Antimalarial Activity of Stem Bark of Periploca linearifolia during Early and Established Plasmodium Infection in Mice

Antimalarial Properties of Sida cordifolia L. Leaf Extract in Mice: Survivability Depends Less on Parasitaemia Suppression

Sida cordifolia has been used to treat malaria in Ghana albeit without scientific evidence of antimalarial activity and safety. This work aimed to assess the antimalarial properties and acute toxicity of the aqueous leaf extract of S. cordifolia in murine models. Aqueous extract of the plant was analysed for both suppressive and curative antimalarial properties in chloroquine-sensitive ANKA strains of rodent Plasmodium berghei-infected mice. Acute toxicity evaluation was performed in rats according to the OECD 425 guidelines. The extract displayed antiplasmodial activity in vivo with ED50 of 117.49 ± 15.22 mg/kg and 144.84 ± 18.17 mg/kg in suppressive and curative studies, respectively. The highest % parasitaemia suppression exerted was 76.90 ± 0.64% and 61.50 ± 0.97%, respectively, in the suppressive and curative studies. Survival of infected mice treated with the extract was significantly prolonged. This was dependent on the dose of the extract but imperfectly related to the % parasitaemia suppression. Related antimalarial parameters including percentage hematocrit, changes in body weight, and temperature of experimental mice indicated alleviation of malarial symptoms of treated animals. The extract did not show toxicity in rats. Sida cordifolia L. has antimalarial properties, and was safe. It suppressed parasitaemia in both suppressive and curative studies, was not toxic to animals and prolonged the life of infected animals under treatment. This, therefore, justifies the traditional use of S. cordifolia for the treatment of malaria in Ghana.

Antimalarial compounds from the climbing stems of salacia debilis

Salacia debilis Walp., (Celastraceae) is used traditionally in West Africa for the treatment of malaria. However, no scientific reports validating these effects and its active constituents are on record. Therefore, this study is aimed at evaluating the antimalarial effects, of its ethanolic extract and isolated compounds against Plasmodium falciparum 3D7 and P. berghei ANKA strains. Using chromatographic, spectrometric and spectroscopic techniques three compounds were isolated and characterised. The extract of S. debilis was active against P. falciparum 3D7, in an in vitro assay with IC50 of 12.0 ± 0.32 µg/ml. The three isolated compounds, namely 1,10-dihydroxy-6H-benzo[c]chromen-6-one (1), 8- hydroxy-3,4-dimethoxydibenzo[b,d]furan-1-carboxylic acid (2) and benzyl-2-methoxybenzoate (3), also showed antimalarial activity against Plasmodium berghei ANKA strain in curative and suppressive in vivo assays. The ethanolic extract and isolated compounds of S. debilis possess antimalarial effects. The isolated compounds may be responsible, at least in part, for the observed activities of the extract.

In vivo antiplasmodial activities of stem bark extracts of Avicennia marina in Plasmodium berghei-infected mice

Introduction

malaria remains the leading cause of morbidity and mortality in developing tropical and subtropical nations. Due to the emergence and spread of drug resistance to currently available drugs, there is a need for the search of novel, safe, and reasonably affordable anti-malarial medications. The objective of this study was to assess the in vivoanti-malarial effectiveness of Avicennia marina stem bark extracts in a mice model.

Methods

guidelines 425 of the Organization for Economic Cooperation and Development were used to determine the extracts' acute toxicity. Mice infected with chloroquine-sensitive Plasmodium berghei (ANKA strain) were tested for in vivoanti-plasmodial activity, and by giving oral doses of 100 mg/kg, 250 mg/kg, and 500 mg/kg body weight of extracts, the plant's suppressive, curative, and preventive effects were assessed.

Results

mice treated with dosages of up to 5000 mg/kg showed no evidence of acute toxicity or mortality. Consequently, it was determined that the acute lethal dosage of Avicennia marina extracts in swiss albino mice was greater than 5000 mg/kg. All doses of the extracts exhibited significant (p<0.05) dose-dependent suppression of P. berghei in the suppressive tests compared to the control group. At the highest dose (500 mg/kg), Methanolic crude extracts exerted the highest (93%) parasitemia suppression during the 4-day suppressive test. The extracts also displayed significant (p<0.001) prophylactic and curative activities at all doses compared to the control.

Conclusion

results from this study ascertained the safety and promising curative, prophylactic and suppressive anti-plasmodial capabilities of the stem bark extracts of Avicennia marina in mice model.

Medicinal plants used in traditional treatment of malaria in Ethiopia: a review of ethnomedicine, anti-malarial and toxicity studies

Background

Malaria is extremely common in Ethiopia, and it is one of the country's most serious public health and economic problems. Traditional medicines have long been utilized in Ethiopia by people of various ethnic groups. As a result, the goal of this study is to record the use of Ethiopian medicinal herbs that have been used to treat malaria. Also, a critical review of the literature on the therapeutic properties of these and other Ethiopian medicinal plants that have been tested against Plasmodium spp. parasites was conducted with the goal of highlighting neglected studies and fostering further research in this area.

Methods

A comprehensive literature search was performed in Scopus, Web of Science Core Collection, PubMed, Science Direct, Google Scholar, and Scientific Electronic Library Online (SciELO) from August 2021 to October 2021. The study databases included original articles published in peer reviewed journals covering anti-malarial plants, dated until October 2021.

Results

The review looked at 51 plant species (28 families) that have been used to treat malaria in Ethiopia. The most often used ethnobotanical plant species for the treatment of malaria were Allium sativum, Croton macrostachyus, Carica papaya, and Lepidium sativum. Leaves were used more frequently as a therapeutic preparation than other parts. Plant extracts were found to have very good, good, and moderate anti-malarial activity in mice with rodent Plasmodium species. The most active species were Ajuga remota and Capsicum frufescens, which suppressed parasitaemia by 77.34% and 72.65%, respectively, at an oral dose of 100 mg/kg and an LD50 of above 2000 mg/kg. The compound Aloinoside reported from Aloe macrocarpa leave latex was the most potent; it suppressed parasitaemia by 100% at 400 mg/kg oral dose of Plasmodium berghei infected mice, and its LD50 was above 2000 mg/kg. Toxicity was shown to be safe in 84% of the plant extracts.

Conclusion

In Ethiopia, medicinal plants have a significant part in reducing the severity of malaria due to their widespread use. As a result, more studies are needed to identify and develop effective novel drugs that could be employed in broader malaria eradication efforts.

In vitro and in vivo antimalarial activity and chemical profiling of sugarcane leaves

Saccharum officinarum Linn. (sugarcane, Family-Poaceae) is employed in Ibibio traditional medicine for the treatment of various infections and diseases such as malaria. We This study aims to assess the antiplasmodial effect of the leaf extract and fractions on human malaria parasite (Plasmodium falciparum) in vitro, and rodent malaria parasite (P. berghei) in vivo, and analyse the bioactive components of the active fraction(s). The leaf extract and fractions of S. officinarum were prepared and their growth inhibitory effects tested against the chloroquine resistant P. falciparum strain (Dd2) and P. berghei infection in mice. An acute toxicity of the extract was determined. A combination of gas chromatography and liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy was applied for metabolites profiling of crude extract and active fractions. The leaf extract and fractions demonstrated moderate activity against P. falciparum with the dichloromethane fraction producing the most potent activity (EC50 = 15.4 µg/mL). The leaf extract (170-510 mg/kg, p.o., LD50 = 1732 mg/kg) and fractions demonstrated significant (p < 0.05-0.001) effect on P. berghei infection in prophylactic  tests as well as in established infection with n-butanol fractions producing the highest effect. An unusual sulphur-containing compound, dilaurylthiodipropionate, fatty acids, phenolic acids, flavonoid and flavonoid glycoside were identified in the active fractions. These results give credence to the use of sugarcane leaves as malarial remedy locally by confirming the in vitro and in vivo antiplasmodial potential of leaf extract/fractions of S. officinarum.

Antimalarial Activity of Solvent Fractions of the Stem Bark of Periploca linearifolia Quart.-Dill. & A.Rich. (Asclepiadaceae) Against Plasmodium berghei in Mice

Background

Currently, malaria elimination is intimidated by the emergence of antimalarial drug and insecticide resistance. This scenario urges scientists to develop new antimalarial drugs, where plant-based compounds are the major candidates.

Objective

The objective of this experiment was to examine the antimalarial activities of the solvent fractions of the stem bark of P. linearifolia in mice.

Methods

The dried hydromethanolic extract was treated with n-hexane, chloroform, and ethyl acetate solvents based on increasing order of polarity. For the suppressive test, after three hours post-inoculation of P. berghei, the first group was administered the vehicle 2 mL/100 g. The second group was given chloroquine 25 mg/kg, whereas the remaining nine groups were administered 100, 200, and 400 mg/kg of each of the chloroform, ethyl acetate and aqueous fractions. Furthermore, the aqueous fraction was evaluated using Rane's model for the curative test. The result was statistically analyzed using a one-way analysis of variance (ANOVA). The results were considered significant at P < 0.05.

Results

In the suppressive test, the solvent fractions suppressed parasitemia level significantly (P < 0.01 for 100 mg/kg, P < 0.001 for 200 and 400 mg/kg of the aqueous and P < 0.01 for 200 mg/kg, P < 0.001 for 400 mg/kg of chloroform fractions) as compared to vehicle-treated mice, whereas in the curative model 400 mg/kg of the aqueous fraction (P < 0.01) showed a significant parasitemia level reduction.

Conclusion

The results of this study indicated that the solvent fractions have promising antiplasmodial activity against Plasmodium berghei, which is consistent with the earlier in vivo study of the hydromethanolic extract.

Studies on Activities and Chemical Characterization of Medicinal Plants in Search for New Antimalarials: A Ten Year Review on Ethnopharmacology

Malaria is an endemic disease that affected 229 million people and caused 409 thousand deaths, in 2019. Disease control is based on early diagnosis and specific treatment with antimalarial drugs since no effective vaccines are commercially available to prevent the disease. Drug chemotherapy has a strong historical link to the use of traditional plant infusions and other natural products in various cultures. The research based on such knowledge has yielded two drugs in medicine: the alkaloid quinine from Cinchona species, native in the Amazon highland rain forest in South America, and artemisinin from Artemisia annua, a species from the millenary Chinese medicine. The artemisinin-based combination therapies (ACTs), proven to be highly effective against malaria parasites, and considered as “the last bullet to fight drug-resistant malaria parasites,” have limited use now due to the emergence of multidrug resistance. In addition, the limited number of therapeutic options makes urgent the development of new antimalarial drugs. This review focuses on the antimalarial activities of 90 plant species obtained from a search using Pubmed database with keywords “antimalarials,” “plants” and “natural products.” We selected only papers published in the last 10 years (2011–2020), with a further analysis of those which were tested experimentally in malaria infected mice. Most plant species studied were from the African continent, followed by Asia and South America; their antimalarial activities were evaluated against asexual blood parasites, and only one species was evaluated for transmission blocking activity. Only a few compounds isolated from these plants were active and had their mechanisms of action delineated, thereby limiting the contribution of these medicinal plants as sources of novel antimalarial pharmacophores, which are highly necessary for the development of effective drugs. Nevertheless, the search for bioactive compounds remains as a promising strategy for the development of new antimalarials and the validation of traditional treatments against malaria. One species native in South America, Ampelozyzyphus amazonicus, and is largely used against human malaria in Brazil has a prophylactic effect, interfering with the viability of sporozoites in in vitro and in vivo experiments.

Antimalarial Property and Acute Toxicity of the Leaves of Theobroma cacao L

The leaf of Theobroma cacao L. is used in traditional medicine in Ghana for the treatment of malaria, yet, with no scientific evidence of its antimalarial property in animals. It was, therefore, studied to validate the antimalarial property in Plasmodium berghei-infected mice. Infected mice were treated with an aqueous extract of T. cacao leaf at different doses of 100, 200, and 400 mg/kg daily for four days. Parasitaemia was determined before treatment and 24 hours following the last dose of extract. The % reduction in parasitaemia and ED₅₀ and ED₉₀ of the extract were determined. Body weight, rectal temperature, and daily mortality of mice were also recorded. The extract had ED₅₀ and ED₉₀ of 242.20 ± 29.38 and 351.00 ± 29.52 mg/kg/day, respectively. Percentage parasitaemia suppression was significant for all doses. The extract at the maximum dose of 400 mg/kg body weight had the highest % parasitaemia suppression of 79.19%; mean survival time of 24.00 ± 2.19 days and median survival of 23 days; body weight increase of 3.82 ± 0.59; and the lowest body temperature reduction of 0.79 ± 0.11°C. T. cacao leaf extract showed an antimalarial property in P. berghei-infected mice. This reinforces the justification for the use of the plant material in treating malaria in Ghana.

Antimalarial Effect of the Root of Silene macrosolen A. Rich (Caryophyllaceae) on Plasmodium-berghei-Infected Mice

Background

Malaria remains a major public health problem globally. Poor access to antimalarial drugs compounded with rapidly evolving drug resistance encourages researchers to continuously look for new drugs. Of importance, traditionally used medicines of plant origin are the highest priority as the ethnobotanical claim can be used as an important clue for its safety and efficacy profiles. Silene macrosolen A. Rich (Caryophyllaceae) has been traditionally used for malaria treatment in Ethiopia. Therefore, this study was aimed to evaluate the in vivo antimalarial activity of the plant against Plasmodium-berghei-infected (ANKA strain) Swiss albino mice.

Methods

The dried powdered root of Silene macrosolen was extracted using 80% methanol. The crude extract was fractionated using chloroform, ethyl acetate, and distilled water that have different affinities to plant phytoconstituents. The in vivo antimalarial activities of the crude extract were evaluated using 4-day suppressive, prophylactic, and curative tests. The antimalarial activity of the solvent fractions was evaluated in a 4-day suppressive test. The oral acute toxicity of the crude extract was also determined according to the OECD guidelines.

Results

The percentage of parasite suppression on the crude extract was 31.02%, 35.82%, and 39.23% in prophylactic, curative, and 4-day suppressive tests, respectively, at the tested dose level of 400 mg/kg. The percentages of chemosuppression of the solvent fractions (400 mg/kg) were 43.07%, 42.61%, and 38.38% in aqueous, ethyl acetate, and chloroform fractions, respectively. Both the crude extract and solvent fractions also significantly prolonged survival time except in the prophylactic test. In addition, prevention of weight loss and reduction in temperature and packed cell volume (PCV) were observed in crude extract as well as solvent fractions. The acute toxicity test of the plant extract also exhibited no sign of toxicity.

Conclusion

The result indicated that Silene macrosolen has a significant antimalarial activity, justifying the traditional use of the plant material for treatment of malaria.

Anti-Oxidant Potential and Antimalarial Effects of Acanthus polystachyus Delile (Acanthaceae) Against Plasmodium berghei: Evidence for in vivo Antimalarial Activity

BACKGROUND

Malaria is among the most devastating and widespread tropical parasitic diseases which is more prevalent in developing countries. Acanthus polystachyus (Acanthaceae) leaves are traditionally used for the treatment of malaria in Ethiopia. This study aimed to investigate the in vivo antimalarial and in vitro antioxidant activity of the leaves extract of Acanthus polystachyus.

MATERIALS AND METHODS

The leaves part of A. polystachyus were extracted using 80% methanol. The antioxidant effect of Acanthus polystachyus extract was evaluated by using (DPPH) diphenyl-2-picrylhydrazyl assay model. To evaluate the antimalarial effect of the A. polystachyus extract, Plasmodium berghei ANKA strain (chloroquine sensitive) was used to infect the mice in three different experimental protocol: suppressive, curative, and prophylactic test models.

RESULTS

The leaves extract of Acanthus polystachyus significantly (P<0.05-0.0001) suppressed the parasitemia in all experimental protocol. The extract exhibited a chemosupression of 27.64%, 33.67% and 49.25% in 4-day suppressive test; 33.76%, 39.24% and 53.59% in curative test, and 25%, 32.84% and 50% in prophylactic tests at dose of 100, 200, and 400mg/kg, respectively. The extract also extended the mean survival time, prevented the bodyweight loss and body temperature drop, and packed cell volume significantly (P<0.05) as compared to the negative control. Dose-dependent antioxidant activity was shown by the leaf extract of A. polystachyus with an IC50 value of 9.37µg/mL.

CONCLUSION

The current finding showed that the leaves extract of Acanthus polystachyus has revealed promising antimalarial effects. Thus, this finding supports the traditional use of A. polystachyus for the treatment of malaria.

In Vivo Antiplasmodial Activity of Different Solvent Extracts of Myrianthus libericus Stem Bark and Its Constituents in Plasmodium berghei-Infected Mice

The emergence and resurgence of P. falciparum resistance to generations of antimalarial drugs have prompted the search for new, effective, and safe antimalarial agents. This study aimed at investigating the in vivo antiplasmodial activity of the 70% hydroethanolic extract and constituents of the stem bark of Myrianthus libericus based on its ethnomedicinal use as an antimalarial agent. The antiplasmodial activity was assessed in Swiss albino mice employing the 4-day suppressive and Rane's tests. MLB significantly (p < 0.0001) suppressed parasitaemia by 52.26%, 65.40%, and 77.11% at 50, 100, and 200 mg·kg⁻¹ doses, respectively, in the 4-day suppressive test. In Rane's test, the highest parasitaemia suppression of 72.50% was recorded at a dose of 200 mg·kg⁻¹ of the extract. Fractionation of the bioactive ethyl acetate fraction by solvent-solvent partitioning and column chromatography led to the isolation of friedelan-3-one and stigmasterol being reported for the first time from this species. The compounds demonstrated remarkable antiplasmodial activity by suppressing parasitaemia by 65–72% in the suppressive test and 61–70% in the curative test at doses of 10–30 mg·kg⁻¹. Both the extract and the isolated compounds significantly prolonged the survival time of infected mice and averted the cardinal signs associated with P. berghei-induced malaria including weight loss, hypothermia, and haemolysis. The results obtained confirm the prospect of M. libericus as an important source of new antimalarial compounds and justifies its folkloric use as an antimalarial agent.

Evaluation of Antimalarial Activity of Methanolic Root Extract of Myrica salicifolia A Rich (Myricaceae) Against Plasmodium berghei-Infected Mice

BACKGROUND

The management and control of malaria has become gradually challenging due to the spread of drug-resistant parasites, lack of effective vaccine, and the resistance of vector to insecticides. Consequently, novel agents are urgently needed from different sources including from medicinal plants. In Ethiopia and Uganda, Myrica salicifolia root is traditionally claimed for the treatment of malaria. The aim of this study was to evaluate the in vivo antimalarial activity of root crude extract of M salicifolia.

METHODS

The parasite, Plasmodium berghei was used in this study since it is an appropriate parasite that is most commonly used because of its higher accessibility. A 4-day suppressive test was employed to evaluate the antimalarial effect of crude extract against early infection. The curative and prophylactic effect of the crude extract was further tested by Rane's test and residual infection procedure. Parasitemia, survival time, packed cell volume, body weight, and rectal temperature of mice were used as evaluation parameters. Windows SPSS version 24 was used to analyze the data and analysis of variance followed by Tukey's honestly significant difference to compare results between groups.

RESULTS

The root crude extract of M salicifolia significantly (P < .05-.0001) suppressed parasitemia. The crude extract exhibited a chemosuppression of 40.90.

CONCLUSION

The development of new antimalarial agents and the finding supports the traditional claims and previous in vitro studies.

Genus Periploca (Apocynaceae): A Review of Its Classification, Phytochemistry, Biological Activities and Toxicology

The genus Periploca belongs to the family Apocynaceae, which is composed of approximately ten species of plants according to incomplete statistics. Most of these plants serve as folk medicines with a long history, especially Periploca sepium and Periploca forrestii. The botanical classifications, chemical constituents, biological activities and toxicities of the genus Periploca were summarized in the literature from 1897 to early 2019. Though the botanical classification of this genus is controversial, these species are well-known to be rich sources of diverse and complex natural products-above all, cardiac steroids and C₂₁ pregnane steroids with special structures and obvious pharmacological activities. The various crude extracts and 314 isolated metabolites from this genus have attracted much attention in intensive biological studies, indicating that they are equipped with cardiotonic, anti-inflammatory, immunosuppressive, antitumor, antimicrobial, antioxidant, insecticidal and other properties. It is noteworthy that some cardiac glycosides showed hepatotoxicity and cardiotoxicity at certain doses. Therefore, in view of the medical and agricultural value of the genus Periploca, in-depth investigations of the pharmacology in vivo, the mechanisms of biological actions, and the pharmacokinetics of the active ingredients should be carried out in the future. Moreover, in order to ensure the safety of clinical medication, the potential toxicities of cardiac glycosides or other compounds should also be paid attention. This systematic review provides an important reference base for applied research on pharmaceuticals and pesticides from this genus.