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.     

In vitro antiplasmodial activity of Brazilian Cerrado plants used as traditional remedies

Twenty-seven species of native Brazilian Cerrado plants commonly used by traditional healers to treat malaria and other diseases were collected and 204 hexanic and ethanolic extracts were obtained by maceration. The antiplasmodial activity of the extracts was tested in vitro against a chloroquine resistant strain (FcB1) of Plasmodium falciparum, and cytotoxicity against the cell lines L-6 of rats and MRC-5 of human was evaluated. Thirty-two extracts showed significant inhibition rates of Plasmodium falciparum growth and of these six showed cytotoxicity against the cell lines. The strongest antiplasmodial activity was found for the hexanic extracts of Xylopia aromatica root wood (IC(50)=4.7 microg/ml), Xylopia emarginata root bark (IC(50)=4.9 microg/ml), Casearia sylvestris var. lingua leaves, stem wood and stem bark, and root wood and root bark (IC(50) values from 0.9 to 2.3 microg/ml), and Cupania vernalis leaves (IC(50)=0.9 microg/ml); and for the ethanolic extract of Aspidosperma macrocarpon root bark (IC(50)=4.9 microg/ml). However, the best selectivity towards Plasmodium falciparum was observed for the hexanic root bark extract of Matayba guianensis (IC(50) on Plasmodium falciparum=6.1 microg/ml, SI=16.4 for MRC-5) and the ethanolic root bark extract of Aspidosperma macrocarpon (IC(50) on Plasmodium falciparum=4.9 micro/ml, SI=16.2 for MRC-5).     

Antiparasitic activities of two sesquiterpenic lactones isolated from Acanthospermum hispidum D.C

Ethnopharmacological relevance

Aerial parts of Acanthospermum hispidum D.C. are often used by traditional healers in Benin for various diseases and especially for malaria.

Aim of the study

To identify active compounds from extracts of Acanthospermum hispidum D.CV. leaves previously shown to possess antimalarial properties and analyse in vivo activity and toxicity of crude extracts.

Materials and methods

Compounds were isolated from aerial part of Acanthospermum hispidum D.C. and structurally elucidated using extensive spectroscopic analysis. Antiplasmodial activity was evaluated in vitro against a chloroquine-sensitive strain of Plasmodium falciparum (3D7) using the measurement of the plasmodial lactate dehydrogenase activity and in vivo against Plasmodium berghei berghei by the 4-day suppressive test. Selectivity of extract and purified compounds on Plasmodium parasites were evaluated by using MTT test on J774 macrophage like murine cells and WI38 human normal fibroblasts and also against two other parasites: Trypanosoma brucei brucei and Leishmania mexicana mexicana. Acute and sub-acute toxicities of a crude extract were evaluated on mice.

Results

Two known sesquiterpenic lactones were isolated: 1 (15-acetoxy-8β-[(2-methylbutyryloxy)]-14-oxo-4,5-cis-acanthospermolide) and 2 (9α-acetoxy-15-hydroxy-8β-(2-methylbutyryloxy)-14-oxo-4,5-trans-acanthospermolide). 1 and 2 showed in vitro antiplasmodial activity against the chloroquine-sensitive strain (3D7) with IC₅₀ of 2.9 ± 0.5 and 2.23 ± 0.09 μM respectively. Only 2 showed a high selectivity index (SI: 18.4) on Plasmodium compared to cytotoxicity against human fibroblasts cell line (WI38). 1 and 2 also showed interesting antiparasitic activities in vitro against Trypanosoma brucei brucei (IC₅₀ of 2.45 ± 0.49 and 6.36 ± 1.42 μM respectively) and Leishmania mexicana mexicana (IC₅₀ of 0.94 ± 0.05 and 2.54 ± 0.19 μM respectively). Furthermore, crude acidic water extract and fractions containing one of the two isolated compounds displayed a weak in vivo antimalarial activity against Plasmodium berghei berghei with a long half-life causing a delayed effect. In vivo acute (2000 mg/kg) and sub-acute (1000 mg/kg) toxicity tests on the crude acidic water extract did not show toxicity.

Conclusion

Crude acidic water extract, fractions and pure isolated compounds from Acanthospermum hispidum showed promising in vitro antiplasmodial activity. Despite our study did not show in vivo acute and subacute toxicities of the crude acidic water extract, its weak in vivo antimalarial activity and the in vitro cytotoxicity of pure compounds and enriched extracts containing 1 and 2 indicate that the aerial parts of Acanthospermum hispidum should be used with caution for malaria treatments.     

In vitro cytotoxic activity of nine plants used in Mayan traditional medicine

Ethnopharmacological relevance

Plants have been used in folk medicine by Mayan ancient people from the Yucatan Peninsula, Mexico, to treat some diseases considered as cancer diseases such as chronic wounds or tumors.

Aim of the study

We collected a selection of nine plants in order to investigate their cytotoxic activity against cancer cell lines.

Materials and methods

Methanolic extracts were tested for their cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on four cancer cell lines; nasopharynx carcinoma (KB), laryngeal carcinoma (Hep-2), cervix adenocarcinoma (HeLa), and cervix squamous carcinoma cells (SiHa) and one normal cell line; canine kidney (MDCK).

Results

All species exhibited some degree of cytotoxic activity. The root bark extract of Hamelia patens exhibited the highest cytotoxic activity on HeLa cells with a CC₅₀ of 13 μg/mL and selectivity index of 13.3, higher than docetaxel. Gossypium schottii and Dioon spinulosum showed similar good cytotoxic activity and selectivity index on HeLa and Hep-2 cells, respectively.

Conclusions

Hamelia patens, Dioon spinulosum and Gossypium schottii demonstrated promising cytotoxic activity and have been selected for future bio-guided fractionation and isolation of active cytotoxic compounds.     

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.     

In vitro antiplasmodial activity and cytotoxicity of nine plants traditionally used in Gabon

Aim of the study

As part of a project to identify new compounds active on malarial parasites, we tested the in vitro antiplasmodial activity of nine plants traditionally used to treat malaria symptoms in Haut-Ogooué Province, South-East Gabon.

Materials and methods

Dichloromethane and methanolic extracts of each plant were tested for their antiplasmodial activity on two chloroquine-resistant strains of Plasmodium falciparum (FCB and W2), based on lactate dehydrogenase activity. Cytotoxicity was assessed with the MTT test on MRC-5 human diploid embryonic lung cells.

Results

The methanolic extract of Staudtia gabonensis and the dichloromethane extract of Adhatoda latibracteata showed high antiplasmodial activity (IC₅₀ < 1 μg/ml) and low cytotoxicity, with selectivity indexes of about 58.25 and 16.43, respectively. The methanolic extract of Monodora myristica and the dichloromethane extract of Afromomum giganteum also showed promising activity (1 < IC₅₀ < 10 μg/ml) and low cytotoxicity, with selectivity indexes about 15.70 and 12.48, respectively. Dichloromethane extracts of Monodora myristica and Leonotis Africana showed moderate activity (10 < IC₅₀ < 40 μg/ml), with selectivity indexes about 6.07 and 28.89, respectively. Both extracts of Culcasia lancifolia had IC₅₀ values of 10-40 μg/ml but high cytotoxicity (selectivity indexes <2.77). The methanolic extract of Dorstenia klaineana had moderate antiplasmodial activity (IC₅₀ around 17 μg/ml) but strong cytotoxicity (0.43 μg/ml), giving a selectivity index of about 0.03.

Conclusions

Most extracts of nine selected plants traditionally used to treat malaria in Gabon had interesting antiplasmodial activity in vitro. This supports continued investigations of traditional medicines in the search for new antimalarial agents. The compounds responsible for the observed antiplasmodial effects are under investigation.     

In vivo antimalarial activity of Keetia leucantha twigs extracts and in vitro antiplasmodial effect of their constituents

Ethnopharmacological relevance

The West African tree Keetia leucantha (Rubiaceae) is used in traditional medicine in Benin to treat malaria. The twigs dichloromethane extract was previously shown to inhibit in vitro Plasmodium falciparum growth with no cytotoxicity (>100 µg/ml on human normal fibroblasts).

Materials and methods

The dichloromethane and aqueous extracts of twigs of K. leucantha were evaluated in vivo against Plasmodium berghei NK 173 by the 4-day suppressive test and in vitro against a chloroquine-sensitive strain of Plasmodium falciparum (3D7) using the measurement of the plasmodial lactate dehydrogenase activity. Bioguided fractionations were realized and compounds were structurally elucidated using extensive spectroscopic analysis.

Results

The in vivo antimalarial activity of K. leucantha dichloromethane and aqueous twigs extracts were assessed in mice at the dose of 200 mg/kg/day. Both extracts exhibited significant effect in inhibiting parasite growth by 56.8% and 53.0% (p<0.0001) on day 7-postinfection. An LC–MS analysis and bioguided fractionations on the twigs dichloromethane extract led to the isolation and structural determination of scopoletin (1), stigmasterol (2), three phenolic compounds: vanillin (3), hydroxybenzaldehyde (4) and ferulaldehyde (5), eight triterpenic esters (6–13), oleanolic acid and ursolic acid. The antiplasmodial activity of the mixture of the eight triterpenic esters showed an antiplasmodial activity of 1.66±0.54 µg/ml on the 3D7 strain, and the same range of activity was observed for isolated isomers mixtures.

Conclusions

This is the first report on the in vivo activity of K. leucantha extracts, the isolation of thirteen compounds and analysis of their antiplasmodial activity. The results obtained may partially justify the traditional use of K. leucantha to treat malaria in Benin.     

In vitro and in vivo trypanocidal effect of lipophilic extracts of medicinal plants from Mali and Burkina Faso

AIM OF THE STUDY: To determine the in vitro and in vivo antitrypanosomal activity of extracts of traditionally used plants. MATERIALS AND METHODS: 47 dichloromethane extracts were tested in vitro in the Long-term Viability Assay (LtVA) on Trypanosoma brucei brucei. The most active ones were also tested in vivo using a standardised mouse test. RESULTS: 13 extracts (28%) were active in vitro with MIC-values相似文献   

Hepatoprotective and in vivo antioxidant effects of Byrsocarpus coccineus Schum. and Thonn. (Connaraceae)

Ethnopharmacological relevance

The leaf decoction of Byrsocarpus coccineus (Connaraceae) is drunk for the treatment of jaundice in West African traditional medicine.

Aim of the study

To investigate the hepatoprotective and in vivo antioxidant effects of Byrsocarpus coccineus in carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats.

Materials and methods

Group allotment in this study included vehicle, CCl₄, Byrsocarpus coccineus 1000 mg/kg alone, Byrsocarpus coccineus 200, 400, and 1000 mg/kg + CCl₄ and Livolin^® 20 mg/kg + CCl₄, and treatment was carried out accordingly. On the 7th day, rats were sacrificed and blood was withdrawn by cardiac puncture. The levels and activities of serum biochemical parameters and antioxidant enzymes were then assayed using standard procedures.

Results

CCl₄ significantly (P < 0.05) increased the levels of ALT and AST and reduced total protein. In CCl₄ treated animals, Byrsocarpus coccineus (200, 400, and 1000 mg/kg) dose-dependently and significantly decreased ALT, AST and ALP levels with peak effect produced at the highest dose. Conversely, Byrsocarpus coccineus produced significant increases in albumin and total protein levels. The standard drug produced significant effects in respect of ALT (↓), albumin (↑), and total protein (↑). CCl₄ also produced significant (P < 0.05) reductions in the activity of catalase, SOD, peroxidase and GSH, and conversely increased MDA level. Byrsocarpus coccineus produced significant and dose-dependent reversal of CCl₄-diminished activity of the antioxidant enzymes and reduced CCl₄-elevated level of MDA. The standard drug also significantly increased CCl₄-diminished antioxidant enzymes activity and reduced CCl₄-elevated MDA level. In general, the effects of the standard drug were comparable and not significantly different from those of Byrsocarpus coccineus.

Conclusion

The results obtained in this study suggest that the aqueous leaf extract of Byrsocarpus coccineus possesses hepatoprotective and in vivo antioxidant effects. This finding justifies the use of this preparation in West African traditional medicine for the treatment of liver disease.     

In vitro and in vivo antioxidant activity of the ethanolic extract from Meconopsis quintuplinervia

Aims of the study

Meconopsis quintuplinervia, a medicinal herb endemic to the Tibetan region, is used to treat hepatitis. The aim of this study is to evaluate the antioxidant potential of the ethanolic extract of this herb using different assays.

Materials and methods

The antioxidant capacity of Meconopsis quintuplinervia was investigated using various established in vitro systems. An in vivo study of carbon tetrachloride (CCl₄)-induced antioxidant activity in mice was also conducted by examining the levels of malondialdehyde (MDA) and the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH).

Results

The extract showed strong in vitro antioxidant ability. In the in vivo study, CCl₄-induced oxidative stress caused significant decreases in the SOD, CAT, and GSH levels and a significant increase in the MDA level, most of which were significantly reversed (except for SOD in the liver.) by treatment with the extract and standard Vitamin E.

Conclusion

This study clearly indicates that the ethanolic extract of Meconopsis quintuplinervia is a valuable source of natural antioxidants. These findings provide scientific support for the traditional use of this herb as a Tibetan medicine for liver diseases.     

Chemical composition,cytotoxicity and in vitro antitrypanosomal and antiplasmodial activity of the essential oils of four Cymbopogon species from Benin

Ethnopharmacological relevance

Cymbopogon species are largely used in folk medicine for the treatment of many diseases some of which related to parasitical diseases as fevers and headaches. As part of our research on antiparasitic essential oils from Beninese plants, we decided to evaluate the in vitro antiplasmodial and antitrypanosomal activities of essential oils of four Cymbopogon species used in traditional medicine as well as their cytotoxicity.

Materials and methods

The essential oils of four Cymbopogon species Cymbopogon citratus (I), Cymbopogon giganteus (II), Cymbopogon nardus (III) and Cymbopogon schoenantus (IV) from Benin obtained by hydrodistillation were analysed by GC/MS and GC/FID and were tested in vitro against Trypanosoma brucei brucei and Plasmodium falciparum respectively for antitrypanosomal and antiplasmodial activities. Cytotoxicity was evaluated in vitro against Chinese Hamster Ovary (CHO) cells and the human non cancer fibroblast cell line (WI38) through MTT assay to evaluate the selectivity.

Results

All tested oils showed a strong antitrypanosomal activity with a good selectivity. Sample II was the most active against Trypanosoma brucei brucei and could be considered as a good candidate. It was less active against Plasmodium falciparum. Samples II, III and IV had low or no cytotoxicity, but the essential oil of Cymbopogon citratus (I), was toxic against CHO cells and moderately toxic against WI38 cells and needs further toxicological studies. Sample I (29 compounds) was characterised by the presence as main constituents of geranial, neral, β-pinene and cis-geraniol; sample II (53 compounds) by trans-p-mentha-1(7),8-dien-2-ol, trans-carveol, trans-p-mentha-2,8-dienol, cis-p-mentha-2,8-dienol, cis-p-mentha-1(7),8-dien-2-ol, limonene, cis-carveol and cis-carvone; sample III (28 compounds) by β-citronellal, nerol, β-citronellol, elemol and limonene and sample IV (41 compounds) by piperitone, (+)-2-carene, limonene, elemol and β-eudesmol.

Conclusions

Our study shows that essential oils of Cymbopogon genus can be a good source of antitrypanosomal agents. This is the first report on the activity of these essential oils against Trypanosoma brucei brucei, Plasmodium falciparum and analysis of their cytotoxicity.     

Anti-Helicobacter pylori activity of plants used in Mexican traditional medicine for gastrointestinal disorders

Aim of the study

Helicobacter pylori is the major etiological agent of chronic active gastritis and peptic ulcer disease and is linked to gastric carcinoma. Treatment to eradicate the bacteria failed in many cases, mainly due to antibiotic resistance, hence the necessity of developing better therapeutic regimens. Mexico has an enormous unexplored potential of medicinal plants. This work evaluates the in vitro anti-H. pylori activity of 53 plants used in Mexican traditional medicine for gastrointestinal disorders.

Materials and methods

To test the in vitro antibacterial activity, agar dilution and broth dilution methods were used for aqueous and methanolic extracts, respectively.

Results

Aqueous extracts of Artemisia ludoviciana subsp. mexicana, Cuphea aequipetala, Ludwigia repens,and Mentha × piperita (MIC 125 to <250 μg/ml) as well as methanolic extracts of Persea americana, Annona cherimola, Guaiacum coulteri, and Moussonia deppeana (MIC <7.5 to 15.6 μg/ml) showed the highest inhibitory effect.

Conclusions

The results contribute to understanding the mode of action of the studied medicinal plants and for detecting plants with high anti-Helicobacter pylori activity.     

In vitro antitrypanosomal and antiplasmodial activities of crude extracts and essential oils of Ocimum gratissimum Linn from Benin and influence of vegetative stage

Ethnopharmacological relevance

Different parts of Ocimum gratissimum Linn are largely used in folk medicine for the treatment of many diseases, some of which related to parasitical infections as fevers and headaches. In order to validate their use and to clarify the plant part which possesses the best antiparasitic properties, we decided to evaluate the in vitro antiplasmodial and antitrypanosomal activities of essential oils and crude extracts from leaves, stems and seeds of Ocimum gratissimum as well as their cytotoxicity.

Materials and methods

The essential oils and ethanol crude extracts of leaves and stems of Ocimum gratissimum from Benin, were obtained in pre and full flowering stages. Seeds obtained only in full flowering stage, were also extracted. The oils were isolated by hydrodistillation and analyzed by GC/MS and GC/FID. Extracts and essential oils were tested in vitro against Trypanosoma brucei brucei and Plasmodium falciparum. Cytotoxicity was evaluated in vitro against Chinese Hamster Ovary (CHO) cells and the human non cancer fibroblast cell line (WI38) through MTT assay to evaluate the selectivity and toxicity was assessed against Artemia salina Leach.

Results

The essential oils and non-volatile crude extracts of Ocimum gratissimum were more active on Trypanosoma brucei brucei than on Plasmodium falciparum (3D7). This activity varies according to the vegetative stage (pre and full flowering) and the plant part (seeds, stems and leaves) extracted. The best growth inhibition of Trypanosoma brucei brucei was observed with ethanol crude extracts of leaves (IC₅₀=1.66±0.48 μg/mL) and seeds (IC₅₀=1.29±0.42 μg/mL) in full flowering stage with good selectivity (SI>10). The chemical composition of the essential oil from aerial parts (47 compounds), characterized by the presence as main constituents of p-cymene, thymol, γ-terpinene, β-myrcene and α-thujene, depends on the vegetative stage. The oil contained some minor compounds such as myrcene (IC₅₀=2.24±0.27 μg/mL), citronellal (IC₅₀=2.76±1.55 μg/mL), limonene (IC₅₀=4.24±2.27 μg/mL), with good antitrypanosomal activities. These oils and crude extracts were not toxic against Artemia salina Leach and had a low cytotoxicity except leaves and seeds ethanol extracts obtained in full flowering which showed toxicity against CHO and WI38 cells.

Conclusions

Our study shows that ethanol crude extracts of leaves and seeds of Ocimum gratissimum in full flowering stage can be a good source of antitrypanosomal agents. This is the first report about the relation between the plant part extracted, the vegetative stage of the plant, the antitrypanosomal and antiplasmodial activities and the cytotoxicity of essential oils and non-volatile extracts of Ocimum gratissimum from Benin.     

In vivo antigiardial activity of three flavonoids isolated of some medicinal plants used in Mexican traditional medicine for the treatment of diarrhea

Mexican traditional medicine uses a great variety of plants in the treatment of gastrointestinal disorders such as diarrhea. In order to understand the properties of some of their chemical constituents, three flavonoids (kaempferol, tiliroside and (-)-epicatechin) isolated from Geranium mexicanum, Cuphea pinetorum, Helianthemum glomeratum, and Rubus coriifolius, were assayed to demonstrate their in vivo antiprotozoal activity; using an experimental infection of Giardia lamblia in suckling female CD-1 mice. Compounds tested showed antigiardial activity with values of ED(50) (micromol/kg) 0.072 for (-)-epicatechin, 2.057 for kaempferol and 1.429 for tiliroside. The most active flavonoid was the (-)-epicatechin, its activity was higher than metronidazole and emetine, drugs used as positive controls. In the case of kaempferol and tiliroside their potency was close to that of the metronidazole, but far less than emetine.     

Antileishmanial and antifungal activity of plants used in traditional medicine in Brazil

The antileishmanial and antifungal activity of 24 methanol extracts from 20 plants, all of them used in the Brazilian traditional medicine for the treatment of several infectious and inflammatory disorders, were evaluated against promastigotes forms of two species of Leishmania (L. amazonensis and L. chagasi) and two yeasts (Candida albicans and Cryptococcus neoformans). Among the 20 tested methanolic extracts, those of Vernonia polyanthes was the most active against L. amazonensis (IC(50) of 4 microg/ml), those of Ocimum gratissimum exhibited the best activity against L. chagasi (IC(50) of 71 microg/ml). Concerning antifungical activity, Schinus terebintifolius, O. gratissimum, Cajanus cajan, and Piper aduncum extracts were the most active against C. albicans (MIC of 1.25 mg/ml) whereas Bixa orellana, O. gratissimum and Syzygium cumini exhibited the best activity against C. neoformans (MIC of 0.078 mg/ml).     

Vasoactive effects of different fractions from two Panamanians plants used in Amerindian traditional medicine

Ethnopharmacological relevance

Cecropia obtusifolia (Cecropiaceae) and Psychotria poeppigiana (Synonym: Cephaelis elata, Rubiaceae) are two Latin American plants broadly used in traditional Amerindian medicine. The former, together with many other species of the genus Cecropia, share the folk reputation of curing heart failure, cough, asthma and bronchitis. The latter is used in Panama by Kuna and Ngäbe Buglé (Guaymies) native Indians for the treatment of dyspnea.

Aim of the study

Based on screening of selected medicinal Panamanian plants by radioligand-binding techniques by Caballero-George et al. (2001), the present study was carried out in order to investigate the vasoactive effects of different fractions from both P. poeppigiana and C. obtusifolia on rat thoracic aorta and identify active fractions and their chemical constituents.

Materials and methods

Both acid and neutral methanol fractions (P-AMeOH and P-NMeOH) and acid and neutral dichlorometane fractions (P-ADCM and P-NDCM) were obtained from P. poeppigiana crude methanolic and dichlorometane extracts, respectively. Identical fractionation was carried out for C. obtusifolia (C-AMeOH, C-NMeOH, C-ADCM and C-NDCM. Vasorelaxant effect of all fractions, and their inhibition of contractile responses to angiotensin II were evaluated in isolated aortic rings.

Results

P-AMeOH, P-NMeOH and P-ADCM fractions induced a concentration-dependent relaxation (43.9 ± 1.8%, 35.3 ± 4.7% and 52.9 ± 3.5%, respectively) in the endothelium-intact aorta precontracted by phenylephrine (PE, 10⁻⁶ M). The relaxation produced by C-AMeOH and C-NMeOH (57.3 ± 2.5% and 53.3 ± 3.3%, respectively) was greater than the effect produced by C-ADCM and C-NDCM (42.2 ± 3.4% and 21.8 ± 0.8%, respectively). Only the incubation of the aortic rings with P-AMeOH reduced the maximum contraction induced by angiotensin II at 20.08 ± 0.55%.

Conclusions

The direct vasorelaxation effect observed could explain in part the ethnomedical use of these plants in Amerindian traditional medicine. The most active fractions contain phenolic and aromatic acid compounds. Furthermore, P-AMeOH, the only fraction that showed both vasorelaxant effect and inhibition of contractile responses to angiotensin II, is the most rich in aromatic acids compounds and the only one that contains scopoletin.     

In vitro and in vivo antioxidant effects of the ethanolic extract of Swertia chirayita

Ethnopharmacological relevance

Swertia chirayita, a medicinal herb endemic to the Tibetan region, is used as a special remedy for liver disorders. The hepatoprotective activity of its plant extracts has been associated with its antioxidant activity. This paper aims to investigate the in vitro and in vivo antioxidant effects of Swertia chirayita extracts (SCE).

Materials and methods

Antioxidant ability of Swertia chirayita was investigated by employing several established in vitro methods. In vivo antioxidant activity was tested against CCl₄-induced toxicity in mice. The levels and activities of malondialdehyde (MDA) and antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), were then assayed using standard procedures.

Results

SCE exhibited strong antioxidant ability in vitro. The liver and kidney of CCl₄-intoxicated animals exhibited a significant (p < 0.001) decrease in SOD, CAT, and GSH levels. Additionally, these organs exhibited a significant (p < 0.001) increase in MDA level. CCl₄ did not exhibit toxicity on mice treated with SCE and Vitamin E. The effects of Swertia chirayita (three dosages) were comparable to those of Vitamin E, except in MDA level in the liver and GSH level in the kidney (p < 0.05).

Conclusion

This study suggests that the ethanolic extract of Swertia chirayita possesses in vitro and in vivo antioxidant effects. This supports the traditional use of Swertia chirayita in Tibetan medicine to cure liver diseases.     

Toxicity of medicinal plants used in traditional medicine in Northern Peru

Ethnopharmacological relevance

The plant species reported here are traditionally used in Northern Peru for a wide range of illnesses. Most remedies are prepared as ethanol or aqueous extracts and then ingested. The aim of this study was to evaluate the potential toxicity of these extracts.

Materials and methods

The toxicity of ethanolic and water extracts of 341 plant species was determined using a brine-shrimp assay.

Results

Overall 24% of the species in water extract and 76% of the species in alcoholic extract showed elevated toxicity levels to brine-shrimp. Although in most cases multiple extracts of the same species showed very similar toxicity values, in some cases the toxicity of different extracts of the same species varied from non-toxic to highly toxic.

Conclusions

Traditional preparation methods take different toxicity levels in aqueous and ethanol extracts into account when choosing the appropriate solvent for the preparation of a remedy.     

In vitro antimicrobial activity of plants used in Cambodian traditional medicine

The purpose of the present study was to screen 27 plant species used in the traditional medicine of Cambodia for in vitro antibacterial and antifungal activities. Thirty-three methanolic extracts were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium smegmatis and Candida albicans. Screened by disk diffusion assay, the extracts showed antimicrobial activity especially on Gram-positive bacteria. None of the crude methanolic extracts showed activity against P. aeruginosa. Twenty-five selected extracts were evaluated using a micro-dilution test. Harrisonia perforata (roots) and Hymenodictyon excelsum (bark) exhibited a bactericidal effect against S. aureus at a concentration of 500 microg/ml. Azadirachta indica (bark), Harrisonia perforata (roots and stem) and Shorea obtusa (roots) exhibited a bactericidal effect against M. smegmatis at 250 microg/ml.     

Potential genotoxicity of plant extracts used in Ethiopian traditional medicine

Aim of the study

Although traditional herbal medicines are widely used in Ethiopia, no information is available on their potential genotoxicity. In the present study, hydroalcoholic extracts of Glinus lotoides, Plumbago zeylanica, Rumex steudelii and Thymus schimperi were evaluated for their DNA damaging effects using the comet assay.

Material and methods

Mouse lymphoma L5178Y cells were exposed to different concentrations of the extracts for 3 h with and without metabolic activation (S9-mix) using 4-nitroquinoline-N-oxide and benzo(a)pyrene as positive controls, and vehicles as negative controls.

Results

In the absence of S9, all extracts were found to induce significant DNA damage without affecting the cell viability. T. schimperi and R. steudelii were the most potent DNA-damaging extracts, and G. lotoides and P. zeylanica the least potent. The addition of S9 had different effects on the DNA damage induced by the extracts: it lowered the DNA damaging effect of P. zeylanica, did not affect the DNA damaging effect of T. schimperi, and increased the DNA damaging effects of R. steudelii and G. lotoides.

Conclusion

The findings of the present study suggest that all extracts evaluated have a genotoxic potential in vitro which needs to be substantiated by further studies.