Polyphenol-associated oxidative stress and inflammation in a model of LPS-induced inflammation in glial cells: do we know enough for responsible compounding?

Cyanidin and chlorogenic acid are polyphenols from plant origin that are present in many common fruits, particularly in berries. To corroborate the protective or detrimental effects of both compounds from a neuro-inflammatory perspective, in vitro experiments were carried out in human astrocytes (U-373). Astrocytes were pre-treated with a range of concentrations of either cyanidin, chlorogenic acid or a combined treatment for a period of 30 min, before exposure to Escherichia coli lipopolysaccharide (LPS) challenge for 23.5 h, after which cytotoxicity (propidium iodide exclusion assay), cytoprotective effects (XTT assay) and effects on functional capacity (secretion of pro-inflammatory cytokines IL-6 and MCP-1) were evaluated. No treatment resulted in cytotoxicity, but high dose (20 µg/mL) LPS significantly reduced mitochondrial reductive capacity (p < 0.001). This effect was prevented in a dose-dependent manner by both cyanidin and chlorogenic acid, as well as by the combination treatment. However, in the absence of LPS, IL-6 secretion was significantly increased in response to 2 µM of either cyanidin or chlorogenic acid (both p < 0.0001), as well as the combination treatment (p < 0.01). MCP-1 secretion followed a similar trend, but did not reach statistical significance. Although we acknowledge the requirement for in vivo investigations to validate our interpretations, current data highlight the potential risk for antioxidant toxicity that is linked to high dose supplementation with single compound antioxidants. Research focused at elucidating synergistic effects between different antioxidants is required to minimise risk of adverse effects.

Natural Products for Vulvovaginal Candidiasis Treatment: Evidence from Clinical Trials.

BACKGROUND: Candida albicans is an opportunistic yeast that causes more than 90% of all vulvovaginal infections. Because of being inherently resistant to antifungals drugs such as azole derivatives, the search for anti-Candida albicans agents with new pharmacological targets is considered as the main therapeutic strategy to prevent and treat these types of infections. In this context, products of natural origin are a promising source of compounds with antifungal activity. OBJECTIVE: The current review analyzes clinical evidence on the effectiveness of natural products in the vulvovaginal Candida albicans infections. METHOD: A literature review in the electronic databases PubMed, Google Scholar, Cochrane Library Plus, Web of Science, Latin American and Caribbean Literature on Health Sciences (Lilacs) and Scientific Electronic Library Online (SciELO) using the search terms "Natural Products", "Phytotherapy", "Vulvovaginal Candidiasis" and "Clinical Trials" together with the Boolean term 'AND' was performed. English, Spanish and French articles without restriction of date of publication were considered. RESULTS: A total of 13 clinical trials (most of them randomized clinical trials which used azoles as control group) evaluated the anti-Candida activity of a total of 11 different natural products (i.e. Zataria multiflora essential oils, Ageratina pichinchensis and Solanum nigrescens extracts and saponins from Solanum chrysotrichum, among others) against vulvovaginitis have been included in the current review. CONCLUSION: Because of the few clinical trials it is difficult to establish a consistent conclusion about the effectiveness of natural products in the prevention and treatment of vulvovaginitis caused by Candida albicans. Future studies should be aimed at evaluating new natural products as well as conducting more clinical research with promising natural substances already investigated in clinical trials.

Ginsenosides Rd and Re co-treatments improve rotenone-induced oxidative stress and mitochondrial impairment in SH-SY5Y neuroblastoma cells.

Oxidative stress and mitochondrial dysfunction play key roles in Parkinson's disease (PD) initiation and progression. Ginsenosides are major compounds of Ginseng species and they are responsible for pharmacological activity. The aim of this study was to investigate the potential neuroprotective effects and mechanism of the major ginsenosides Rd and Re in rotenone-induced oxidative stress model in human neuroblastoma SH-SY5Y cells. Co-treatments with both ginsenosides inhibited the increased intracellular ROS production and by-products lipid peroxidation accumulation caused by rotenone. Moreover, these ginsenosides upregulated SOD and aconitase enzymes activities, and glutathione system; these antioxidant properties are related to Nrf2 induction and radical scavenger effect. Additionally, the results showed that both Rd and Re attenuated the extent of depolarization of mitochondrial membrane potential and restored calcium levels. Furthermore, these compounds prevented apoptosis by modulating Bax and Bcl-2 proteins and inhibiting cytochrome c release and caspase-3 activation. The ginsenoside Rd resulted to be more active than ginsenoside Re. These findings highlighted the efficacy of these compounds as neuroprotectant compounds for PD prevention and treatment through reducing oxidative stress, improving mitochondrial integrity and functions, and inhibiting apoptosis.

Basophil Histamine Release Induced by Amoxicilloyl-poly-L-lysine Compared With Amoxicillin in Patients With IgE-Mediated Allergic Reactions to Amoxicillin.

BACKGROUND: Amoxicillin (AX) is the ß-lactam most often involved in IgE-mediated reactions. Diagnosis is based mainly on skin testing, although sensitivity is not optimal. We produced a new AX derivative, amoxicilloyl-poly-L-lysine (APL), and analyzed its recognition of IgE using the passive histamine release test (pHRT). METHODS: The study population comprised patients (n=19) with confirmed AX allergy and specific IgE to AX and controls (n=10) with good tolerance to AX. pHRT was performed using "IgE-stripped" blood from a single donor that was sensitized in vitro by patient sera and incubated with AX or APL. Histamine release was determined and expressed as nanograms of histamine released per milliliter of blood. RESULTS: The clinical symptoms were anaphylaxis (n=9), urticaria (n=7), erythema (n=2), and nondefined immediate reactions (n=1). The median (IQR) time interval between reaction and study was 90 (60-240) days and between drug intake and development of symptoms 24 (10-60) minutes. The median sIgE level was 3.37 (0.95-5.89) kUA/L. The sensitivity of pHRT to APL was 79% and the specificity 100%, which were higher than data obtained with pHRT to AX (63% sensitivity and 90% specificity). There was a positive correlation between maximal histamine release levels obtained with AX and APL (r=0.63). CONCLUSIONS: In patients with immediate hypersensitivity reactions to AX, APL showed higher sensitivity and specificity than the culprit drug, AX, when tested in vitro by pHRT. This indicates that APL can improve the in vitro diagnostic accuracy of allergic reactions to AX. Further assessment of skin testing is necessary.

Geographic origin influences the phenolic composition and antioxidant potential of wild Crataegus monogyna from Spain.

CONTEXT: Crataegus monogyna Jacq L. (Lind.) (Rosaceae) is used in folk medicine as a sedative, aerial parts being rich in polyphenols with antioxidant ability. OBJECTIVES: To study the variation in polyphenolic composition and antioxidant ability of spontaneous samples of C. monogyna in order to assess the relationship among these variables. MATERIALS AND METHODS: Aerial parts of C. monogyna were collected from nine different locations in central Spain and extracted with methanol after drying. Total polyphenols were determined by the Folin-Ciocalteu method using gallic acid (GA) as standard. Sixteen polyphenolic compounds (11 flavonoids and 5 phenolic acids) were identified and quantified by reversed-phase HPLC in one single analysis. The antioxidant ability was evaluated by the oxygen radical absorbance capacity (ORAC) and the free radical scavenging activity (DPPH) methods. Linear correlation analysis was used to explore the relationships between the studied variables. RESULTS: Total polyphenol content ranged between 117.729 ± 0.011 and 204.286 ± 0.015 mg GAE/g extract, depending on the geographic origin. No relationship was found between total polyphenols and antioxidant ability by the ORAC or DPPH methods. Chromatographic analysis yielded lower amounts of polyphenols (23.3-143.26 mg/kg), as only flavonoids and phenolic acids were quantified. All the samples exhibited antioxidant activity between 1.32 ± 0.08 and 2.76 ± 0.007 µmol Trolox equivalents/mg and IC50 from 0.82 ± 0.10 to 3.76 ± 0.67 µg/mL. CONCLUSION: A statistically significant relationship between flavonoids and phenolic acids content and the antioxidant potential obtained by the ORAC method for C. monogyna samples was proven.

Evaluation of the Antioxidant Capacities and Cytotoxic Effects of Ten Parmeliaceae Lichen Species.

Parmeliaceae represents the largest and widespread family of lichens and includes species that attract much interest regarding pharmacological activities, due to their production of unique secondary metabolites. The current work aimed to investigate the in vitro antioxidant and cytotoxic activities of the methanol extracts of ten Parmeliaceae species, collected in different continents. Methanol extraction afforded high phenolic content in the extracts. The antioxidant activity displayed by lichens was evaluated through chemical assays, such as the ORAC (Oxygen Radical Absorbance Capacity) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities and the ferric reducing antioxidant power (FRAP). A moderately positive correlation was found between the phenolic content and the antioxidant properties for all the species: R: 0.7430 versus ORAC values, R: 0.7457 versus DPPH scavenging capacity, and R: 0.7056 versus FRAP reducing power. The methanol extract of Flavoparmelia euplecta exhibited the highest ORAC value, the extract of Myelochroa irrugans showed the maximum DPPH scavenging capacity, and Hypotrachyna cirrhata methanol extract demonstrated the highest reducing power. Further, the cytotoxic activity of the ten species was investigated on the human cancer cell lines HepG2 and MCF-7; Myelochroa irrugans exhibited the highest anticancer potential. The pharmacological activities shown here could be attributed to their phytochemical constituents.

Major selected monoterpenes α-pinene and 1,8-cineole found in Salvia lavandulifolia (Spanish sage) essential oil as regulators of cellular redox balance.

CONTEXT: Salvia lavandulifolia has been employed in folk medicine for the treatment of memory and dementia problems. This specie contains numerous bioactive terpenes which may contribute to its effectiveness. OBJECTIVE: To analyze the composition of essential oil of S. lavandulifolia and to investigate the potential in vitro cytoprotective and antioxidant activities of its major compounds, α-pinene and 1,8-cineole, against H2O2-induced oxidative stress in the U373-MG cell line. MATERIALS AND METHODS: Chemical composition was analyzed by gas chromatography; antioxidant capacity was measured using the ORAC assay, and cytoprotective activity was evaluated using the MTT assay (for cell viability) (range of concentrations: 10-400 µM), DCFH-DA assay (for intracellular ROS generation), thiobarbituric acid reactive substances (TBARS) method (for lipid peroxidation), and spectrofometric techniques and Western blot (for enzymatic activity and protein expression, respectively) at 10 and 25 µM. RESULTS: α-Pinene (18.39%) and 1,8-cineole (19.57%) were identified as major compounds in S. lavandulifolia essential oil. Pretreatments with these monoterpenes protected U373-MG cells against H2O2-induced oxidative injury by attenuating the loss of cell viability (IC50 : 79.70 µM to α-pinene and 66.23 µM to 1,8-cineole) and cell morphology, inhibiting ROS production (the most active compound was 1,8-cineole by decreasing the ROS production over 30-45% at 10 and 25 µM) and lipid peroxidation and increasing the endogenous antioxidant status (glutathione levels and CAT, SOD, GR, GPx, and HO-1 activity and protein expression). CONCLUSIONS: These findings demonstrate for the first time the effects of the monoterpenes 1,8-cineole and α-pinene identified in S. lavandulifolia essential oil as regulators of cellular redox balance in astrocytes.

Biological activity of HPLC-characterized ethanol extract from the aerial parts of Haplophyllum tuberculatum.

CONTEXT: The search for new sources of natural antioxidants from plant material may have beneficial therapeutic potential for those diseases associated with oxidative stress. The medicinal plant Haplophyllum tuberculatum (Forsskal) A. Juss. (Rutaceae) contains phenolic compounds as main phytochemicals; however, there are no reports on its antioxidant properties. OBJECTIVE: To evaluate antioxidant and cytoprotective potential of ethanol extract of Haplophyllum tuberculatum aerial parts. MATERIALS AND METHODS: Total phenol content was determined using Folin-Ciocalteu reagent; antiradical activity was measured using ORAC assay and the analysis of the major polyphenols was carried out using a HPLC-MS method. The antioxidant and cytoprotective effect were also investigated by the MTT assay and DCFH-DA method. The human astrocytoma U373-MG cell line was pretreated with ethanol extract (from 0.025 to 250 µg/mL) for 24 h, prior to 1 mM H2O2 exposure (30 min). RESULTS AND CONCLUSION: Total phenol content was 46.2 mg gallic acid/g sample and ORAC value was 1.283 µmol TE/mg sample. Chemical constituents were methoxyflavones, flavonols (mainly quercetin derivatives), cinnamic acids and benzoic acids. In cell system model of oxidative stress, pretreatments with ethanol extract at the concentrations of 2.5, 0.25 and 0.025 µg/mL significantly attenuated H2O2-induced loss in viability by 13.5, 17 and 20.5%, respectively. Furthermore, these ethanol extract concentrations markedly inhibited intracellular ROS production with IC50 0.026 µg/mL. These findings demonstrate the beneficial properties of ethanol extract of Haplophyllum tuberculatum aerial parts, rich in phenolic compounds, as antioxidant and radical scavenger ameliorating ROS-related processes and diseases such as several neurodegenerative disorders.

Ethnopharmacological study of medicinal plants used in the treatment of CNS disorders in Sinai Peninsula, Egypt.

ETHNOPHARMACOLOGICAL RELEVANCE: To provide ethnopharmacological information on the use of medicinal plants for central nervous system (CNS) disorders in the Sinai Peninsula region (Egypt). To collect, analyze and evaluate the ethnobotanical knowledge about these medicinal plants in the Sinai Peninsula region with 61,000 km (2) and 379,000 inhabitants. METHODOLOGY: Field work was concluded between March 2006 and May 2011, using semi-structured questionnaire with 700 informants (mean age: 59; 100% men) from 117 settlements of 17 Bedouin tribes. Transects walks in wild herbal plant collection areas and bibliographical review on the collected plants were also conducted. The Interview/ Inhabitant index (I/P), relative importance value of the species and informant consensus factor (FIC) were calculated. RESULTS: More than 300 species were traditionally used in folk medicine in the Sinai Peninsula; 101 of these species belonging to 40 families were reported as useful in different CNS disorders. Only 5 species are endemic of the studied area. All different part plants were used, leaves and aerial parts being the most frequent. Most of the remedies were prepared as infusion or decoction, while oral administration was the most common way to be used. Gastrointestinal (67.3%) and respiratory disorders (42.57%) were also reported as frequently treated by Bedouins with herbal remedies. CONCLUSIONS: Only a few species were found where the traditional use is supported by pharmacological studies (Acacia nilotica, Achillea fragrantissima, Ajuga iva or Mentha longifolia). No bibliographical references in the scientific literature were found for 22 species (21.78%); finally, several studies were published with different pharmacological activities than those provided by Bedouins.

Kaurane diterpenes from Sideritis spp. exert a cytoprotective effect against oxidative injury that is associated with modulation of the Nrf2 system.

Kaurane diterpenes have been shown to possess antioxidant properties. As a part of our ongoing studies on the identification of biologically active diterpenes from Sideritis spp., we have previously isolated and structurally elucidated the major kaurane diterpenes foliol, linearol and sidol, in a previous study from the aerial parts of Sideritis linearifolia and Sideritis leucantha. We have now examined the ability of these compounds to protect PC12 cells in an H2O2-induced oxidative stress model. Linearol and sidol (5 and 10 µM, 24 h) significantly attenuated loss of mitochondrial function (MTT assay) and membrane integrity (LDH assay) and morphological changes associated with H2O2-mediated cytotoxicity. Moreover, pretreatments with linearol and sidol effectively reduced intracellular ROS production, decreased MDA levels (lipid peroxidation product) and restored GSH/GSSG ratio. Furthermore, analysis of the effect of diterpenes on antioxidant enzymes showed that linearol and sidol induced the upregulation and protein expression of the main antioxidant enzymes CAT, SOD, GPx, GR and HO-1. Considering molecular mechanisms for maintaining cellular redox homeostasis by linearol and sidol, it would appear that the Nrf2 transcription factor seems to be involved. These results indicate that linearol and sidol are potential cytoprotective compounds, through antioxidant mechanisms, under H2O2-induced oxidative stress.

Involvement of Nrf2 signaling pathway in the neuroprotective activity of natural kaurane diterpenes.

Oxidative stress is a common harmful condition of several neurodegenerative diseases. Antioxidants represent the medical choice strategy for protection against this unbalanced oxidant-antioxidant status. The present study was undertaken to address the role of kaurane diterpenes foliol, linearol and sidol in the protection against H(2)O(2)-induced oxidative stress in the human astrocytoma U373-MG cell line and to establish the underlying mechanisms. U373-MG cells were pretreated with diterpenes (5 and 10 µM, 24h) prior to H(2)O(2) exposition (1mM, 30 min). We found that linearol and sidol exerted a significant astroprotective action, and foliol was the least active one. Linearol and sidol especially increased cell viability as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide and lactate dehydrogenase assay and attenuated morphological changes of U373-MG cells induced by H(2)O(2). Moreover, these compounds significantly decreased the level of intracellular reactive oxygen species, counteracted glutathione/oxidized glutathione changes, reduced lipid peroxidation and restored antioxidant and protein expression of antioxidant enzymes (catalase, superoxide dismutase, glutathione reductase, glutathione peroxidase and hemooxigenase-1). Furthermore, these natural products increased Nrf2 nuclear levels, suggesting the activation of this master regulator of antioxidative gene expressions in the protective effect exhibited by the kaurane diterpenes studied. Collectively, these results suggest that the studied kaurane diterpenes, mainly linearol and sidol, protect U373-MG cells from H(2)O(2)-induced injury or degeneration presumably by antioxidant mechanisms. These compounds may be useful agents for counteracting the oxidative damage occurring during the pathological development of several CNS disorders.

Terpene compounds in nature: a review of their potential antioxidant activity.

Reactive Oxygen Species are involved in the pathological development of many important human diseases such as neurodegenerative diseases, cardiovascular processes, diabetes and many others. The most promising strategy to prevent from the oxidative damage caused by these reactive species is the use of antioxidant molecules. These compounds can act as direct antioxidants through free radical scavenging mechanisms and/or as indirect antioxidants by enhancing the antioxidant status (enzymatic and non-enzymatic). Terpenes, one of the most extensive and varied structural compounds occurring in nature, display a wide range of biological and pharmacological activities. Here we highlight their antioxidant properties. Due to their antioxidant behaviour terpenes have been shown to provide relevant protection under oxidative stress conditions in different diseases including liver, renal, neurodegenerative and cardiovascular diseases, cancer, diabetes as well as in ageing processes. Evidence for this comes from the increasing number of publications on this issue in recent years. This review provides a complete overview of the natural terpenes with potential antioxidant properties, focusing on their source, structures, antioxidant mechanisms through which they exert their pharmacological and possible therapeutic activities.

Sideritis spp.: uses, chemical composition and pharmacological activities--a review.

The genus Sideritis (Lamiaceae) comprises more than 150 perennial and annual vegetal species widely distributed in the Mediterranean area, together with Canary and Madeira islands. It is a controversial botanic genus, with a complex taxonomical classification due to the high number of hybridizations that occur between species; their study requires a deep research experience. Sideritis species have been traditionally used as teas for feeding, flavoring agents and in folk medicine as antiinflammatory, antiulcerative, antimicrobial, vulnerary, antioxidant, antispasmodic, anticonvulsant, analgesic and carminative agents. The chemical components found in Sideritis genus include terpenes, flavonoids, essential oil, iridoids, coumarins, lignanes and sterols, among others. Diterpenes, flavonoids and essential oil occur in almost every species and are the main compounds responsible for the observed in vivo and in vitro pharmacological activities. The aim of this review is to provide a comprehensive overview on the botanical, phytochemical and pharmacological aspects from the genus Sideritis, with the objective of establishing scientific basis that explains its ethnopharmacological use.

HPLC isolation of antioxidant constituents from Xanthoparmelia spp.

A chromatographic method is described for the purification and characterization of secondary lichen substances with biological activity. A simple reversed-phase high-performance liquid chromatography method with gradient elution has been developed that allows the determination and isolation of salazinic, usnic and stictic acids from lichen samples in a single run and the quantification of every acid in the tested extracts. The antioxidant activity of both the isolated compounds and the respective lichen belonging to Xanthoparmelia genus was determined by the Oxygen Radical Absorbance Capacity (ORAC) assay; their effect as free radical scavengers, effect on cell survival by the 3(4,5-dimethyltiazol-2-yl)-2,5-diphenyltetrazolium reduction assay and 2',7'-dichlorofluorescin diacetate method were tested on U373 MG human astrocytome cell line. Both lichens extracts and all isolated compounds protected U373 MG cells from hydrogen peroxide-induced damage, suggesting that they could act as antioxidant agents in those neurodegenerative disorders associated with oxidative damage, such as Alzheimer's disease and Parkinson's disease.

Neuroprotective effect of a ginseng (Panax ginseng) root extract on astrocytes primary culture.

A standardized aqueous extract of Panax ginseng radix was tested for its antioxidant effect on primary astrocytes culture on an oxidant stress model generated by H(2)O(2). The results indicated that this extract had a significant effect on the reduction of astrocytic death induced by H(2)O(2). Dose-response experiments revealed that this ginseng extract increased cell viability at a wide range of concentrations. Therefore, we investigated the effects of this extract on antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), glutathione peroxidases (GPx) and glutathione reductase (GR), on glutathione content (reduced and oxidized forms and red/ox index) and on the intracellular reactive oxygen species (ROS) formation. Exposure of astrocytes to H(2)O(2) decreased the activities of antioxidant enzymes, and increased ROS formation. Ginseng root extract reversed the effect of almost all of these parameters in H(2)O(2)-injured primary cultures of rat astrocytes.

Value of high-performance liquid chromatographic analysis of amino acids in the determination of Panax ginseng radix extract effect in cultured neurons.

The present research describes a reversed-phase high-performance liquid chromatographic (RP-HPLC) method that allows the determination of several amino acids in primary cultured cortical neurons of rats. The concentration of amino acids was determined by using pre-column derivatization with dansyl chloride and UV-diode array detection. Data show that Panax ginseng radix extract (GS) can modulate amino acid release in neurons. The levels of glutamate (Glu), aspartate (Asp), gamma-aminobutyric acid (GABA) and glycine (Gly) in the GS-treated groups were higher than in the non-treated groups dose-dependentwise. In this case, Glu and GABA were the most released amino acids (74.43% +/- 0.97 and 88.41% +/- 4.12 at ginseng dose 0.01 mg/ml after 1h from treatment, respectively). The values obtained in the determination of the analytical parameters (linearity, precision, limit of detection and accuracy) confirm the quality of the method. The average recoveries for intra and inter-day assay (n = 5) were 101.18 and 102.38 for Asp, 99.35 and 98.44 for Glu, 99.59 and 99.66 for Gly, and 100.06 and 100.37 for GABA. These data proved that the method yields accurate results, with RSD lower than 2.2%. The precision of the method was estimated on the basis of RSD of six injections at two different concentrations of amino acids. This technique is useful in studying the GS-mediated modulation of the dynamic equilibrium of amino acids and neurotransmission in neurons.

Analysis and retention behaviour in high-performance liquid chromatography of terpenic plant constituents (Sideritis spp.) with pharmacological interest.

Terpenoids are natural products with an important pharmacological interest, which are present in a number of medicinal plants. The species of Sideritis genus are valuable due to their high content in those compounds and they have been used in the Mediterranean area in folk medicine as anti-inflammatory and anti-ulcer agents. The present study describes a gradient elution reversed-phase method that uses diode array detection to determine ten pharmacologically active diterpenoids occurring in 12 species of Sideritis. First, we studied the chromatographic behaviour of standard diterpenoids to analyse the variation on retention time and the chromatographic properties with the mobile phase. Standard calibration curves were generated by plotting the area of peaks against a concentration range of the compounds. Second, the validated method was applied to the analyses of hexanic and methanolic extracts from 12 species of Sideritis, which were collected from different areas of Spain. Finally, we established for this plant a relationship between their use in folk medicine and their diterpenoid content.

Lepidium peruvianum chacon restores homeostasis impaired by restraint stress.

Lepidium peruvianum root has been traditionally utilized by native Peruvians, since before the time of the Incas, for both nutritional and putative medicinal purposes as an adaptogen and also to enhance fertility in humans and animals. The present research was conducted to evaluate the anti-stress activity of the methanolic extract of Lepidium peruvianum. The drug is capable of attenuating or even eliminating variations in homeostasis produced by stress since it reduces or abolishes stress-induced ulcers, elevated corticosterone levels, the reduction of glucose and the increase in the weight of adrenal glands produced by stress. It also eliminates the decrease in free fatty-acids (FFA) in plasma produced by stress and we obtain a positive result in the forced-swimming test. Thus, it did not appear to affect restraint stress-induced immunosuppression.

Neuropharmacological activity of Nigella sativa L. extracts.

Pharmacological studies have been conducted on the aqueous and methanol extracts of defatted Nigella sativa L. seeds to evaluate their effects on the central nervous system (CNS) and on analgesic activity. The observations suggest that the two extracts of Nigella sativa possesses a potent CNS and analgesic activity (depressant action especially in the case of the methanolic extract).

Preliminary screening of five ethnomedicinal plants of Guatemala.

We performed the Irwin test on some different extracts of the aerial parts of Tridax procumbens L., of the leaves of Neurolaena lobata (L.) R. Br., of the bark and leaves of Byrsonima crassifolia (L.) Kunth. and Gliricidia sepium Jacq. Walp. and of the root and leaves of Petiveria alliacea L. At a dosage of 1.25 g extract/100 g dried plant, the aqueous extracts of bark and leaves of Byrsonima crassifolia (L.) Kunth. and G. sepium Jacq. Walp. showed higher activity: decrease in motor activity, back tonus, reversible parpebral ptosis. catalepsy and strong hypothermia.