using rats as animal model. Micellar electrokinetic capillary chromatography, MEKC, has been used for the simultaneous detection of the polymer reabsorption and the drug release for the in vitro experiments. The composition and microstructural distribution of the copolymer system controls the solubilization rate which modulates the in vitro release of the drug (with time profiles from a few days to several weeks for the VP--HEMA 60--40 and 40--60, respectively) and the in vivo response that correlates with the previous in vitro results: the more hydrophobic implant (VP--HEMA 40--60) reverts the immune response more slowly (2--4 weeks) compared to the more hydrophilic one (VP--HEMA 60--40, 1--2 weeks).

Animals↗

PubMed2001

Anti-HIV activity of medicinal plant extracts.

As part of our screening of anti-AIDS agents from natural sources, ethanolic and aqueous extracts of 15 medicinal plants widely used in the folk medicine of the Iberian Peninsula were evaluated in vitro. Most of the extracts tested were relatively nontoxic to human lymphocytic MT-2 cells, but only the extracts of Tuberaria lignosa and Sanguisorba minor magnolii exhibited anti-HIV activity in an in vitro MTT assay. The aqueous extracts of these plants showed inhibitory effects against HIV-1 induced infections in MT-2 cells at concentrations ranging from 12.5 to 50 microg/ml and 50 microg/ml, respectively. Both extracts showed no appreciable cytotoxicity at these concentrations.

Anti-HIV Agents↗

PubMed2001

Copper fractionation by SEC-HPLC and ETAAS: study of breast milk and infant formulae whey used in lactation of full-term newborn infants.

This method will allow the determination of bound copper to low relative molecular mass compounds in milk. The milk whey obtained by ultracentrifugation was submitted to fractionation by size exclusion chromatography (SEC) on a TSK-Gel2000 (Toso Haas) column with a mobile phase of 0.2 M NH4NO3 + NH3, pH 6.7. Fractions of effluent corresponding to the protein peaks were collected and the copper content was determined by ETAAS. The method was sensitive (LOD 0.4 microgram l-1 and LOQ 1.5 micrograms l-1 in the fraction; LOQ 7.5-22.5 micrograms l-1 referred to the milk sample and depended on fraction volume) and precise (RSD +/- 10%). Media sample recoveries from the column were 101.2%. Cu was predominantly present in fractions corresponding to relative molecular mass 76 and 15 kDa of breast milk while copper was mostly found in fractions corresponding to 14 and 38 kDa of cow's milk-based infant formulae; moreover, copper was eluted in the relative molecular mass region < 6 kDa.

Chromatography, High Pressure Liquid↗

PubMed2001

Effects of furocoumarins from Cachrys trifida on some macrophage functions.

Phytochemical and biological studies aimed at the discovery and development of novel antiinflammatory agents from natural sources have been conducted in our laboratory for a number of years. In this communication, three naturally occurring furocoumarins (imperatorin, isoimperatorin and prantschimgin) were evaluated as potential inhibitors of some macrophage functions involved in the inflammatory process. These furocoumarins have been tested in two experimental systems: ionophore-stimulated mouse peritoneal macrophages serve as a source of cyclooxygenase-1 and 5-lipoxygenase, and mouse peritoneal macrophages stimulated with E. coli lipopolysaccharide are the means of testing for anti-cyclooxygenase-2 and nitric-oxidesynthase activity. All above-mentioned furocoumarins showed significant effect on 5-lipoxygenase (leukotriene C4) with IC50 values of < 15 microM. Imperatorin and isoimperatorin exhibited strong-to-medium inhibition on cyclooxygenase-1- and cyclooxygenase-2-catalysed prostaglandin E2 release, with inhibition percentages similar to those of the reference drugs, indometacin and nimesulide, respectively. Of the three furocoumarins, only imperatorin caused a significant reduction of nitric oxide generation. Imperatorin and isoimperatorin can be classified as dual inhibitors, since it was evident that both cyclooxygenase and lipoxygenase pathways of arachidonate metabolism were inhibited by these compounds. However, selective inhibition of the 5-lipoxygenase pathway is suggested to be the primary target of action of prantschimgin.

Animals↗

PubMed2000

Search for antiviral activity in higher plant extracts.

In the course of our search for plant natural products as antiviral agents, extracts of ten plants from the Iberian Peninsula were tested for antiviral activity against herpes simplex type I (HSV-1), vesicular stomatitis virus (VSV) and poliovirus type 1. Aqueous extracts of five of these medicinal plants, namely Nepeta nepetella (150-500 microg/mL), Nepeta coerulea (150-500 microg/mL), Nepeta tuberosa (150-500 microg/mL), Dittrichia viscosa (50-125 microg/mL) and Sanguisorba minor magnolii (50-125 microg/mL), showed a clear antiviral activity against two different DNA and RNA viruses, i.e. HSV-1 and VSV. Only the medicinal plant Dittrichia viscosa was active against an additional virus, poliovirus type 1.

Antiviral Agents↗

PubMed2000

Controlled release of cyclosporine from VP-HEMA copolymer systems of adjustable resorption monitorized by MEKC.

Soluble, uncrosslinked and high molecular weight copolymers of vinylpyrrolidone, VP, with 2-hydroxyethyl methacrylate, HEMA, prepared by free radical copolymerization, are proposed as supports for the modulated release of drugs, taking cyclosporine as a model system. The copolymerization parameters described as reactivity ratios, rVP = 0.08 and rHEMA = 7.97, indicate that the copolymer systems prepared at high conversion have two main components with a microstructural arrangement which depends on the average composition, i.e., an initial HEMA-rich copolymer and a final PVP homopolymer or VP-rich copolymer. This microstructural distribution controls the resorption rate of the polymeric support and therefore the release process of cyclosporine which is demonstrated experimentally by the application of a modern technique known as micellar electrokinetic capillary chromatography (MEKC).

Chromatography, Micellar Electrokinetic Capillary↗

PubMed2000

In vitro anti-inflammatory activity of iridoids and triterpenoid compounds isolated from Phillyrea latifolia L.

Two iridoids, oleuropeoside and ligustroside, and two triterpenoid compounds, oleanolic acid and ursolic acid, have been isolated from the leaves of Phillyrea latifolia L. (Oleaceae). These compounds were tested for interactions with the cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) pathways of arachidonate metabolism in calcium ionophore-stimulated mouse peritoneal macrophages and human platelets, and for their effect on cell viability. Structure-activity relationships obtained for in vitro screening results were discussed. These compounds are capable of exerting inhibitory actions on enzymes of the arachidonate cascade. All compounds assayed showed a significant effect on prostaglandin E2 (PGE2)-release, with inhibition percentages similar to the reference drug indomethacin (IC50 = 0.95 microM). The IC50 values of the active compounds are: oleuropeoside 47 microM, ligustroside 48.53 microM, oleanolic acid 23.51 microM and ursolic acid 60.91 microM. In the leukotriene C4 (LTC4)-assay, only oleanolic acid showed a significant effect (IC50 = 16.79 microM). We also investigated the action of compounds on thromboxane B2 (TXB2)-release induced by calcium ionophore in human platelets. Of all the tested compounds, only ligustroside (IC50 = 122.63 microM) and ursolic acid (IC50 = 50.21 microM) showed a significant effect, although with less potency than the reference drug ibuprofen (IC50 = 1.27 microM). Thus, our compounds possess an array of potentially beneficial anti-inflammatory properties which may, alongside other constituents, contribute to the claimed therapeutic properties of the plant from which they are derived.

Animals↗

PubMed2000

Inhibition of prostaglandin E2 and leukotriene C4 in mouse peritoneal macrophages and thromboxane B2 production in human platelets by flavonoids from Stachys chrysantha and Stachys candida.

Seven flavonoids of Stachys chrysantha and Stachys candida have been isolated. The structures of the compounds were elucidated by spectroscopic methods, particularly highfield NMR spectroscopy. The effects of the methanol extracts of these two endemic Greek Stachys sp. and their main flavonoids were examined on arachidonic acid (AA) metabolism in the cellular system (mouse peritoneal macrophages and human platelets). Their cytotoxicity on cells was also investigated. Most samples assayed did not exhibit any significant effect on prostaglandin E2 (PGE2)-release from calcium ionophore-stimulated mouse peritoneal macrophages. Only chrysoeriol-7-O-beta-(3''-E-p-coumaroyl)-glucopyranoside, at the highest non-cytotoxic dose (50 microM), inhibited the release of PGE2, but this effect is not statistically significant. The release of leukotriene C4 (LTC4) by mouse peritoneal macrophages stimulated with calcium ionophore was inhibited by a crude extract of S. chrysantha, with an IC50 value of 34.3 microg/ml. Xanthomicrol (IC50 = 29.2 microM) and chrysoeriol-7-O-beta-D-(3''-E-p-coumaroyl)-glucopyranoside (IC50 = 11.1 microM) also inhibited the release of LTC4, although it showed less potency than the reference compound nordihydroguaiaretic acid (NDGA) (IC50 = 2 microM). However, most samples assayed showed a significant effect on thromboxane B2 (TXB2)-release from calcium ionophore-stimulated human platelets, with inhibition percentages slightly lower than the reference drug ibuprofen (IC50 = 7 microM). The IC50 values are: crude extract of S. candida 23.3 microg/ml; crude extract of S. chrysantha 23.1 microg/ml; xanthomicrol 28.8 microM; calcycopterin 2.66 microM and chrysoeriol-7-O-beta-D-(3''-E-p-coumaroyl)-glucopyranoside 8.8 microM. Our results indicate that the selective inhibition of TX-synthase enzyme may be the primary target of action of most of these samples, and one of the mechanisms through which thus exert their antiinflammatory effects.

Animals↗

PubMed1999

Antiviral activity of some South American medicinal plants.

Folk medicinal plants are potential sources of useful therapeutic compounds including some with antiviral activities. Extracts prepared from 10 South American medicinal plants (Baccharis trinervis, Baccharis teindalensis, Eupatorium articulatum, Eupatorium glutinosum, Tagetes pusilla, Neurolaena lobata, Conyza floribunda, Phytolacca bogotensis, Phytolacca rivinoides and Heisteria acuminata) were screened for in vitro antiviral activity against herpes simplex type I (HSV-1), vesicular stomatitis virus (VSV) and poliovirus type 1. The most potent inhibition was observed with an aqueous extract of B. trinervis, which inhibited HSV-1 replication by 100% at 50-200 micrograms/mL, without showing cytotoxic effects. Good activities were also found with the ethanol extract of H. acuminata and the aqueous extract of E. articulatum, which exhibited antiviral effects against both DNA and RNA viruses (HSV-1 and VSV, respectively) at 125-250 micrograms/mL. The aqueous extracts of T. pusilla (100-250 micrograms/mL), B. teindalensis (50-125 micrograms/mL) and E. glutinosum (50-125 micrograms/mL) also inhibited the replication of VSV, but none of the extracts tested had any effect on poliovirus replication.

Antiviral Agents↗

PubMed1999

Antiviral activity of Bolivian plant extracts.

Ethanolic and aqueous extracts of seven plant species used in the traditional medicine of Bolivia have been tested for their antiviral activity against herpes simplex type I (HSV-1), vesicular stomatitis virus (VSV), and poliovirus type 1. The aqueous extracts of most of the species investigated showed antiviral activity. Two of these plants-namely, Satureja boliviana and Baccharis genistelloides-were active against two different viruses-HSV-1 and VSV.

Animals↗

PubMed1999

New resorbable polymeric systems with antithrombogenic activity.

The synthesis and application as resorbable coatings of vascular grafts of a new polyacrylic derivative of Triflusal (2-acetyloxy-4-trifluoromethyl)benzoic acid, a commercial drug with antithrombogenic properties, are described. The high-molecular-weight polyacrylic system is rather stable in physiological conditions and provides a chemical support for the slow release of the pharmacologically active compound, Triflusal, or its main metabolite (2-hydroxy-4-trifluoromethyl)benzoic acid (HTB). Experiments of deposition and retention of platelets in static basal conditions using plasma-rich medium from blood of sheep, seem to indicate that the polymeric coating of the polyacrylic derivative of Triflusal improves the antiaggregating character for platelets of the surface of small-diameter vascular grafts without the application of other antithrombogenic drugs.

Journal Article↗

PubMed1999

Inhibition of NOS-2 expression in macrophages through the inactivation of NF-kappaB by andalusol.

1. Andalusol, ent-6alpha,8alpha,18-trihydroxy-13(16),14-labdadiene, is a naturally occurring diterpene, isolated from Sideritis foetens (Lamiaceae). This compound exhibited therapeutic activity when evaluated in in vivo models of paw and ear inflammation (Navarro et al., 1997: Z. Naturforsch., 52, 844-849). The pharmacological effects of this diterpene have been analysed on the activation of the macrophage cell line J774 with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). 2. Incubation of J774 macrophages with andalusol (0.1 - 100 microM) inhibited the synthesis of nitrite caused by LPS (1 microg ml-1) in concentration and time-dependent manners. The maximal inhibition was observed when andalusol was added 30 min before LPS stimulation and decreased progressively as the interval between andalusol and LPS challenge increased up to 14 h. 3. Incubation of J774 cells with LPS resulted in the expression of NOS-2 protein (130 kDa) as identified by Western blot analysis. The levels of this enzyme decreased significantly in the presence of andalusol (IC50=10.5 microM), suggesting that this diterpene inhibited NOS-2 expression. 4. Andalusol inhibited nuclear factor kappaB activation, a transcription factor necessary for NOS-2 expression in response to LPS and IFN-gamma. This compound also inhibited the degradation of IkappaBalpha favouring the retention of the inactive NF-kappaB complexes in the cytosol. 5. Related compounds to andalusol but lacking the polyol groups were less effective inhibiting NOS-2 expression in LPS-activated macrophages. The present findings provide a mechanism by which the anti-inflammatory properties of this diterpene could be mediated.

Animals↗

PubMed1998

Antiinflammatory and antioxidant activity of plants used in traditional medicine in Ecuador.

Ethanolic extracts from 15 plant species, representing eight different families, used in traditional medicine in Ecuador were evaluated for antiinflammatory and antioxidant activities. Conyza floribunda, Eupatorium articulatum, Bonafousia longituba, Bonafousia sananho, Tagetes pusilla and Piper lenticellosum extracts showed a significant antiinflammatory activity in vivo in the carrageenan-induced paw oedema model in mice. The extracts were also tested in vitro for their ability to inhibit lipid peroxidation and to scavenge superoxide and hydroxyl radicals. E. articulatum extract possesses both activities. Baccharis trinervis, E. articulatum and Phytolacca rivinoides extracts were active as antioxidants.

Animals↗

PubMed1998

Effects of compounds extracted from Tanacetum microphyllum on arachidonic acid metabolism in cellular systems.

In the present study, the effects of compounds extracted from Tanacetum microphyllum, four flavonoids and one sesquiterpene lactone, on arachidonic acid metabolism in cellular systems were examined. In the PGE2- and LTC4-release assay, most compounds did not exhibit any significant effect. Only hydroxyachillin, and the flavonoids centaureidin and 5,3'-dihydroxy-4'-methoxy-7-methoxycarbonylflavonol showed a significant effect, although with less potency than the reference drugs, indomethacin and NDGA. However, all compounds inhibited the release of TXB2 from ionophore-stimulated human platelets. The action is more marked with the flavonoids santin and ermanin.

Animals↗