Ethnopharmacology, Chemistry and Biological Properties of Four Malian Medicinal Plants

Ethnomedicinal, Chemical, and Biological Aspects of Lannea Species-A Review

Lannea L. genus belongs to the Anacardiaceae botanical family and has long been used in traditional medicinal systems of many countries to manage several health conditions, but no studies have been conducted regarding its usefulness as a source of herbal medicine for human use. A literature review was conducted on scientific papers indexed on B-On, Pubmed, and Web of Science databases. Our results showed that medicinal plants from this botanical genus, mostly constituted by bark and leaf, are often used to approach a wide variety of disease symptoms, like fever, inflammatory states, pain, and gastrointestinal disorders. Phytochemical profiles of Lannea species revealed that phenolic acid derivatives including hydroquinones, phenolic acids, flavonoids, condensed tannins, and triterpenoids are the main classes of secondary metabolites present. Among the total of 165 identified compounds, 57 (34.5%) are flavonoids, mostly quercetin- and myricetin-derived flavonols and catechin and epicatechin flavan-3-ol derivatives also containing a galloyl group. In vitro and in vivo studies allowed the identification of 12 different biological activities, amongst which antimicrobial, antioxidant, anti-inflammatory, and cytotoxic activities were the most frequently cited and observed in in vitro essays. Our review contributes useful information for the scientifical validation of the use of Lannea species in traditional medicinal systems and shows that more research needs to be conducted to better understand the concrete utility of these as herbal medicines.

Contribution to the Preclinical Safety Assessment of Lannea velutina and Sorindeia juglandifolia Leaves

Dried leaves of Lannea velutina A. Rich. and Sorindeia juglandifolia (A. Rich.) Planch. ex Oliv. (family Anacardiaceae) are used in African traditional medicine. Although these medicinal plants have widespread use in the treatment of inflammatory diseases, there is no scientific data concerning their preclinical or clinical safety. This work aimed to investigate the phytochemical properties of the leaves of both species using HPLC-UV/DAD, as well as the in vivo oral repeated-dose toxicity of 70% hydroethanolic leaf extract of S. juglandifolia and the in vitro genotoxicity of 70% hydroethanolic leaf extracts of L. velutina and S. juglandifolia. Clinical signs of toxicity, body weight variations, and changes in food consumption, mortality, and blood biochemical parameters were monitored. Genotoxicity was assessed using the bacterial reverse mutation assay (Ames test) with and without metabolic activation, according to OECD guidelines. The obtained results showed the presence of gallic acid and anacardic acid as the main marker constituents in both species. No significant changes in general body weight or food intake were observed; small significant changes with no critical relevance were observed in the blood biochemistry of animals treated with S. juglandifolia hydroethanolic extract (50, 400, and 1000 mg/kg body weight) compared to those in the control group. No genotoxicity was observed in the bacterial reverse mutation assay with S. juglandifolia and L. velutina extracts (up to 5 mg/plate). The safety data obtained in vivo and lack of genotoxic potential in vitro points to the safe medicinal use of S. juglandifolia and L. velutina extracts.

Anticonvulsant Activity of Hydro Alcoholic Extract and Solvent Fractions of Biophytum umbraculum Welw. Syn (Oxalidaceae) Root in Mice

Background

Scientists and researchers continue to focus on medicinal plants as a potential source of lead chemicals in the search for and development of new antiepileptic medicines. Biophytum umbraculum Welw. Syn is used to treat epilepsy in Ethiopian traditional medicine. The anticonvulsant effect of Biophytum umbraculum Welw. Syn hydroalcoholic extract and solvent fractions was evaluated in this study since the claim has not been thoroughly explored.

Methods

The plant’s root was extracted using the maceration procedure, with aqueous, butanol, and chloroform as solvents. The maximum electroshock and pentylenetetrazol model tests were used to assess anticonvulsant activity. Mice were divided into five groups (n = 6) at random. The test groups received 100, 200, and 400 mg/kg of hydroalcoholic extract and solvent fraction, respectively. For the maximum electric shock test, the positive control groups received 25 mg/kg phenytoin and 200 mg/kg valproate for the pentylenetetrazol test. The negative control was given 10 mL/kg of pure water or 2% Tween 80.

Results

There were no signs of toxicity in the hydroalcoholic extract or solvent extraction. When compared to the negative control, the hydro-alcoholic extract had a significant anticonvulsant effect in both the maximum electric shock test and the pentylenetetrazol test. In both cases, the butanol component had a comparable impact. In the pentylenetetrazol test, the chloroform fraction had a significant anticonvulsant effect when compared to the control at dosages of MB200 and MB400. Flavonoids, phenols, tannins, steroids, terpenoids, and saponins were found in both the hydroalcoholic and solvent fractions of the plant extract.

Conclusion

The plant appears to have promising anticonvulsant properties, and it might be used to generate novel anti-epileptic drugs, according to this study.

In vitro antiplasmodial activity-directed investigation and UPLC-MS fingerprint of promising extracts and fractions from Terminalia ivorensis A. Chev. and Terminalia brownii Fresen

ETHNOPHARMACOLOGICAL SIGNIFICANCE

Medicinal plants from the Terminalia genus are widely used as remedies against many infectious diseases, including malaria. As such, Terminalia ivorensis A. Chev. and Terminalia brownii Fresen. are famous due to their usefulness in traditional medicines to treat malaria and yellow fever. However, further information is needed on the extent of anti-Plasmodium potency of extracts and fractions from these plants and their phytochemical profile.

AIM OF THE STUDY

This study was designed to investigate the in vitro antiplasmodial activity and to determine the chemical profile of promising extracts and fractions from T. ivorensis and T. brownii stem bark.

MATERIALS AND METHODS

Crude aqueous, ethanolic, methanolic, hydroethanolic and ethyl acetate extracts were prepared by maceration from the stem barks of T. brownii and T. ivorensis. They were subsequently tested against chloroquine-sensitive (Pf3D7) and multidrug-resistant (PfDd2) strains of P. falciparum using the parasite lactate dehydrogenase (PfLDH) assay. Extracts showing very good activity on both plasmodial strains were further fractionated using column chromatography guided by evidence of antiplasmodial activity. All bioactive extracts and fractions were screened for their cytotoxicity on Vero and Raw cell lines using the resazurin-based assay and on erythrocytes using the hemolysis assay. The phytochemical profiles of selected potent extracts and fractions were determined by UPLC-QTOF-MS analysis.

RESULTS

Of the ten extracts obtained from both plant species, nine showed inhibitory activity against both P. falciparum strains (Pf3D7 and PfDd2), with median inhibitory concentration (IC₅₀) values ranging from 0.13 μg/ml to 10.59 μg/ml. Interestingly, the aqueous extract of T. ivorensis (Ti^W) and methanolic extract of T. brownii (Tb^M) displayed higher antiplasmodial activities against both strains (IC₅₀ 0.13-1.43 μg/ml) and high selectivity indices (SI > 100). Their fractionation led to two fractions from T. ivorensis and two from T. brownii that showed very promising antiplasmodial activity (IC₅₀ 0.15-1.73 μg/mL) and SI greater than 100. The hemolytic assay confirmed the safety of crude extracts and fractions on erythrocytes. UPLC-MS-based phytochemical analysis of the crude aqueous extract of T. ivorensis showed the presence of ellagic acid (1) and leucodelphidin (2), while analysis of the crude methanol extract of T. brownii showed the presence of ellagic acid (1), leucodelphinidin (2), papyriogenin D (3), dihydroactinidiolide (4) and miltiodiol (5).

CONCLUSIONS

The extracts and fractions from T. ivorensis and T. brownii showed very good antiplasmodial activity, thus supporting the traditional use of the two plants in the treatment of malaria. Chemical profiling of the extracts and fractions led to the identification of chemical markers and the known antimalarial compound ellagic acid. Further isolation and testing of other pure compounds from the active fractions could lead to the identification of potent antiplasmodial compounds.

Specific sub fractions from Terminalia mantaly (H. Perrier) extracts potently inhibit Plasmodium falciparum rings, merozoite egress and invasion

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia mantaly (H. Perrier) and Terminalia superba (Engl. & Diels) are sources of treatment for various diseases, including malaria and/or related symptoms in parts of Southwestern Cameroon. However, there is limited information on the extent of the antiplasmodial potential of their extracts.

AIM OF THE STUDY

The present study was designed to investigate the antiplasmodial potential of chromatographic sub fractions (SFs) from promising fractions of Terminalia mantaly (Tm) [Tmsb^wChl, the chloroform fraction from water extract of Tm, IC₅₀ (μg/mL) PfINDO: 0.56, Pf3D7: 1.12; SI > 357 (HEK/PfINDO) & 178 (HEK/Pf3D7)] and Terminalia superba (Ts) [Tsr^mEA, the ethyl acetate fraction from methanolic extract of Ts, IC₅₀ (μg/mL) PfINDO: 1.82, Pf3D7: 1.65; SI > 109 (HEK/PfINDO) & 121 (HEK/Pf3D7)] obtained from previous studies. The SFs were tested against Plasmodium falciparum 3D7 (Pf3D7-chloroquine sensitive) and INDO (PfINDO-chloroquine resistant) strains in culture. Also, the phytochemical profile of potent SFs was determined and finally, the inhibition of the asexual blood stages of Plasmodium falciparum by the SFs with the highest promise was assessed.

MATERIAL AND METHODS

Selected SFs were submitted to a second bio-guided fractionation using silica gel column chromatography. The partial phytochemical composition of potent antiplasmodial SFs was determined using gas chromatography coupled to mass spectrometry (GC-MS). The SYBR Green I-based fluorescence microtiter plate assay was used to monitor the growth of Plasmodium falciparum parasites in culture in the presence or absence of extracts. Microscopy and flow cytometry counting was used to assess the Plasmodium falciparum stage-specific inhibition and post-drug exposure growth suppression by highly potent extracts.

RESULTS

Twenty-one of the 39 SFs afforded from Tmsb^wChl showed activity (IC₅₀: 0.29-4.74 μg/mL) against both Pf3D7 and PfINDO strains. Of note, eight SFs namely, Tm25, Tm28-30, Tm34-36 and Tm38, exerted highly potent antiplasmodial activity (IC₅₀ < 1 μg/mL) with IC₅₀PfINDO: 0.41-0.84 μg/mL and IC₅₀Pf3D7: 0.29-0.68 μg/mL. They also displayed very high selectivity (50 < SI_PfINDO, SI_Pf3D7 > 344) on the two Plasmodial strains. On the other hand, 7 SFs (SFs Ts03, Ts04, Ts06, Ts09, Ts10, Ts12 and Ts13) from Tsr^mEA showed promising inhibitory potential against both parasite strains (IC₅₀: 2.01-5.14 μg/mL). Sub fraction Tm36 (IC₅₀PfINDO: 0.41 μg/mL, SI_PfINDO > 243; IC₅₀Pf3D7: 0.29 μg/mL, SI_Pf3D7 > 344) showed the highest promise. The GC-MS analysis of the 8 selected SFs led to the identification of 99 phytometabolites, with D-limonene (2), benzaldehyde (12), carvone (13), caryophyllene (35), hexadecanoic acid, methyl ester (74) and 9-octadecenoic acid, methyl ester (82) being the main constituents. Sub fractions Tm28, Tm29, Tm30, Tm36 and Tm38 inhibited all the three intraerythrocytic stages of P. falciparum, with strong potency against ring stage development, merozoite egress and invasion processes.

CONCLUSIONS

This study has identified highly potent antiplasmodial SFs from Terminalia mantaly with significant activity on the intraerythrocytic development of Plasmodium falciparum. These SFs qualify as promising sources of novel antiplasmodial lead compounds. Further purification and characterization studies are expected to unravel molecular targets in rings and merozoites.

When silence goes viral, Africa sneezes! A perspective on Africa's subdued research response to COVID-19 and a call for local scientific evidence

By mid-September 2020, over 1.33 million confirmed COVID-19 cases and 32 thousand deaths had been reported in Africa. Global research on COVID-19 went 'viral' with a record 3487 research contributions comprising of 2062 journal papers and 1425 preprints published within the first three months following the outbreak of COVID-19. Surprisingly, the silence of the African research community has been unprecedented - contributing a paltry 0.6% (22 contributions), a figure nearly matched by Colombia (18 publications). Until now, a comprehensive perspective on the reasons for this subdued research response, and COVID-19 themes critical to Africa has been missing. We posit that while a milieu of factors accounts for this silence, unprecedented research opportunities exist to support COVID-19 decision and policy formulation in Africa. The subdued response reflects weak research systems, characterized by deep-rooted challenges, including severe lack of research expertise, funding, and infrastructure, coupled with poor working conditions. Hence, Africa's contribution to research on infectious diseases, including COVID-19, remains weak. Perceptions and attitudes among researchers and policy-makers on COVID-19, and the role of science in decision and policy-making also exist. Moreover, COVID-19 and earlier severe acute respiratory syndromes are considered as 'imported diseases' originating from outside Africa. Thus, notions may exist that the control methods will come from outside Africa through 'technology-transfer' or 'capacity-building'. Yet local COVID-19 research is needed to address knowledge gaps, including; (1) potential novel transmission of SARS-CoV-2, (2) adaption of generic COVID-19 control measures to suit African settings, (3) occurrence and persistence of SARS-CoV-2 in solid waste, wastewaters, on-site sanitation systems, and drinking water, and (4) the 'human factor' including the role of gender, perceptions, myths, attitudes, and religious beliefs in the transmission and control of COVID-19. Therefore, there is a need to: (1) strengthen local research capacity and evaluation systems, (2) consider biosafety and ethical issues, (3) initiate cross-disciplinary research and global collaboration on COVID-19, and (4) integrate science communication in COVID-19 programs.

Antiplasmodial, antinociceptive and antipyretic potential of the stem bark extract of Burkea africana and identification of its antiplasmodial-active fraction

Background and aim

Burkea africana stem bark is used as a remedy for malaria in north-central and southern Nigeria. Based on its traditional use, this study was conducted to investigate the antiplasmodial, antinociceptive and antipyretic potential of an extract of B. africana stem bark.

Experimental procedure

A 70% v/v ethanol extract of stem bark of B. africana was prepared by cold maceration. Fractions (dichloromethane, ethyl acetate, and residual) were also prepared. The extract was screened for hemolytic, cytotoxic and antiplasmodial activity effects. The effect of the extract and fractions against chloroquine-sensitive (3D7) and multi-drug resistant (W2mef) P. falciparum was assessed. Acute toxicity test, acetic acid-induced abdominal writhing in mice, and lipopolysaccharide-induced fever in rats were also employed to screen the extract. Chromatographic fingerprints of the extract and active fraction were obtained.

Results

B. africana extract showed no cytotoxic or significant hemolytic effects and did not cause acute toxicity or mortality. The ethanol extract exhibited moderate antiplasmodial activity while the dichloromethane fraction showed high activity against P. falciparum 3D7 (IC₅₀ = 6.44 μg/ml) and W2mef (IC₅₀ = 6.30 μg/ml) respectively. The extract elicited significant (p < 0.05) attenuation of acetic acid-induced writhing and significantly (p < 0.05) ameliorated lipopolysaccharide-induced pyrexia at 300 mg/kg. The HPLC profile of the dichloromethane fraction showed peaks with retention times that corresponded with those of rutin and caffeic acid.

Conclusion

Burkea africana extract has antiplasmodial, antinociceptive and antipyretic potential and its antiplasmodial constituents are concentrated in its dichloromethane fraction.

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Burkea africana used as antimalarial remedy alleviates peripheral pain and fever.

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The extract and its dichloromethane fraction possess antiplasmodial activity.

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Antiplasmodial activity is concentrated in the dichloromethane fraction.

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Intra-erythrocytic targets may be distinct from those of chloroquine and artesunate.

Antimicrobial investigation of ethnobotanically selected guinean plant species

ETHNOPHARMACOLOGICAL RELEVANCE

In Guinea, medicinal plants play an important role in the management of infectious diseases including urinary disorders, skin diseases and oral diseases. This study was carried out to collect medicinal plant species employed for the treatment of these diseases and to investigate their antimicrobial potential.

MATERIALS AND METHODS

Based on an ethnobotanical investigation carried out in three Guinean regions, 74 traditional healers and 28 herbalists were interviewed and medicinal plants were collected. The most quoted plant species were evaluated for their antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, and in addition against Plasmodium falciparum.

RESULTS

A total of 112 plant species belonging to 102 genera distributed over 42 botanical families were inventoried. Among the selected plant species, promising activities against C. albicans were obtained for the methanolic extracts of the stem bark of Terminalia albida (IC₅₀ 1.2 μg/ml), the leaves of Tetracera alnifolia (IC₅₀ 1.6 μg/ml) and the root bark of Swartzia madagascariensis (IC₅₀ 7.8 μg/ml). The highest activity against S. aureus was obtained for the dichloromethane extracts of the leaves of Pavetta crassipes (IC₅₀ 8.5 μg/ml) and the root of Swartzia madagascariensis (IC₅₀ 12.8 μg/ml). Twenty one extracts, obtained from twelve plant species, were strongly active against Plasmodium falciparum, including the dichloromethane extracts of the root and stem bark of Terminalia albida root (IC₅₀ 0.6 and 0.8 μg/ml), the leaves of Landolphia heudelotii (IC₅₀ 0.5 μg/ml), the stem bark of Combretum paniculatum (IC₅₀ 0.4 μg/ml) and the leaves of Gardenia ternifolia (IC₅₀ 1.3 μg/ml).

CONCLUSION

The present study provides a comprehensive overview of medicinal plants employed by Guinean traditional healers for the treatment of various microbial diseases, including urinary disorders, skin diseases and oral diseases. Some of the studied plant species showed promising antimicrobial activity and could be considered as a potential source for the development of new antifungal and/or antimalarial agents.

NMR-Based Metabolomic Analysis and Microbial Composition of Soil Supporting Burkea africana Growth

Burkea africana is a leguminous tree used for medicinal purposes, growing in clusters, on soils impoverished from most nutrients. The study aimed to determine the factors responsible for successful reproduction and establishment of the B. africana trees in nature, as all efforts for commercial production has been proven unsuccessful. An investigation was carried out to determine the metabolomic profile, chemical composition, and microbial composition of the soils where B. africana grows (Burkea soil) versus the soil where it does not grow (non-Burkea soil). 1H-NMR metabolomic analysis showed different metabolites in the respective soils. Trehalose and betaine, as well as a choline-like and carnitine-like compound, were found to be in higher concentration in Burkea soils, whereas, acetate, lactate, and formate were concentrated in non-Burkea soils. Liquid Chromatography-Mass Spectrometry analysis revealed the presence of numerous amino acids such as aspartic acid and glutamine to be higher in Burkea soils. Since it was previously suggested that the soil microbial diversity is the major driver for establishment and survival of seedlings in nature, Deoxyribonucleic acid (DNA) was extracted and a BLAST analysis conducted for species identification. Penicillium species was found to be highly prevalent and discriminant between the two soils, associated with the Burkea soils. No differences in the bacterial composition of Burkea and non-Burkea soils were observed. The variances in fungal composition suggests that species supremacy play a role in development of B. africana trees and is responsible for creating a supporting environment for natural establishment and survival of seedlings.

Plants of the Genus Terminalia: An Insight on Its Biological Potentials, Pre-Clinical and Clinical Studies

The evaluation and confirmation of healing properties of several plant species of genus Terminalia based on their traditional uses and the clinical claims are of utmost importance. Genus Terminalia has received more attention to assess and validate the therapeutic potential and clinical approval due to its immense folk medicinal and traditional applications. Various species of Terminalia genus are used in the form of herbal medicine and formulations, in treatment of diseases, including headache, fever, pneumonia, flu, geriatric, cancer, to improve memory, abdominal and back pain, cough and cold, conjunctivitis, diarrhea, heart disorder, leprosy, sexually transmitted diseases, and urinary tract disorders. These are reported to possess numerous biological properties, counting: antibacterial, antifungal, antiinflammatory, antiviral, antiretroviral, antioxidant, and antipa7rasitic. This current research review aims to update the detailed biological activities, pre-clinical and clinical studies of various extracts and secondary metabolites from several plant species under the genus Terminalia, along with information on the traditional uses and chemical composition to develop a promising strategy for their potential applications in the form of medicine or use in modern drug formulations for treating diseases like pneumonia, flu, and other types of viral infections or controlling human contagions.

Systematic review and bibliometric analysis of African anesthesia and critical care medicine research part I: hierarchy of evidence and scholarly productivity

BACKGROUND

Research is an essential component of Anesthesia, and the contributions of researchers and institutions can be appreciated from the analysis of scholarly outputs. Such analyses help identify major contributors and trends in publication. Little is known about the state of Anesthesia and Critical Care Medicine (A.C.C.M.) research in Africa. We aimed to describe African A.C.C.M. research's current landscape by determining its productivity per country and point towards possible ideas for improvement.

METHODS

The authors searched PubMed, Embase, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) from inception to May 4, 2020, for articles on or about A.C.C.M. in Africa. Studies were selected based on their titles and abstracts. Rayyan software was later on used for data management in the review selection process. Then, the full-text of eligible articles were screened. Data were extracted, and the number of articles per physician anesthesia providers and provider density were calculated. Kruskal Wallis test and Spearman's correlation were used, and a P-value < 0.05 was considered statistically significant.

RESULTS

Of the 4690 articles, only 886 (18.9%) were included in the analysis. The articles were published between 1946 and 2020 in 278 target journals. 55 (6.2%) articles were published in the South African Journal of Surgery, 51 (5.8%) in Anesthesia and Analgesia, and 46 (5.2%) in Anaesthesia. 291 (32.8%) studies were cross-sectional. 195 (22.0%) first authors were from Nigeria, 118 (13.3%) from South Africa, and 88 (9.9%) from the U.S.A. Malawi (1.67), Togo (1.06), and Sierra Leone (1.00) had the highest number of articles per provider. Whereas Ethiopia (580.00), Nigeria (336.21), and Malawi (333.33) had the highest number of articles per provider density.

CONCLUSION

We identified the most and least productive African countries in A.C.C.M. research and a low-quality hierarchy of evidence in these publications. Hence, the study's findings may aid in driving the A.C.C.M. research agenda and capacity building in Africa.

In Vivo Antiplasmodial Activity of Terminalia mantaly Stem Bark Aqueous Extract in Mice Infected by Plasmodium berghei

Background

Terminalia mantaly is used in Cameroon traditional medicine to treat malaria and related symptoms. However, its antiplasmodial efficacy is still to be established.

Objectives

The present study is aimed at evaluating the in vitro and in vivo antiplasmodial activity and the oral acute toxicity of the Terminalia mantaly extracts.

Materials and Methods

Extracts were prepared from leaves and stem bark of T. mantaly, by maceration in distilled water, methanol, ethanol, dichloromethane (DCM), and hexane. All extracts were initially screened in vitro against the chloroquine-resistant strain W2 of P. falciparum to confirm its in vitro activity, and the most potent one was assessed in malaria mouse model at three concentrations (100, 200, and 400 mg/kg/bw). Biochemical, hematological, and histological parameters were also determined.

Results

Overall, 7 extracts showed in vitro antiplasmodial activity with IC₅₀ ranging from 0.809 μg/mL to 5.886 μg/mL. The aqueous extract from the stem bark of T. mantaly (Tmsb^w) was the most potent (IC₅₀ = 0.809 μg/mL) and was further assessed for acute toxicity and efficacy in Plasmodium berghei-infected mice. Tmsb^w was safe in mice with a median lethal dose (LD₅₀) higher than 2000 mg/kg of body weight. It also exerted a good antimalarial efficacy in vivo with ED₅₀ of 69.50 mg/kg and had no significant effect on biochemical, hematological, and histological parameters.

Conclusion

The results suggest that the stem bark extract of T. mantaly possesses antimalarial activity.

Plants of Genus Mentha: From Farm to Food Factory

Genus Mentha, a member of Lamiaceae family, encompasses a series of species used on an industrial scale and with a well-described and developed culture process. Extracts of this genus are traditionally used as foods and are highly valued due to the presence of significant amounts of antioxidant phenolic compounds. Many essential oil chemotypes show distinct aromatic flavor conferred by different terpene proportions. Mint extracts and their derived essential oils exert notable effects against a broad spectrum of bacteria, fungi or yeasts, tested both in vitro or in various food matrices. Their chemical compositions are well-known, which suggest and even prompt their safe use. In this review, genus Mentha plant cultivation, phytochemical analysis and even antimicrobial activity are carefully described. Also, in consideration of its natural origin, antioxidant and antimicrobial properties, a special emphasis was given to mint-derived products as an interesting alternative to artificial preservatives towards establishing a wide range of applications for shelf-life extension of food ingredients and even foodstuffs. Mentha cultivation techniques markedly influence its phytochemical composition. Both extracts and essential oils display a broad spectrum of activity, closely related to its phytochemical composition. Therefore, industrial implementation of genus Mentha depends on its efficacy, safety and neutral taste.

Potent antiplasmodial extracts and fractions from Terminalia mantaly and Terminalia superba

Background

The emergence and spread of malaria parasites resistant to artemisinin-based combination therapy stresses the need for novel drugs against malaria. Investigating plants used in traditional medicine to treat malaria remains a credible option for new anti-malarial drug development. This study was aimed at investigating the antiplasmodial activity and selectivity of extracts and fractions from Terminalia mantaly and Terminalia superba (Combretaceae) that are used in Cameroon to treat malaria.

Methods

Twelve methanolic (m) and water (w) extracts obtained by maceration of powdered dried leaves (l), stem bark (sb) and root (r) of Terminalia mantaly (Tm) and Terminalia superba (Ts) and 12 derived fractions of hexane, chloroform, ethyl acetate and 4 final residues of selected extracts were assessed for antiplasmodial potential in vitro against the chloroquine-resistant PfINDO and the chloroquine-sensitive Pf3D7 strains of Plasmodium falciparum using the SYBR green I-based fluorescence assay. The cytotoxicity of potent extracts and fractions was evaluated in vitro using the MTT assay on HEK239T cell line.

Results

The antiplasmodial IC₅₀ of extracts from both plants ranged from 0.26 to > 25 µg/mL. Apart from the extracts Tmrm and Tsrw that exerted moderate antiplasmodial activities (IC₅₀: 5–20 µg/mL) and Tmrw that was found to be non-active at the tested concentrations (IC₅₀ > 25 µg/mL), all other tested crude extracts exhibited potent activities with IC₅₀ < 5 µg/mL. The aqueous extracts from the stem bark of Terminalia mantaly (Tmsbw) and the leaf of Terminalia superba (Tslw) displayed the highest antiplasmodial activities (IC₅₀: 0.26–1.26 µg/mL) and selectivity (SI > 158) on both resistant PfINDO and sensitive Pf3D7 strains. Four fractions upon further extraction with chloroform and ethyl acetate (TmlwChl, TmsbwChl, TmsbwEA, TsrmEA) afforded from three selected crude extracts (Tmlw, Tmsbw, Tsrm) exhibited highly potent activities against both P. falciparum strains (IC₅₀ < 2 µg/mL) and high selectivity (SI > 109).

Conclusions

The results achieved in this work validate the reported traditional use of Terminalia mantaly and Terminalia superba to treat malaria. Moreover, the highly potent and selective fractions warrant further investigation to characterize the active antiplasmodial principles and progress them to rodent malaria models studies if activity and selectivity are evidenced.

In vivo validation of anti-malarial activity of crude extracts of Terminalia macroptera, a Malian medicinal plant

BACKGROUND

Plasmodium falciparum malaria is still one of the most deadly pathology worldwide. Efficient treatment is jeopardized by parasite resistance to artemisinin and its derivatives, and by poor access to treatment in endemic regions. Anti-malarial traditional remedies still offer new tracks for identifying promising antiplasmodial molecules, and a way to ensure that all people have access to care. The present study aims to validate the traditional use of Terminalia macroptera, a Malian plant used in traditional medicine.

METHODS

Terminalia macroptera was collected in Mali. Leaves (TML) and roots ethanolic extracts (TMR) were prepared and tested at 2000 mg/kg for in vivo acute toxicity in Albino Swiss mice. Antiplasmodial activity of the extracts was assessed against a chloroquine resistant strain P. falciparum (FcB1) in vitro. In vivo, anti-malarial efficacy was assessed by a 4-day suppressive test at 100 mg/kg in two malaria murine models of uncomplicated malaria (Plasmodium chabaudi chabaudi infection) and cerebral malaria (Plasmodium berghei strain ANKA infection). Constituents of TMR were characterized by ultra-high-performance liquid chromatography coupled to high resolution mass spectrometry. Top ranked compounds were putatively identified using plant databases and in silico fragmentation pattern.

RESULTS

Lethal dose of TML and TMR were greater than 2000 mg/kg in Albino Swiss mice. According to the OECD's Globally Harmonized System of Classification, both extracts are non-toxic orally. Antiplasmodial activity of T. macroptera extracts was confirmed in vitro against P. falciparum FcB1 strain with IC50 values of 1.2 and 1.6 µg/mL for TML and TMR, respectively. In vivo, oral administration of TML and TMR induced significant reduction of parasitaemia (37.2 and 46.4% respectively) in P. chabaudi chabaudi infected mice at the 7th day of infection compared to untreated mice. In the cerebral malaria experimental model, mice treated with TMR and TML presented respectively 50 and 66.7% survival rates at day 9 post-infection when all untreated mice died. Eleven major compounds were found in TMR. Among them, several molecules already known could be responsible for the antiplasmodial activity of the roots extract of T. macroptera.

CONCLUSIONS

This study confirms both safety and anti-malarial activity of T. macroptera, thus validating its traditional use.