In vitro antiplasmodial activity of stem and root extracts of Nauclea latifolia S.M. (Rubiaceae)

Bioguided Fractionation and Isolation of an Antiplasmodial Saponin from the Roots of Nauclea xanthoxylon (A.Chev.) Aubrév. (Rubiaceae)

The root extract of Nauclea xanthoxylon (A.Chev.) Aubrév. displayed significant 50 % inhibition concentration (IC50 s) of 0.57 and 1.26 μg/mL against chloroquine resistant and sensitive Plasmodium falciparum (Pf) Dd2 and 3D7 strains, respectively. Bio-guided fractionation led to an ethyl acetate fraction with IC50 s of 2.68 and 1.85 μg/mL and subsequently, to the new quinovic acid saponin named xanthoxyloside (1) with IC50 s of 0.33 and 1.30 μM, respectively against the tested strains. Further compounds obtained from ethyl acetate and hexane fractions were the known clethric acid (2), ursolic acid (3), quafrinoic acid (4), quinovic acid (5), quinovic acid 3-O-β-D-fucopyranoside (6), oleanolic acid (7), oleanolic acid 3-acetate (8), friedelin (9), β-sitosterol (10a), stigmasterol (10b) and stigmasterol 3-O-β-D-glucopyranoside (11). Their structures were characterised with the aid of comprehensive spectroscopic methods (1 and 2D NMR, Mass). Bio-assays were performed using nucleic acid gel stain (SYBR green I)-based fluorescence assay with chloroquine as reference. Extracts and compounds exhibited good selectivity indices (SIs) of >10. Significant antiplasmodial activities measured for the crude extract, the ethyl acetate fraction and xanthoxyloside (1) from that fraction can justify the use of the root of N. xanthoxylon in ethnomedicine to treat malaria.

Antiplasmodial, antimalarial activities and toxicity of African medicinal plants: a systematic review of literature

BACKGROUND

Malaria still constitutes a major public health menace, especially in tropical and subtropical countries. Close to half a million people mainly children in Africa, die every year from the disease. With the rising resistance to frontline drugs (artemisinin-based combinations), there is a need to accelerate the discovery and development of newer anti-malarial drugs. A systematic review was conducted to identify the African medicinal plants with significant antiplasmodial and/or anti-malarial activity, toxicity, as wells as assessing the variation in their activity between study designs (in vitro and in vivo).

METHODS

Key health-related databases including Google Scholar, PubMed, PubMed Central, and Science Direct were searched for relevant literature on the antiplasmodial and anti-malarial activities of African medicinal plants.

RESULTS

In total, 200 research articles were identified, a majority of which were studies conducted in Nigeria. The selected research articles constituted 722 independent experiments evaluating 502 plant species. Of the 722 studies, 81.9%, 12.4%, and 5.5% were in vitro, in vivo, and combined in vitro and in vivo, respectively. The most frequently investigated plant species were Azadirachta indica, Zanthoxylum chalybeum, Picrilima nitida, and Nauclea latifolia meanwhile Fabaceae, Euphorbiaceae, Annonaceae, Rubiaceae, Rutaceae, Meliaceae, and Lamiaceae were the most frequently investigated plant families. Overall, 248 (34.3%), 241 (33.4%), and 233 (32.3%) of the studies reported very good, good, and moderate activity, respectively. Alchornea cordifolia, Flueggea virosa, Cryptolepis sanguinolenta, Zanthoxylum chalybeum, and Maytenus senegalensis gave consistently very good activity across the different studies. In all, only 31 (4.3%) of studies involved pure compounds and these had significantly (p = 0.044) higher antiplasmodial activity relative to crude extracts. Out of the 198 plant species tested for toxicity, 52 (26.3%) demonstrated some degree of toxicity, with toxicity most frequently reported with Azadirachta indica and Vernonia amygdalina. These species were equally the most frequently inactive plants reported. The leaves were the most frequently reported toxic part of plants used. Furthermore, toxicity was observed to decrease with increasing antiplasmodial activity.

CONCLUSIONS

Although there are many indigenous plants with considerable antiplasmodial and anti-malarial activity, the progress in the development of new anti-malarial drugs from African medicinal plants is still slothful, with only one clinical trial with Cochlospermum planchonii (Bixaceae) conducted to date. There is, therefore, the need to scale up anti-malarial drug discovery in the African region.

Mining Sudanese Medicinal Plants for Antiprotozoal Agents

Neglected tropical diseases are major health hazards in developing countries. Annually, up to 30 million people are affected by either Chagas disease, African trypansomiasis or leishmaniasis, and more than 200 million by malaria. Most of the currently available drugs have drawbacks in terms of toxicity, limited oral availability, development of resistance, or non-affordability. Tropical plants of the arid zones are a treasure chest for the discovery of bioactive secondary metabolites. This study aims to compile Sudanese medicinal plants, validate their antiprotozoal activities, and identify active molecules. We have performed a survey of medicinal plants of Sudan and selected 62 that are being used in Sudanese traditional medicine. From these, we collected materials such as leaves, stem, bark, or fruit. The plant materials were extracted in 70% ethanol and further fractionated by liquid-liquid partitioning using solvents of increasing polarity. This resulted in a library of 235 fractions. The library was tested in vitro against Plasmodium falciparum (erythrocytic stages), Trypanosoma brucei rhodesiense (bloodstream forms), Trypanosoma cruzi (intracellular amastigotes), and Leishmania donovani (axenic amastigotes). Active fractions were also tested for cytotoxicity. Of the 235 fractions, 125 showed growth inhibitory activity >80% at 10 μg/ml, and >50% at 2 μg/ml against at least one of the protozoan parasites. Plasmodium falciparum was the most sensitive of the parasites, followed by T. b. rhodesiense and L. donovani. Only few hits were identified for T. cruzi, and these were not selective. Contrary to expectation based on phylogeny, but in agreement with previous results, a large number of extracts displayed mutual activity against T. brucei and P. falciparum. HPLC-based activity profiling for selected active extracts was performed to identify the bioactive principles. Active compounds identified by dereplication were guieranone A from Guiera senegalensis J.F.Gmel.; pseudosemiglabrin from Tephrosia apollinea (Delile) DC; ellagic acid and quercetin from Terminalia leiocarpa (DC.) Baill.; and catechin, ethyl gallate, and epicatechin gallate from Vachellia nilotica (L.) P.J.H.Hurter & Mabb. Also the extracts of Croton gratissimus var. gratissimus and Cuscuta hyalina Roth ex Schult. exhibited promising antitrypanosomatid activity. This assessment provides a comprehensive overview of Sudanese medicinal plants and supports the notion that they are a potential source of bioactive molecules against protozoan parasites.

Natural Products as Sources of Antimalarial Drugs: Ethnobotanical and Ethnopharmacological Studies

MATERIALS AND METHODS

For this study, relevant information was procured from the inhabitants via a structured questionnaire to procure the general knowledge of antimalarial medicinal plants. Results and Discussion. A total of 90 interviewees (44 men and 46 women) were involved in this survey. A total of 59 medicinal species were identified, which were dispersed in 33 families (Asteraceae (6), Apocynaceae (5), Anacardiaceae, Annonaceae, Fabaceae, Malvaceae, Meliaceae, Poaceae, and Rubiaceae (3 each), Phyllanthaceae (2)) totaling 49% of the cited species. The most cited plants are Azadirachta indica (42), Mangifera indica (38), Carica papaya (28), Cymbopogon citratus (27), Cassia fistula (15), Morinda lucida (14), Anacardium occidentale and Vernonia amygdalina (13 each), Helianthus annuus (11), Enantia chlorantha (10), and Moringa oleifera (9) A total of 105 citations were recorded for the plant parts used (leaf (46), bark (17), fruits (9), root (9), latex (11), stem (11), and inflorescence (2)) while decoction (59%), maceration (25%), infusion (9%), and exudation (7%) were the methods of preparation. Use Values (UVs) of 0.47 to 0.11 were recorded for the frequently used antimalarial plants. The Efficiency Levels (ELs) of 11 different medicinal plants stated by the respondents were Azadirachta indica, Cassia fistula and Morinda lucida (12), Chromolaena odorata (10), Mangifera indica, Enantia chlorantha and Helianthus annuus (8), Cymbopogon citratus (7), Gossypium arboretum (4), Landolphia dulcis (3), and Aloe vera (2) Cocos nucifera, Curcuma longa, Forkia biglobosa, and Musa acuminate are mentioned for the first time in the study area with little or no reported antiplasmodial activities.

CONCLUSION

The study appraised the commonly used antimalarial plants in the study areas. Therefore, commitment to scientifically explore the bioactive compounds, antimalarial potential and toxicological profile of these plants is inevitable as they could lead to novel natural products for effective malaria therapy.

Medicinal plants used by the people of Nsukka Local Government Area, south-eastern Nigeria for the treatment of malaria: An ethnobotanical survey

ETHNOBOTANICAL RELEVANCE

Malaria is a serious public health problem especially in sub-Saharan African countries such as Nigeria. The causative parasite is increasingly developing resistance to the existing drugs. There is urgent need for alternative and affordable therapy from medicinal plants which have been used by the indigenous people for many years.

AIM OF STUDY

This study was conducted to document the medicinal plant species traditionally used by the people of Nsukka Local Government Area in south-eastern Nigeria for the treatment of malaria.

METHODS

A total of 213 respondents, represented by women (59.2%) and men (40.8%), were interviewed using a semi-structured questionnaire. The results were analysed and discussed in the context of previously published information on anti-malarial and phytochemical studies of the identified plants.

RESULTS

The survey revealed that 50 plant species belonging to 30 botanical families were used in this region for the treatment of malaria. The most cited families were Apocynaceae (13.3%), Annonaceae (10.0%), Asteraceae (10.0%), Lamiaceae (10.0%), Poaceae (10.0%), Rubiaceae (10.0%) and Rutaceae (10.0%). The most cited plant species were Azadirachta indica (11.3%), Mangifera indica (9.1%), Carica papaya (8.5%), Cymbopogon citratus (8.5%) and Psidium guajava (8.5%).

CONCLUSION

The present findings showed that the people of Nsukka use a large variety of plants for the treatment of malaria. The identified plants are currently undergoing screening for anti-malarial, toxicity and chemical studies in our laboratory.

Traditional uses, phytochemistry and pharmacological properties of African Nauclea species: A review

ETHNOPHARMACOALOGICAL RELEVANCE

The genus Nauclea in Africa comprises seven species. Among them, N. latifolia, N. diderrichii and N. pobeguinii are widely used by the local population in traditional remedies. Preparation from various parts of plants (e.g. roots, bark, leaves) are indicated by traditional healers for a wide range of diseases including malaria, pain, digestive ailments or metabolic diseases.

MATERIALS AND METHODS

A literature search was conducted on African species of the genus Nauclea using scientific databases such as Google Scholar, Pubmed or SciFinder. Every document of ethnopharmacological, phytochemical or pharmacological relevance and written in English or French were analyzed.

RESULTS AND DISCUSSION

The Nauclea genus is used as ethnomedicine all along sub-Saharan Africa. Several local populations consider Nauclea species as a major source of remedies for malaria. In this regard, two improved traditional medicines are currently under development using extracts from N. latifolia and N. pobeguinii. Concerning the chemical composition of the Nauclea genus, indoloquinolizidines alkaloids could be considered as the major class of compounds as they are reported in every analyzed Nauclea species, with numerous structures identified. Based on traditional indications a considerable amount of pharmacological studies were conducted to ensure activity and attempt to link them to the presence of particular compounds in plant extracts.

CONCLUSION

Many experimental studies using plant extracts of the African species of the genus Nauclea validate traditional indications (e.g. malaria and pain). However, bioactive compounds are rarely identified and therefore, there is a clear need for further evaluations as well as for toxicity experiments. The sustainability of these plants, especially of N. diderrichii, a threatened species, should be kept in mind to adapt local uses and preparation modes of traditional remedies.

Medicinal plants for in vitro antiplasmodial activities: A systematic review of literature

The increasing resistance of malaria to drugs raise the need to new antimalarial agents. Antiplasmodial herbs and their active compounds are the most promising source the new antimalarial agents. This study aimed to identify the medicinal plants with very good in vitro antiplasmodial activities, with half-maximal inhibitory concentration (IC₅₀)≤1μg/ml, and to determine trends in the process of screening their antiplasmodial activities. A total of 58 reports published in the English language were retrieved from the bibliographical databases. Screening and data extraction were performed by two independent reviewers. The herbs were categorized as very good, good, moderate and inactive if the IC₅₀ values were <0.1μg/ml, 0.1-1μg/ml, >1-5μg/ml and >5μg/ml respectively. We documented 752 medicinal plants belonging to 254 genera. The majority of the plants were reported from Africa followed by Asia. The traditional use for malaria treatment was the most common reason for the selection of the plants for investigation. About 80% of the plants experimented were reported to be inactive. Among plants identified as having very good to good antiplasmodial crude extracts are Harungana madagascariensis, Quassia africana, and Brucea javanica, while Picrolemma spruce, Aspidosperma vargasi, Aspidosperma desmanthum, and Artemisia annua were reported to have individual compound isolates with very good antiplasmodial activities. In conclusion, the number of plant species assessed so far is still small compared with the stock in nature's plant library. A mechanism of systematically approaching and exploring the untouched plant genera needs to be designed.

Nauclea latifolia: biological activity and alkaloid phytochemistry of a West African tree

Covering up to 2016Nauclea latifolia (syn. Sarcocephalus latifolius, Rubiaceae), commonly called the African pincushion tree, is a plant widely used in folk medicine in different regions of Africa for treating a variety of illnesses, including malaria, epilepsy and pain. N. latifolia has not only drawn the interest of traditional healers but also of phytochemists, who have identified a range of bioactive indole alkaloids in its tissue. More recently, following up on the traditional use of extracts in pain management, a bio-guided purification from the roots of the tree led to the identification of the active ingredient as tramadol, available as a synthetic analgesic since the 1970s. The discovery of this compound as a natural phytochemical was highlighted worldwide. This review focuses on the correlation between extracted compounds and pharmacological activities, paying special attention to infectious diseases and neurologically-related disorders. A critical analysis of the data reported so far on the natural origin of tramadol and its proposed biosynthesis is also presented.

Ethnobotanical Study of Medicinal Plants Used for the Treatment of Malaria in the Plateau Region, Togo

BACKGROUND

In Togo, malaria constitutes a major public health problem but, until now, the population still mostly relies on herbal medicine for healing. This study aimed to document medicinal plants used for malaria therapy in the Plateau region of the country.

METHODOLOGY

Semi-structured questionnaire interviews were used to gather ethnobotanical and sociodemographic data from traditional healers of the study area.

RESULTS

A total of 61 plants species belonging to 33 families were found to be in use for malaria therapy in the Plateau region. Caesalpiniaceae were the most represented family with 7 species, followed by Euphorbiaceae and Poaceae with 4 species each. According to the relative frequency of citation (RFC), Newbouldia laevis Seem. (RFC =0.52), Sarcocephalus latifolius (Sm.) E.A. Bruce (RFC =0.48), Acanthospermum hispidum DC. (RFC =0.43), and Senna siamea (Lam.) H.S. Irwin and Barneby (RFC =0.40) were the most cited in the treatment of malaria in the traditional medicine in the Plateau region. The parts of plants used could either be the barks, roots, leaves, or whole plants. The recipes also could be a combination of various species of plants or plant parts.

CONCLUSION

This study highlights the potential sources for the development of new antimalarial drugs from indigenous medicinal plants found in the Plateau region of Togo. Such results could be a starting point for in vitro antimalarial screenings.

SUMMARY

61 plants species from 33 families are use for malaria therapy in the Plateau region of TogoThe main families are Caesalpiniaceae Euphorbiaceae and PoaceaeThe most used species are Newbouldia laevis Seem. (RFC = 0.52), Sarcocephalus latifolius (Sm.) E.A. Bruce (RFC = 0.48), Acanthospermum hispidum DC. (RFC = 0.43), and Senna siamea (Lam.) H.S. Irwin and Barneby (RFC = 0.40) Abbreviations Used: RFC: Relative frequency of citation, FC: Frequency of citation, Dec: Decoction, Orl: Oral route, Mac: Maceration, Jui: Juice, Inf: Infusion, Sau: Sauce, Kne: Kneading, Le: Leaves, Rt: Roots, Wp: Whole plant, St: Stem, Stb: Stem bark, Rh: Rhizome, Fr: Fruits, Pf: Plasmodium falciparum, IC50: Concentration of extract killing 50% parasites.

An ethnobotanical survey of medicinal plants used by communities of Northern Kordofan region, Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

The present study provides significant ethnopharmacological information on plant species used in North Kordofan region, western Sudan. The study was undertaken with an aim to document the medicinal uses of the species known to some Northern Kordofan communities.

MATERIAL AND METHODS

The study was conducted between 2012 and 2013. The plants were identified and voucher specimens prepared. Information was collected by means of semi-structured interviews with 258 informants (195 men and 63 women). In addition, the use value (UV) of the species was determined and the informant consensus factor (ICF) was calculated for the medicinal plants researched in the study. Further analysis was carried out to compare results with previous studies from the study area and other regions of Sudan.

RESULTS

A total of 44 plant species representing 24 families were found to be commonly used in the treatment of 73 different human health problems. The families most represented were Leguminosae (18%), Caesalpiniaceae (9%), Malvaceae (9%), Asclepiadaceae (6.8%) and Combretaceae (6.8%). The highest number of plant species are used against digestive system disorders (23 species) followed by microbial infections (21 species) and dermatology (19 species). Among all the plant parts leaves (20%), roots (19%), fruits and bark (14% each) were the most preferred plant parts used by the informants. There was strong agreement among the informants as to the usages of the plants (informant consensus factor 0.63-0.93). The most important plants on the basis of use-value were Acacia nilotica, Acacia seyal, Balanites aegyptiaca, Cassia occidentalis, Cassia senna, Guiera senegalensis and Tamarindus indica.

CONCLUSION

This study has helped to document information that may otherwise be lost to future generations. This is the first ethnobotanical study in which statistical calculations about plants are carried out by means of the ICF and UV methods in the study area. Plants with high ICF and UV values should be subjected for further phytochemical and pharmacological investigation for scientific validation.

Potential antimalarials from African natural products: A reviw

Malaria remains an overwhelming infectious disease with significant health challenges in African and other endemic countries globally. Resistance to antimalarial drugs has become one of the most momentous challenges to human health, and thus has necessitated the hunt for new and effective drugs. Consequently, few decades have witnessed a surfeit of research geared to validate the effectiveness of commonly used traditionally medicines against malaria fever. The present review work focuses on documenting natural products from African whose activity has been reported in vivo or in vitro against malaria parasite. Literature was collected using electronic search of published articles (Google Scholar, PubMed, Medline, Sciencedirect, and Science domain) that report on antiplasmodial activity of natural products from differernts Africa region. A total of 652 plant taxa from 146 families, 134 isolated antimalarial compounds from 39 plants species, 2 herbal formulations and 4 insect/products were found to be reported in literature from 1996 to 2015. Plants species from family Asteraceae (11.04%), Fababceae (8.128%), Euphorbiaceae (5.52%), Rubiaceas (5.52%), and Apocyanaceae (5.214%), have received more scientific validation than others. African natural products possess remarkable healing properties as revealed in the various citations as promising antimalarial agents. Some of these natural products from Africa demonstrate high, promising or low activities against Plasmodium parasite. This study also shows that natural products from Africa have a huge amount of novel antimalarial compounds that could serve as a leads for the development of new and effective antiplasmodial drugs. However, in a view of bridging the gap in knowledge, clinical validation of these natural products are of paramount importance.

Ethnomedicinal survey of plants used in the treatment of malaria in Southern Nigeria

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is one of the most severe public health problems worldwide. It is a leading cause of death and disease in many developing countries, where young children and pregnant women are the groups most affected. Spread of multidrug-resistant strains of Plasmodium and the adverse side effects of the existing anti-malarial drugs have necessitated the search for novel, well tolerated and more efficient antimalarial drugs. This ethnomedicinal study surveyed the different types of medicinal plants used for the treatment of malaria in Southern Nigeria with the intent of identifying plants that are traditionally employed in the treatment of malaria across geopolitical boundaries.

MATERIALS AND METHODS

Data were collected from 79 respondents composed of 50 traditional herbsellers and 29 herbal practitioners using a semi-structured questionnaire. Data was analyzed using frequency and percentages.

RESULTS

Of the 79 respondents interviewed, 24% were males while 76% were females. A total of 156 species belonging to 60 families were reported being used to treat malaria in the study area. Fabaceae was the most represented family having fourteen (14) plant species. Of the plants identified during the survey, Azadirachta indica was the species of highest relative frequency of citation (RFC - 1.0). The dominant plant parts used in the preparation of remedies were leaves (50.50%) and Decoction was the main method of preparation. Analysis of regional plant occurrence revealed that South-Western Nigeria represented the region with the highest plant occurrence (60.7%) followed by South-South (24%) and South-East (15.3%). Regional occurrence of plants used in the treatment of malaria in Southern Nigeria is reported here for the first time.

CONCLUSION

This study has documented a great diversity of plants used in the treatment of malaria in Southern Nigeria. Extracts prepared strictly according to the practitioners' recipes should therefore be screened for antiplasmodial activity and toxicity by in vitro and in vivo standard tests to justify their local usage. These studies might lead to the isolation and possible identification of potentially active compounds, which may be regarded as future promising phytomedicines in the treatment of malaria. Conservation of these plant species is also recommended to ensure their continuous availability for future use.

Antiplasmodial potential of traditional antimalarial phytotherapy remedies used by the Kwale community of the Kenyan Coast

ETHNOPHARMACOLOGICAL RELEVANCE

In Kenya, 22 million people are at risk of malaria, 70% of them are in rural areas and most of these people use traditional plant based medicines to treat malaria. The aim of the study was to escalate documentation, from an earlier study of medicinal plants, traditionally used to treat malaria by the Digo community of Kwale County, taking cognizance of their pharmacological information by evaluating their antiplasmodial efficacies.

MATERIALS AND METHODS

The study was carried out in Kwale County at Shimba Hills Game Reserve and adjoining part of Kinango. Traditional health practitioners (THP) were interviewed with a standard questionnaire to obtain information on medicinal plants traditionally used for management of malaria. Group interviews were also held among THPs and members of the community. The plant samples collected were tested for antiplasmodial activity against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum using the ability of extracts, prepared from the plant species, to inhibit the incorporation of [G-3H] hypoxanthine into the malaria parasites.

RESULTS

Fifty seven (57) species in forty eight (48) genera and thirty (30) families were documented and evaluated for in vitro antiplasmodial activity. Apocynaceae, Euphorbiaceae, and Rubiaceae families had each about 12% of the plant species reported as antimalarial remedy and represented the species that are most commonly used. Twelve species (21.1%) showed antiplasmodial efficacy of IC50<5µg/ml and these were Boscia salicifolia, Cissampelos mucronata, Clerodendrum myricoides, Commiphora schimperi, Flueggea virosa, Maytenus undata, Maytenus senegalensis, Maytenus putterlickioides, Vernonia amygdalina, Warburgia stuhlmannii, Zanthoxylum chalybeum and Tabernaemontana pachysiphon.

CONCLUSIONS

These results seem to indicate that ethnopharmacological inquiry used in search for new herbal remedies as predictive and could form the basis of an ethnopharmacopoeia and search for new active principles. This is the first report on traditional use of T. pachysiphon for malaria and its antiplasmodial activity.

Herbs and herbal combinations used to treat suspected malaria in Bo, Sierra Leone

ETHNOPHARMACOLOGICAL RELEVANCE

Most adults in West Africa treat acute febrile illnesses with local herbs, but the patterns of herbs used for malaria have not been recently described in Sierra Leone.

MATERIALS AND METHODS

We used a population-based cross-sectional approach to interview 810 randomly-sampled rural and urban adult residents of Bo, Sierra Leone, in December 2013 and January 2014 about their use of herbal remedies when they suspect they have malaria.

RESULTS

In total, 55% of the participants reported taking one or more of seven herbs to treat symptoms of malaria. Among herb users, the most commonly used anti-malarial herbs were Moringa oleifera (moringa, 52%) and Sarcocephalus latifolius (yumbuyambay, 50%). The other herbs used included Senna siamea (shekutoure, 18%), Cassia sieberiana (gbangba, 18%), Uvaria afzelii (gone-botai, 14%), Morinda chrysorhiza (njasui, 14%), and Craterispermum laurinum (nyelleh, 7%). Combination herbal therapy was common, with 37% of herb users taking two or more herbs together when ill with suspected malaria.

CONCLUSIONS

Indigenous medical knowledge about herbal remedies and combinations of local herbs remains an integral part of malaria case management in Sierra Leone.

Does the description of a root system matter for sustainable use and conservation? A case study in Burkina Faso

Sarcocephalus latifolius (Sm.) E. A. Bruce is one of the most useful medicinal plants in many African countries. The root being the part generally used for this purpose. In the context of land degradation and overexploitation of biological resources in many parts of Burkina Faso, a good description of the root system is necessary to better plan for sustainable use and conservation. We aim to answer the following: i) What is the root system architecture of S. latifolius in the Sudanian zone of Burkina Faso? ii) What amount of root biomass is produced by the species? iii) Can we use a semi-destructive method to establish a model for root biomass prediction?

Forty plants were randomly selected and their dendrometric parameters were measured. For each sampled tree, the quarter of the roots were harvested and weighed. Results show the species has a superficial lateral root system. The roots grow towards other species, but do not form anatomical links with roots of other species. An allometric equation for root biomass prediction was developed through a multiple linear model. As a practical use of the present study, we propose, that people using this plant to treat illness should search for roots at approximately 10m between the trunk of mature individuals of S. latifolius and another species, instead of using roots near the trunk. Thus, only the ends of roots would be cut. Using this method could limit tree mortalities due to root harvesting and contribute to the preservation of this important species.

In vivo antiplasmodial potentials of the combinations of four nigerian antimalarial plants

Various combinations of Nauclea latifolia root, Artocarpus altilis stem bark, Murraya koenigii leaf and Enantia chlorantha stem bark used in African ethnomedicine as decoctions for malaria and fevers, and combinations with standard drugs, were investigated for antiplasmodial activities using Plasmodium berghei berghei-infected mice. The respective prophylactic and curative ED50 values of 189.4 and 174.5 mg/kg for N. latifolia and chemosuppressive ED50 value of 227.2 mg/kg for A. altilis showed that they were the best antimalarial herbal drugs. A 1.6-fold increase of the survival time given by the negative control was elicited by M. koenigii, thereby confirming its curative activity. Pyrimethamine with an ED50 of 0.5 ± 0.1 mg/kg for the prophylactic, and chloroquine with ED50 = 2.2 ± 0.1 and 2.2 ± 0.0 mg/kg for the chemosuppressive and curative tests, respectively, were significantly (p < 0.05) more active. Co-administrations of N. latifolia with the standard drugs significantly reduced their prophylactic, chemosuppressive and curative actions, possibly increasing the parasites' resistance. Binary combinations of N. latifolia or M. koenigii with any of the other plants significantly increased the prophylactic and suppressive activities of their individual plants, respectively. Also, E. chlorantha with A. altilis or N. latifolia enhanced their respective prophylactic or curative activities, making these combinations most beneficial against malaria infections. Combinations of three and four extracts gave varied activities. Hence, the results justified the combinations of ethnomedicinal plants in antimalarial herbal remedies and showed the importance of the three in vivo models in establishing antimalarial activity.

In vitro study on the antioxidant potentials of the leaves and fruits of Nauclea latifolia

This study was carried out to investigate the in vitro antioxidant potentials of the leaves and fruits of Nauclea latifolia, a straggling shrub or small tree, native to tropical Africa and Asia. Hot water extracts of the leaves and fruits of Nauclea latifolia were assessed for their total polyphenolic, flavanol, and flavonol contents as well as 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, ferric reducing antioxidant power (FRAP), Trolox equivalence antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC) assays. The aqueous extract of the leaves was found to contain higher level of total polyphenols (11.63 ± 0.023 mg GAE/g), flavanol (1.45 ± 0.10 mg CE/g), and flavonol (2.22 ± 0.37 mg QE/g) than the extract of the fruits with values of 1.75 ± 0.02 mg GAE/g (total polyphenol), 0.15 ± 0.01 mg CE/g (flavanol), and 1.00 ± 0.13 mg QE/g (flavonol). Similarly, the aqueous extract of the leaves also exhibited higher DPPH (IC50 20.64 mg/mL), FRAP (86.10 ± 3.46 μmol AAE/g), TEAC (94.83 ± 3.57 μmol TE/g), and ORAC (196.55 ± 0.073 μmol TE/g) than the extract of the fruits with DPPH (IC50 120.33 mg/mL), FRAP (12.23 ± 0.40 μmol AAE/g), TEAC (12.48 ± 0.21 μmol TE/g), and ORAC (58.88 ± 0.073 μmol TE/g). The present study showed that Nauclea latifolia has strong antioxidant potentials with the leaves demonstrating higher in vitro antioxidant activities than the fruits.

In vitro anti-Herpes simplex virus activity of crude extract of the roots of Nauclea latifolia Smith (Rubiaceae)

Background

Nauclea latifolia Smith, a shrub belonging to the family Rubiaceae is a very popular medicinal plant in Cameroon and neighboring countries where it is used to treat jaundice, yellow fever, rheumatism, abdominal pains, hepatitis, diarrhea, dysentery, hypertension, as well as diabetes. The ethno-medicinal use against yellow fever, jaundice and diarrhea prompted us to investigate on the antiviral activity of the root bark of N. latifolia. In this study, HSV-2 was chosen as a viral model because of its strong impact on HIV transmission and acquisition.

Methods

The crude extract under study was prepared by maceration of air-dried and powdered roots barks of N. latifolia in CH₂Cl₂/MeOH (50:50) mixture for 48 hours, then it was subjected to filtration and evaporation under vacuum. A phytochemical analysis of the crude extract was performed by High Performance Liquid Chromatography coupled with a photodiode array and mass spectrometry (HPLC-PDA-ESI-qMS). The anti-HSV-2 activity was assayed in vitro by plaque reduction and virus yield assays and the major mechanism of action was investigated by virucidal and time of addition assays. Data values were compared using the Extra sum of squares F test of program GraphPad PRISM 4.

Results

The main components detected in the extract belong to the class of indole alkaloids characteristic of Nauclea genus. Strictosamide, vincosamide and pumiloside were tentatively identified together with quinovic acid glycoside. N. latifolia crude extract inhibited both acyclovir sensitive and acyclovir resistant HSV-2 strains, with IC₅₀ values of 5.38 μg/ml for the former and 7.17 μg/ml for the latter. The extract was found to be most active when added post-infection, with IC₅₀ of 3.63 μg/ml.

Conclusion

The results of this work partly justify the empirical use of N. latifolia in traditional medicine for the treatment of viral diseases. This extract could be a promising rough material for the development of a new and more effective modern anti-HSV-2 medication also active against acyclovir-resistant HSV-2 strains.

Novel indole alkaloids from Nauclea latifolia and their renin-inhibitory activities

Chemical studies on the crude MeOH extract of stems and barks of Nauclea latifolia resulted in the isolation of five new indole alkaloids, latifoliamides A-E (1-5, resp.), along with one known alkaloid, angustoline (6). The structures of these compounds were elucidated by means of extensive NMR spectral studies. Compound 1 has a 20-ethylidenetetrahydrofuran ring incorporated in its structure and represents the first example of this class of indole alkaloids. All of the isolates exhibited moderate in vitro renin inhibitory activities.

Antimalarial activities and toxicities of three plants used as traditional remedies for malaria in the Democratic Republic of Congo:Croton mubango , Nauclea pobeguiniiandPyrenacantha staudtii

The antimalarial activities of crude extracts and 17 fractions from the partition of 80%-methanolic extracts of three plants (the stem bark of Croton mubango, the stem bark of Nauclea pobeguinii and the leaves of Pyrenacantha staudtii) used as antimalarial remedies in the Democratic Republic of Congo were studied both in vitro (against Plasmodium falciparum) and in mice infected with Pl. berghei berghei. The toxic effects of dried aqueous extracts of the plants were also investigated, in uninfected mice. The most active crude extracts in vitro, with median inhibitory concentrations (IC(50)) of <1 microg/ml, were found to be the methanolic and dichloromethane extracts of C. mubango, and the dichloromethane extracts of N. pobeguinii and Py. staudtii. The aqueous extract with the most antimalarial activity in vitro was that of C. mubango (IC(50) = 3.2 microg/ml), followed by that of N. probeguinii (IC(50) = 5.3 microg/ml) and then that of Py. staudii (IC(50) = 15.2 microg/ml). Results from the in-vivo tests of antimalarial activity showed that, at a daily oral dose of 200 mg/kg, all the dichloromethane extracts, the petroleum-ether, chloroformic, ethyl-acetate and residual water-soluble fractions from C. mubango, and the chloroformic, ethyl-acetate and n-butanolic fractions from Py. staudtii produced >80% chemosuppression of the parasitaemias by day 4. The aqueous extracts of C. mubango and N. probeguinii produced a slightly lower but still significant inhibition of parasitaemia (60%-80%) whereas that of Py. staudtii only suppressed the day-4 parasitaemias by 37%. The dried aqueous extract of the stem bark of C. mubango showed some signs of toxicity in mice, with median lethal doses (LD(50)) of 350 mg/kg in the female mice and 900 mg/kg in the male. The extract significantly increased the serum concentrations of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) in mice of both sexes, but had no effect on the blood levels of creatinine or urea. No significant toxic effect was observed for the dried aqueous extracts of N. pobeguinii and Py. staudtii (LD(50) >5 g/kg). Neither of these extracts affected the serum concentrations of GPT or the blood concentrations of creatinine and urea, although the N. pobeguinii extract did increase the serum concentration of GOT.

Ethnobotanical study of medicinal plants used for the treatment of malaria in plateau of Allada, Benin (West Africa)

BACKGROUND

Malaria remains one of the most important illnesses in sub-Saharan Africa. In Benin, it constitutes a major public health preoccupation particularly for children and pregnant women. Until now, population still mostly relies on herbal medicine for malaria healing. Hence this study was carried out to document the medicinal plants used in the plateau of Allada in Benin and to assess local knowledge on traditional medicine in the management of malaria and related symptoms.

MATERIALS AND METHODS

Data were collected from 53 informants composed of 23 traditional healers and 30 medicinal plants sellers using a structured questionnaire.

RESULTS

A total of 82 plants species belonging to 78 genera in 43 plant families were recorded as antimalarial in the study area. The families of Rubiaceae and Caesalpiniaceae were the most represented with seven species each. High informant consensus factor (ICF) was recorded in the treatment of malaria (ICF=0.90). High fidelity level (FL=100%) was also recorded for 45.67% of the species used as antimalarial. Dichapetalum madagascariense was the species of high relative frequency of citation (RFC=0.81). The dominant plant parts used in the preparation of remedies were leaves (68%). The decoction (79%) was the main mode of preparation, while oral route (92%) was the principal route of remedies administration.

CONCLUSION

This study provides plant species used in the plateau of Allada for malaria and related symptoms treatment. We hope that this study could be important for the conservation of traditional knowledge on the antimalarial plants and the improvement of malaria management. However, several plant species used as antimalarial by the traditional medicine practitioners in the study area need to be screened in order to identify the species having antiplasmodial activity.

Ethnobotanical survey for potential anti-malarial plants in south-western Nigeria

AIM OF STUDY

The ethnobotanical study surveyed the different types of medicinal plants used for the treatment of malaria in the south-western region of Nigeria.

MATERIALS AND METHODS

Information was collected by interviewing indigenous people, using a semi-structured questionnaire. Collected plant samples were identified and authenticated in Forestry Research Institute of Nigeria, Ibadan, Nigeria.

RESULTS

A total of 151 respondents were interviewed of which 64% were females and 36% males. This population comprised of herbal medicine sellers (39%), traditional doctors (15%), housewives (24%) and farmers (22%). Twenty two plants species used in the treatment of malaria belonging to 18 families were identified and compiled detailing information such as common and vernacular names, parts used, methods of preparation and previous scientific reports. Of the plants identified during the survey, Azadirachta indica (12.9%), Alstonia congensis (11.9%) and Cymbopogon citratus (11.3%) showed the highest incidence of encounter whereas Nauclea latifolia recorded the lowest incidence of encounter (0.2%). The traditional usage of Persea americana and Ludwigia peruviana in the treatment of malaria is reported here for the first time.

CONCLUSION

Though a large number of traditionally used plants for the treatment of malaria were identified, scientific validation of the traditional claims of anti-malarial properties is imperative. This would establish their candidature for any possible future research for active principles and the possible development of new cheaper and more effective anti-malarial drugs, as well as in the conservation of this rich diversity of anti-malarial plants.

Investigations of antimicrobial activity of some Cameroonian medicinal plant extracts against bacteria and yeast with gastrointestinal relevance

ETHNOPHARMACOLOGICAL RELEVANCE

Resistance against antibiotics of many bacteria is accumulating. Therefore, searches for new substances with antimicrobial activity have become an urgent necessity. Medicinal plants are frequently used in popular medicine as remedies for many infectious diseases (intestinal infection, malaria, tuberculosis, etc.).

AIM OF THE STUDY

This study aimed to determine the in vitro antimicrobial activity of hexane, ethyl acetate and methanol extracts from different parts (leaves, stem bark, entire plant) of five different plant species against bacteria and yeast of gastrointestinal relevance.

MATERIAL AND METHODS

Twenty-one extracts from all the following plants (Albizia gummifera (leaf), Ficus exasperata (leaf and stem bark), Nauclea latifolia (leaf and stem bark), Ricinodendron heudelotii (stem bark), Senna hirsuta (entire plant) have been screened for their antimicrobial activity against eight bacteria species including Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), Gram-negative bacteria (Escherichia coli, Shigella dysenteriae, Shigella flexneri, Salmonella typhi, Pseudomonas aeruginosa, and Klebsiella pneumoniae) and one yeast species (Candida albicans) using agar disc-diffusion, and microbroth dilution assays.

RESULTS

Results demonstrated that F. exasperata and N. latifolia were active against the whole set of tested microorganisms. The methanol extract of N. latifolia (leaf and stem bark) was the most active against against C. albicans, E. coli, S. aureus, P. aeruginosa with a minimum inhibitory concentration (MIC) of 2, 32, 64 and 64 μg/ml, respectively. The methanol extract of leaf of F. exasperata was also most active with significant inhibitory activity against E. coli, S. dysenteriae, S. Typhi and P. aeruginosa with MIC values of 128 μg/ml. Only the extract of N. latifolia (stem bark and leaf) showed anticandidal property.

CONCLUSION

The results show that these plant extracts exhibit antimicrobial activity and N. latifolia proved to be most effective as an antibacterial and antifungal.

In vitro antiplasmodial activity and cytotoxicity of extracts and fractions of Vitex madiensis, medicinal plant of Gabon

Vitex madiensis Oliv. (Lamiaceae) is traditionally used to treat malaria symptoms in Haut-Ogooué, Gabon. Leaves and stem barks extracts were obtained using dichloromethane (CH(2)Cl(2)), ethyl acetate (EtOAc) and methanol (MeOH) as extraction solvents and fractionated on silica gel column. The in vitro antiplasmodial activity of CH(2)Cl(2), EtOAc and MeOH extracts and fractions was evaluated against the chloroquine-resistant FCB strain and field isolates of Plasmodium falciparum using the DELI test. The cytotoxicity of the extracts was tested on MRC-5 and THP1 cells using the tetrazolium salt MTT colorimetric assay, and the selectivity index (SI) of each extract was calculated. CH(2)Cl(2) extract, the EA1 fraction from EtOAc extract of stem barks and cyclohexane (L(cycl)), dichloromethane (L(DM)) and butanol (L(but)) fractions from MeOH/H(2)O extract of leaves exhibited the highest in vitro antiplasmodial activity on FCB strain and field isolates (IC(50) from 0.53 to 4.87 μg/ml) with high selectivity index (of 20.15-1800). These data support the use of V. madiensis in malaria treatment along with continued investigations within traditional medicines in the search of new antimalarial agents. The EA1, C(6)H(12) and CH(2)Cl(2) fractions could be selected for future investigation or/and for the treatment of malaria symptoms after standardization.

Indole and aminoimidazole moieties appear as key structural units in antiplasmodial molecules

From a library of compounds of natural sources, a big series of molecules was chosen by random sampling to evaluate their in vitro antimalarial activity against Plasmodium falciparum and their antifungal activity against Candida sp. From 184 molecules tested, no molecules were active against Candida sp. (MIC>10μg/ml) whereas 13 clearly showed high antiplasmodial activity in vitro, with an IC(50) less than 1μg/ml against the chloroquine-resistant strain of P. falciparum FcM29-Cameroon. The molecules with the best antiplasmodial efficacy were 10-hydroxy-ellipticin (IC(50): 0.08μg/ml), tchibangensin (IC(50): 0.13μg/ml), ellipticin hydrochloride (IC(50): 0.17μg/ml), usambarensin (IC(50): 0.23μg/ml), 7S,3S-ochropposinine oxindole (IC(50): 0.25μg/ml), 3,14-dihydro-ellipticin (IC(50): 0.25μg/ml), tetrahydro-4',5',6'17-usambarensin 17S (IC(50): 0.26μg/ml), ellipticine (IC(50): 0.28μg/ml), aricin (IC(50): 0.3μg/ml), 10-methoxy-ellipticin (IC(50): 0.32μg/ml), aplysinopsin (IC(50): 0.43μg/ml), descarbomethoxydihydrogambirtannin (IC(50): 0.46μg/ml) and ochrolifuanin A (IC(50): 0.47μg/ml). Among these 13 promising molecules, all except descarbomethoxydihydrogambirtannin, ochrolifuanine A and usambarensine presented here novel biological activities since they had never been described in the literature for their antiplasmodial activity. In spite of the large diversity of the molecules which have been tested, it is interesting to note that the ones active against Plasmodium are all indole derivatives (and one is both indolic and aminoimidazolic). To find new antiplasmodial compounds, ethnopharmacological approaches studying traditional medicine treatments for malaria is largely used but random research produced here an interesting yield (7%) of new antiplasmodial hits and appears therefore complementary to the traditional medicine way.

Genotoxic and clastogenic activity of saponins extracted from Nauclea bark as assessed by the micronucleus and the comet assays in Chinese Hamster Ovary cells

ETHNOPHARMACOLOGICAL RELEVANCE

Bark extracts of Nauclea latifolia, Nauclea diderrichii, Nauclea pobeguinii and Nauclea vandergutchii are used in traditional medicine in West and South Africa for the treatment of fevers, diarrhea and malaria.

AIM OF THE STUDY

To estimate the possible long-term toxicity and genotoxicity of plant extracts (dichloromethane, methanol, water/methanol, water) and saponins.

MATERIALS AND METHODS

The clastogenicity of plant extracts and saponins was assessed by the micronucleus assay performed on Chinese Hamster Ovary cells. The DNA-damaging activity of saponin mixture was assessed by the comet assay on Chinese Hamster ovary cells.

RESULTS

Hydromethanolic extracts from Nauclea latifolia, Nauclea diderrichii and Nauclea pobeguinii exhibited a significant clastogenic/aneugenic activity without S9 mix. The hydromethanolic extract from Nauclea diderrichii was the most clastogenic/aneugenic fraction with a Minimal Active Concentration (MAC) of 23.1 μgm L(-1). It was submitted to a separation step leading to six main saponins identified as quinovic acid glycosides (saponins A, D, E, G, J, K). None of the isolated saponins exerted a significant clastogenic/aneugenic activity by the micronucleus assay, however a mixture made with equal quantities of each of the six saponins exhibited a direct genotoxic/clastogenic activity as assessed by both the micronucleus assay and the comet assay on Chinese Hamster Ovary cells.

CONCLUSION

Saponins present in the hydromethanolic extracts of Nauclea induced synergistic in vitro DNA-damage and chromosome mutations in mammalian cells. This genotoxic activity was probably due to the capacity of Nauclea saponins to reduce cell defense against oxidative stress through the inhibition of glutathione-S-transferase activity.

Icacina senegalensis (Icacinaceae), traditionally used for the treatment of malaria, inhibits in vitro Plasmodium falciparum growth without host cell toxicity

Background

With the aim of discovering new natural active extracts against malaria parasites, Icacina senegalensis was selected after an ethnopharmacological survey conducted on plants used in traditional malaria treatment in Senegal.

Methods

Different concentrations of the plant extract and fractions were tested on synchronized Plasmodium falciparum cultures at the ring stage using the parasite lactate dehydrogenase assay. Their haemolytic activity and in vitro cytoxicity were evaluated. The chromatographic profiles of active fractions were also established.

Results

The plant extract and fractions revealed anti-plasmodial activity (IC₅₀ < 5 μg/mL) with no toxicity (Selectivity indexes >10). The dichloromethane fraction showed stronger anti-plasmodial activity than the total extract.

Conclusion

Anti-plasmodial activity and toxicity of I. senegalensis are reported for the first time and showed promising results in malaria field research.

Potential antimalarials from Nigerian plants: a review

Malaria, caused by parasites of the genus Plasmodium, is one of the leading infectious diseases in many tropical regions, including Nigeria, a West African country where transmission occurs all year round. Many of the inhabitants use plants as remedies against fever and other symptoms of acute malaria, as reported herein. Some of these plants have their antimalarial efficacies scientifically demonstrated and the active compounds isolated with their probable mechanisms of action studied. Medicinal plants are used to treat diseases also where the biodiversity of plants occur in parallel with endemic transmission of malaria. This review focuses on medicinal plants which are used to treat malaria in Nigeria, and on antimalarial testing of extracts and purified compounds from plants. Some show intense activity against malaria parasites in vitro and in experimentally infected mice. The search for new drugs based on plants is important due to the emergence and widespread of chloroquine-resistant and multiple drug-resistant malaria parasites, which require the development of new antimalarials. An acquaintance with antimalarial plants may be a springboard for new phytotherapies that could be affordable to treat malaria, especially among the less privileged native people living in endemic areas of the tropics, mostly at risk of this devastating disease.

The effects of an investigational antimalarial agent, NIPRD-AM1 on the single dose pharmacokinetics of metronidazole in healthy human volunteers

The effect of concurrent administration of a novel phytomedicine, NIPRD-AM1 used for the treatment of malaria on the pharmacokinetics of metronidazole was investigated in healthy volunteers. The study was a completely randomized one, crossover involving administration of single dose metronidazole tablets (200 mg×2) concomitantly with NIPRD-AM1 capsules (250 mg×2) to 11 healthy volunteers. Blood samples were collected before and at pre-determined time intervals following administration of the drugs. Serum concentrations of the unchanged metronidazole were analyzed using a modified simple and sensitive reversed phase high performance liquid chromatography (HPLC) method. The method showed good precision for metronidazole with coefficient of variation less than 10%. The Pharmacokinetic parameters (AUC, Cmax, and Tmax) were generated using GraphPad Prism software version 2. The derived pharmacokinetic parameters (AUC, Cmax) following the administration of metronidazole alone and co-administration with NIPRD-AM1 were 76.12 μg/ml per hour, 7.94 μg/ml and 73.52 μg/ml per hour, 7.83 μg/ml, respectively. This differences were not statistically significant (P<0.05) and the relative bioavailability was found to be about 96%. The comparable relative bioavailabilty value obtained shows that there is little or no interaction between NIPRD-AM1 and metronidazole. The findings, therefore, showed that metronidazole can be administered with the phytomedicine NIPRD-AM1 without any significant effect on the pharmacokinetic profiles of metronidazole.

Antimalarial activity and toxicity evaluation of a quantified Nauclea pobeguinii extract

AIM OF THE STUDY

To evaluate the in vitro and in vivo antiplasmodial activity and toxicity of the aqueous and 80% EtOH extract of the stem bark of Nauclea pobeguinii (Pob. Ex. Pell.) Petit (Rubiaceae), a plant used in traditional medicine in DR Congo against malaria.

MATERIALS AND METHODS

The aqueous and 80% EtOH extract from N. pobeguinii stem bark, and its constituents (5S)-5-carboxystrictosidine, 19-O-methylangustoline, 3-O-beta-fucosylquinovic acid, 3-ketoquinovic acid and strictosamide, were evaluated for their in vitro activity against Plasmodium falciparum (chloroquine-sensitive Ghana-strain). The 80% EtOH extract, containing 5.6% strictosamide, was evaluated in vivo in the 4-day P. berghei mouse model, and in the P. yoelii N67 model.

RESULTS

All compounds were inactive or only moderately active in vitro. The aqueous and 80% EtOH extract displayed moderate in vitro activity with IC(50) values of 44 and 32 microg/mL, respectively, without apparent cytotoxicity on MRC-5 cells (CC50>64 microg/mL). Daily oral dosing of the 80% EtOH extract, at 300 mg/kg, resulted in 86% reduction of parasitaemia in the 4-day P. berghei mouse model, and 75% reduction in the P. yoelii N67 model. Prolonging oral dosing to 2 x 5 days, with an interval of 2 days, and oral administration of the 80% EtOH extract at 300 mg/kg induced 92% reduction of parasitaemia, and a mean survival time of 17 days. Strictosamide, the putative active constituent, may be metabolically activated in the gastrointestinal tract after oral administration. Levels of creatinin, urea, ALAT and ASAT remained unchanged after treatment. No acute toxicity was observed in mice after a single 2g/kg oral dose, nor after 4 weekly doses. No significant macroscopic or microscopic lesions were observed in heart, lung, spleen, kidney, liver, large intestine and brain.

CONCLUSIONS

These results can partly support and justify the use of N. pobeguinii in traditional medicine in the DR Congo for the treatment of uncomplicated malaria.

Pharmacological evidence favouring the use of Nauclea latifolia in malaria ethnopharmacy: effects against nociception, inflammation, and pyrexia in rats and mice

AIM OF THE STUDY

Nauclea latifolia Smith is used traditionally in the treatment of uncomplicated malaria and painful conditions among its several other applications. The objective of this study is to investigate the pharmacological activities of the plant relevant to the symptomatic treatment of malaria fever and other painful conditions as an initial step towards developing an effective therapy for the symptomatic management of malaria fever and relief of other painful conditions.

MATERIALS AND METHODS

Various concentrations of the aqueous extract of the root bark of this plant were evaluated for its anti-nociceptive, anti-inflammatory and anti-pyretic activities in mice and rats. Investigation of the anti-nociceptive activities was performed using the acetic acid-induced abdominal constriction and hot-plate tests in mice and formalin-induced pain test in rats, as models of nociception. The extract was also investigated for its effect against inflammation induced by egg-albumin and pyrexia induced by yeast in rats.

RESULTS

Our data showed that the aqueous extract of Nauclea latifolia root bark (50-200mg/kg p.o.) significantly (P<0.05) attenuated writhing episodes induced by acetic acid and increased the threshold for pain perception in the hot-plate test in mice, dose-dependently. The product also remarkably decreased both the acute and delayed phases of formalin-induced pain in rats and also caused a significant reduction in both yeast-induced pyrexia and egg-albumin-induced oedema in rats. These effects were produced in a dose-dependent manner.

CONCLUSION

The results suggest the presence of biologically active principles in the extract with anti-nociceptive, anti-inflammatory and anti-pyretic activities that justifies its use in malaria ethnopharmacy and subsequent development for clinical application.

Traditional antimalarial phytotherapy remedies in herbal markets in southern Ghana

ETHNOPHARMACOLOGICAL RELEVANCE

Although traditional antimalarial plant remedies in herbal markets are a very important component of the health care system in Ghana this has not been previously studied to allow for the formulation of effective strategy for malaria control in Ghana.

AIM OF STUDY

The main objective of the present study was to collect and analyse data on the antimalarial plant remedies in herbal markets in southern Ghana.

MATERIALS AND METHODS

Herborists were interviewed using a validated questionnaire and species of plants were identified using a combination of field photo guides, local names and voucher specimens.

RESULTS

A total of 71 herborists (95.8% female) were interviewed. There were potential correlations between different parameters and variables such as ethnic groups, type of vendor and age-groups. The study revealed 29 species of plants belonging to 22 families being sold for the treatment of malaria. The detailed use of these plants is documented. The most frequently mentioned species of plants were Morinda lucida Benth., Indigofera sp. and Nauclea latifolia Sm. The majority (82.8%) of the plant materials were sold in the dried state and 6.9% were sold in fresh state. About 76.2% of the herbal remedies were sold throughout the year while 23.8% were scarce in the dry season. The cost of treatment of malaria using the herbal remedies ranged from 1 to 2 United States Dollars (USD).

CONCLUSION

Standardization of names and authentication of plant materials using organoleptic, phytochemical and DNA barcoding techniques as well as further research on efficacy, safety and dosage prescriptions for both fresh and dried plant materials being sold for the treatment of malaria in southern Ghana are needed.

Chemical Constituents of Nauclea latifolia and their Anti-GST and Anti-Fungal Activities

The crude ethanolic extract of Nauclea latifolia yielded five known compounds, strictosamide (1), naucleamides A (2), naucleamide F (3), quinovic acid-3-O-β-rhamnosylpyranoside (4), and quinovic acid 3-O-β-fucosylpyranoside (5). Microbial reactions, using a whole cell culture of Rhizopus circinans on compound (1), yielded three analogues, 10-hydroxystrictosamide (6), 10-4bT-glucosyloxyvincoside lactam (7) and 16,17-dihydro-10-β-glucosyloxyvincoside lactam (8). Compounds 1-8 were identified with the aid of extensive NMR spectral studies. Compound 8 was found to be a new metabolite. Compounds 1-8 exhibited different levels of anti-GST and antifungal activities.

Anticonvulsant, anxiolytic, and sedative properties of the roots of Nauclea latifolia Smith in mice

Root bark of Nauclea latifolia Smith (Rubiaceae) was evaluated for its anticonvulsant, anxiolytic, and sedative activity in mice. Animal models (maximal electroshock-, pentylenetetrazol-, and strychnine-induced convulsions; N-methyl-D-aspartate-induced turning behavior; elevated plus maze; stress-induced hyperthermia; open field; and diazepam-induced sleep) were used. The decoction from the bark of the roots of N. latifolia strongly increased the total sleep time induced by diazepam. It also protected mice against maximal electroshock-, pentylenetetrazol-, and strychnine-induced seizures. In addition, turning behavior induced by N-methyl-D-aspartate was inhibited. N. latifolia antagonized, in a dose-dependent manner, stress-induced hyperthermia and reduced body temperature. In the elevated plus maze, N. latifolia increased the number of entries into, percentage of entries into, and percentage of time in open arms, and reduced rearing, head dipping, and percentage of time in closed arms. In the open field test, N. latifolia increased crossing and reduced rearing and defecation. It could be concluded that the decoction of N. latifolia, used in traditional medicine in Cameroon in the treatment of fever, malaria, insomnia, anxiety and epilepsy seemed to possess, sedative, anticonvulsant, anxiolytic and antipyretic properties in mice.

Effects of strictosamide on mouse brain and kidney Na+, K+-ATPase and Mg2+-ATPase activities

Present study reports on the general bioactivity of strictosamide and on its effects on Na(+),K(+)-ATPase and Mg(2+)-ATPase activities of Charles River male mouse. Strictosamide is the main glycoalkaloid of Sarcocephalus latifolius (Rubiaceae) leaves and roots, used as medicinal plant in folk medicine. In this work, we studied the in vitro effects of various concentrations of strictosamide (0.25, 0.5, 1 or 2 mg/mL) and the in vivo effects of single doses (50, 100 or 200 mg/kg, i.p.) of this compound on kidney and brain Na(+),K(+)-ATPase and Mg(2+)-ATPase activities. Results of general study showed that strictosamide is slightly toxic to Charles River mouse (LD(50)=723.17 mg/kg), producing CNS depression and kidney toxicity, but the exact mechanism of these effects could not be defined. Strictosamide inhibited the in vitro and in vivo Mg(2+)-ATPase activity on kidney but had nonsignificant effect on brain. Furthermore, strictosamide had nonsignificant in vitro and in vivo effect on kidney Na(+),K(+)-ATPase activity but produced an in vivo increase of Na(+),K(+)-ATPase activity of brain, these findings suggesting that strictosamine may be related to the induction of alpha(2) isoform of Na(+),K(+)-ATPase and may account for the folk use of Sarcocephalus latifolius root infusion on hypertension.

Evaluation of Senegalese plants used in malaria treatment: focus on Chrozophora senegalensis

An ethnobotanical study was conducted in the Dakar area of Senegal to investigate the species used in the treatment of malaria. Seven plants are principally used: Cissampelos mucronata, Maytenus senegalensis, Terminalia macroptera, Bidens engleri, Ceratotheca sesamoides, Chrozophora senegalensis and Mitracarpus scaber. From a bibliographic study, it had been shown that the Cissampelos mucronata, Maytenus senegalensis and Terminalia macroptera have already been studied by several authors, and so only Bidens engleri, Ceratotheca sesamoides, Chrozophora senegalensis and Mitracarpus scaber were evaluated in the present study. For each plant, extracts were prepared with different solvents and tested in vitro on two chloroquine-resistant Plasmodium falciparum strains. Crude extracts from the leaves and the stems of Chrozophora senegalensis showed the best in vitro results. The IC(50) value of an aqueous extract of Chrozophora senegalensis was 1.6 microg/ml without cytotoxicity. The in vivo antiplasmodial activity of Chrozophora extracts was determined by both the oral and the intraperitoneal ways. The stages of Plasmodium cycle targeted by Chrozophora were then studied in vitro. These results could justify the traditional use of this plant in malaria treatment.

Are West African plants a source of future antimalarial drugs?

Ethnopharmacology is a very interesting resource in which new therapies may be discovered. In the case of malaria, two major antimalarial drugs widely used today came originally from indigenous medical systems, that is quinine and artemisinin, from Peruvian and Chinese ancestral treatments, respectively. There is an urgent need for the discovery of new drugs due to the critical epidemiological situation of this disease. New inexpensive therapies that are simple to use and that will limit the cost of drug research are good justifications for this ethnopharmacological approach. Therefore, the aim of this review is to empirically analyse plants that are used for antimalarial treatment in West Africa, and to determine those with real promising antimalarial activity. The major leads such as those extracted from Cochlospermum, Cryptolepsis, Guiera and Azadirachta have been highlighted. Indeed, some extracts seem to be promising in future research, but development of new isolation and characterization techniques, for designing new derivatives with improved properties need to be discussed.

Anti-plasmodial Activity of Some Constituents of the Root Bark of Harungana madagascariensis LAM. (Hypericaceae)

Bazouanthrone (1), a new anthrone derivative, has been isolated from the root bark of Harungana madagascariensis, together with known compounds, feruginin A (2), harunganin (3), harunganol A (4), harunganol B (5), friedelan-3-one (6) and betulinic acid (7). The structure of the compound (1) was assigned as 3,5,8,9-tetrahydroxy-2,4,4-tri-(3,3-dimethylallyl)-6-methyl-1-(4H)-anthracenone, by means of spectroscopic analysis. The anti-plasmodial activity of the isolated compounds was evaluated in culture against W2 strain of Plasmodium falciparum. All the compounds were found to be active against the Plasmodium parasites with bazouanthrone (1) showing particular potency (IC50=1.80 microM).

Antimalarial activity of some plants traditionally used in Meru district of Kenya

Ten plant extracts commonly used by the Meru community of Kenya were evaluated for the in vitro antiplasmodial, in vivo antimalarial, cytotoxicity and animal toxicity activities. The water and methanol extracts of Ludwigia erecta and the methanol extracts of Fuerstia africana and Schkuhria pinnata exhibited high antiplasmodial activity (IC(50) < 5 microg/mL) against chloroquine sensitive (D6) and resistant (W2) Plasmodium falciparum clones. The cytotoxicity of these highly active extracts on Vero E6 cells were in the range 161.5-4650.0 microg/mL with a selectivity index (SI) of 124.2-3530.7. In vivo studies of these extracts showed less activity with chemosuppression of parasitaemia in Plasmodium berghei infected mice of 49.64-65.28%. The methanol extract of Clerodendrum eriophyllum with a lower in vitro activity (IC(50) 9.51-10.56 microg/mL) exhibited the highest chemosuppression of 90.13%. The methanol and water extracts of Pittosporum viridiflorum were toxic to mice but at a lower dose prolonged survival of P. berghei infected mice (p < 0.05) with no overt signs of toxicity. However, the extracts were cytotoxic (SI, 0.96-2.51) on Vero E6 cells. These results suggest that there is potential to isolate active non-toxic antimalarial principles from these plants.

Antiplasmodial activity and cytotoxicity of plants used in West African traditional medicine for the treatment of malaria

Eighteen plants originating from Ivory Coast were selected by ethnobotanical survey as plants commonly used by traditional healers for the treatment of malaria. Extracts of these plants were tested on two strains of Plasmodium falciparum: FcM29-Cameroon (chloroquine-resistant strain) and a Nigerian chloroquine-sensitive strain. The powdered plants were used to prepare three kinds of extracts: by decoction in water, in ethanol (95%) and in pentane. A radioactive micromethod allowed the evaluation of the antiplasmodial in vitro activity of the extracts on P. falciparum. Concentrations inhibiting 50% of the parasite growth (IC50) ranged from 18 microg/ml to more than 500 microg/ml for aqueous and ethanol extracts and from 4.3 microg/ml to more than 500 microg/ml for pentane extracts. Cytotoxicity was estimated on A375 melanoma cells and a cytotoxicity/antiplasmodial index (CAR) was calculated for each extract, ranging from 1 to 10. The pentane extracts of Cola caricaefolia and Uvaria afzelii, which revealed the strongest antiplasmodial activity had CAR values of about 10.

In vitro antiplasmodial activity and cytotoxicity of 33 West African plants used for treatment of malaria

Thirty-three plants commonly used in West tropical Africa by traditional healers for the treatment of malaria were collected and ethanolic extracts were obtained by decoction. The antiplasmodial activity of extracts was evaluated in vitro against the chloroquine-resistant FcB1 strain of Plasmodium falciparum. Cytotoxicity was determined on the human MRC-5 and the rat L-6 cell lines. Of the 33 plant extracts, eight (24.5%) showed significant antimalarial activity (IC(50) values ranging from 2.3 to 13.7 microg/ml), 14 (42.5%) weak activity (IC(50) values ranging from 15 to 50 microg/ml) and 11 (33%) appeared inactive (IC(50) values >50 microg/ml). Five plants were of particular interest, associating good antiplasmodial activity and weak cytotoxicity. These five included Nauclea latifolia with known antiplasmodial activity and four, Fagara macrophylla, Funtumia elastica, Phyllanthus muellerianus and Rauvolfia vomitoria, for which the description of antiplasmodial activity is entirely novel.

Neuropharmacological effects of the aqueous extract of Nauclea latifolia root bark in rats and mice

The present study evaluated the neuropharmacological effects of the aqueous extract of Nauclea latifolia root bark in rodents. Effects on the spontaneous motor activity (SMA), exploratory behaviour, pentobarbital sleeping time, apomorphine-induced stereotypic behaviour and motor coordination (rota-rod performance) were investigated. The extract (50-200 mg/kg p.o.) significantly (P<0.05) decreased the SMA and exploratory behaviour in mice and prolonged pentobarbital sleeping time in rats dose-dependently. The extract also remarkably attenuated the intensity of apomorphine-induced stereotypy dose-dependently in mice, but had no effect on motor coordination as determined by the performance on rota-rod. These results indicate the presence of psychoactive substances in the aqueous extract of the root bark of Nauclea latifolia.

Alteration of oral salivary pharmacokinetics of paracetamol by an investigational anti-malarial phytomedicine, in healthy human volunteers

Effect of an investigational anti-malarial phytomedicine (AM1) on the salivary pharmacokinetics of paracetamol (PCM), in healthy human volunteers was examined. The drug salivary level of paracetamol was determined using spectrophotometric method. Lower concentrations of PCM was observed in concomitant administration of 1000mg PCM tablets with 250mg AM1 capsule compared with administration of 1000mg paracetamol tablets alone (control). The area under the curve (AUC), time for maximum concentration (t(max)), maximum concentration (Cmax) were generated using the GRAPHPAD PRISM software version 2.0. The pharmacokinetic parameters were calculated from the semi-logarithmic plots of concentration-time data for PCM. The absorption kinetics parameters kab, lag-time, t1/2ab for both test (0.03min(-1), 9min, 18min.) and control (0.03min(-1), 9min, 22.8min.) were identical. There were statistically significant reductions in the bioavailability parameters AUC, Cmax, between control (1856microg/ml/min, 8.08microg/ml) and test (847.87microg/ml/min, 4.59microg/ml/) experiments. There were also insignificant but definite alterations in the elimination phase kinetic parameters kel, t1/2el, between control (0.1172min(-1), 69min.) and test (0.01027min(-1), 75min). The study shows that the botanical anti-malarial remedy (AM1) reduced the systemic availability of PCM when used concomitantly.

Antiplasmodial activity of naphthoquinones and one anthraquinone from Stereospermum kunthianum

A lipophilic extract of the root bark of Stereospermum kunthianum revealed antiplasmodial activity in vitro. Bioassay-guided fractionation led to the isolation of four novel naphthoquinones (sterekunthals A and B, pyranokunthones A and B) and one novel anthraquinone (anthrakunthone) together with the known naphthoquinone pinnatal. The structures of the novel compounds were determined by comprehensive analyses of their 1D and 2D NMR data. The antiplasmodial activities and toxicity against the endothelial cell line ECV-304 of the isolated compounds have been assessed.

The antiplasmodial activity of isolates from Ajuga remota

Ajuga remota is the most frequently used medicinal herb for malaria treatment in Kenya. Its two known isolates ajugarin-1 (1) and ergosterol-5,8-endoperoxide (3) and a new isolate 8-O-acetylharpagide (2) were evaluated for their in vitro antiplasmodial activity. Ajugarin-1 was moderately active, with an IC(50) of 23.0 +/- 3.0 microM, as compared to chloroquine (IC(50) = 0.041 +/- 0.003 microM) against the chloroquine-sensitive (FCA 20/GHA) strain of Plasmodium falciparum. Ergosterol-5,8-endoperoxide was about 3x as potent (IC(50) = 8.2 +/- 1.1 microM), while 8-O-acetylharpagide, whose structure was established by spectroscopic evidence, was inactive. Both ajugarin-1 and ergosterol-5,8-endoperoxide did not exhibit cytotoxicity against A431 (skin carcinoma) cell line, but 8-O-acetylharpagide was significantly cytotoxic. This iridoid glucoside, which has been formerly isolated from Ajuga decumbens, was identified in A. remota for the first time.