Peter's 4-day Suppressive Test Research Articles

Optimization of in vivo antimalarial efficacy of combinations of aqueous leaf extracts of Artemisia annua L., Vernonia amygdalina Del, and Microglossa pyrifolia (Lam.) Kuntze using factorial design.

Malaria continues to be among the leading causes of mortality in Africa including Uganda, with the emergence of parasite resistance to the first-line therapeutics (Artemisinin- based Combination Therapy). To find new therapeutics, this study has reported an in vivo antimalarial efficacy of combinations of Artemisia annua (Aa), Vernonia amygdalina (Va), and Microglossa pyrifolia (Mp) in mice model using factorial design. The Aa and Va were extracted by hot infusion, and Mp by cold maceration using distilled water. The dry extracts were screened for different phytochemicals, and later subjected to in vivo antimalarial activity using Peter's 4-day suppressive test. The 23 factorial design used Aa, Va, and Mp aqueous extracts as independent variables at two levels (-1 and 1), and the percentage chemo suppression and survival time as response variables. The data was analyzed using Design Expert 13 and GraphPad Prism employing ANOVA linear regression modelling and t-test respectively. All the extracts had alkaloids, phenols, saponins, terpenoids, cardiac glycosides, tannins, steroids, and carbohydrates. The various combinations showed chemo suppression from 41.5 to 91.0% and survival time of 19 to 23days. The first three combinations having lower levels of Aa (200mg/kg) exhibited higher chemo suppression (> 90%) compared to Artemisinin-Lumefantrine positive control at 4mg/kg with 87.5%. Lower levels of Aa in the combinations contributed to high chemo suppression while higher levels of Va prolonged survival times. Interactions between Aa and Mp showed higher chemo suppression, and that between Aa and Va increased survival time. An optimized prediction of 94.4% chemo suppression was made by the ANOVA model at lower levels of Aa and Va, and a higher level of Mp, which is similar to an experimental run which gave a response of 90. 6%. An optimum combination of the three plants as a natural herbal antimalarial therapy was obtained using factorial design, and it offers an alternative to first line Artemisinin based Combination Therapy (ACTs) as parasite resistance looms. This combination could be further developed into a standard phytopharmaceutical and subjected to Randomized Controlled Trials (RCTs).

Antiplasmodial Properties of Ethanol Stem-Bark Extract of <i>Newbouldia Laevis</i> (P. Beauv) Seem in <i>P. Berghei</i> Infected Mice

Background: Despite substantial improvement in the management of malaria infection over the last centuries, it remains a significant public threat especially to those in the tropical and subtropical African regions due to the emergence of drug-resistant P. falciparum strains, delayed diagnosis, high cost as well as contraindications of some available antimalarial medications. Hence, the need for necessary measures in terms of alternative therapeutic approaches to counter this threat is of utmost importance. The present study was aimed at determining the antimalarial potential of ethanol stem-bark extract of Newbouldia laevis in P. berghei (NK65) infected mice. 
 Methodology: The antimalarial activity of Newbouldia laevis stem-bark at 250, 500 and 1,000 mg/kg was investigated in mice infected with 1 x 107 parasitized erythrocytes using three experimental animal models: Peter's 4-day suppressive, curative and prophylactic models. Phytochemical screening of the stem bark was also conducted.
 Results: The extract at all tested doses of 250, 500 and 1000 mg/ kg showed significant (p<0.01) and dose-dependent reductions in the parasitemia levels of the treated rats with percentage chemosuppresion of 90.7, 91.8 and 94% respectively in the Peters 4-day suppressive test. There were also significant (p<0.01) dose- dependent reductions in parasitemia density of the treated rats at all doses of 250, 500 and 1000 mg/kg in the curative and prophylactic studies compared to the distilled water group. Phytochemical screening revealed the presence of carbohydrates, tannins, alkaloids, flavonoids, saponins, terpenoids, cardiac glycosides, steroids and anthraquinones in the crude extract.
 Conclusion: The results suggest that ethanol stem-bark extract of Newbouldia laevis possesses antimalarial activity and this justifies the traditional use of the stem-bark of the plant in antimalarial herbal remedy.

Assessment of antimalarial activity of crude extract of Chan-Ta-Lee-La and Pra-Sa-Chan-Dang formulations and their plant ingredients for new drug candidates of malaria treatment: In vitro and in vivo experiments.

The emergence and spread of antimalarial drug resistance have become a significant problem worldwide. The search for natural products to develop novel antimalarial drugs is challenging. Therefore, this study aimed to assess the antimalarial and toxicological effects of Chan-Ta-Lee-La (CTLL) and Pra-Sa-Chan-Dang (PSCD) formulations and their plant ingredients. The crude extracts of CTLL and PSCD formulations and their plant ingredients were evaluated for in vitro antimalarial activity using Plasmodium lactate dehydrogenase enzyme and toxicity to Vero and HepG2 cells using the tetrazolium salt method. An extract from the CTLL and PSCD formulations exhibiting the highest selectivity index value was selected for further investigation using Peter's 4-day suppressive test, curative test, prophylactic test, and acute oral toxicity in mice. The phytochemical constituents were characterized using gas chromatography-mass spectrometry (GC-MS). Results showed that ethanolic extracts of CTLL and PSCD formulations possessed high antimalarial activity (half maximal inhibitory concentration = 4.88, and 4.19 g/mL, respectively) with low cytotoxicity. Ethanolic extracts of the CTLL and PSCD formulations demonstrated a significant dose-dependent decrease in parasitemia in mice. The ethanolic CTLL extract showed the greatest suppressive effect after 4 days of suppressive (89.80%) and curative (35.94%) testing at a dose of 600 mg/kg. Moreover, ethanolic PSCD extract showed the highest suppressive effect in the prophylactic test (65.82%) at a dose of 600 mg/kg. There was no acute toxicity in mice treated with ethanolic CTLL and PSCD extracts at 2,000 mg/kg bodyweight. GC-MS analysis revealed that the most abundant compounds in the ethanolic CTLL extract were linderol, isoborneol, eudesmol, linoleic acid, and oleic acid, whereas ethyl 4-methoxycinnamate was the most commonly found compound in the ethanolic PSCD extract, followed by 3-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-chromen-4-one, flamenol, oleic acid amide, linoleic acid, and oleic acid. In conclusions, ethanolic CTLL and PSCD extracts exhibited high antimalarial efficacy in vitro. The ethanolic CTLL extract at a dose of 600 mg/kg exhibited the highest antimalarial activity in the 4-day suppressive and curative tests, whereas the ethanolic PSCD extract at a dose of 600 mg/kg showed the highest antimalarial activity in the prophylactic test.

Fabrication of Phytosome with Enhanced Activity of Sonneratia alba: Formulation Modeling and in vivo Antimalarial Study.

Sonneratia alba extract exhibits antimalarial activity, mainly due to its secondary metabolites-naphthoquinones, flavonoids, tannins, and saponins-where naphthoquinone is the primary active component. However, its low bioavailability limits its effectiveness. To improve this, a phytosome-based vesicular system was proposed. This study focused on formulating a phytosome with S. alba and developing a predictive model to enhance its antimalarial activity. Phytosomes were produced using antisolvent precipitation and optimized with 3-factor, 3-level Box-behnken model. Particle size, zeta potential, and entrapment efficiency were assessed. The optimized phytosomes were characterized by their physical properties and release profiles. Their antimalarial activity was tested in white BALB/c mice infected with Plasmodium berghei using Peter's 4-day suppressive test. The optimal phytosome formulation used a phospholipid-to-extract ratio of 1:3, reflux temperature of 50°C, and a duration of 2.62 hours. The phytosomes had a particle size of 471.8 nm, a zeta potential of -54.1 mV, and an entrapment efficiency (EE) of 82.4%. In contrast, the phytosome-fraction showed a particle size of 233.4 nm, a zeta potential of -61.5 mV, and an EE of 87.08%. TEM analysis confirmed both had a spherical shape. In vitro release rates at 24 hours were 86.2 for the phytosome-extract and 95.9% for the phytosome-fraction, compared to 46.9% and 37.7% for the extract and fraction alone. Overall, the phytosome formulation demonstrated good stability. The actual experimental values closely matched the predicted values from the Box-Behnken model, indicating a high degree of accuracy in the model. Additionally, the phytosomes exhibited significantly greater antimalarial activity than the S. alba extract and fraction alone. The findings indicated that the vesicular formulation in phytosomes can enhance the antimalarial activity of S. alba extract and fraction.

Efficacy of Khaya grandifoliola Stem Bark Ethanol Extract in the Treatment of Cerebral Malaria in Swiss albino Mice Using Plasmodium berghei NK65 Strain.

Cerebral malaria is one of the most severe and dangerous forms of malaria and is potentially fatal. This study was aimed at evaluating the anticerebral malaria efficacy of Khaya grandifoliola used by traditional healers. Fifty grams of Khaya grandifoliola stem bark was macerated in 1 L ethanol (95%) for 72 h. The filtrate was dried at 40°C until the obtention of a dry extract. The antimalarial test was evaluated using the Peter 4-day suppressive test and the Rane curative test. Mice were group into 6 groups of 6 mice each. For the antioxidant test, parameters such as malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), catalase (CAT), and nitric oxide (NO) were assessed. The livers of mice were crushed and centrifuged in order to be measured. Aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) using the Dutch Diagnostics Kit and blood were collected for haematological parameters. The ethanol extract showed a suppressive activity of 78.12%, 75.30%, and 68.69% at 500 mg/kg, 250 mg/kg, and 125 mg/kg, respectively. Similarly, the curative activity showed a statistically significant reduction in parasitemia (p < 0.05). Antioxidant parameter assays showed a low value of MDA and a high value of SOD, CAT, NO, and GSH in the negative control group. A statistically significant higher values of ASAT and ALAT were observed in the negative control compared to the other test groups (p < 0.05). Haematological parameters showed a statistically significant decrease in white blood cells, red blood cells, haemoglobin, and platelets in the negative control group (p < 0.05). The results of this study justify the traditional usage of Khaya grandifoliola in the treatment of cerebral malaria. However, in vivo toxicity assessment is still necessary to verify its safeness.

In vitro and in vivo antiplasmodial activities of leaf extracts from Sonchus arvensis L.

BackgroundMalaria continues to be a global problem due to the limited efficacy of current drugs and the natural products are a potential source for discovering new antimalarial agents. Therefore, the aims of this study were to investigate phytochemical properties, cytotoxic effect, antioxidant, and antiplasmodial activities of Sonchus arvensis L. leaf extracts both in vitro and in vivo.MethodsThe extracts from S. arvensis L. leaf were prepared by successive maceration with n-hexane, ethyl acetate, and ethanol, and then subjected to quantitative phytochemical analysis using standard methods. The antimalarial activities of crude extracts were tested in vitro against Plasmodium falciparum 3D7 strain while the Peter's 4-day suppressive test model with P. berghei-infected mice was used to evaluate the in vivo antiplasmodial, hepatoprotective, nephroprotective, and immunomodulatory activities. The cytotoxic tests were also carried out using human hepatic cell lines in [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay.ResultThe n-hexane, ethyl acetate, and ethanolic extracts of S. arvensis L. leaf exhibited good in vitro antiplasmodial activity with IC50 values 5.119 ± 3.27, 2.916 ± 2.34, and 8.026 ± 1.23 μg/mL, respectively. Each of the extracts also exhibited high antioxidant with low cytotoxic effects. Furthermore, the ethyl acetate extract showed in vivo antiplasmodial activity with ED50 = 46.31 ± 9.36 mg/kg body weight, as well as hepatoprotective, nephroprotective, and immunomodulatory activities in mice infected with P. berghei.ConclusionThis study highlights the antiplasmodial activities of S. arvensis L. leaf ethyl acetate extract against P. falciparum and P. berghei as well as the antioxidant, nephroprotective, hepatoprotective, and immunomodulatory activities with low toxicity. These results indicate the potential of Sonchus arvensis L. to be developed into a new antimalarial drug candidate. However, the compounds and transmission-blocking strategies for malaria control of S. arvensis L. extracts are essential for further study.

Exploring Potential Antimalarial Candidate from Medicinal Plants of Kheaw Hom Remedy.

The Kheaw Hom remedy is a traditional Thai medicine widely used to treat fevers. Some plant ingredients in this remedy have been investigated for their antimicrobial, antiviral, anti-inflammatory, and antioxidant activities. However, there have been no reports on the antimalarial activities of the medicinal plants in this remedy. Therefore, this study focuses on identifying potential antimalarial drug candidates from the medicinal plant ingredients of the Kheaw Hom remedy. Eighteen plants from the Kheaw Hom remedy were extracted using distilled water and ethanol. All extracts were investigated for their in vitro antimalarial activity and cytotoxicity. An extract that exhibited good in vitro antimalarial activity and low toxicity was selected for further investigation by using Peter's 4-day suppressive test and an acute oral toxicity evaluation in mice. Based on the in vitro antimalarial activity and cytotoxicity studies, the ethanolic extract of Globba malaccensis rhizomes showed promising antimalarial activity against the Plasmodium falciparum K1 strain (IC50 = 1.50 µg/mL) with less toxicity to Vero cells (CC50 of &gt;80 µg/mL). This extract exhibited a significant dose-dependent reduction in parasitemia in P. berghei-infected mice. The maximum suppressive effect of this extract (60.53%) was observed at the highest dose administered (600 mg/kg). In a single-dose acute toxicity test, the animals treated at 2000 mg/kg died within 48 h after extract administration. In conclusion, our study indicates that the ethanolic extract of G. malaccensis rhizomes exhibited in vitro and in vivo antimalarial activities, which could serve as a promising starting point for antimalarial drug.

In Vivo Antimalarial Activity of the Leaf Extract of Osyris quadripartita Salzm. ex Decne and Its Major Compound (-) Catechin.

Background The leaves of Osyris quadripartita Salzm. ex Decne, endemic to Ethiopia, are traditionally used for the treatment of malaria. Previous phytochemical investigations of Osyris species showed the presence of flavonoids, anthracene derivatives, and sesquiterpene lactones as the main constituents. The aim of the present study was to investigate the antimalarial activity of the leaf extract of O. quadripartita and its isolated constituent against mice infected with Plasmodium berghei. Methods Isolation of a compound was carried out on silica gel column chromatography of the extract eluting with gradient mixtures of CHCl3/MeOH. Structural elucidation of the isolated compound was achieved by ESI-MS and 1D-and 2D-NMR spectral data. Peter's 4-day suppressive test method was used to determine the antimalarial activity of the test substances. Level of parasitemia, survival time, and body weight change were used to determine the antimalarial activity of the test substances. Results (–) Catechin was isolated and characterized from the hydroalcoholic extract of O. quadripartita. At a concentration of 400 mg/kg, both the extract and (–) catechin exhibited antimalarial activity with the highest chemosuppression values of 70.61% and 64.26%, respectively. Conclusion These findings indicate that O. quadripartita is endowed with genuine antimalarial activity attributed in part, to its (–) catechin content. Hence, the present study may validate the traditional use of the plant for the treatment of malaria.

Ananas comosus (L) Merrill (pineapple) fruit peel extract demonstrates antimalarial, anti-nociceptive and anti-inflammatory activities in experimental models

Ethnopharmacology relevancePineapple (Ananas comosus) peel is a major waste in pineapple canning industry and it is reported to be used in ethnomedicine as a component of herbal remedies for malarial management. This study aimed to evaluate the antimalarial, antinociceptive and anti-inflammatory properties of Ananas comosus peel extract (PEAC). MethodsAnanas comosus peel was extracted with 80% methanol. PEAC (100, 200 and 400 mg/kg) was investigated for antimalarial effect using Peter's 4-day suppressive test (4-DST) model in mice. Antinociceptive activity of PEAC was investigated in hot plate, acetic acid-induced writhing and formalin tests in mice. The anti-inflammatory activity was evaluated using the lipopolysaccharides-induced sickness behavior in mice and carrageenan-induced air pouch in rats' models. ResultsPEAC could not significantly (p > 0.05) suppressed parasitemia level at 7-day post-infection in 4-DST. PEAC (400 mg/kg) mildly prolongs survival of infected mice up till day 21. PEAC demonstrated significant (p < 0.05) antinociceptive activity by increasing latency to jump on the hot plate, reduced number of writhings in acetic acid test and reduced paw licking time in 2nd phase of formalin test. PEAC significantly reduced anxiogenic and depressive-like symptoms of sickness behavior in LPS-injected mice. PEAC demonstrated significant anti-inflammatory activity in carrageenan-induced air pouch experiment by reducing exudates formation, inflammatory cell counts, and nitrite, tumor necrosis factor-alpha and interleukin-6 levels. ConclusionAnanas comosus peel extract demonstrated mild antimalarial activity but significant anti-nociceptive and anti-inflammatory properties probably mediated via inhibition of pro-inflammatory mediators.

In vivo Antimalarial, Antioxidant Activities and Safety of Carapa procera DC. (Meliaceae).

<b>Background and Objectives:</b> <i>Carapa procera</i> is a popular herb used by traditional healers in the western part of Burkina Faso. In a previous study, <i>Carapa procera </i>showed interesting antiplasmodial activity <i>in vitro </i>against <i>P. falciparum</i>. The present study aimed to evaluate its <i>in vivo</i> potential against malaria parasites and its safety in mice. <b>Materials and Methods:</b> The antimalarial activity of the ethanolic extract was evaluated on <i>Plasmodium berghei </i>Anka in the Naval Medical Research Institute (NMRI) mice using the Peters 4-day suppressive test. The acute toxicity was performed according to the Lorke method and sub-acute toxicity following the Seewaboon method. The polyphenols and flavonoids were determined by colorimetric methods. The antioxidant activity of the extract was evaluated <i>in vitro</i> by Ferric Reducing Antioxidant Power (FRAPP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. <b>Results:</b> <i>Carapa procera</i> had a good antiplasmodial activity at a dose of 250 mg kg¹ b.wt. Phytochemical screening revealed the presence of polyphenols and flavonoids in the extracts. Soxhlet ethanolic extracts had the highest content in polyphenols and flavonoids. The antioxidant activity of Soxhlet ethanolic extracts was better than macerated extract by DPPH method and FRAP method. Besides, no mortality in mice was recorded with the soxhlet ethanolic extract. No toxic signs were observed in animals in the sub-acute toxicity test. <b>Conclusion:</b> <i>Carapa procera </i>soxhlet ethanolic stem bark extract had a good <i>in vivo</i> antimalarial activity against <i>Plasmodium berghei </i>infection in mice and the extract was relatively safe when administered orally in mice.

Antiplasmodial and Antipyretic Activity and Safety Evaluation of the Methanolic Leaf Extract of Murraya exotica (L.).

Background The increasing mortality and morbidity of malaria in Africa coupled with the recent reports of antimalarial drug resistance reinforces the need for novel antimalarial agents from natural plant products with folkloric use for the disease. Murraya exotica (L.) (Rutaceae) is widely used as an ornamental plant used indigenously to treat fever, cough, and infectious wounds and eliminate pain from injury and trauma. This study was conducted to evaluate extracts of the leaves of Murraya exotica (L.) (Rutaceae) for its safety and antipyretic and antimalarial activity in rodent models. Method In this study, the Peters 4-day suppressive and curative test in Plasmodium berghei-infected mice was used to demonstrate the antiplasmodial activity of the methanolic leaf extract of Murraya exotica (L.) (MEE). The study also evaluated the subacute toxicity study and the antipyretic activity of MEE on baker's yeast-induced hyperthermia in rodent models. Results Murraya exotica (L.) extract demonstrated curative antimalarial activity, with a percentage suppression of 45.84, 64.32 ± 0.33, 56.74 ± 2.16, and 64.61 ± 0.67 at doses of 50, 100, 300, and 600 mg/kg, respectively. In the Peters 4-day suppressive test, MEE at dose 600 mg/kg had the highest chemosuppression (76.02 ± 1.38%) compared with artesunate (2 mg/kg, p.o.) (82.56 ± 0.97%). Subacute oral toxicity studies in Sprague-Dawley rats documented no deaths, with no significant changes in clinical signs, organ weights, and hematological and biochemical parameters. The LD50 of MEE was estimated to be above 1000 mg/kg in Sprague-Dawley rats. All doses of MEE and paracetamol reduced pyrexia in 1 h and 2 h after their administration. The percentage reduction of rectal temperature (TR) for the positive control (paracetamol, 150 mg/kg, p.o.) was 44.36% while the Murraya exotica extract at doses 50 mg/kg, 100 mg/kg, 300 mg/kg, and 600 mg/kg recorded 67.74%, 40.78%, 66.42%, and 59.42%, respectively. Murraya exotica at dose 100 mg/kg exhibited significant reduction (p < 0.05) in baker's yeast-induced pyrexia. Conclusions The findings in this study show the antipyretic, curative, and suppressive antiplasmodial activity as well as the safety of the methanolic leaf extract of Murraya exotica (L.) supporting its traditional use for malaria and fever.

English

Vernonia amygdalina has been widely utilized in Ghana and other West African states for numerous parasitic infections, diabetes and some inflammatory conditions. In this study we evaluated the antipyretic and antimalarial properties as well as in vitro antioxidant activities of an ethanolic stem bark extract of V. amygdalina (VAE). The antipyretic effect of VAE was assessed using Baker&rsquo;s yeast-induced pyrexia and the antimalarial activities of plant extract against Plasmodium berghei-infected mice in the Peters 4-day suppressive test. The antioxidant activities of the stem bark extract were determined by DPPH radical scavenging and total phenol content assay. Phytochemical screening was carried out using standard methods. V. amygdalina (100-600 mg kg-1) dose related decreased the Baker&rsquo;s yeast-induced fever in young rats. Also, it exhibited a significant (F (5, 24) = 91.35, P &lt; 0.0001) anti-plasmodial activity in the mouse model. It caused a percentage suppression of 81.80 &plusmn; 3.76 at 600 mg kg-1and a relative antioxidant activity in the DPPH radical scavenging assay with an IC50 of 146.4 &plusmn; 2.31 &micro;gml-1 and a total phenol content of 345.7 &plusmn; 4.56 mg g-1 of gallic acid equivalence. Preliminary phytochemical screening showed that the extract contained tannins, reducing sugars, flavonoids, terpenoids and alkaloids. V. amygdalina hydroethanolic stem bark extract evoked promising antipyretic, anti-plasmodial and antioxidant effects. Key words: Vernonia amygdalina, pyrexia, malaria, antioxidants, Baker&rsquo;s Yeast, Plasmodium berghei. &nbsp;

Antimalarial Activity of Meriandra dianthera Leaf Extracts in Plasmodium berghei-Infected Mice.

Objective To evaluate the antimalarial effect of aqueous methanolic extract and solvent fractions of Meriandra dianthera leaves against Plasmodium berghei in mice model. Method M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the in vivo antimalarial activity of the extract and fractions. Result The crude leaf extract of Meriandra dianthera leaves against P < 0.001) chemosuppression compared to the negative control. Both the extract and fractions were able to prevent P. berghei induced body weight loss and body temperature reduction and also increased the survival time of the mice as compared to the negative control. The aqueous methanolic leaf extract of M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the Conclusion The extracts of M. dianthera leaves showed promising antimalarial activity, with no sign of toxicity and therefore may support its traditional use for the treatment of malaria.M. dianthera leaves were extracted with 80% methanol and dried. The dried crude extract was then defatted and further fractionated with chloroform, ethyl acetate, and butanol. Acute oral toxicity test was performed as per the Organization for Economic Cooperation and Development guideline 425. Peter's 4-day suppressive test was used to determine the

Evaluation of Antimalarial Activity of Hydromethanolic Crude Extract and Solvent Fractions of the Leaves of Nuxia congesta R. Br. Ex Fresen (Buddlejaceae) in Plasmodium berghei Infected Mice.

BackgroundIn Ethiopia, malaria control has been complicated due to resistance of the parasite and its vectors to the current drugs. Therefore, new drugs are required to avert the problem posed by drug-resistant Plasmodium strains. There is need to investigate alternative sources of antimalarial agents and plants are potential source of antimalarial drugs. This study aimed to investigate the antimalarial activity of the leaves of N. congesta crude extract (hydromethanolic extract) and solvent fractions (n-hexane, chloroform, and aqueous fractions of crude extract) traditionally used to treat malaria in many parts of Ethiopia.MethodsAcute oral toxicity of the leaves of N. congesta extract was assessed in mice up to a dose of 5,000 mg/kg body weight. Antiplasmodial activities of crude extract and solvent fractions were assessed in P. berghei infected female Swiss albino mice models using the Peter’s 4-day suppressive test. The curative activities of crude extract and fractions were evaluated using Rane’s test.ResultsPlant extract exhibited no signs of toxicity on mice at a dose of 5,000 mg/kg body weight. Crude extract showed significant parasitemia suppressions at doses of 500 mg/kg (P<0.05), 750 mg/kg (P<0.01), and 1,000 mg/kg (P<0.001) as compared to negative control in the Peter’s 4-day suppressive test, but failed to reach a significant level at 500 mg/kg and 750 mg/kg in the curative test (Rane’s test). Aqueous fraction showed significant parasitemia suppression at a dose of 400 mg/kg (P<0.05) in curative test and 600 mg/kg (P<0.05) in Peter’s 4-day suppressive and curative tests. Maximum suppressive effects of extract (58.13%) and aqueous fraction (44.9%) were observed at the highest doses administered.ConclusionHydromethanolic leaf extract of N. congesta and its aqueous fraction exhibited antimalarial activities. The antimalarial activity and lack of acute toxicity are suggested to uphold the earlier claims made by the Ethiopian traditional practitioners.

Synthesis and antiplasmodial activity of novel phenanthroline derivatives: An in vivo study.

Due to the rapid increased drug resistance to Plasmodium parasites, an urgent need to achieve new antiplasmodial drugs is felt. Therefore, in this study, the new synthetic phenanthroline derivatives were synthesized with antiplasmodial activity. A series of 1,10-phenanthroline derivatives containing amino-alcohol and amino-ether substituents were synthesized via facile procedures, starting with 5,6-epoxy-1,10-phenanthroline. Their antiplasmodial activity was then evaluated using Peter's 4-day suppressive test against Plasmodium berghei-infected mice (ANKA strain). Furthermore, the mean survival time of the mice treated with synthetic compounds was compared with the negative control group. The results demonstrated that the compounds 6-(3-(dibutylamino)propylamino)-5,6-dihydro-1,10-phenanthroline-5-ol(7b) at the dose of 150 mg/kg/day and 4-(1,10-phenanthroline-5-yloxy)-N, N-dipropylbutan-1-amine (8b) at the dose of 15 mg/kg/day have 90.58% and 88.32% suppression, respectively. All synthetic compounds prolonged the mean survival time of treated mice in comparison with negative control groups, indicating the in vivo antiplasmodial activity of these new compounds. The present study is the first attempt to achieve new, effective synthetic compounds based on phenanthroline scaffold with the antiplasmodial activity. However, more research is needed to optimize their antimalarial activity.

Hydroethanolic Extracts of Erigeron floribundus and Azadirachta indica Reduced Plasmodium berghei Parasitemia in Balb/c Mice.

Malaria is one of the most important infectious diseases in Africa especially in Cameroon. The nonaccessibility to current treatments for poor people and the appearance of drug-resistant Plasmodium falciparum parasites stimulate the search for alternative treatments. The aim of this study was to evaluate the antimalarial activity and the safety of hydroethanolic extracts from Erigeron floribundus and Azadirachta indica. The crude hydroethanolic extracts of E. floribundus (HEEF) and A. indica (HEAI) were prepared via maceration of the whole plant powder of E. floribundus and the leaves of A. indica in 70% ethanol. The antimalarial activity was determined according to Peter's 4-day suppressive test using the murine model Plasmodium berghei/Balb C mice, while the acute and subacute toxicity tests were assessed according to the OECD 425 and 407 guidelines, respectively. The results indicate a reduction of parasitemia ranging from 49.75 ± 3.64 to 69.28 ± 1.36% for HEAI and from 30.46 ± 4.30 to 62.36 ± 2.32% for HEEI. Overall, HEEF and HEAI at doses of 60, 120, and 240 mg/kg b.w. and 75, 150, and 300 mg/kg b.w., respectively, showed a significant (p≤0.001) parasitemia reduction on P. berghei infecting BALB/c mice. HEEF and HEAI caused a significant (p<0.001) attenuation of body temperature drop in mice compared to negative control, except for the 150 mg/kg b.w. dose in the female group. Moreover, there was no mice mortality observed with these extracts even at 5000 mg/kg, while the aspartate amino transferase (ASAT) level of mice treated with 300 mg/kg b.w. of HEAI extract increased when compared with the control. The results of this study support the traditional use of these plants species extracts against malaria infection in rural zones of Northern Cameroon, therefore confirming their potential as sources for the development of efficient phytomedicines for malaria-poverty disease alleviation.

Traditional Consumption of the Fruit Pulp of Chrysophyllum albidum (Sapotaceae) in Pregnancy may be Serving as an Intermittent Preventive Therapy against Malaria Infection.

Background:The bark of Chrysophyllum albidum is reported to possess antimalarial property. The fruit pulp of C. albidum consumed by pregnant women of south eastern Nigeria may also possess antimalarial activity. The present preliminary study investigated the antimalarial potential of the pulp juice and seed of C. albidum.Methods:Schizonticidal activity was evaluated using the Peter’s 4-day suppressive test. The prophylactic and curative antimalarial activities of the extracts were evaluated in Albino mice inoculated with Plasmodium berghei.Results:The oral acute toxic dose of the pulp extract is beyond 5000 mg/kg. The seed and pulp possess both suppressive and curative properties. The seed extract suppressed early infection by 72.97% and 97.30%, at 500 and 1000 mg/kg, respectively. The pulp juice recorded 72.97% and 81.08%, at 500 and 1000 mg/kg, respectively. At 500 mg/kg dose, the level of parasite control on Day 7 was the same (96.10%) for both seed and pulp.Conclusion:This study demonstrates the presence of antimalarial constituents in the chemically uncharacterized samples (fruit pulp and seed) of C. albidum. Its ethnomedicinal use may be valuable in pregnancy where it may possibly serve as an intermittent preventive therapy against malaria.

Evaluation of the use of Ocimum suave Willd. (Lamiaceae), Plectranthus barbatus Andrews (Lamiaceae) and Zanthoxylum chalybeum Engl. (Rutaceae) as antimalarial remedies in Kenyan folk medicine

Ethnopharmacological relevanceCrude extracts from the leaves of Ocimum suave Willd (Lamiaceae) and the root barks of Plectranthus barbatus Andrews (Lamiaceae) and Zanthoxylum chalybeum Engl. (Rutaceae) were studied to ascertain the ethnopharmacological standing of their antimalarial usage in Kenyan folk medicine. Materials and methodsAqueous and Chloroform: Methanol (1:1) extracts of the plants were used in this study. Toxicity of the extracts was investigated by using brine shrimp lethality test and acute oral toxicity in mice. The antimalarial activity at a dose of 100mg/kg was screened in Swiss albino mice against chloroquine sensitive Plasmodium berghei (D6) using Peters 4-day suppressive test. Chloroquine, at a dosage rate of 20mg/kg was used as a reference drug. ResultsThe extracts showed some signs of acute toxicity in the brine shrimp lethality test. However, no signs of toxicity were observed in the mice at a dose of 2000mg/kg of the crude extracts. The results revealed that all the tested crude extracts were safe. Z. chalybeum aqueous extract and P. barbatus organic extract showed chemosuppressive activities of 81.45% and 78.69%, respectively. This antimalarial activity was not significantly different from that of chloroquine (P<0.05). ConclusionThe findings suggest that the Kenyan folkloric medicinal application of these plants has a pharmacological basis. Bioactivity guided fractionation and isolation of bioactive molecules from the two species could lead to new hits against Plasmodiumfalciparum malaria.

Antimalarial and safety evaluation of extracts from Toddalia asiatica (L) Lam. (Rutaceae)

Ethnopharmacological relevanceToddalia asiatica (L) Lam. (Rutaceae) is a medicinal plant traditionally used in Kenya by many communities for the treatment of malaria and other ailments. All parts of the plant are claimed to have medicinal value, but the root bark in particular is believed to be more potent. Decoctions or infusions of the roots are taken orally to treat malaria, fever and stomach ache. Aim of the studyTo evaluate antimalarial activity of aqueous and organic extracts prepared from Toddalia asiatica and determine in vitro and in vivo safety of the extracts. Materials and methodsAqueous, ethyl acetate, hexane and methanol extracts were obtained from Toddalia asiatica root bark, fruits and leaves. In vitro antiplasmodial activity was done using chloroquine-sensitive (D6) and chloroquine-resistant (W2) Plasmodium falciparum strains and the concentration causing 50% inhibition of radioisotope incorporation (IC50) was determined. In vivo assay was done by administering mice infected with Plasmodium berghei four consecutive daily doses of the extracts through oral route following Peters 4-Day suppressive test. The percentage suppression of parasitaemia was calculated for each dose level by comparing the parasitaemia in untreated control with those of treated mice. Quinine hydrochloride was used as positive control while double distilled water or 20% Tween-80 was used as a negative control. In vivo acute toxicity was determined in mice using standard procedures. In vitro cytotoxicity assay was carried out using actively dividing sub-confluent Vero cells. ResultsInhibitory concentrations of ethyl acetate extract of Toddalia asiatica fruits showed high activity against chloroquine resistant (W2) strains of Plasmodium falciparum (IC50=1.87μg/ml), followed by root bark aqueous extract (IC50=2.43μg/ml). Tested in vivo against Plasmodium berghei, the fruit ethyl acetate extract (500mg/kg) and root bark aqueous extract (250mg/kg) reduced malaria parasitaemia by 81.34% and 56.8% respectively. Higher doses were found to be less effective in vivo. Acute toxicity and cytotoxictiy of the tested extracts, with the exception of hexane extract from the roots, showed LD50>1000mg/kg and CC50>100μg/ml respectively. ConclusionsThe results obtained contribute to the validation of traditional use of Toddalia asiatica and provides in vivo and safety data of the plant extracts tested for the first time. Ethyl acetate extract of the fruits was active against chloroquine resistant Plasmodium falciparum as well as against Plasmodium berghei. These findings confirm the suitability of Toddalia asiatica as a good candidate for further tests to obtain a prototype for antimalarial medicine.

In VivoandIn VitroAntimalarial Properties of Azithromycin-Chloroquine Combinations That Include the Resistance Reversal Agent Amlodipine

Evidence of emerging Plasmodium falciparum resistance to artemisinin-based combination therapies, documented in western Cambodia, underscores the continuing need to identify new antimalarial combinations. Given recent reports of the resurgence of chloroquine-sensitive P. falciparum parasites in Malawi, after the enforced and prolonged withdrawal of this drug, and indications of a possible synergistic interaction with the macrolide azithromycin, we sought to further characterize chloroquine-azithromycin combinations for their in vitro and in vivo antimalarial properties. In vitro 96-h susceptibility testing of chloroquine-azithromycin combinations showed mostly additive interactions against freshly cultured P. falciparum field isolates obtained from Mali. Some evidence of synergy, however, was apparent at the fractional 90% inhibitory concentration level. Additional in vitro testing highlighted the resistance reversal properties of amlodipine for both chloroquine and quinine. In vivo experiments, using the Peters 4-day suppressive test in a P. yoelii mouse model, revealed up to 99.9% suppression of parasitemia following treatment with chloroquine-azithromycin plus the R enantiomer of amlodipine. This enantiomer was chosen because it does not manifest the cardiac toxicities observed with the racemic mixture. Pharmacokinetic/pharmacodynamic analyses in this rodent model and subsequent extrapolation to a 65-kg adult led to the estimation that 1.8 g daily of R-amlodipine would be required to achieve similar efficacy in humans, for whom this is likely an unsafe dose. While these data discount amlodipine as an additional partner for chloroquine-based combination therapy, our studies continue to support azithromycin as a safe and effective addition to antimalarial combination therapies.