In vitro antiplasmodial activity of extracts of Alchornea cordifolia and identification of an active constituent: ellagic acid

Effect of Alchornea cordifolia on Glycemic Indices of Varieties of Fufu Among Healthy Subjects

Background

Glycemic index (GI) is a measure of the ability of carbohydrate food to raise blood glucose concentration. The GI of a food and its negative effects has caused an adverse increase in the prevalence of diabetes and other metabolic diseases.

Objective

This study aimed to determine the effect of Alchornea cordifolia on glycemic indices of varieties of fufu.

Methods

The research was a crossover experimental study involving 10 healthy individuals. A 50-g measure of pure glucose was served on 2 separate occasions and, subsequently, a measured amount of the test foods containing 50 g of available carbohydrates. The GI values were determined by the measure of the blood glucose concentrations of the subjects at fasting and after ingestion of the glucose and the test foods (fufu) within 2 h. Collection of capillary blood for blood glucose measurement started 30 min after consumption and was subsequently taken at 60, 90, and 120 min for both noncomposited and composited fufu GI determination. The phytoconstituents of the A. cordifolia were also determined.

Results

For the noncomposited fufu, plantain fufu had the least glycemic response (46%), followed by cassava fufu (50%) and cassava-plantain fufu (53%); however, all were in the low-GI category. For the composited fufu, plantain fufu had the least response (12%), followed by cassava-plantain fufu (14%) and cassava fufu (14%), with all in the low-GI category. A multiple comparison of GI on the various foods by analysis of variance revealed a significant difference between the GI of cassava-plantain fufu and composite cassava-plantain fufu (P = 0.001); cassava fufu and composite cassava fufu (P = 0.004); and plantain fufu and composite plantain fufu (P = 0.006). The phytochemical screening of the A. cordifolia revealed the presence of flavonoids and tannins.

Conclusions

Composited A. cordifolia fufu affects the glycemic response.

Antimalarial activity of Toona ciliata MJ Roem aqueous methanolic leaf extract and its antioxidant and phytochemical properties

Background and aim

Malaria is a global health issue causing substantial morbidity and mortality. Screening of various traditionally important medicinal plants is a key source for the discovery of new antimalarials. We evaluated the antimalarial and antioxidant activities, and performed detailed phytochemical analyses of Toona ciliata MJ Roem aqueous methanolic leaf extract (TcMLE).

Experimental procedures

In vitro antiplasmodial studies in Plasmodium falciparum (Pf) 3D7 and PfCam3.IR539T strains were performed by [3H]-hypoxanthine uptake assays. In vitro cytotoxicity in HeLa and HEK293T cell lines was evaluated using MTT assays. Hemolysis assay was performed using RBCs. Phytochemical analysis by GC-MS and in vitro antioxidant studies by DPPH and ABTS assays were performed. In vivo antimalarial studies in Pb-infected mice were carried out using Rane's test and Peters' 4-day test.

Results and conclusions

TcMLE showed significant in vitro antioxidant activity and had phytochemicals reported for antimalarial activity. In vitro studies showed prominent antiplasmodial activity against Pf3D7 strain (IC50 ∼22 μg/ml) and PfCam3. IR539Tstrain (IC50 value ∼43 μg/ml). In vitro cytotoxicity studies, in vitro hemolytic assays, and in vivo acute toxicity studies further suggested that TcMLE is nontoxic. In vivo antimalarial studies using Rane's test showed a significant decrease in parasitemia by ∼70% at 1200 mg/kg doses and delayed the mortality of mice by ∼10-14 days. Peters' 4-day test also showed a similar pattern. The present study demonstrated the antimalarial potential of TcMLE. These findings deliver a platform for further studies to identify the active components of TcMLE and discover new antimalarials.

Dimeric polyphenols to pave the way for new antimalarial drugs

Because of the threat of resistant Plasmodium sp., new orally active antimalarials are urgently needed. Inspired by the structure of ellagic acid, exhibiting potent in vivo and in vitro antiplasmodial effects, polyphenolic structures possessing a similar activity-safety profile were synthesized. Indeed, most exhibited a marked in vitro effect (IC50 < 4 μM) on resistant P. falciparum, without any detrimental effects reported during the toxicity assays (hemolysis, cytotoxicity, in vivo). In addition, they possessed a greater hydrosolubility (from 7 μM to 2.7 mM) compared to ellagic acid. Among them, 30 is the most promising for antimalarial purposes since it displayed a significant parasitaemia reduction after oral administration in mice (50 mg kg-1) compared to the orally ineffective ellagic acid. In conclusion, our investigations led to the identification of a promising scaffold, which could bring new insights for malaria treatment.

Assessment of toxicity and anti-plasmodial activities of chloroform fractions of Carapa procera and Alchornea cordifolia in murine models

Background: Plant as a source of medicine has gained international popularity in recent times because of its natural origin, availability in local communities, cheaper to purchase, ease of administration, and its usefulness as an alternative treatment in case of numerous side effects and drug resistance. However, the use of herbal formulations can also result in short-term and long-term organ damage or dysfunction to the host. In this study, chloroform fractions of the leaves of two medicinal plants, Alchornea cordifolia (ACL) and Carapa procera (CPL), were investigated for their toxicological and anti-malarial effects in murine models. Method: Acute (14-day) and sub-acute (28-day) studies were conducted based on the Organization for Economic Cooperation and Development (OECD) Guidelines in Institute for Cancer Research (ICR) mice and Sprague Dawley (SD) rats respectively. A dosage of 2000 mg/kg body weight was administered orally to each ICR mouse during the acute study and 100, 300, and 1000 mg/kg body weight to each SD rat during the sub-acute study. A 5-day curative anti-plasmodial activity was assessed in ICR mouse model. Results: The assessment of toxicity revealed that all three fractions did not influence mortality, clinical appearance, body weight gain, or necropsy at the various doses. Hematological and serum biochemical analysis indicated no significant elevations in liver and renal function parameters. Histopathological examinations of the liver indicated reversible liver degeneration with the chloroform fraction of the 100% ethanol extract of Carapa procera leaves (CPL100%) at 1000 mg/kg. Anti-plasmodial assessments showed CPL100% exhibiting dose-dependent anti-plasmodial activity from 16% to 26.67%. On the other hand, chloroform fraction of the 100% ethanol extract of Alchornea cordifolia leaves (ACL100%) showed declining anti-plasmodial activity from 21.1% to 15.1%. Conclusion: These preliminary findings demonstrate that chloroform fractions of the leaves of Carapa procera and Alchornea cordifolia may be safe agents for treating malaria hence further development for drug discovery must be pursued.

Phytochemical, Antimalarial, and Acute Oral Toxicity Properties of Selected Crude Extracts of Prabchompoothaweep Remedy in Plasmodium berghei-Infected Mice

Malaria remains a life-threatening health problem and encounters with the increasing of antimalarial drug resistance. Medicinal plants play a critical role in synthesizing novel and potent antimalarial agents. This study aimed to investigate the phytochemical constituents, antiplasmodial activity, and evaluate the toxicity of crude ethanolic extracts of Myristica fragrans, Atractylodes lancea, and Prabchompoothaweep remedy in a mouse model. The phytochemical constituents were characterized by liquid chromatography-mass spectrometry (LC-MS). Antimalarial efficacy against Plasmodium berghei was assessed using 4-day suppressive tests at doses of 200, 400, and 600 mg/kg body weight. Acute toxicity was assessed at a dose of 2000 mg/kg body weight of crude extracts. The 4-day suppression test showed that all crude extracts significantly suppressed parasitemia (p < 0.05) compared to the control group. Higher parasitemia suppression was observed both in Prabchompoothaweep remedy at a dose of 600 mg/kg (60.1%), and A. lancea at a dose of 400 mg/kg (60.1%). The acute oral toxicity test indicated that the LD50 values of all extracts were greater than 2000 mg/kg and that these extracts were not toxic in the mouse model. LC-MS analysis revealed several compounds in M. fragrans, A. lancea, and Prabchompoothaweep remedy. For quantitative analysis, 1,2,6,8-tetrahydroxy-3-methylanthraquinone 2-O-b-D-glucoside, chlorogenic acid, and 3-O-(beta-D-glucopyranosyl-(1->6)-beta-D-glucopyranosyl) ethyl 3-hydroxyoctanoate were found in A. lancea, while (7′x,8′x)-4,7′-epoxy-3,8′-bilign-7-ene-3,5′-dimethoxy-4′,9,9′-triol, edulisin III, and tetra-hydrosappanone A trimethyl ether are found in M. fragrans. 6′-O-Formylmarmin was present in the Prabchompoothaweep remedy, followed by pterostilbene glycinate and amlaic acid. This study showed that the ethanolic extracts of A. lancea and Prabchompoothaweep remedy possess antimalarial activity against Plasmodium berghei. None of the extracts had toxic effects on liver and kidney function. Therefore, the ethanolic extract of A. lancea rhizome and Prabchompoothaweep remedy could be used as an alternative source of new antimalarial agents. Further studies are needed to determine the active compounds in both extracts.

In silico investigation of phytoconstituents from Cameroonian medicinal plants towards COVID-19 treatment

In silico studies performed on the metabolites of four Cameroonian medicinal plants with a view to propose potential molecules to fight against COVID-19 were carried out. At first, molecular docking was performed for a set of 84 selected phytochemicals with SARS-CoV-2 main protease (PDB ID: 6lu7) protein. It was further followed by assessing the pharmacokinetics and pharmacological abilities of 15 compounds, which showed low binding energy values. As the screening criteria for their ADMET properties were performed, only two compounds have shown suitable pharmacological properties for human administration which were shortlisted. Furthermore, the stability of binding of these compounds was assessed by performing molecular dynamics (MD) simulations. Based on further analysis through molecular dynamics simulations and reactivity studies, it was concluded that only the Pycnanthuquinone C (17) and the Pycnanthuquinone A (18) extracted from the Pycnanthus angolensis could be considered as candidate inhibitors for targeted protein. Indeed, we expect that these compounds could show excellent in vitro and in vivo activity against SARS-CoV-2.

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.

Identification of 3,3'-O-dimethylellagic acid and apigenin as the main antiplasmodial constituents of Endodesmia calophylloides Benth and Hymenostegia afzelii (Oliver.) Harms

Background

Endodesmia calophylloides and Hymenostegia afzelii belong to the Guttiferae and Caesalpiniaceae plant families with known uses in African ethno-medicine to treat malaria and several other diseases. This study aimed at identifying antiplasmodial natural products from selected crude extracts from H. afzelii and E. calophylloides and to assess their cytotoxicity.

Methods

The extracts from H. afzelii and E. calophylloides were subjected to bioassay-guided fractionation to identify antiplasmodial compounds. The hydroethanol and methanol stem bark crude extracts, fractions and isolated compounds were assessed for antiplasmodial activity against the chloroquine-sensitive 3D7 and multi-drug resistant Dd2 strains of Plasmodium falciparum using the SYBR green I fluorescence-based microdilution assay. Cytotoxicity of active extracts, fractions and compounds was determined on African green monkey normal kidney Vero and murine macrophage Raw 264.7 cell lines using the Resazurin-based viability assay.

Results

The hydroethanolic extract of H. afzelii stem bark (Hasb^HE) and the methanolic extract of E. calophylloides stem bark (Ecsb^M) exhibited the highest potency against both Pf3D7 (EC₅₀ values of 3.32 ± 0.15 μg/mL and 7.40 ± 0.19 μg/mL, respectively) and PfDd2 (EC₅₀ of 3.08 ± 0.21 μg/mL and 7.48 ± 0.07 μg/mL, respectively) strains. Both extracts showed high selectivity toward Plasmodium parasites (SI > 13). The biological activity-guided fractionation led to the identification of five compounds (Compounds 1–5) from Hasb^HE and one compound (Compound 6) from Ecsb^M. Of these, Compound 1 corresponding to apigenin (EC₅₀Pf3D7, of 19.01 ± 0.72 μM and EC₅₀PfDd2 of 16.39 ± 0.52 μM), and Compound 6 corresponding to 3,3′-O-dimethylellagic acid (EC₅₀Pf3D7 of 4.27 ± 0.05 μM and EC₅₀PfDd2 of 1.36 ± 0.47 μM) displayed the highest antiplasmodial activities. Interestingly, both compounds exhibited negligible cytotoxicity against both Vero and Raw 264.7 cell lines with selectivity indices greater than 9.

Conclusions

This study led to the identification of two potent antiplasmodial natural compounds, 3,3′-O-dimethylellagic acid and apigenin that could serve as starting points for further antimalarial drug discovery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-021-03352-9.

Botanical Medicines Cryptolepis sanguinolenta, Artemisia annua, Scutellaria baicalensis, Polygonum cuspidatum, and Alchornea cordifolia Demonstrate Inhibitory Activity Against Babesia duncani

Human babesiosis is a CDC reportable disease in the United States and is recognized as an emerging health risk in multiple parts of the world. The current treatment for human babesiosis is suboptimal due to treatment failures and unwanted side effects. Although Babesia duncani was first described almost 30 years ago, further research is needed to elucidate its pathogenesis and clarify optimal treatment regimens. Here, we screened a panel of herbal medicines and identified Cryptolepis sanguinolenta, Artemisia annua, Scutellaria baicalensis, Alchornea cordifolia, and Polygonum cuspidatum to have good in vitro inhibitory activity against B. duncani in the hamster erythrocyte model. Furthermore, we found their potential bioactive compounds, cryptolepine, artemisinin, artesunate, artemether, and baicalein, to have good activity against B. duncani, with IC₅₀ values of 3.4 μM, 14 μM, 7.4 μM, 7.8 μM, and 12 μM, respectively, which are comparable or lower than that of the currently used drugs quinine (10 μM) and clindamycin (37 μM). B. duncani treated with cryptolepine and quinine at their respective 1×, 2×, 4× and 8× IC₅₀ values, and by artemether at 8× IC₅₀ for three days could not regrow in subculture. Additionally, Cryptolepis sanguinolenta 90% ethanol extract also exhibited no regrowth after 6 days of subculture at doses of 2×, 4×, and 8× IC₅₀ values. Our results indicate that some botanical medicines and their active constituents have potent activity against B. duncani in vitro and may be further explored for more effective treatment of babesiosis.

The Effectiveness of Varying Combination Ratios of A. cordifolia and M. indica against Field and Laboratory Strains of P. falciparum In Vitro

Background

Drug resistance in malaria is a global problem, with reports of Plasmodium parasites resistant to the current first-line antimalarial drug, artemisinin, expanding from Southeast Asia to Africa. There is therefore an urgent need to identify new drug candidates that will be effective against the existing malaria parasites. Drug combination therapy presents a myriad of advantages over monotherapy including delayed onset of resistance, potentiation, and synergism. This present study explored the effectiveness of combinations of aqueous extracts of Alchornea cordifolia (A. cordifolia) and Mangifera indica (M. indica) at clearing both laboratory and field isolates of P. falciparum.

Methods

Synchronized ring stage cultures of field (FA08) and laboratory strains (NF54 and CamWT_C580Y) of P. falciparum were subjected to combinations of different concentrations and ratios of aqueous extracts of A. cordifolia and M. indica. The growth inhibition of the individual plant extracts and their combinatory effects were studied in vitro using SYBR Green I drug assay.

Results

The A. cordifolia extract exhibited 50% inhibitory concentration (IC₅₀) of 2.71, 7.80, and 3.56 μg/mL against the NF54, CamWT_C580Y, and FA08 parasite strains, respectively. Mangifera indica exhibited IC₅₀ of 18.11, 20.08, and 10.23 μg/mL against the NF54, CamWT_C580Y, and FA08 parasite strains, respectively. Additive, synergistic and antagonistic interactions were observed at different combinations of A. cordifolia and M. indica extracts.

Conclusion

A combination product containing A. cordifolia and M. indica has the potential to serve as an effective antimalarial as majority of the tested combinations of aqueous extracts of A. cordifolia and M. indica extracts exhibited synergistic effects in vitro against the NF54, CamWT_C580Y, and FA08 P. falciparum strains.

The In Vitro Antiplasmodial Activities of Aqueous Extracts of Selected Ghanaian Herbal Plants

Background

The asexual and sexual stages (gametocytes) of Plasmodium falciparum parasites are known to respond differently to antimalarial drugs. Herbal products with extended treatment regimens and inadequate dosing information are widely used to treat malaria in Ghana. This study set out to determine the in vitro activity of selected herbal extracts on the development of asexual and sexual stage malaria parasites.

Methods

The 72-hour SYBR Green 1-based in vitro drug assay was used to determine the asexual parasite growth inhibitory effects exhibited by aqueous extracts of Alchornea cordifolia, Polyalthia longifolia, Moringa oleifera, and Mangifera indica on the NF54, CamWT_C580Y, and IPC 4912 strains of Plasmodium falciparum. The effects of exposure of asexual and early-stage NF54 gametocytes to varying concentrations of the aqueous herbal extracts were assessed by microscopy after 7 days of continuous culturing in the presence of the herbal extract. Qualitative and quantitative phytochemical screening were also performed on the herbal extracts.

Results

In the SYBR Green 1 assay, aqueous extracts of Alchornea cordifolia exhibited moderate (IC₅₀ of 5.8, 17.4, and 15.8 μg/ml) and Mangifera indica exhibited low (IC₅₀ of 65.4, 96.7, and 81.7 μg/ml) activities against the NF54, Cam WT_C580Y, and IPC 4912 parasites, respectively, whilst Polyalthia longifolia and Moringa oleifera were inactive. Long-term treatment of NF54 parasites with 1 mg/ml of Polyalthia longifolia produced the highest densities of gametocytes and the least (56%) inhibition of asexual parasites on Day 7. Long-term treatment of NF54 parasites with 10 μg/ml Alchornea cordifolia resulted in complete parasite (asexual and gametocyte) clearance on Day 7. Conclusions. Alchornea cordifolia exhibited a ‘moderate' activity against the three parasites tested in the 72-hour SYBR Green 1 assay and also effectively cleared both asexual parasites and gametocytes. Long-term treatment of malaria parasites with herbal extracts mimics a treatment regimen and should be used to determine the antimalarial properties of herbal extracts.

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.

Exploring Antimalarial Herbal Plants across Communities in Uganda Based on Electronic Data

Malaria is one of the most rampant diseases today not only in Uganda but also throughout Africa. Hence, it needs very close attention as it can be severe, causing many deaths, especially due to the rising prevalence of pathogenic resistance to current antimalarial drugs. The majority of the Ugandan population relies on traditional herbal medicines for various health issues. Thus, herein, we review various plant resources used to treat malaria across communities in Uganda so as to provide comprehensive and valuable ethnobotanical data about these plants. Approximately 182 plant species from 63 different plant families are used for malaria treatment across several communities in Uganda, of which 112 plant species have been investigated for antimalarial activities and 96% of the plant species showing positive results. Some plants showed very strong antimalarial activities and could be investigated further for the identification and validation of potentially therapeutic antimalarial compounds. There is no record of an investigation of antimalarial activity for approximately 39% of the plant species used for malaria treatment, yet these plants could be potential sources for potent antimalarial remedies. Thus, the review provides guidance for areas of further research on potential plant resources that could be sources of compounds with therapeutic properties for the treatment of malaria. Some of the plants were investigated for antimalarial activities, and their efficacy, toxicity, and safety aspects still need to be studied.

Bioprospection for antiplasmodial activity, and identification of bioactive metabolites of native plants species from the Mata Atlântica biome, Brazil

A total of 33 extracts of eleven different plants species from Mata Atlântica biome, Brazil, and different fractions of the bioactive extracts were evaluated against chloroquine-resistant Plasmodium falciparum W2 strain by PfLDH method and cytotoxicity to HepG2 cells by the MTT assay, and chemically characterized by LC-DAD-ESI-MS/MS analysis. The results allowed the identification of Alchornea glandulosa, Miconia latecrenata, and Psychotria suterella as the most active plant species. Different flavonoids and tannins in Alchornea glandulosa and Miconia latecrenata besides alkaloids in Psychotria suterella were identified. Bioguided fractionation of A. glandulosa and M. latecrenata leaves extracts led to fractions exhibiting high parasite growth inhibition. Seven known alkaloids were identified in the P. suterella extract, and of these, only 5-carboxystrictosidine had been assayed for antiplasmodial activity what points to this species as the most promising among the eleven one assayed.

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.

Study of aflatoxicosis reduction: effect of Alchornea cordifolia on biomarkers in an aflatoxin B1 exposed rats

The toxicity of aflatoxins results in cancer and liver disease. Several natural substances such as plants exhibited their ability to inhibit the initiation of aflatoxin carcinogenesis. The aim of this study was to evaluate the effect of Alchornea cordifolia on biomarkers in an aflatoxin B1 (AFB1) exposed rats. The contents of polyphenols, flavonoids and the antioxidant activity of A. cordifolia ethanolic leaf extract (EELac) were assessed. Groups of rats were treated orally with a daily dose of a mixture of AFB1 at a dose of 150 μg/kg body weight and EELac (50, 100 and 300 mg/kg body weight) for 21 days. Biomarkers of AFB1, such as the AFB1-lysine adduct and aflatoxin M1 were assayed in blood and urine, respectively, using an HPLC system with a fluorescence detector. The contents of polyphenols and flavonoids were 6783.23 ± 272.76 μg EAG/g and 10.54 ± 3.15% of dry matter, respectively. EELac showed a good antioxidant activity (IC50 = 12.65 ± 0.13 μg/mL). The administration of the mixture (AFB1 + EELac) at different doses significantly reduced the level of AFB1-lysine adduct from 14.04 ± 2.1 to 4.13 ± 0.9 ng/mg albumin and that of Aflatoxin M1 (AFM1) from 456 ± 16 to 220 ± 24 ng/mL (p <0.05). The rate of reduction was 70.58% for AFB1-lysine adduct and 51.75% for AFM1. A. cordifolia could be used in the prevention of toxicity induced by AFB1 on account of its high content in phenolic compounds.

Antimalarial Activities of Alkyl Cyclohexenone Derivatives Isolated from the Leaves of Poupartia borbonica

Bioactivity-guided fractionation of the ethyl acetate extract of the leaves of Poupartia borbonica led to the isolation of three new alkyl cyclohexenone derivatives 1-3, and named Poupartone A-C. The structures of the new compounds were elucidated by 1D and 2D NMR spectroscopic data analysis and MS, whereas calculated and experimental ECD spectra were used to define the absolute configurations. These compounds were active against 3D7 and W2 Plasmodium falciparum strains with IC₅₀ values between 0.55 and 1.81 μM. In vitro cytotoxicity against WI38 human fibroblasts and the human cervical cancer cell line HeLa (WST-1 assay) showed that these compounds were also cytotoxic, but no hemolytic activity was observed for the extract and pure compounds. An in vivo antimalarial assay was performed on the major cyclohexenone using P. berghei-infected mice at a dose of 15 mg/kg/day ip. The assay revealed growth inhibition of 59.1 and 69.5% at days 5 and 7 postinfection, respectively, although some toxicity was observed. Zebrafish larvae were used as a model to determine the type of toxicity, and the results showed cardiac toxicity. The methanol extract was also studied, and it displayed moderate antiplasmodial properties in vitro. This extract contained the known flavonoids, quercetin, 3'-O-hydroxysulfonylquercetin, quercitrin, and isoquercitrin as well as ellagic acid, which showed high to low activity against the 3D7 P. falciparum strain.

Recent trends in phytochemistry, ethnobotany and pharmacological significance of Alchornea cordifolia (Schumach. & Thonn.) Muell. Arg

ETHNOPHARMACOLOGICAL RELEVANCE

Alchornea cordifolia (Schumach. & Thonn.) Muell. Arg. (Euphorbiaceae) (A. cordifolia) is widely distributed throughout tropical Africa, where it is used extensively in traditional medicine. Conditions for which the plant has enjoyed wide use are: coughs, gonorrhoea, infertility, prostatitis, bacterial infections, diarrhoea, ulcers, pain, inflammation, fever and bronchial troubles. This review summarizes the achievements of the investigations in traditional uses, ethnobotany, phytochemistry, biological activities and toxicological profile of A. cordifolia; this review also describes the shortcomings of studies on this herbal drug and thus serves as the basis of further scientific research and development of this traditional herbal drug.

MATERIALS AND METHODS

A. cordifolia-related information was collected from various resources including published articles in peer-reviewed journals, unpublished materials, textbooks, government survey reports and scientific databases such as Scifinder®, Pubmed, Science Direct, Wiley, Springer, ACS, Scielo, Web of Science and other web search instruments (Google, Yahoo), published on the subject from 1950 to 2016. 'The Plant List' (www.theplantlist.org) and 'Kew Royal Botanic Gardens' (mpns.kew.org) were used to validate the scientific name of the plant.

RESULTS

The literature revealed several reports on traditional uses, biological activities, chemical constituents and toxicological evaluation of A. cordifolia. The phytochemical information indicates identification of 95 compounds including fatty acids, terpenoids, flavonoids, phenolic acids, alkaloids, which exhibited various pharmacological activities such as wound healing, anti-inflammation, anticancer, antioxidant, immunomodulation, antidiarrhoeal, antimicrobial, antidepressant, hepatoprotective, antiplasmodial and anxiolytic. However, there are still significant gaps in the completeness of our understanding of A. cordifolia bioactivity, therapeutic value, and roles played by each of the numerous phytoconstituents.

CONCLUSIONS

The present review indicated that A. cordifolia is a valuable medicinal plant with multiple pharmacological effects. However, further research on the pharmacological mechanism of action of this plant is recommended in order to unravel the pharmacokinetics, pharmacodynamics, clinical relevance and toxicity of its extracts as well as constituents.

In vitro antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Isolona hexaloba

ETHNOPHARMACOLOGICAL RELEVANCE

Isolona hexaloba (Pierre) Engl. and Diels (Annonaceae) is traditionally used in D.R. Congo against parasitic diseases including malaria.

MATERIALS AND METHODS

Two crude aqueous extracts, 3 crude methanol extracts and 3 crude 80% ethanol extracts from the leaves, root bark and stem bark together with 12 subfractions from the crude 80% ethanol extracts were evaluated in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, T. cruzi, Leishmania infantum and the chloroquine and pyrimethamine resistant K1 strain of Plasmodium falciparum. Their cytotoxic effects against MRC-5 cell lines were also assessed.

RESULTS

Results indicated that the most pronounced activities against T. b. brucei were recorded for the crude methanol extracts of root bark (IC50=1.97 µg/ml; SI>32.49) and leaves (IC50=2.65 µg/ml; SI>24.15). Three samples displayed good activity against T. cruzi: the 80% methanol extract of leaves (IC50=8.33 µg/ml; SI>3.92), its petroleum ether fraction (IC50=8.50 µg/ml; SI=2.52) and the crude aqueous extract of the stem bark (IC50=9.31 µg/ml; SI=3.46). The crude aqueous extract of the leaves exhibited a pronounced and selective activity against L. infantum (IC50=2.00 µg/ml; SI>32). The crude methanol extract of leaves (IC50=6.35 µg/ml; SI>10.10) and the 2 dichloromethane soluble fractions of the 80% ethanol extracts from root bark (IC50=6.96 µg/ml; SI=6.1) and stem bark (IC50=8 µg/ml; SI>8.00) showed good activity and selectivity against L. infantum. The most active samples against Plasmodium falciparum K1 were the leaves crude 80% ethanol extract (0.92 µg/ml) and its fractions: alkaline aqueous (IC50=0.27 µg/ml), 90% methanol (0.90 µg/ml) and dichloromethane (1.04 µg/ml), respectively, with promising selectivity indexes of 35<SI<237. None of all the tested crude extracts and fractions was found to be cytotoxic against MRC-5 cell lines except the petroleum ether soluble fraction from the leaves which displayed a cytotoxic effect (CC50=21.40 µg/ml).

CONCLUSION

Overall, extracts of I. hexaloba tested here, showed good results concerning parasitic infections such as Chagas' disease, leishmaniasis, malaria and/or sleeping sickness without considerable toxicity. The 80% ethanol extracts from leaves and their fractions turned out to be of special interest as they were the most useful in the treatment of malaria.

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.

Medicinal plants and finished marketed herbal products used in the treatment of malaria in the Ashanti region, Ghana

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical survey was performed to document medicinal plants employed in the management of malaria in the Bosomtwe and Sekyere East Districts of the Ashanti Region (Ghana), in comparison with the plant ingredients in herbal antimalarial remedies registered by the Ghana Food and Drug Administration.

MATERIALS AND METHODS

Two hundred and three (203) herbalists from 33 communities within the two districts were interviewed on medicinal plants they use to manage malaria. A literature search was made to determine already documented plants. In addition, 23 finished marketed herbal products indicated for the management of malaria were identified and their labels examined to find out which of the plants mentioned in our survey were listed as ingredients and whether these products are in anyway regulated.

RESULTS

Ninety-eight (98) species of plants were cited for the management of malaria. In comparison with literature citations, 12 (12.2%) species were reported for the management of malaria for the first time and 20 (20.4%) others for the first time in Ghana. Twenty-three (23) finished marketed herbal antimalarial products examined contained aerial or underground parts of 29 of the plants cited in our survey as ingredients. Twenty-two (22) of these products have been registered by the Ghana Food and Drugs Authority, four (4) of which were included in the recommended herbal medicine list for treating malaria in Ghana.

CONCLUSION

This study provides new additions to the inventory of medicinal plants used for the management of malaria and reports the commercial availability and regulation of finished marketed labelled herbal products intended for the treatment of malaria in Ghana.

Ellagic acid induces apoptosis in TSGH8301 human bladder cancer cells through the endoplasmic reticulum stress- and mitochondria-dependent signaling pathways

To investigate the effects of ellagic acid on the growth inhibition of TSGH8301 human bladder cancer cells in vitro, cells were incubated with various doses of ellagic acid for different time periods. The phase-contrast microscope was used for examining and photographing the morphological changes in TSGH8301 cells. Flow cytometric assay was used to measure the percentage of viable cells, cell cycle distribution, apoptotic cells, ROS, mitochondrial membrane potential (ΔΨm), Ca(2+) , caspase-9 and -3 activities in TSGH8301 cells after exposure to ellagic acid. Western blotting was used to examine the changes of cell cycle and apoptosis associated proteins levels. Results indicated that ellagic acid induced morphological changes, decreased the percentage of viable cells through the induction of G0/G1 phase arrest and apoptosis, and also showed that ellagic acid promoted ROS and Ca(2+) productions and decreased the level of ΔΨm and promoted activities of caspase-9 and -3. The induction of apoptosis also confirmed by annexin V staining, comet assay, DAPI staining and DNA gel electrophoresis showed that ellagic acid induced apoptosis and DNA damage in TSGH8301 cells. Western blotting assay showed that ellagic acid promoted p21, p53 and decreased CDC2 and WEE1 for leading to G0/G1 phase arrest and promoting BAD expression, AIF and Endo G, cytochrome c, caspase-9 and -3 for leading to apoptosis in TSGH8301 cells. On the basis of these observations, we suggest that ellagic acid induced cytotoxic effects for causing a decrease in the percentage of viable cells via G0/G1 phase arrest and induction of apoptosis in TSGH8301 cells.

The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system.

MATERIALS AND METHODS

Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. 'Diabetes' and 'Nigeria' were used as keywords for the primary searches; and then 'Plant name - accepted or synonyms', 'Constituents', 'Drug interaction' and/or 'Toxicity' for the secondary searches.

RESULTS

The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs.

CONCLUSION

This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb-drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided.

In vivo anti-inflammatory activity of Tabernaemontana divaricata leaf extract on male albino mice

AIM

To study the in vivo anti-inflammatory activity of Tabernaemontana divaricata leaf extract on male albino mice.

METHODS

Aqueous decoction and methanol leaf extracts were tested for their ability to reduce croton oil-induced edema in the mouse ear after topical application. The methanol leaf extract dose-dependently inhibited the croton oil-induced ear edema in mice (ID50 <500 μg·cm(-2)). A bioassay-guided liquid-liquid fractionation of this methanol extract gave four active fractions: water insoluble (F1), hexane (F2), ethyl acetate (F3) and water (F4).

RESULTS

The hexane fraction showed a very high activity (42.1% inhibition at 0.7 μg·cm(-2)) as compared to the control. The other fractions were less active (F1: 56.1% at 506.2 μg·cm(-2); F3: 57.3% at 289.3 μg·cm(-2); and F4: 31.9% for 203.8 μg·cm(-2)) while indomethacin gave 48.8% of inhibition at 90 μg·cm(-2). The activity of F1 and F3 may be at least in part explained by the presence of anti-inflammatory flavonoids, while the activity was not correlated to the tannin contents. No compounds were detected in the most active F2 fraction.

CONCLUSIONS

The results give a rational support to the traditional use of T. divaricata in tropical India as anti-inflammatory agent.

The potential of anti-malarial compounds derived from African medicinal plants, part II: a pharmacological evaluation of non-alkaloids and non-terpenoids

Malaria is currently a public health concern in many countries in the world due to various factors which are not yet under check. Drug discovery projects targeting malaria often resort to natural sources in the search for lead compounds. A survey of the literature has led to a summary of the major findings regarding plant-derived compounds from African flora, which have shown anti-malarial/antiplasmodial activities, tested by in vitro and in vivo assays. Considerations have been given to compounds with activities ranging from "very active" to "weakly active", leading to >500 chemical structures, mainly alkaloids, terpenoids, flavonoids, coumarins, phenolics, polyacetylenes, xanthones, quinones, steroids and lignans. However, only the compounds that showed anti-malarial activity, from "very active" to "moderately active", are discussed in this review.

Virtualizing the p-ANAPL library: a step towards drug discovery from African medicinal plants

Background

Natural products play a key role in drug discovery programs, both serving as drugs and as templates for the synthesis of drugs, even though the quantities and availabilities of samples for screening are often limitted.

Experimental approach

A current collection of physical samples of > 500 compound derived from African medicinal plants aimed at screening for drug discovery has been made by donations from several researchers from across the continent to be directly available for drug discovery programs. A virtual library of 3D structures of compounds has been generated and Lipinski’s “Rule of Five” has been used to evaluate likely oral availability of the samples.

Results

A majority of the compound samples are made of flavonoids and about two thirds (2/3) are compliant to the “Rule of Five”. The pharmacological profiles of thirty six (36) selected compounds in the collection have been discussed.

Conclusions and implications

The p-ANAPL library is the largest physical collection of natural products derived from African medicinal plants directly available for screening purposes. The virtual library is also available and could be employed in virtual screening campaigns.

A bioactivity versus ethnobotanical survey of medicinal plants from Nigeria, west Africa

Traditional medicinal practices play a key role in health care systems in countries with developing economies. The aim of this survey was to validate the use of traditional medicine within local Nigerian communities. In this review, we examine the ethnobotanical uses of selected plant species from the Nigerian flora and attempt to correlate the activities of the isolated bioactive principles with known uses of the plant species in African traditional medicine. Thirty-three (33) plant species were identified and about 100 out of the 120 compounds identified with these plants matched with the ethnobotanical uses of the plants.

The uniqueness and therapeutic value of natural products from West African medicinal plants, part III: least abundant compound classes

In this review, a continuation of our in-depth coverage of natural products derived from West African medicinal plants with diverse biological activities has been given.

Ethnobotanical survey on medicinal plants used by Guinean traditional healers in the treatment of malaria

ETHNOPHARMACOLOGICAL RELEVANCE

The objective of the present study was to collect and document information on herbal remedies traditionally used for the treatment of malaria in Guinea.

MATERIALS AND METHODS

The survey was carried out from May 2008 to September 2010 and targeted traditional medical practitioners and herbalists. The questionnaire and oral interviews were based on the standardized model which was prepared by the "Centre de Recherche et de Valorisation des Plantes Médicinales (CRVPM) - Dubréka".

RESULTS AND DISCUSSION

A total of 258 people (141 males and 117 females) from which 150 traditional healers and 108 herbalists were interviewed. The age of informants ranged from 28 to 82 years old. 57% (149/258) of the interviewees were more than 50 years old. The respondents had good knowledge of the symptoms of malaria, and a fairly good understanding of the causes. One hundred thirteen plant species were recorded, out of which 109 were identified. They belonged to 84 genera and 46 families. The most frequently cited plants were Vismia guineensis, Parkia biglobosa, Nauclea latifolia, Harungana madagascariensis, Terminalia macroptera, Crossopteryx febrifuga, Terminalia albida, Annona senegalensis, and Nauclea pobeguinii. The leaves were most frequently used (80/113 species), followed by stem bark (38/113 species) and roots (4/113 species). The remedies were mostly prepared by decoction (111 species), followed by maceration (seven species). Only one species was prepared by infusion.

CONCLUSION

The present study showed that traditional healers in Guinea have a consistent knowledge of antimalarial plants. Further research should be carried out to compare the anti-malarial activity of the different species, and to check if their use against malaria can be scientifically validated.

In vitro antiplasmodial activity of some medicinal plants of Burkina Faso

Malaria remains a major public health problem due to the emergence and spread of Plasmodium falciparum drug resistance. There is an urgent need to investigate new sources of antimalarial drugs which are more effective against Plasmodium falciparum. One of the potential sources of antimalarial drugs is traditional medicinal plants. In this work, we studied the in vitro antiplasmodial activity of chloromethylenic, methanolic, and MeOH/H2O (1/1) crude extracts and decoction obtained from eight medicinal plants collected in Burkina Faso and of total alkaloids for five plants. Extracts were evaluated in vitro for efficacy against Plasmodium falciparum strain K1, which is resistant to chloroquine, pyrimethamine and proguanil using the fluorescence-based SYBR Green I assay. The antiproliferative activity on human-derived hepatoma cell line HepG2 and Chinese hamster ovary (CHO) cells was evaluated using the 3-[4,5-dimethylthyazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test in order to determine the selectivity index. Among the plant extracts tested for in vitro antiplasmodial activity, 16 were considered to be inactive (with IC50 > 10 μg/ml), six showed a moderate activity (5 < IC50 ≤ 10 μg/ml), and six were found to have a good in vitro activity with IC50 value ≤ 5 μg/ml. The highest antiplasmodial activity was found for extracts from: the alkaloid leaf extract and the chloromethylenic extracts of Combretum fragrans (IC50 = 3 μg/ml, IC50 = 5 μg/ml), the total alkaloids and the chloromethylenic leaf extracts of Combretum collinum (IC50 = 4 μg/ml), the MeOH/H2O leaf extract of Terminalia avicennioides (IC50 = 3.5 μg/ml), and the alkaloid leaf extract of Pavetta crassipes (IC50 = 5 μg/ml). Three other extracts showed moderate antiplasmodial activity (5 < IC50 ≤ 10 μg/ml): Terminalia avicennioides and Combretum fragrans methanolic extracts and Acacia kirkii alkaloid leaf extract (IC50 = 6.5, 9 and 10 μg/ml respectively). The Terminalia avicennioides crude MeOH/H2O (80:20 v/v) extract of the leaves was submitted to a successive liquid/liquid extraction with ethylacetate and n-butanol respectively. The extracts were investigated for in vitro antiplasmodial activity and antioxidant properties using DPPH(·), ABTS(+) and FRAP methods. The ethylacetate extract showed the best antiplasmodial activity (7 μg/ml) and the active constituent was isolated as ellagic acid by bioguided fractionation with an IC50 = 0.2 μM on Plasmodium falciparum and SI = 152. Besides, Terminalia avicennioides leaf extract and ellagic acid showed a good antioxidant activity. Our finding confirms the importance of investigating the antimalarial activity of plant species used in traditional medicine. Overall, two plants belonging to the Combretaceae family, Combretum fragrans and Combretum collinum appeared to be the best candidates and will be further investigated for their antiplasmodial properties, in order to isolate the molecules responsible for the antiplasmodial activity.

Density functional predictions of antioxidant activity and UV spectral features of nasutin A, isonasutin, ellagic acid, and one of its possible derivatives

The antioxidant ability of ellagic acid and some of its derivatives was explored at density functional level of theory within the framework of the following three different reaction mechanisms: hydrogen atom transfer (HAT), electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET). Computations were performed in gas phase and in both water and methanol media. Results show that the HAT mechanism is preferred by this class of compounds in all environments, although, in principle, polar solvents should promote the SET-PT and SPLET mechanisms. Among the considered compounds, the derivative not yet experimentally characterized seems to be the most promising candidate as antioxidant. For a more detailed spectroscopic characterization and to help in the identification of these compounds, the simulated UV spectra of all investigated molecules were done by using the time-dependent formulation of density functional theory (TDDFT).

Bioactive natural products derived from the Central African flora against neglected tropical diseases and HIV

This review discusses the medicinal potential of bioactive metabolites isolated from medicinal plants in Central Africa for the treatment of neglected tropical diseases and HIV. A correlation is established between the biological activities of the isolated compounds and the uses of the plants in traditional medicine. Insight is provided on how secondary metabolites from medicinal plants in Central Africa could be exploited for drug discovery.

Antiplasmodial potential of selected medicinal plants from eastern Ghats of South India

Malaria caused by the protozoan parasite Plasmodium falciparum, is a major health problem of the developing world. In the present study medicinal plants from Eastern Ghats of South India have been extracted with ethyl acetate and assayed for growth inhibition of asexual erythrocytic stages of chloroquine (CQ)-sensitive (3D7) and (CQ)-resistant (INDO) strains of P. falciparum in culture using the fluorescence-based SYBR Green I assay. Studied extracts showed a spectrum of antiplasmodial activities ranging from (a) very good (IC(50)<10-10 μg/mL: Cyperus rotundus and Zingiber officinale); (b) good (IC(50), >10-15 μg/mL: Ficus religiosa and Murraya koenigii); (c) moderate (IC(50)>15-25 μg/mL: Ficus benghalensis); (d) poor activity (IC(50)>25-60 μg/mL) and (e) inactive (IC(50)>60 μg/mL). Resistance indices ranging from 0.78 to 1.28 suggest that some of these extracts had equal promise against the CQ resistant INDO strain of P. falciparum. Cytotoxicity assessment of the extracts against HeLa cell line using MTT assay revealed that the selectivity indices in the range of 3-15 suggesting a good margin of safety.

Immunomodulatory activity of polysaccharides isolated from Alchornea cordifolia

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of leaves from different species of the genus Alchornea have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts.

OBJECTIVE

The aim of this study was to evaluate the immunomodulatory activity of polysaccharides isolated from the leaves of Alchornea cordifolia.

MATERIALS AND METHODS

Water-soluble polysaccharides from leaves of Alchornea cordifolia were extracted and fractionated by DEAE-cellulose, Diaion HP-20, and size-exclusion chromatography. Molecular weight, sugar analysis, and other physical and chemical characterization of the fractions were performed. Immunomodulatory activity of the polysaccharide fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO) and cytokine production. Activation of mitogen activated protein kinases (MAPK) was also assessed using a phospho-MAPK array. Activation of nuclear factor κB (NF-κB) was measured using an alkaline phosphatase reporter gene assay in THP1-Blue monocytic cells.

RESULTS

Six polysaccharide fractions from Alchornea cordifolia were isolated. Fractions containing type II arabinogalactan had potent immunomodulatory activity. Particularly, the parent fraction AP-AU and its high-molecular weight sub-fraction AP-AU1 (average M(r) was estimated to be 39.5kDa) induced production of NO and cytokines [interleukin (IL)-1β, -6, -10, tumor necrosis factor (TNF)-α, and granulocyte-macrophage-colony stimulating factor (GM-CSF)] in human peripheral blood mononuclear cells and human and murine monocyte/macrophages cell lines in vitro. Furthermore, treatment with AP-AU1 induced phosphorylation of Akt2, p38δ/p38γ, p70S6K1, RSK2, and mTOR, as well as stimulation of NF-κB transcriptional activity.

CONCLUSION

Our results provide a molecular basis to explain a portion of the beneficial therapeutic properties of water extracts from Alchornea cordifolia leaves in traditional folk medicine of Africa.

Implication of glutathione in the in vitro antiplasmodial mechanism of action of ellagic acid

The search for new antimalarial chemotherapy has become increasingly urgent due to parasite resistance to current drugs. Ellagic acid (EA) is a polyphenol, recently found in various plant products, that has effective antimalarial activity in vitro and in vivo without toxicity. To further understand the antimalarial mechanism of action of EA in vitro, we evaluated the effects of EA, ascorbic acid and N-acetyl-L-cysteine (NAC), alone and/or in combination on the production of reactive oxygen species (ROS) during the trophozoite and schizonte stages of the erythrocytic cycle of P. falciparum. The parasitized erythrocytes were pre-labelled with DCFDA (dichlorofluorescein diacetate). We showed that NAC had no effect on ROS production, contrary to ascorbic acid and EA, which considerably reduced ROS production. Surprisingly, EA reduced the production of the ROS with concentrations (6.6×10⁻⁹ − 6.6×10⁻⁶ M) ten-fold lower than ascorbic acid (113×10⁻⁶ M). Additionally, the in vitro drug sensitivity of EA with antioxidants showed that antiplasmodial activity is independent of the ROS production inside parasites, which was confirmed by the additive activity of EA and desferrioxamine. Finally, EA could act by reducing the glutathione content inside the Plasmodium parasite. This was consolidated by the decrease in the antiplasmodial efficacy of EA in the murine model Plasmodium yoelii- high GSH strain, known for its high glutathione content. Given its low toxicity and now known mechanism of action, EA appears as a promising antiplasmodial compound.

Quantitative determination of bioactive 4-hydroxy-α-tetralone, tetralone-4-O-β-D-glucopyranoside and ellagic acid in Ammannia baccifera (Linn.) by reversed-phase high-performance liquid chromatography

Ammannia baccifera is an important component of various Chinese herbal formulations for which a rapid, simple, sensitive, gradient and reproducible reversed-phase high-performance liquid chromatographic method has been developed for the quantitative estimation of its bioactive constituents, 4-hydroxy-α-tetralone (4H), tetralone-4-O-β-D-glucopyranoside (T4) and ellagic acid (EA). The chromatographic separation of samples was performed on a Chromatopak Peerless C18 (250 × 4.6 mm i.d., 5 µm) column by gradient elution with 0.1% trifluoroacetic acid in water and methanol at a flow rate of 0.6 mL/min, a column temperature at 25°C and ultraviolet detection at λ 254 nm. The limit of detection (LOD) and limit of quantification (LOQ) were 1.51 and 5.06 µg/mL for EA, 0.70 and 2.33 µg/mL for T4 and 0.22 and 0.73 µg/mL for 4H, respectively. Good results were achieved with respect to linearity (r(2) > 0.999), repeatability (relative standard deviation ≤ 1.73%) and recovery (99.06-100.76%). The method was validated for linearity, accuracy, repeatability, LOQ and LOD. The method is simple, accurate and precise and was successfully applied to the analysis of these three analytes in five different leaf and root samples of A. baccifera; the method may be recommended for routine quality control analysis of various Chinese herbal formulations containing A. baccifera.

Phytochemical analysis, hepatoprotective and antioxidant activity of Alchornea cordifolia methanol leaf extract on carbon tetrachloride-induced hepatic damage in rats

OBJECTIVE

To investigate the hepatoprotective and antioxidant activities of Alchornea cordifolia (A. cordifolia) leaf extract.

METHODS

Various solvent fractions of the methanol extract of the leaf of the plant A. cordifolia Mull. Arg (Fam: Euphorbiaceae) were evaluated for hepatoprotective activity by carbon tetrachloride-induced liver damage in rats. The degree of protection was measured by using biochemical parameters such as serum glutamate oxalate transaminase (SGOT/AST), serum glutamate pyruvate transaminase (SGPT/ALT), alkaline phosphatase (ALP) and total bilirubin. The in vitro antioxidant activity of the extract was also evaluated by the 1, 1-diphenyl- 2-picrylhydrazyl (DPPH) free radical scavenging assay. The extract was subjected to preliminary phytochemical screening.

RESULTS

The ethyl acetate and chloroform fractions, at a dose of 300 mg/kg, produced significant (P<0.05) hepatoprotection by decreasing the activities of the serum enzymes and bilirubin while there were marked scavenging of the DPPH free radicals by the fractions. The effects were comparable to those of the standard drugs used for the respective experiments, silymarin and ascorbic acid. Alkaloids, flavonoids, saponins and tannins were detected in the phytochemical screening.

CONCLUSION

From this study, it was concluded that the plant of A. cordifolia possesses hepatoprotective as well as antioxidant activities and these activities reside mainly in the ethyl acetate and acetone fractions of methanol leaf extract.

In vitro antiprotozoal and cytotoxic activity of 33 ethonopharmacologically selected medicinal plants from Democratic Republic of Congo

ETHNOPHARMACOLOGICAL RELEVANCE

The antiprotozoal and cytotoxic activity of the aqueous extracts from 33 medicinal plants, used by traditional healers for the treatment of various parasitic diseases and collected after an ethnopharmacological inventory conducted in the Bolongo area, Bandundu province in DR Congo, was evaluated.

MATERIALS AND METHODS

Decoctions were prepared, lyophilized and evaluated for in vitro antiprotozoal activity against Trypanosoma b. brucei, Trypanosoma cruzi, Leishmania infantum, and the chloroquine- and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Cytotoxicity against MRC-5 cells was included to assess selectivity of activity.

RESULTS

Most of the tested extracts exhibited pronounced (IC(50)≤5μg/ml) or good (5<IC(50)≤10μg/ml) antiprotozoal activity against one or more of the selected protozoa. A total of 19 plant extracts inhibited Trypanosoma b. brucei, especially the extract from Isolona hexaloba stem bark (IC(50)=1.95μg/ml, SI=16.5); 8 plant extracts were active against Trypanosoma cruzi, the extracts from Enanatia chlorantha stem bark and Quassia africana root bark being the most active with IC(50) values of 1.87 and 1.88μg/ml, respectively (SI=3.0 and 3.3, respectively); 8 plant extracts showed activity against Leishmania infantum, with extracts from Napoleona vogelii stem bark and Quassia africana root bark as the most active with IC(50) values of 5.66 and 5.04μg/ml (SI=11.3 and 1.2). Finally, 9 plant extracts inhibited Plasmodium falciparum K1 with the extracts from Quassia africana (root bark and stem bark) being the most active ones with IC(50) values of 0.46 and 1.27μg/ml (SI=13.7 and 13.6). Extracts from Enantia chlorantha stem bark, Piptadeniastrum africanum stem bark and Quassia africana root bark were cytotoxic for MRC-5 cells (CC(50)<10μg/ml).

CONCLUSIONS

These results can partly support and justify the traditional use of some of these plant species for the treatment of parasitic diseases.

The quantification of ellagic acid in the crude extract of Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae)

INTRODUCTION

Phyllanthus amarus Schum. & Thonn. (Euphorbiaceae), already well known for its antiviral, antihyperglycaemic and antihepatotoxic effects, is also investigated for its antimalarial activity. The major constituent of the crude extract of the whole plant was isolated and identified in this research to be ellagic acid, for which antiplasmodial activity already has been reported.

OBJECTIVE

Because of the potential of the plant and the interesting properties of ellagic acid, an analytical method can be useful for the standardisation of the extracts to allow further biological and pharmacological investigations. In order to obtain an easily performable and inexpensive method, an HPLC analysis was developed and validated.

METHODOLOGY

The samples were dissolved in DMSO, ultrasonicated for 15 min, and diluted with 50% methanol. Analysis was performed using water and methanol containing 0.06% TFA and the peaks were detected at 254 nm.

RESULTS

Ellagic acid showed a linear relationship in the range of 1.74-20.91 µg/mL and a single-point calibration was allowed. The method was shown to be precise with respect to time (RSD of 1.84%, 3 days, n = 6) and concentration (RSD of 2.54%, 3 levels, n = 6). The overall mean content of ellagic acid was 2.06%. A recovery experiment was performed and it showed an accuracy of 100.4%.

CONCLUSION

Based on the obtained results, it can be concluded that the newly developed method is suitable for its purpose, namely the determination of ellagic acid in the crude extract of P. amarus.

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.

Antiplasmodial activity of botanical extracts against Plasmodium falciparum

The absence of a vaccine and the rampant resistance to almost all antimalarial drugs have accentuated the urgent need for new antimalarial drugs and drug targets for both prophylaxis and chemotherapy. The aim of the study was to discover effective plant extracts against Plasmodium falciparum. In the present study, the hexane, chloroform, ethyl acetate, acetone, and methanol extracts of Citrus sinensis (peel), Leucas aspera, Ocimum sanctum, Phyllanthus acidus (leaf), Terminalia chebula (seed) were tested for their antimalarial activity against chloroquine (CQ)-sensitive (3D7) strain of P. falciparum which was cultured following the candle-jar method. Antimalarial evaluations of daily replacement of culture medium containing CQ and different plant crude extracts were performed on 96-well plates at 37°C for 24 and 48 h. Parasitemia was determined microscopically on thin-film Giemsa-stained preparations. Plant extracts were tested for their cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay on human laryngeal cancer cell line (HEp-2) and normal cell line (Vero). Out of the 25 extracts tested, six showed good (IC(50) 4.76-22.76 μg/mL), 15 exhibited moderate (IC(50) 31.42-88.03 μg/mL), while four displayed mild (IC(50) > 100 μg/mL) antiplasmodial activity. The leaf ethyl acetate and methanol extracts of L. aspera; ethyl acetate, acetone, and methanol extracts of P. acidus; and seed acetone extract of T. chebula had good antiplasmodial activity (IC(50) = 7.81, 22.76, 9.37, 14.65, 12.68, and 4.76 μg/mL) with selectivity indices 5.43, 2.04, 4.88, 3.35, 3.42, and 9.97 for HEp-2 and >5.79, >2.20, >11.75, >3.41, >3.94, and >7.38 for Vero cells, respectively. These analyses have revealed for the first time that the components present in the solvent extracts of L. aspera, P. acidus, and T. chebula have antiplasmodial activity. The high antiplasmodial activity observed make these plants good candidates for isolation of anti-protozoal compounds which could serve as new lead structures for drug development.

Phenolic Compounds in Leaves of Alchornea Triplinervia: Anatomical Localization, Mutagenicity, and Antibacterial Activity

Phenolic compounds are produced by secretory idioblasts and hypodermis, and by specialized cells of the epidermis and chlorenchyma of leaves of Alchornea triplinervia. Phytochemical investigation of these leaves led to the isolation of the known substances quercetin, quercetin-7- O-β-D-ghicopyranoside, quercetin-3- O-β-D-glucopyranoside, quercetin-3- O-β-D-galactopyranoside, quercetin-3- O-α-L-arabinopyranoside, amentoflavone, brevifolin carboxylic acid, gallic acid, and methyl gallate from the methanolic extract, and stigmasterol, campesterol, sitosterol, lupeol, friedelan-3-ol, and friedelan-3-one from the chloroform extract. In studies of antibacterial activity and mutagenicity, the methanolic extract showed promising activity against Staphylococcus aureus (MIC=62.5 μg/mL) and was slightly mutagenic in vitro and in vivo at the highest concentrations tested (1335 mg/kg b.w.).

Activation of murine lymphocytes and modulation of macrophage functions by fractions of Alchornea cordifolia (Euphorbiaceae) leaf extract

The immune system is highly complex, intricately regulated group of cells whose integrated function is essential to health. Modulating the functions of these cells offers important pharmacological and therapeutic approaches in many disease conditions.This study reports on the in vitro immunostimulant activities of two flavonoid-rich fractions of Alchornea cordifolia (Euphorbiaceae) leaf extract: EAC and AAC, obtained by fractionating the methanol extract into ethylacetate and acetone soluble fractions, respectively.The lymphoproliferative effect of the fractions on naïve murine splenocytes and thymocytes as well as the modulatory effects on the phagocytic and lysosomal enzyme activities of elicited murine macrophages was investigated. A. cordifolia fractions, EAC and AAC, produced significant (P<0.05) and concentration-related (10-250 microg/ml) increases in the proliferation of splenocytes and thymocytes cultures which were comparable to the mitogenic effects of lipopolysaccharide, LPS (10 microg/ml) and concanavalin A, ConA (2 microg/ml) used as standard mitogens. EAC and AAC (15.6-250 microg/ml) significantly (P<0.05) increased phagocytosis and intracellular killing capacity measured as percentage increase in nitroblue tetrazolium (NBT) dye reduction. Lysosomal phosphatase activity of peritoneal macrophages, measured by p-nitrophenyl phosphate (p-NPP) hydrolysis, was also increased significantly (P<0.05) by EAC and AAC (15.6-250 microg/ml). Treatment of macrophage cultures with EAC and AAC (15.6-250 microg/ml) decreased the expression of nitric oxide significantly (P<0.05) in the supernatant. This study demonstrates strong immunomodulatory activities of A. cordifolia leaf extracts which could explain some of the therapeutic benefits attributed to the plant in traditional medicine and could also be exploited as a source of novel immunoregulating substances.

Ellagic Acid Derivatives from Syzygium cumini Stem Bark: Investigation of their Antiplasmodial Activity

Bioguided fractionation of Syzygium cumini (Myrtaceae) bark decoction for antiplasmodial activity was performed, leading to the isolation of three known ellagic acid derivatives (ellagic acid, ellagic acid 4-O-α-L-2″-acetylrhamnopyranoside, 3-O-methylellagic acid 3′-O-α-L-rhamnopyranoside), as well as the new derivative 3-O-methylellagic acid 3′-O-β-D-glucopyranoside. Activity investigation was based on the reduction of P. falciparum (PfK1) parasitaemia in vitro and the inhibition of β-hematin formation, a known mechanism of action of some antimalarial drugs. Among the investigated ellagic acid derivatives, only ellagic acid was able to reduce P. falciparum parasitaemia in vitro and inhibit β-hematin formation, suggesting that free hydroxyl groups are necessary for activity within this class of compounds.