Potent antiplasmodial extracts from Cameroonian Annonaceae

Evaluation of packaging, labels, and some physicochemical properties of herbal antimalarial products on the Ghanaian market

Introduction

Malaria is a parasitic disease that is endemic in tropical areas and can be life-threatening. There has been a decrease in the prevalence of malaria in Ghana but the burden of the disease is still high in the country. Many Ghanaians depend on herbal products for malaria treatment. This study aimed to survey and evaluate commercial herbal antimalarials in the Volta Region of Ghana.

Methods

A survey of finished herbal antimalarials was done at herbal shops, pharmacies, and over-the-counter medicine seller shops. Products available on shelves were purchased and their details were recorded, after which they were examined using a visual inspection tool. The density, pH, and extract weight per dose of each sample were also determined.

Results

Thirty-four liquid formulations (A-1-34) containing 1-9 different herbs were found. The majority of the product labels had errors in consumer age classifications. Unconventional ways of stating doses were found on two products (A-13, "tot"; A-19, cupful). Six products did not have dosing devices. No duration of treatment was indicated on 24 products. Dose errors were found on A-14 and A-22. Samples A-17 and A-28 did not have registration or batch numbers. Product A-28 did not have its herbs listed on it and was indicated for persons aged 3-8 years at a dose of 45 mL. The relative density range for the products was 0.997-1.015. From the pH investigation, no product was extremely erosive; however, 10 samples were deemed erosive (pH, 3.0-3.99), whereas 24 were minimally erosive (pH, ≥4.0). The extract weight per dose volume (20-90 mL) was 0.048-1.766 g, indicating that unit dose capsules or tablets could be formulated from the products.

Conclusion

The findings clearly show that Ghanaian authorities responsible for regulating herbal products must enforce guidelines for the formulation, label details, and sale of antimalarial products. Additionally, the unpleasant taste of liquid herbal mixtures can affect patient compliance and dosing convenience; therefore, it is recommended that oral solid dosage forms of herbal antimalarials are produced as alternatives to the liquid mixtures.

Ethnomedicinal Uses, Phytochemistry, and Anticancer Potentials of African Medicinal Fruits: A Comprehensive Review

Africa is home to diverse medicinal plants that have been used for generations for the treatment of several different cancers and, presently, they are gaining interest from researchers as promising approaches to cancer treatment. This review aims to provide a comprehensive review of dietary and medicinal African fruits including their traditional uses, botanical description, ethnobotanical uses, bioactive phytochemical compositions, and anticancer properties investigated to date in vitro, in vivo, and in clinical studies. Data on recent updates concerning the traditional uses and anticancer properties of these fruits were collected from a myriad of available publications in electronic databases, such as Web of Science, PubMed, ScienceDirect, Scopus, SpringerLink, and Google Scholar. The results suggest that approximately 12 native or commercially grown African fruits belonging to different plant species, including Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum, have been reported for their potential as treatment options for the management of cancer. We further found that approximately eight different fruits from native plant species from Africa, namely, Sclerocarya birrea, Dovyalis caffra, Parinari curatellifolia, Mimusops caffra, Carpobrotus edulis, Vangueria infausta, Harpephyllum caffrum, and Carissa macrocarpa, have been widely used for the traditional treatment of different ailments but somehow failed to gain the interest of researchers for their use in anticancer research. In this review, we show the potential use of various fruits as anticancer agents, such as Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum; unfortunately, not enough reported research data have been published to gain thorough mechanistic insights and clinical applications. Additionally, we discuss the possibility of the utilization of potential phytochemicals from fruits like Persea americana and Punica granatum in anticancer research, as well as future directions.

Evaluation of Antimalarial Activity of Ethanolic Extract of Annona muricata L.: An in vivo and an in silico Approach

In Nigeria, Annona muricata L. has been used to treat a variety of ailments. The mechanism of the antimalarial activity of ethanolic leaf extract of Annona muricata (EEAML) was investigated using both an in vivo and an in silico approach. The experimental mice were divided into five groups: A-F. The mice in groups B-F were inoculated with Plasmodium berghei NK-65 and treated accordingly. Groups A and B are the negative and positive controls (infected and untreated), respectively. Group C received 10 mg/kg chloroquine (standard drug), whereas groups D-F received 100, 200, and 300 mg/kg body weight of the extract orally respectively. The mice were euthanized eight days after infection, and their liver and blood were collected and used in biochemical tests. Molecular docking was performed using the extract's HPLC compounds and Plasmodium falciparum proteins. In the suppressive, prophylactic, and curative tests, there was a significant decrease (p < 0.05) in parasitemia levels in groups treated with the extract compared to the positive control and standard drug. When compared to the positive control, there was a significant (p < 0.05) reduction in liver MDA, total cholesterol, and total triglyceride levels. The binding energies of luteolin and apigenin-pfprotein complexes were significantly (p < 0.05) higher compared to their respective references. The anti-plasmodial activity of the extract may result from its hypolipidemic effect, which deprives the parasite of essential lipid molecules needed for parasite growth, as well as from the inhibitory effects of apigenin and luteolin on specific proteins required for the Plasmodium metabolic pathway.

The Antiplasmodial Potential of Medicinal Plants Used in the Cameroonian Pharmacopoeia: An Updated Systematic Review and Meta-Analysis

Malaria is a real public health problem. It is the leading cause of morbidity and mortality in the world. Research in herbal medicine has so far shown that the use of plants against malaria is not to be neglected. This review aims to highlight the antiplasmodial potential of Cameroonian plants. In order to achieve this objective, we conducted a bibliographic search in April 2022 using the PubMed search engine. This research included both the published and unpublished studies. A narrative approach was used to describe the antiplasmodial potential of the various species of plants investigated. Quantitative data were analyzed using R studio 4.1.1 software and random effects model was used to estimate the effect size. The research of the antiplasmodial activity of Cameroonian plants dates back to 2000. This area of research has since provided extensive data to indicate the antiplasmodial potential of several plants, most of which originate from the central region. Despite the heterogeneity observed between the different plant families studied in Cameroon for their in vitro antiplasmodial effect, there is strong evidence that 17 active compounds from these plants would be ideal candidates for the synthesis of new antimalarial drugs. The Dacryodes edulis species could be considered as the best natural alternative in the treatment of uncomplicated malaria according to its properties. It is clear that the traditional Cameroonian pharmacopoeia has many species that contain compounds with antiplasmodial activity. More studies need to be conducted to explore the multitude of unexplored plants that are used in traditional medicine. These studies should take into account the nature of the cell model used for cytotoxicity assessment.

Evaluation of Annona muricata (Graviola) leaves activity against experimental trichinellosis: in vitro and in vivo studies

Our work aimed to evaluate the possible effect of Annona muricata (Graviola) leaf extract on Trichinella spiralis in in vitro and in vivo studies. Trichinella spiralis worms were isolated from infected mice and transferred to three culture media - group I (with no drugs), group II (contained Graviola) and group III (contained albendazole) - then they were examined using the electron microscope. In the in vivo study, mice were divided into five groups: GI (infected untreated), GII (prophylactically treated with Graviola for seven days before infection), GIII (infected and treated with Graviola), GIV (infected and treated with albendazole) and GV (infected and treated with a combination of Graviola plus albendazole in half doses). Drug effects were assessed by adults and larvae load beside the histopathological small intestinal and muscular changes. A significant reduction of adult and larval counts occurred in treated groups in comparison to the control group. Histopathologically, marked improvement in the small intestinal and muscular changes was observed in treated groups. Also, massive destruction of the cultured adults' cuticle was detected in both drugs. This study revealed that Graviola leaves have potential activity against trichinellosis, especially in combination with albendazole, and could serve as an adjuvant to anti-trichinellosis drug therapy.

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.

Annona muricata Linn and Khaya grandifoliola C.DC. Reduce Oxidative Stress In Vitro and Ameliorate Plasmodium berghei-Induced Parasitemia and Cytokines in BALB/c Mice

Background.

Annona muricata and Khaya grandifoliola are ethnomedicinally used for the treatment of malaria and have been experimentally shown to have an anti-plasmodial effect, but the mechanisms involved are not fully understood. This study investigated the effect of the ethanol extracts of their leaves on parasitemia, radical scavenging and cytokines in Plasmodium berghei ANKA-infected BALB/c mice.

Methods.

BALB/c mice were infected with P. berghei and treated with chloroquine, A. muricata or K. grandifoliola extract for 4 days. The percentage of parasitemia and the level of cytokine expression were determined after treatment. Trace element, phytochemical and nitric oxide (NO) scavenging activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging properties assays were done to study the antioxidant effects of AN and KG in vitro.

Results.

P. berghei consistently increased parasitemia in BALB/c mice. The tested doses (100-, 200-, and 400 mg/kg) of A. muricata and K. grandifoliola attenuated the P. berghei-induced elevation of parasitemia and cytokines (TNF-α, IL-5, and IL-6) in vivo during the experimental period, though not as much as chloroquine. Moreover, both extracts scavenged the DPPH and NO radicals, though A. muricata had more anti-oxidant effect than K. grandifoliola in-vitro.

Conclusion.

The ethanol extracts of A. muricata and K. grandifoliola reduce parasitemia in P. berghei-treated mice BALB/c by scavenging free radicals and reducing cytokines, though the extracts were not as effective as chloroquine.

Annona muricata silver nanoparticles exhibit strong anticancer activities against cervical and prostate adenocarcinomas through regulation of CASP9 and the CXCL1/CXCR2 genes axis

BACKGROUND

Green synthesized nanoparticles have been earmarked for use in nanomedicine including for the development of better anticancer drugs.

OBJECTIVE

The aim of this study was to undertake biochemical evaluation of anticancer activities of green synthesized silver nanoparticles (AgNPs) from ethanolic extracts of fruits (AgNPs-F) and leaves (AgNPs-L) of Annona muricata.

METHODS

Previously synthesized silver nanoparticles were used for the study. The effects of the AgNPs and 5-Fluorouracil were studied on PC3, HeLa and PNT1A cells. The resazurin, migration and colonogenic assays as well as qRT-PCR were employed.

RESULTS

The AgNPs-F displayed significant antiproliferative effects against HeLa cells with an IC50 of 38.58μg/ml and PC3 cells with an IC50 of 48.17μg/ml but selectively spared normal PNT1A cells (selectivity index of 7.8), in comparison with first line drug 5FU and AgNPs-L whose selectivity index were 3.56 and 2.26 respectively. The migration assay revealed potential inhibition of the metastatic activity of the cells by the AgNPs-F while the colonogenic assay indicated the permanent effect of the AgNPs-F on the cancer cells yet being reversible on the normal cells in contrast with 5FU and AgNPs-L. CASP9 was significantly over expressed in all HeLa cells treated with the AgNPs-F (1.53-fold), AgNPs-L (1.52-fold) and 5FU (4.30-fold). CXCL1 was under expressed in HeLa cells treated with AgNPs-F (0.69-fold) and AgNPs-L (0.58-fold) and over expressed in cells treated with 5FU (4.95-fold), but the difference was not statistically significant. CXCR2 was significantly over expressed in HeLa cells treated with 5FU (8.66-fold) and AgNPs-F (1.12-fold) but under expressed in cells treated with AgNPs-L (0.76-fold).

CONCLUSIONS

Here we show that biosynthesized AgNPs especially AgNPs-F can be used in the development of novel and better anticancer drugs. The mechanism of action of the AgNPs involves activation of the intrinsic apoptosis pathway through upregulation of CASP9 and concerted down regulation of the CXCL1/ CXCR2 gene axis.

Biochemical investigation of the upstream anti-sickling mechanisms of soursop (Annona muricata): 15-acetyl guanacone as an inhibitor of deoxyhaemoglobin polymerisation

Current sickle cell disease (SCD) therapies are limited and inefficient. The ethnomedicinal values of Annona muricata in the treatment of SCD, leading to this present research. Leaves and fruits of Annona muricata were processed using solvent extraction and partitioning; aqueous, chloroform and ethyl acetate fractions. In vitro (anti-oxidant and anti-sickling), in silico, quantitative (amino acids) and kinetic simulation experiments were done. 15-acetyl guanacone, was used, in silico against 2,3-bisphosphoglycerate (2, 3-BPG) mutase and deoxyhaemoglobin. The ethyl acetate and chloroform fractions better NO^● scavengers, iron-chelators and ferric reducing. In vitro unsickling (UT₅₀) had ethyl acetate = 5 h and methanol = 7 h. Chloroform fraction had EC₅₀ 1.00 mg/mL (EC₅₀ = 546 mg/mL) to 10.00 mg/mL (EC₅₀ = 99 mg/mL). EC₅₀ and IC₅₀ of ethyl acetate fraction had steady-decrease. At higher concentration, chloroform fraction had higher Bmax (1.48 × 10²¹ U/mL) and higher Kd (3.66 × 10¹⁹ mg/mL), whereas, at a lower concentration, the ethyl acetate fraction demonstrated higher Bmax (7.23 × 10¹² U/mL) and lower Kd (2.12 × 10¹¹ mg/mL); The relative affinity (BP) of chloroform fraction increased progressively with concentration. The amino acid profile revealed rich concentrations glycine, valine, leucine, lysine, phenylalanine, histidine, arginine, and tryptophan. From the in silico experiments, 15-acetyl guanacone specifically targeted the A and B chains, with greater affinity for the beta subunit. This suggested that 15-acetyl guanacone might be able to prevent the polymerisation of deoxyHbSS, induce an allosteric conformational change that increases the oxygen affinity, and decrease the cellular 2, 3-BPG concentration.Communicated by Ramaswamy H. Sarma.

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.

Ti-Catalyzed Cross-Cyclomagnesiation of 1,2-Dienes in the Total Z,Z,Z-Stereoselective Synthesis of Natural Acetogenin-Chatenaytrienin-1

The first total synthesis of natural acetogenin, chatenaytrienin-1, was performed in 10 steps and in 41% overall yield using cross-cyclomagnesiation of (6Z)-heptadeca-1,2,6-triene and trideca-11,12-dien-1-ol tetrahydropyran acetal with EtMgBr in the presence of Mg metal and the Cp₂TiCl₂ catalyst (10 mol %) as the key step of the synthesis.

Antiplasmodial potential and GC-MS fingerprint of endophytic fungal extracts derived from Cameroonian Annona muricata

ETHNOPHARMACOLOGICAL RELEVANCE

Annona muricata (Annonaceae) is a commonly used medicinal plants in Cameroonian traditional medicines to treat various diseases including malaria. Previous studies have shown that extracts from this plant have antiplasmodial activity.

AIM OF THE STUDY

This study aimed to explore the endophyic fungi associated with some parts of this plant for their ability to produce antiplasmodial metabolites.

MATERIALS AND METHODS

One hundred and fifty-two endophytic fungi isolated from twelve different organs of A. muricata were cultured and the ethyl acetate extracts of conditioned media screened for antiplasmodial activity using the 96-well microtiter plate format SYBR green florescence assay against Chloroquine-sensitive Pf3D7 and Chloroquine-resistant PfINDO/PfDd2 strains of Plasmodium falciparum.

RESULTS

Twenty-seven (17.76%) of fungi tested were found to completely inhibit the growth of Plasmodium parasites at 10 µg/mL. The 5.8S rDNA sequencing data revealed the strongly active (IC₅₀ < 2 µg/mL against at least 2 P. falciparum strains) isolates to be Trichoderma afroharzianum AMrb7, Penicillium citrinum AMrb11, Neocosmospora rubicola AMb22, Penicillium tropicum AMb3, Penicillium citrinum AMrb23, Aspergillus versicolor AMb7, and Fusarium sp AMst1. Of these, the extracts from Penicillium citrinum AMrb11 (IC₅₀ 0.84-0.93 μg/mL) and Neocosmospora rubicola AMb22 (IC₅₀ 0.39-1.92 μg/mL) showed the highest promise against all three plasmodial strains with selectivity indices ranging from 34.71 to 180.97. Dynamic head space GC-MS analysis of ethyl acetate extracts of promising fungi revealed broad-spectrum antimicrobial compounds such as Penicidin, Aromadendrene, Ethyl p-methoxycinnamate, 2-Coumaranone and 2-Methyl resorcinol.

CONCLUSION

These results have opened new avenues for discovery of novel antimalarial lead compounds from endophytic fungi associated with Annona muricata - a medicinally important plant.

Anti-Plasmodium falciparum Activity of Extracts from 10 Cameroonian Medicinal Plants

Background: In the midst of transient victories by way of insecticides against mosquitoes or drugs against malaria, the most serious form of malaria, caused by Plasmodium falciparum, continues to be a major public health problem. The emergence of drug-resistant malaria parasites facilitated by fake medications or the use of single drugs has worsened the situation, thereby emphasizing the need for a continued search for potent, safe, and affordable new antimalarial treatments. In line with this need, we have investigated the antiplasmodial activity of 66 different extracts prepared from 10 different medicinal plants that are native to Cameroon. Methods: Extracts were evaluated for their capacity to inhibit the growth of the chloroquine-sensitive (Pf3D7) and resistant (PfINDO) strains of P. falciparum using the SYBR green fluorescence method. The cytotoxicity of promising extracts against human embryonic kidney cells (HEK293T) mammalian cells was assessed by MTT assay. Results: The antiplasmodial activity (50% inhibitory concentration, IC50) of plant extracts ranged from 1.90 to >100 μg/mL against the two strains. Six extracts exhibited good activity against both Pf3D7 and PfINDO strains, including cold water, water decoction, and ethyl acetate extracts of leaves of Drypetes principum (Müll.Arg.) Hutch. (IC503D7/INDO = 4.91/6.64 μg/mL, 5.49/5.98 μg/mL, and 6.49/7.10 μg/mL respectively), water decoction extract of leaves of Terminalia catappa L. (IC503D7/INDO = 6.41/8.10 μg/mL), and water decoction extracts of leaves and bark of Terminalia mantaly H.Perrier (IC503D7/INDO = 2.49/1.90 μg/mL and 3.70/2.80 μg/mL respectively). These promising extracts showed no cytotoxicity against HEK293T up to 200 μg/mL, giving selectivity indices (SIs) in the range of >31.20⁻80.32. Conclusions: While providing credence to the use of D. principum, T. catappa, and T. mantaly in the traditional treatment of malaria, the results achieved set the stage for isolation and identification of active principles and ancillary molecules that may provide us with new drugs or drug combinations to fight against drug-resistant malaria.

Anticancer Properties of Graviola (Annona muricata): A Comprehensive Mechanistic Review

Graviola (Annona muricata) is a small deciduous tropical evergreen fruit tree, belonging to the Annonaceae family, and is widely grown and distributed in tropical and subtropical regions around the world. The aerial parts of graviola have several functions: the fruits have been widely used as food confectionaries, while several preparations, especially decoctions of the bark, fruits, leaves, pericarp, seeds, and roots, have been extensively used in traditional medicine to treat multiple ailments including cancers by local communities in tropical Africa and South America. The reported therapeutic benefits of graviola against various human tumors and disease agents in in vitro culture and preclinical animal model systems are typically tested for their ability to specifically target the disease, while exerting little or no effect on normal cell viability. Over 212 phytochemical ingredients have been reported in graviola extracts prepared from different plant parts. The specific bioactive constituents responsible for the major anticancer, antioxidant, anti-inflammatory, antimicrobial, and other health benefits of graviola include different classes of annonaceous acetogenins (metabolites and products of the polyketide pathway), alkaloids, flavonoids, sterols, and others. This review summarizes the current understanding of the anticancer effects of A. muricata and its constituents on diverse cancer types and disease states, as well as efficacy and safety concerns. It also includes discussion of our current understanding of possible mechanisms of action, with the hope of further stimulating the development of improved and affordable therapies for a variety of ailments.

Exploring the Leaves of Annona muricata L. as a Source of Potential Anti-inflammatory and Anticancer Agents

The use of anti-inflammatory natural products to treat inflammatory disorders for cancer prevention and therapy is an appealing area of interest in the last decades. Annona muricata L. is one of the many plant extracts that have been explored owing to their anti-inflammatory and anticancer effects. Different parts of A. muricata especially the leaves have been used for various ethnomedicinal purposes by traditional healers to treat several diseases including cancer, inflammation, diabetes, liver diseases, and abscesses. Some of these experience-based claims on the use of the plant have been transformed into evidence-based information by scientific investigations. The leaves of the plant have been extensively investigated for its diverse pharmacological aspects and found eminent for anti-inflammatory and anticancer properties. However, most studies were not on the bioactive isolates which were responsible for the activities but were based on crude extracts of the plant. In this comprehensive review, all significant findings from previous investigations till date on the leaves of A. muricata, specifically on their anti-inflammatory and anticancer activities have been compiled. The toxicology of the plant which has been shown to be due to the presence of neurotoxic annaceous acetogenins and benzyltetrahydro-isoquinoline alkaloids has also been updated to provide recent information on its safety aspects. The present knowledge of the plant has been critically assessed, aimed at providing direction toward improving its prospect as a source of potential anti-inflammatory and anticancer agents. The analysis will provide a new path for ensuring research on this plant to discover new agents to treat inflammatory diseases and cancer. Further in vitro and in vivo studies should be carried out to explore the molecular mechanisms underlying their anti-inflammatory responses in relation to anticancer activity and more detail toxicity study to ensure they are safe for human consumption. Sufficient preclinical data and safety data generated will allow clinical trials to be pursued on this plant and its bioactive compounds.

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.

Extracts from Annona Muricata L. and Annona Reticulata L. (Annonaceae) Potently and Selectively Inhibit Plasmodium Falciparum

The aim of this work was to screen extracts from Annona muricata and Annona reticulata in vitro against Plasmodium falciparum. Crude ethanolic extracts, methylene chloride fractions, aqueous fractions, subfractions and isolated compounds (stigmasterol-3-O-β-d-glucopyranoside, lichexanthone, gallic acid and β-sitosterol-3-O-β-d-glucopyranoside) were tested for cytotoxicity on erythrocytes and Human Foreskin Fibroblasts cells and against the W2 strain of P. falciparum in culture. Results indicated that none of the extracts was cytotoxic at concentrations up to 10 µg/mL. Most of the extracts, fractions and subfractions inhibited the growth of P. falciparum with IC₅₀ values ranging from 0.07 to 3.46 µg/mL. The most potent was the subfraction 30 from A. muricata stem bark (IC₅₀ = 0.07 µg/mL) with a selectivity index of ˃ 142. Subfraction 3 from A. muricata root also exhibited very good activity (IC₅₀ = 0.09 µg/mL) with a high selectivity index (SI ˃ 111). Amongst the isolated compounds, only gallic acid showed activity with IC₅₀ of 3.32 µg/mL and SI > 10. These results support traditional claims for A. muricata and A. reticulata in the treatment of malaria. Given their limited cytotoxicity profile, their extracts qualify as promising starting points for antimalarial drug discovery.

In vitro antiplasmodial screening of ethnopharmacologically selected South African plant species used for the treatment of malaria

ETHNOPHARMACOLOGICAL RELEVANCE

Plant species used by Venda people of South Africa in the treatment of malaria and associated symptoms were evaluated for their antiplasmodial efficacy as well as cytotoxic properties and some showed significant activity.

MATERIALS AND METHODS

In vitro antiplasmodial activity and cytotoxic properties were evaluated on 20 indigenous plant species. Ground plant material was extracted in dichloromethane: 50% methanol (1:1). Antiplasmodial activity was evaluated against the chloroquine-sensitive strain of Plasmodium falciparum (NF54). The cytotoxicity of the plant extracts were assessed against mammalian L-6 rat skeletal myoblast cells and the selectivity index (SI) calculated.

RESULTS

Of the 43 plant extracts evaluated, 10 exhibited pronounced antiplasmodial activity (IC₅₀ ≤ 5 μg/ml) with good therapeutic indices (SI ≥ 10). Lipophilic plant extracts were relatively more potent than polar extracts. Tabernaemontana elegans Stapf. (Apocynaceae) and Vangueria infausta Burch. subsp. infausta (Rubiaceae) extracts displayed significant antiplasmodial activity (IC₅₀ < 2 μg/ml).

CONCLUSION

Findings of this study partly support the ethnomedical use of the investigated plant species by Venda people as antimalarial remedies. The study also highlights some of the knowledge gaps that require further phytochemical studies on the specified plant species.

In vivo antimalarial efficacy of acetogenins, alkaloids and flavonoids enriched fractions from Annona crassiflora Mart

Annona crassiflora and Annonaceae plants are known to be used to treat malaria by traditional healers. In this work, the antimalarial efficacy of different fractions of A. crassiflora, particularly acetogenin, alkaloids and flavonoid-rich fractions, was determined in vivo using Plasmodium berghei-infected mice model and toxicity was accessed by brine shrimp assay. The A. crassiflora fractions were administered at doses of 12.5 mg/kg/day in a 4-day test protocol. The results showed that some fractions from woods were rich in acetogenins, alkaloids and terpenes, and other fractions from leaves were rich in alkaloids and flavonoids. The parasitaemia was significantly (p < 0.05, p < 0.001) reduced (57-75%) with flavonoid and alkaloid-rich leaf fractions, which also increased mean survival time of mice after treatment. Our results confirm the usage of this plant in folk medicine as an antimalarial remedy.

Compounds from Sorindeia juglandifolia (Anacardiaceae) exhibit potent anti-plasmodial activities in vitro and in vivo

Background

Discovering new lead compounds against malaria parasites is a crucial step to ensuring a sustainable global pipeline for effective anti-malarial drugs. As far as we know, no previous phytochemical or pharmacological investigations have been carried out on Sorindeia juglandifolia. This paper describes the results of an anti-malarial activity-driven investigation of the fruits of this Cameroonian plant.

Methods

Air-dried fruits were extracted by maceration using methanol. The extract was fractionated by flash chromatography followed by column chromatography over silica gel, eluting with gradients of hexane-ethyl acetate mixtures. Resulting fractions and compounds were tested in vitro against the Plasmodium falciparum chloroquine-resistant strain W2, against field isolates of P. falciparum, and against the P. falciparum recombinant cysteine protease falcipain-2. Promising fractions were assessed for acute toxicity after oral administration in mice. One of the promising isolated compounds was assessed in vivo against the rodent malaria parasite Plasmodium berghei.

Results

The main end-products of the activity-guided fractionation were 2,3,6-trihydroxy benzoic acid (1) and 2,3,6-trihydroxy methyl benzoate (2). Overall, nine fractions tested against P. falciparum W2 and falcipain-2 were active, with IC₅₀ values of 2.3-11.6 μg/ml for W2, and 1.1-21.9 μg/ml for falcipain-2. Purified compounds (1) and (2) also showed inhibitory effects against P. falciparum W2 (IC50s 16.5 μM and 13.0 μM) and falcipain-2 (IC50s 35.4 and 6.1 μM). In studies of P. falciparum isolates from Cameroon, the plant fractions demonstrated IC₅₀ values of 0.14-19.4 μg/ml and compounds (1) and (2) values of 6.3 and 36.1 μM. In vivo assessment of compound (1) showed activity against P. berghei strain B, with mean parasitaemia suppressive dose and curative dose of 44.9 mg/kg and 42.2 mg/kg, respectively. Active fractions were found to be safe in mice after oral administration of 7 g/kg body weight.

Conclusions

Fractions of Sorindeia juglandifolia and two compounds isolated from these fractions were active against cultured malaria parasites, the P. falciparum protease falcipain-2, and in a rodent malaria model. These results suggest that further investigation of the anti-malarial activities of natural products from S. juglandifolia will be appropriate.

Ethnopharmacological survey of Annonaceae medicinal plants used to treat malaria in four areas of Cameroon

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria endemic countries have vital resources that are medicinal plants on which their traditional medicines depend. In some Cameroonian settings, in addition to the commonly used potions from plants like Alstonia boonei, Zanthoxylum macrophylla and Mangifera indica, other herbal species are being increasingly used to treat malaria. So, specialized traditional healers have developed alternative reasonably priced therapies, relying on the signs and/or symptoms of malaria. Within this framework, Annonaceae plants were found to be increasingly utilized and therefore, highlighting the need to document this traditional knowledge for better malaria control.

MATERIALS AND METHODS

Interview approach was used to document indigenous knowledge, usage customs and practices of Annonaceae species in the treatment of malaria in four Cameroonian areas (Yaoundé and its surroundings, Ngoyang, Kon-Yambetta and Mbalmayo).

RESULTS

A total of 19/30 users of plants accepted to share their experiences during a semi-structured survey. Twelve of the respondents were men and seven were women. Thirty recipes based on twenty-one plants were recorded.

CONCLUSION

Annickia chlorantha was the only plant commonly found in the four study sites. Seven species of Annonaceae were found to be used to treat malaria, while 14 were used to treat symptoms that might be related to malaria.