Screening of the topical anti-inflammatory activity of the bark of Acacia cornigera Willdenow, Byrsonima crassifolia Kunth, Sweetia panamensis Yakovlev and the leaves of Sphagneticola trilobata Hitchcock

Ethnopharmacological relevance

An investigation of topical anti-inflammatory activity was undertaken on plants used in Central America traditional medicine.

Aim of study

Four herbal drugs used in the folk medicine of Central America to treat inflammatory skin affections (Acacia cornigera bark, Byrsonima crassifolia bark, Sphagneticola trilobata leaves and Sweetia panamensis bark) were evaluated for their topical anti-inflammatory activity.

Materials and methods

Petroleum ether, chloroform and methanol extracts were obtained for herbal medicines and then extracts were tested on Croton oil-induced ear dermatitis model in mice.

Results

Almost all the extracts reduced the Croton oil-induced ear dermatitis in mice and the chloroform ones showed the highest activity, with ID₅₀ (dose giving 50% oedema inhibition) values ranging from 112 μg/cm² (Byrsonima crassifolia) to 183 μg/cm² (Sphagneticola trilobata). As reference, ID₅₀ of the non-steroidal anti-inflammatory drug indomethacin was 93 μg/cm².

Conclusions

Lipophilic extracts from these species can be regarded as potential sources of anti-inflammatory principles.     

Determination of the wound healing effect of Calendula extracts using the scratch assay with 3T3 fibroblasts

Pharmacological relevance

Presentation of the scratch assay as a convenient and inexpensive in vitro tool to gain first insights in the wound healing potential of plant extracts and natural compounds.

Aim of the study

The present study deals with the optimization of the scratch assay which can be used as an in vitro model for quantification of fibroblast migration to and proliferation into the wounded area. It is suitable for the first evaluation of the wound re-epithelialization potential of crude herbal extracts, isolated compounds and pharmaceutical preparations. As a proof of concept three preparations from traditional medicinal plants were investigated.

Materials and methods

Swiss 3T3 albino mouse fibroblasts were used in monolayers and platelet derived growth factor as positive control. Hexane and ethanolic extracts from Calendula officinalis and Matricaria recutita, Hypericum oil as well as the triterpenoids faradiol myristate and palmitate were studied. To differentiate between proliferation and migration antimitotic mitomycin C was added.

Results

Both extracts of Calendula officinalis stimulated proliferation and migration of fibroblasts at low concentrations, e.g. 10 μg/ml enhanced cell numbers by 64.35% and 70.53%, respectively. Inhibition of proliferation showed that this effect is mainly due to stimulation of migration. Faradiol myristate and palmitate gave comparable stimulation rates at an almost 50 μg/ml concentration, indicating that they contribute partially, but not most significantly to the wound healing effects of Calendula preparations. Extracts from Matricaria recutita were only moderately active. Hypericum oil was cytotoxic at concentrations higher than 0.5 μg/ml.

Conclusions

The scratch assay in the present form can be used as a promising scientific approach and platform to differentiate between plant extracts known for their wound healing and their anti-inflammatory properties.     

Permeability of rosmarinic acid in Prunella vulgaris and ursolic acid in Salvia officinalis extracts across Caco-2 cell monolayers

Ethnopharmacological relevance

Rosmarinic acid (RA), a caffeic acid-related compound found in high concentrations in Prunella vulgaris (self-heal), and ursolic acid (UA), a pentacyclic triterpene acid concentrated in Salvia officinalis (sage), have been traditionally used to treat inflammation in the mouth, and may also be beneficial for gastrointestinal health in general.

Aim of the study

To investigate the permeabilities of RA and UA as pure compounds and in Prunella vulgaris and Salvia officinalis ethanol extracts across human intestinal epithelial Caco-2 cell monolayers.

Materials and methods

The permeabilities and phase II biotransformation of RA and UA as pure compounds and in herbal extracts were compared using Caco-2 cells with HPLC detection.

Results

The apparent permeability coefficient (P_app) for RA and RA in Prunella vulgaris extracts was 0.2 ± 0.05 × 10⁻⁶ cm/s, significantly increased to 0.9 ± 0.2 × 10⁻⁶ cm/s after β-glucuronidase/sulfatase treatment. P_app for UA and UA in Salvia officinalis extract was 2.7 ± 0.3 × 10⁻⁶ cm/s and 2.3 ± 0.5 × 10⁻⁶ cm/s before and after β-glucuronidase/sulfatase treatment, respectively. Neither compound was affected in permeability by the herbal extract matrix.

Conclusion

RA and UA in herbal extracts had similar uptake as that found using the pure compounds, which may simplify the prediction of compound efficacy, but the apparent lack of intestinal glucuronidation/sulfation of UA is likely to further enhance the bioavailability of that compound compared with RA.     

Antimutagenic effects of ethanolic extracts from selected Palestinian medicinal plants

Aim of the study

Eryngium creticum, Nigella sativa, and Teucrium polium have been traditionally used for the treatment of inflammations, liver disorders, and arthritis. Various studies on these plants revealed anti-inflammatory, hepatoprotective and antimutagenic activities. Previous results of our research group, however, indicate that aqueous extracts prepared as for the traditional use (tea) have neither cytoprotective nor antimutagenic activity. Instead, there is evidence for a mutagenic potential. Since the described antimutagenic activity may not be present in effective amounts in the aqueous extracts this study focuses on ethanolic extracts.

Materials and methods

Ethanolic extracts of the three plant species were prepared and tested against N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), a directly acting mutagen. Since it cannot be excluded that the active constituents of the plant extracts require biotransformation or induce metabolic enzymes, causing antimutagenic or detoxifying effects, primary cultures of rat hepatocytes were used for this study. Plant ethanolic extracts were applied along with MNNG in three protocols: pre-treatment, combined treatment and post-treatment.

Results and conclusions

The results of this investigation clearly indicate an inhibitory effect of the plant extracts on MNNG mutagenicity, while the extracts had no effect on cytotoxicity indicators such as necrosis and apoptosis. The effects obtained can be attributed to a direct antimutagenic activity and an increased recovery at the chromosomal level. In order to identify the responsible compounds extracts will in a next step have to be fractionated, tested and chemically analyzed.     

Comparative acute toxicities and immunomodulatory potentials of five Eastern Nigeria mistletoes

Ethnopharmacological relevance

Traditionally, mistletoes of Eastern Nigeria origin, Loranthus micranthus Linn. have been used as immunostimulant for the management of certain diseases with high profile immune depleting potentials. This practice has remained till date without scientific validation.

Aim of study

To obtain and validate evidence for or against its continued use as immunostimulant and afford data for further studies on this specie of mistletoe. The present work is an in vivo proof of ethnopharmacological concept of the age long immunomodulatory use of our local mistletoe.

Materials and methods

Aqueous-methanol extracts of the plant leaves from five different host trees were evaluated for immunomodulatory activity using four in vivo models in mice or rats, namely; total and differential leukocyte count (TLC and DLC), the cellular mediated delayed-type hypersensitivity reaction (DTHR) test, the humoral mediated antibody titration (AT) test and the cyclophosphamide-induced myelosuppression (CIM) test at different dose levels (100, 200 and 400 or 50, 100 and 250 mg kg⁻¹; depending on model) against standard controls. Phytochemical and acute toxicity tests were equally carried out on all the extracts.

Results

Results obtained indicate that all the mistletoes contained the same phytochemical constituents, although in varying amounts. The mistletoes exhibited statistically significantly different (p < 0.05 or p < 0.001, ANOVA) immunomodulatory (up-regulatory) activities in the overall order of that from Kola acuminata > Citrus spp > Persia americana > Parkia biglobosa > Pentaclatra macrophylla. LD₅₀ values were generally greater than 5000 mg/kg.

Conclusion

The present study confirms the Eastern Nigeria mistletoe as a potent and safe alternative or complementary medicine for the management of immunodeficiency diseases.     

Interactions of Magnolia and Ziziphus extracts with selected central nervous system receptors

Ethnopharmacological relevance

Magnolia officinalis Rehder and Wilson [Magnoliaceae] bark and Ziziphus spinosa (Buhge) Hu ex. Chen. [Fam. Rhamnaceae] seed have a history of use in traditional Asian medicine for mild anxiety, nervousness and sleep-related problems.

Aim of the study

To identify pharmacological targets, extracts of Magnolia officinalis (ME), Ziziphus spinosa (ZE), and a proprietary fixed combination (MZE) were tested for affinity with central nervous system receptors associated with relaxation and sleep.

Methods

In vitro radioligand binding and cellular functional assays were conducted on: adenosine A₁, dopamine (transporter, D₁, D_2S, D₃, D_4.4 and D₅), serotonin (transporter, 5-HT_1A, 5-HT_1B, 5-HT_4e, 5-HT₆ and 5-HT₇) and the GABA benzodiazepine receptor.

Results

Interactions were demonstrated with the adenosine A₁ receptor, dopamine transporter and dopamine D₅ receptor (antagonist activity), serotonin receptors (5-HT_1B and 5-HT₆ antagonist activity) and the GABA benzodiazepine receptor at a concentration of 100 μg/ml or lower. ME had an affinity with adenosine A₁ (K_i of 9.2 ± 1.1 μg/ml) and potentiated the GABA activated chloride current at the benzodiazepine subunits of the GABA receptor (maximum effect at 50 μg/ml). ME had a modest antagonist action with 5-HT₆ and ZE with the 5-HT_1B receptor.

Conclusion

The interactions in the receptor binding models are consistent with the traditional anxiolytic and sleep-inducing activities of Magnolia officinalis bark and Ziziphus spinosa seed.     

The hepatoprotective effect and chemical constituents of total iridoids and xanthones extracted from Swertia mussotii Franch

Ethnopharmacological relevance

Total iridoids and xanthones (TIXS) were extracted from Swertia mussotii Franch, one of the most important eight Tibetan medicines in China, which was recorded in the book of Jingzhu Bencao and used for clinical treatment of cholestatic hepatitis for many years. Our aim was to study the hepatoprotective effect and chemical constituents of the TIXS.

Materials and methods

Crude extracts were prepared using 90% ethanol, and individual fractions were collected following HPD-300 macroporous resin column chromatography. HPLC/MS was applied to qualitatively and quantitatively analyze the TIXS. Then, the alpha-naphthylisot hiocyanate-induced liver damage model was used to assess the hepatoprotective effect of the TIXS.

Results

A total of 12 compounds were identified by the fingerprint chromatography of the TIXS, and swertiamarin and swertianolin were shown to be its two main components. Oral administration of the TIXS at a dose of 35, 70 or 140 mg kg⁻¹, swertiamarin at a dose of 20 mg kg⁻¹ or swertianolin at a dose of 20 mg kg⁻¹, for 7 days in mice significantly reduced the alpha-naphthylisot hiocyanate-induced levels of alanine aminotransferase, aspartate aminotransferase and the total and direct bilirubins, and increased the bile flow (P<0.01).

Conclusion

These findings suggest that the TIXS exhibits significant hepatoprotective effect in the liver damage model induced by alpha-naphthylisot hiocyanate. Its active constituents include swertiamarin and swertianolin.     

Augmentation of expression of immunocytes’ functions by seed extract of Ziziphus mauritiana (Lamk.)

Aim of the study

The present study was carried out to evaluate the immunomodulatory potential of Ziziphus mauritiana (Lamk.) seed extract to ascertain the folkloric claim as immunomodulator.

Materials and methods

The aqueous-ethanolic seed extract (100–400 mg kg⁻¹) of Z. mauritiana was investigated for immunomodulatory potential in mice. The extract was standardized with HPLC using betulinic acid as a marker. Functions of various immunocytes in the form of humoral (development of anti-SRBC (sheep red blood cells) antibody titers) and cell-mediated immune response (delayed type hypersensitivity, nitroblue tetrazolium reduction, inducible nitric oxide synthase activity and bactericidal activity) was studied in SRBC immunized mice. The cytokine, IFN-γ (interferon-gamma) and IL-4 (interleukin-4) secretion was also measured quantitatively by ELISA as the expression of functions of Th-1 and Th-2 respectively. Levamisole (2.5 mg kg⁻¹) was used as standard drug.

Results

The seed extract demonstrated significant (P < 0.05–0.001) up-regulation of cell-mediated, humoral immune response and Th-1 mediated cytokine IFN-γ and decline in Th-2 mediated cytokine IL-4. At higher dose of extract the results were comparable to that of the levamisole.

Conclusion

The immunostimulatory potential of this seed extract is likely to be mediated through its effect on macrophage function and Th-1 mediated immunity confirming the folkloric use of this plant.     

In vitro antiplasmodial activity of plants used in Benin in traditional medicine to treat malaria

Aim of the study

The aim of the study was to evaluate the in vitro antiplasmodial activity of crude extracts of 12 plant species traditionally used in Benin for the treatment of malaria in order to validate their use.

Materials and methods

For each species, dichloromethane, methanol and total aqueous extracts were tested. The antiplasmodial activity of extracts was evaluated using the measurement of the plasmodial lactate dehydrogenase activity on chloroquine-sensitive (3D7) and resistant (W2) strains of Plasmodium falciparum. The selectivity of the different extracts was evaluated using the MTT test on J774 macrophage-like murine cells and WI38 human normal fibroblasts.

Results

The best growth inhibition of both strains of Plasmodium falciparum was observed with the dichloromethane extracts of Acanthospermum hispidum DC. (Asteraceae) (IC₅₀ = 7.5 μg/ml on 3D7 and 4.8 μg/ml on W2), Keetia leucantha (K. Krause) Bridson (syn. Plectronia leucantha Krause) (Rubiaceae) leaves and twigs (IC₅₀ = 13.8 and 11.3 μg/ml on 3D7 and IC₅₀ = 26.5 and 15.8 μg/ml on W2, respectively), Carpolobia lutea G.Don. (Polygalaceae) (IC₅₀ = 19.4 μg/ml on 3D7 and 8.1 μg/ml on W2) and Strychnos spinosa Lam. (Loganiaceae) leaves (IC₅₀ = 15.6 μg/ml on 3D7 and 8.9 μg/ml on W2). All these extracts had a low cytotoxicity.

Conclusion

Our study gives some justifications for the traditional uses of some investigated plants.     

Evaluation of the diuretic and analgesic activities of the rhizomes of Rumex abyssinicus Jacq in mice

Aim of the study

Rumex abyssinicus Jacq (Polygonaceae) has been used traditionally for treatment of hypertension, inflammatory and painful conditions in Ethiopia. The present study aimed to evaluate the diuretic and analgesic activities of extracts of Rumex abyssinicus at different doses in mice.

Materials and methods

The effect on urine volume and urinary electrolyte (Na⁺, K⁺ and Cl⁻) was assessed for a period of 5 h following oral administration of aqueous (500 mg/kg, 750 mg/kg or 1000 mg/kg) or 80% methanolic (250 mg/kg, 500 mg/kg or 750 mg/kg) extract or furosemide (10 mg/kg). Acetic acid-induced writhing and hot-plate tests were employed to study the analgesic effect of 80% methanolic extracts (250 mg/kg, 500 mg/kg or 1000 mg/kg, P.O.) and compared with that of aspirin (100 mg/kg, P.O.) or morphine (10 mg/kg, sc).

Results

The extracts displayed dose-dependent diuretic and analgesic effects. The highest doses of both extracts markedly and significantly increased (P < 0.001) urine volume and urinary electrolytes, qualitatively similar to that of furosemide. 1000 mg/kg of the extract reduced the number of writhing by 67.6% (P < 0.001) and conferred more than 70% protection against thermally induced pain stimuli after 45 min of treatment comparable to that of aspirin and morphine, respectively.

Conclusion

These findings collectively indicate that the extracts exhibited significant diuretic and analgesic activities, providing evidence, at least in part, for its folkloric use.     

In vitro and in vivo antimalarial and cytotoxic activity of five plants used in congolese traditional medicine

Aim of the study

The in vitro antiplasmodial activity and cytotoxicity of methanolic and dichloromethane extracts from five Congolese plants were evaluated. The plants were selected following an ethnobotanical survey conducted in D.R. Congo and focusing on plants used traditionally to treat malaria. The in vivo antimalarial activity of aqueous and methanolic extracts active in vitro was also determined in mice infected by Plasmodium berghei berghei.

Materials and methods

The growth inhibition of Plasmodium falciparum strains was evaluated using the measurement of lactate dehydrogenase activity. The extracts (aqueous, CH₃OH, EtOH and CH₂Cl₂) were prepared by maceration and tested in vitro against the 3D7 (chloroquine sensitive) and W2 (chloroquine resistant) strains of Plasmodium falciparum and against the human normal fetal lung fibroblasts WI-38 to determine the selectivity index. Some extracts were also used at the dose of 300 mg/kg to evaluate their activity in mice infected since 4 days by Plasmodium berghei.

Results

Two plants presented a very high activity (IC₅₀ < 3 μg/ml). These plants were Strychnos icaja roots bark (MeOH and CH₂Cl₂) and Physalis angulata leaves (MeOH and CH₂Cl₂). One plant (Anisopappus chinensis whole plant, MeOH and CH₂Cl₂) presented a high activity (IC50 < 15 μg/ml). The extracts of Anisopappus chinensis and Physalis angulata showed also a good inhibition of parasitemia in vivo. Flavonoids, phenolic acids and terpenes were identified in these plants by a general phytochemical screening method.

Conclusion

Three plants showed a very interesting antiplasmodial activity (Anisopappus chinensis, Physalis angulata and Strychnos icaja) and one of them showed a good selectivity index (>10, Anisopappus chinensis). Anisopappus chinensis and Physalis angulata were also active in vivo.     

Leucas cephalotes regulates carbohydrate and lipid metabolism and improves antioxidant status in IDDM and NIDDM rats

Ethnopharmacological relevance

Leucas cephalotes (Roth.) Spreng. (Laminaceae) is an ayurvedic traditional medicinal plant used in India, Nepal and Pakistan to treat several ailments including diabetes.

Aim of the study

The aim of the present study is to investigate the antidiabetic, antihyperlipaemic and antioxidant activities of Leucas cephalotes for its purported use in diabetes.

Materials and methods

The ethanol extract of leaves of Leucas cephalotes was administered (150, 300 and 450 mg kg⁻¹ bw) to diabetes induced (IDDM and NIDDM) rats and carbohydrate, lipid, antioxidant, urea and creatinine profiles were assessed.

Results

All the three doses of extract decreased plasma glucose and lipid profiles and, improved the antioxidant status of both types of diabetic rats. The extract administration improved hepatic glycogen content and hexokinase activity, decreased glucose-6-phosphatase activity, blood urea, creatinine contents and decreased lipid peroxidation in diabetic rats. Of the three doses used, 450 mg kg⁻¹ bw dose was found to be more potent in its effects comparable to those of glibenclamide and metformin.

Conclusion

Leucas cephalotes regulates both carbohydrate and lipid metabolism and, improves body antioxidant defense systems in both types of diabetes.     

Anti-spasmodic effects of Zizyphus lotus (L.) Desf. extracts on isolated rat duodenum

Aim of the study

The present study deals with the anti-spasmodic activity of the aqueous and the methanolic extracts of the leaves and the root barks of Zizyphus lotus (L.) Desf. on male rats.

Materials and methods

This activity was assessed on contractions of isolated rat duodenum, induced by acetylcholine, KCl, and BaCl₂ and compared with the effect of atropine and papaverine.

Results

Both extracts of leaves and root barks caused significant relaxation of spontaneous contractions and produced a concentration-dependent inhibition (P < 0.01–0.001) of contraction induced by spasmogenic agents.

Conclusion

These results indicate that Zizyphus lotus extracts contain anti-spasmodic constituents mediating their effect through cholinergic receptors and blockade Ca²⁺ influx. This could explain the traditional use of Zizyphus lotus in the treatment of the intestinal diseases.     

Aqueous ethanol extract of the fruit of Xylopia aethiopica (Annonaceae) exhibits anti-anaphylactic and anti-inflammatory actions in mice

Ethnopharmacological relevance

Xylopia aethiopica has been traditionally used in the form of the dried fruit decoction to treat bronchitis, asthma, arthritis and rheumatism in Ghana, Nigeria and Cameroon. Aim of the study is to evaluate the anti-anaphylactic and anti-inflammatory effects of a 70% aqueous ethanol extract of the fruits of Xylopia aethiopica.

Materials and methods

Systemic anaphylaxis was induced by the injection of either compound 48/80 or lipopolysaccharide, LPS and survival rates of mice monitored for 1 h or 7 days respectively while IgE-mediated anaphylaxis in a local allergic reaction was studied in the pinnal inflammation model in mice. Clonidine-induced catalepsy in mice was used to evaluate the indirect antihistamine effect of Xylopia aethiopica, XAE. The effects of XAE assessed on the maximal and total oedema responses in the carrageenan-induced paw oedema in mice was used to evaluate the anti-inflammatory action of the extract.

Results

Administered at 30, 100, 300 and 1000 mg kg⁻¹ p.o., XAE dose dependently suppressed compound 48/80-induced mouse systemic anaphylactic shock and offered 63% protection to mice against LPS-induced endotoxic shock at a dose of 300 mg kg⁻¹. In addition, the extract (30–300 mg kg⁻¹) in a dose dependent manner significantly inhibited by 23–62% the mouse pinnal inflammation. Clonidine-induced catalepsy in mice was significantly suppressed in a dose and time dependent manner when administered both prophylactically and therapeutically. In the same doses, when administered before the induction of the mouse carrageenan-induced paw oedema, the mean maximal swelling attained during 6 h was reduced to 41.02±6.94%, 35.61±4.30%, and 29.09±4.90% of the inflamed control response respectively and total paw swellings induced over the 6 h were also dose-dependently and significantly suppressed to 74.84±14.84%, 63.95±9.37%, and 48.13±10.90% of the inflamed control response respectively. Administered after the induction of the carrageenan paw oedema the mean maximal swelling attained during 6 h was suppressed to 49.84±3.95%, 43.62±1.01%, and 35.97±1.34% of the inflamed control response respectively while the total paw swellings induced over the 6 h were also dose-dependently and significantly suppressed at 100 and 300 mg kg⁻¹ to 72.39±4.38% and 60.81±3.25% of the inflamed control response respectively.

Conclusion

These findings suggest that XAE inhibits mast cell-dependent immediate allergic reactions and exhibit anti-inflammatory actions through the inhibition of histamine release from mast cells via stabilizing the cell membrane. Our results contribute towards validation of the traditional use of Xylopia aethiopica in the treatment of bronchitis, asthma, arthritis and rheumatism.     

Substantiation of the ethnopharmacological use of Conyza sumatrensis (Retz.) E.H.Walker in the treatment of malaria through in-vivo evaluation in Plasmodium berghei infected mice

Ethnopharmacological relevance

Scientific validation of ethnopharmacologically used plants and their utilization for therapeutic interventions can be a source of affordable treatment especially for neglected diseases in endemic areas. Conyza sumatrensis is a plant which finds its use in treating malaria like fevers but lacks proper scientific validation. Our study has tried to address this gap by authenticating its traditional use for the treatment of malaria.

Aim of the study

Evaluate the antimalarial activity of extracts derived from Conyza sumatrensis for its ethnopharmacological validation.

Materials and methods

Shade dried leaves were extracted with varying concentrations of ethanol and concentrated for bio-evaluation. Swiss albino mice infected with 1×10⁶ parasitized red blood cells, were orally administered with test extracts for 7 days in two sets of experiments. The first set was used to evaluate alcoholic, hydroalcoholic and aqueous extracts while the second set was used to evaluate the dose response of alcoholic extract ranging from 500–1600 mg/kg. Mean survival time, parasitaemia and haemoglobin levels were considered to interpret the antimalarial potential. Phytochemical analysis for the presence of flavonoids, alkaloids tannins, total phenolics, riboflavin and thiamine was also carried out.

Results

Among the three extracts administered at 1000 mg/kg, chemo suppression was significantly (p<0.001) observed in the alcoholic extract (62.59±12.52%) followed by hydroalcoholic (41.81±19.04%, p<0.01) and aqueous (32.04±19.04%, P<0.05) indicating that the active constituents leach out in ethanol. The dose response study involving the ethanol extract concluded the optimum dose to be 1000 mg/kg, as also evidenced by the haemoglobin levels.

Conclusion

The plant exhibits moderate antimalarial activity which can be further prospected for active fractions or pure molecules for adjunctive therapy.     

Anticonvulsant effect of aqueous extract of Valeriana officinalis in amygdala-kindled rats: Possible involvement of adenosine

Ethnopharmacological relevance

Valeriana officinalis L. (valerian) root extract has been used as an antiepileptic herbal medicine in Iran.

Aim of this study

In the present study the effect of valerian extracts on an experimental model of temporal lobe epilepsy (TLE) was evaluated. Moreover, the involvement of adenosine system in the actions of aqueous extract of valerian was evaluated.

Materials and methods

Bipolar stimulating and monopolar recording electrodes were implanted stereotaxically in the right basolateral amygdala of male Sprague–Dawley rats. After kindling, the effect of aqueous (200, 500 and 800 mg/kg; intraperitoneal) and petroleum ether (PE; 50 and 100 mg/kg; intraperitoneal) extracts of valerian and CPT (selective A₁ receptor antagonist; 10 and 20 μM; intracerebroventricular) on afterdischarge duration (ADD), duration of stage 5 seizure (S5D) and latency to the onset of bilateral forelimb clonuses (S4L) were measured. The effect of CPT (10 μM) on the response of aqueous extract of valerian (500 mg/kg) was also determined.

Results

The results showed that aqueous extract of valerian had anticonvulsant effect. However, PE extract and CPT (20 μM) had proconvulsant effect. Administration of CPT (10 μM) before the administration of aqueous extract decreased the anticonvulsant effect of valerian.

Conclusions

The results showed significant anticonvulsant effect for aqueous but not PE extract of valerian. Moreover, CPT as a selective adenosine A₁ receptor antagonist decreased the anticonvulsant effect of valerian aqueous extract. Therefore, we concluded that part of anticonvulsant effect of valerian probably is mediated through activation of adenosine system.     

Comparison of the chemical composition and biological effects of the roots,branches and leaves of Heteropterys tomentosa A. Juss

Ethnopharmacological relevance: Heteropterys tomentosa

A. Juss (Malpighiaceae), commonly mistaken as Heteropterys aphrodisiaca, is chronically used by the Brazilian population to improve general health due to its claimed protective effects against a wide range of medical conditions.

Aim of the study

This study in rodents aimed to verify the adaptogenic potential of the hydroalcoholic extracts of the roots (the most commonly used portion), branches and leaves of the plant.

Materials and methods

The phytochemical constitution of the extracts was analyzed through thin-layer chromatography and high-performance liquid chromatography. Restriction- and cold-induced stress in rats treated for 14 days with 100 or 300 mg/kg of the extracts were used to evaluate parameters such as ulceration, adrenals, thymus and spleen weights, as well as ACTH and corticosterone plasmatic levels. The stress response also was evaluated in mice by self-analgesia induced by restraint stress, after 7 days of treatment at doses of 100 and 300 mg/kg. The learning and memory of aged rats treated with extracts of root or branches at the dose of 50 mg/kg for 80 days were evaluated in the elevated T-maze test.

Results

The chemical constituents of the three parts of the plant were relatively similar in the presence of saponins, hydrolysable tannins, flavonoids, polyphenols and triterpenes. None of the three extracts were capable of protecting the stomach from ulcerations in rats submitted to cold restraint stress or protecting from alterations in adrenal or spleen weight (p>0.05). Furthermore, the extracts did not inhibit increases in plasma levels of corticosterone and adrenocorticotropic hormone. Moreover, the extracts did not inhibit self-analgesia induced by restraint stress in mice and did not improve the performance of aged rats in the T-maze test (p>0.05).

Conclusion

The tests employed in this study did not show evidence of adaptogenic activity in the three extracts of Heteropterys tomentosa.     

Evaluation of 13 selected medicinal plants from Burkina Faso for their antiplasmodial properties

Aim of the study

The aim of this study was to evaluate the antiplasmodial properties of 13 plants used against malaria in traditional medicine in Burkina Faso.

Materials and methods

In vitro antiplasmodial activity of dichloromethane, methanol and aqueous crude extracts obtained from vegetal samples collected in Burkina Faso was first evaluated on the Plasmodium falciparum 3D7 chloroquine-sensitive strain using a colorimetric method.

Results

Thirteen extracts obtained from 8 different species were found to exhibit antiplasmodial activity (IC₅₀ < 50 μg/ml). Five species demonstrated a moderate activity (15 μg/ml < IC₅₀ < 50 μg/ml): Boswellia dalzielii (leaves), Waltheria indica (roots and aerial parts), Bergia suffruticosa (whole plant), Vitellaria paradoxa (bark) and Jatropha gossypiifolia (leaves). The best results were obtained with extracts from the Dicoma tomentosa whole plant, from Psorospermum senegalense leaves and from Gardenia sokotensis leaves. These extracts found to display promising antiplasmodial activity, with IC₅₀ values ranging from 7.0 to 14.0 μg/ml.The most active plant extracts were then tested for in vitro activity on the Plasmodium falciparum W2 chloroquine-resistant strain and also for in vitro cytotoxicity on normal human fibroblasts (WI-38) in order to determine the selectivity index.

Conclusions

Dicoma tomentosa (Asteraceae) and Psorospermum senegalense (Clusiaceae) appeared to be the best candidates for further investigation of their antiplasmodial properties, reported for the first time by this study.     

Vascular effects and antioxidant activity of two Combretum species from Democratic Republic of Congo

Ethnopharmacological relevance

Combretum racemosum P. Beauv (Combretaceae) leaves (CrLv) and root bark (CrRB) and Combretum celastroides subsp. laxiflorum Welw (Combretaceae) leaves (ClLv) are used in Congolese traditional medicine for several therapeutic purposes, notably for the treatment of conditions consistent with hypertension. The present study aims to investigate the vasorelaxant and in vitro antioxidant activities of these plants polar extracts and to examine the in vivo antihypertensive effect of the extract which displays the most potent vasorelaxant effect.

Material and methods

The vasorelaxant effect of CrLv, CrRB and ClLv methanolic extracts was studied on rat aorta rings pre-contracted with phenylephrine (PE, 1 μM) in the presence or absence of the endothelium. In some experiments, prior to the addition of the extract, rings were incubated for 30 min with either L-N^G-nitroarginine methyl ester (L-NAME; 100 μM), a nitric oxide synthase (NOS) inhibitor, indomethacin (10 μM), a cyclooxygenase inhibitor, or 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 μM), a guanylate cyclase inhibitor. The antioxidant activity was determined by the measurement of the scavenging ability of extracts towards the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Blood pressure was measured on normotensive Wistar rats and spontaneously hypertensive rats (SHR) treated orally with a daily dose (40 mg/kg) of the CILv extract for 5 weeks. Tested extracts have been characterised by TLC profiles targeted at flavonoids.

Results

All tested extracts showed an important DPPH scavenging activity, ranging from 0.6 to 1.1 quercetin-equivalents. They caused a concentration-dependent vasorelaxation on intact aortic rings pre-contracted with PE (1 μM). The responses to CrRB and CrLv methanolic extracts reached 74.0±5.1% and 62.2±8.6% at a cumulative concentration of 50 μg/ml, respectively. The ClLv (10 μg/ml) extract was more active and, in the same conditions, relaxed aortic rings by 90.3±5.8%. The vasorelaxant activity of all extracts disappeared or was significantly attenuated by removal of the endothelium or after pretreatment with L-NAME or ODQ. Indomethacin only inhibited the activity of CrLv and CrRB extracts. The ClLv extract was able to lower the systolic blood pressure in SHR rats by 7% after a 5-week treatment.

Conclusions

The present study shows that methanolic extracts from ClLv, CrRB and CrLv have an antioxidant activity and an endothelium-dependent vasorelaxant effect. ClLv induces the vasorelaxant effect through the NO-cGMP pathway while CrLv and CrRB extracts also act via a prostanoid pathway. ClLv extract demonstrated a modest but significant antihypertensive activity in SHR rats.