Schizont Maturation Inhibition Assay Research Articles

Antimalarial potential of homeopathic medicines against schizont maturation of Plasmodium berghei in short-term in vitro culture

In vitro assessment of antimalarial drug susceptibility of Plasmodium has been a major research success, which has paved the way for the understanding of parasite and rapid screening of antimalarial drugs for their effectiveness. In the present study a preliminary screening to check the antiplasmodial activity of mother tincture (ϕ) and various potencies (6C, 30C, 200C) of homeopathic medicines Cinchona officinalis/china (Chin.), Chelidonium majus (Chel.) and Arsenicum album (Ars.) were done by assessing the in vitro schizont maturation inhibition assay. A significant reduction in the growth of intraerythrocytic stages of P. berghei was observed with decreasing dilution of ϕ and various potencies of Chin., Chel. and Ars. exhibiting a dose dependent effect. Maximum schizont maturation inhibition was observed by Chin. ϕ (1:1), Chin. 30 (1:1, 1:2) and Chel. 30 (1:1) i.e. 80%. The standard drug CQ at 10 µM concentration exhibited 95.4±1.6% inhibition of schizont maturation. Ars. 30 (1:1) also have been found to possess strong antiplasmodial efficacy with 75.5±2.6% schizont inhibition. The presence of free merozoites in Ars. 200 with weak schizonticidal inhibition activity (40-45%) also pointed towards the ability of parasite to survive in the given drug pressure.

Preparation, Standardization and Anti-plasmodial Efficacy of Novel Malaria Nosodes.

Resistance to artemisinin and its partner drugs has threatened the sustainability of continuing the global efforts to curb malaria, which urges the need to look for newer therapies to control the disease without any adverse side effects. In the present study, novel homeopathic nosodes were prepared from Plasmodium falciparum and also assessed for their in vitro and in vivo anti-plasmodial activity. Three nosodes were prepared from P. falciparum (chloroquine [CQ]-sensitive [3D7] and CQ-resistant [RKL-9] strains) as per the Homeopathic Pharmacopoeia of India, viz. cell-free parasite nosode, infected RBCs nosode, mixture nosode. In vitro anti-malarial activity was assessed by schizont maturation inhibition assay. The in vitro cytotoxicity was evaluated by MTT assay. Knight and Peter's method was used to determine in vivo suppressive activity. Mice were inoculated with P. berghei-infected erythrocytes on day 1 and treatment was initiated on the same day. Biochemical, cytokine and histopathological analyses were carried out using standard methods. In vitro: the nosodes exhibited considerable activity against P. falciparum with maximum 71.42% (3D7) and 68.57% (RKL-9) inhibition by mixture nosode followed by cell-free parasite nosode (62.85% 3D7 and 60% RKL-9) and infected RBCs nosode (60.61% 3D7 and 57.14% RKL-9). The nosodes were non-toxic to RAW macrophage cell line with >70% cell viability. In vivo: Considerable suppressive efficacy was observed in mixture nosode-treated mice, with 0.005 ± 0.001% parasitemia on day 35. Levels of liver and kidney function biomarkers were within the normal range in the mixture nosode-treated groups. Cytokine analysis revealed increased levels of IL-4 and IL-10, whilst a decline in IL-17 and IFN-γ was evident in the mixture nosode-treated mice. The mixture nosode exhibited promising anti-malarial activity against P. falciparum and P. berghei. Biochemical and histopathological studies also highlighted the safety of the nosode for the rodent host. The study provides valuable insight into a novel medicament that has potential for use in the treatment of malaria.

Ethanol extract of Bergenia ciliata (Haw.) Sternb. (rhizome) impedes the propagation of the malaria parasite

Ethnopharmacological relevanceThe increasing resistant cases even against artemisinin-based combination therapy have necessitated the need to develop new antimalarials. Phytomedicinal therapy is a benchmark for malaria in the Himalayan region. As the dialect and traditional variations have been seen along with this, usage of medicinal plant, its portion (shoot and root system) and mode of preparation also varies. There is no scientific evidence available for illustrating the antiplasmodial activity of the rhizomes of Bergenia ciliata (Saxifragaceae), which is known to be an antipyretic (fever akin to malaria), hepato-protective, and also for spleen enlargement. Aim of the studyThe present study evaluates the antimalarial activity of ethanol extract of B. ciliata rhizomes (EREBC). Materials and methodsHPTLC was performed to identify and quantify three marker compounds in EREBC. The in vitro antimalarial activity was evaluated by schizont maturation inhibition assay. MTT assay was employed to test the cytotoxicity of EREBC. Peter's 4-day test and Peters method was employed to discern the suppressive and preventive activity of the extract respectively. ResultsHPTLC analysis revealed the presence of bergenin, epicatechin and gallic acid in the extract. EREBC exhibited considerable inhibition (IC50 < 5 μg/mL) of schizont maturation of both RKL-9 and MRC-2 strains of P. falciparum. EREBC was non-toxic to both HeLa cells and normal dermal fibroblasts (CC50 > 1000 μg/mL). The selectivity index was > 200 for both strains. Acute toxicity of EREBC was > 4 g/kg. EREBC exhibited considerable in vivo suppressive activity with 96.48% inhibition at 500 mg/kg in comparison to chloroquine (96.08%). The ED50 of the extract was < 50 mg/kg. No mortality was evident in mice administered with different doses of EREBC (50–500 mg/kg) throughout the follow up period of 28 days. EREBC exhibited safety to liver and kidney function of mice as observed from biochemical analysis. ConclusionOverall, the study illustrates the marked efficacy and potential of EREBC as an antimalarial agent with bergenin, epicatechin and gallic acid its major constituents, which played a pivotal role in the generation of the immune response.

Phytochemical constituents from Xanthium strumarium L. and evaluation of their in vitro antimalarial activities

Malaria is a major threat to global health and continues to claim lives of many people each year, especially in developing countries. Xanthium strumarium L., is used by traditional health practitioners in the management of malaria fever in North East India. Bioassay guided fractionation of X. strumarium L. extracts, led to the isolation of five compounds from the aerial part and fruit of Xanthium strumarium, namely, stigmasta-5,22-dien-3β-ol (1), xanthinosin (2), stigmasterol-3-O-β-D-glucopyranoside (3), oleic acid (4) and (E)-2, 3-dihydroxypropyl-octadec-9-enoate (5). Antimalarial potential of isolated compounds were evaluated against 3D7 strain of Plasmodium falciparum by schizont maturation inhibition assay method. The structures of isolated compounds were established by HR-MS, NMR experiments and comparison from literature data. Compounds 2 and 3 showed significant antimalarial properties against 3D7 strain of P.falciparum with IC50 value 27.25 and 7.14μM respectively. The antimalarial activities of xanthinosin (2) and stigmasterol-3-O-β-D-glucopyranoside (3) lend credence to the application of X. strumarium against malaria and thus provides new template for development of antimalarial molecules. X. strumarium has also scope for the development of antimalarial phyto-pharmaceutical with five identified compounds with P.falciparum inhibitory activity as per the drugs and cosmetics act of India (1940, amended 31st December 2016).

Gas Chromatography-Mass Spectrometry Characterization of Bioactive Compounds from Ziziphus nummularia (Burm. F.) Stem Bark with Promising In Vitro Antiplasmodial Activity.

Objective:This study was carried out to evaluate the in vitro antiplasmodial activity of alcoholic and hydroalcoholic extract of Ziziphus nummularia stem bark as well as the determination of core structure fractionated from its crude extract.Materials and Methods:The antiplasmodial activity of stem bark extracts was investigated by in vitro schizont maturation inhibition assay against Plasmodium falciparum (both chloroquine sensitive and resistant). The crude extract was analyzed by gas chromatography–mass spectrophotometry (GC–MS).Result:Both alcoholic and hydroalcoholic extracts showed their potential toward in vitro antiplasmodial activity against P. falciparum strains MRC-02 (CQ sensitive) and RKL-09 (CQ resistant). Alcoholic extract showed more promising antiplasmodial activity with Inhibitory concentration (IC50) of 0.130 and 1.191 for MRC-02 and RKL-09 strains, respectively, as compared to hydroalcoholic extract with IC50 of 1.856 and 2.981 for MRC-02 and RKL-09 strains, respectively. No morphological changes in erythrocytes were observed when investigated for chemical injury to the erythrocytes. Chemical characterization of alcoholic extract was performed by GC–MS analysis to identify the bioactive compounds that are responsible for antiplasmodial activity. Alkyl esters, phenolics, and flavonoids were found as major compounds and also showed resemblance to existing antimalarial drugs.Conclusion:The findings suggested that the investigated extracts will provide a foundation for combating the resistant strains of P. falciparum. Also, the compounds isolated from Z. nummularia crude extract are viable newer chemical antimalarial candidates requiring further investigation.

In vitro anti-malarial efficacy of chalcones: cytotoxicity profile, mechanism of action and their effect on erythrocytes

BackgroundMalaria extensively leads to mortality and morbidity in endemic regions, and the emergence of drug resistant parasites is alarming. Plant derived synthetic pharmaceutical compounds are found to be a foremost research to obtain diverse range of potent leads. Amongst them, the chalcone scaffold is a functional template for drug discovery. The present study involves synthesis of ten chalcones with various substitution pattern in rings A and B and assessment of their anti-malarial efficacy against chloroquine sensitive and chloroquine resistant strains as well as of their cytotoxicity and effect on haemozoin production.MethodsThe chalcones were synthesized by Claisen-Schmidt condensation between equimolar quantities of substituted acetophenones and aryl benzaldehydes (or indole-3-carboxaldehyde) and were screened for anti-malarial activity by WHO Mark III schizont maturation inhibition assay. The cytotoxicity profile of a HeLa cell line was evaluated through MTT viability assay and the selectivity index (SI) was calculated. Haemozoin inhibition assay was performed to illustrate mode of action on a Plasmodium falciparum strain.ResultsThe IC50 values of all compounds were in the range 0.10–0.40 μg/mL for MRC-2 (a chloroquine sensitive strain) and 0.14–0.55 μg/mL for RKL-9 (a chloroquine resistant strain) of P. falciparum. All the chalcones showed low cellular toxicity with minimal haemolysis. The statistically significant reduction (p < 0.05) in the haemozoin production suggests a similar mechanism than that of chloroquine.ConclusionsOut of ten chalcones, number 7 was found to be a lead compound with the highest potency (IC50 = 0.11 µg/mL), as compared to licochalcone (IC50 = 1.43 µg/mL) and with high selectivity index of 85.05.

Evaluation of antiplasmodial properties in 15 selected traditional medicinal plants from India

ObjectiveThe objective of this study was to evaluate the in vitro antiplasmodial properties against malaria parasite in 15 plants mentioned in Indian traditional medicine texts. MethodsIn vitro antiplasmodial activity of methanolic extracts obtained from Indian traditional medicinal plants was evaluated on Plasmodium falciparum of FCK2 and INDO strains using schizont maturation inhibition assay and parasite lactate dehydrogenase inhibition assay. ResultsMethanolic extracts of Adhatoda zeylanica, Embelia ribes, Piper nigrum and Plumbago zeylanica exhibited more than 50% inhibition in both the stains in schizont maturation inhibition assay. Methanolic extracts of seven medicinal plants exhibited antiplasmodial activity at half maximal inhibitory concentration (IC50) < 100 µg/mL, and methanolic extracts of five medicinal plants exhibited antiplasmodial activity at IC50 < 50 µg/mL in P. falciparum lactate dehydrogenase (PfLDH) inhibition assay. A. zeylanica, E. ribes and P. nigrum exhibited promising antiplasmodial activity in PfLDH inhibition assay. A. zeylanica and E. ribes exhibited improved activity against resistant in comparison to sensitive strain. ConclusionA. zeylanica and E. ribes were the most promising extracts from this study and deserve further investigation of their antiplasmodial properties.

Targeting malaria and leishmaniasis: Synthesis and pharmacological evaluation of novel pyrazole-1,3,4-oxadiazole hybrids. Part II

In continuance with earlier reported work, an extension has been carried out by the same research group. Mulling over the ongoing condition of resistance to existing antimalarial agents, we had reported synthesis and antimalarial activity of certain pyrazole-1,3,4-oxadiazole hybrid compounds. Bearing previous results in mind, our research group ideated to design and synthesize some more derivatives with varied substitutions of acetophenone and hydrazide. Following this, derivatives 5a–r were synthesized and tested for antimalarial efficacy by schizont maturation inhibition assay. Further, depending on the literature support and results of our previous series, certain potent compounds (5f, 5n and 5r) were subjected to Falcipain-2 inhibitory assay. Results obtained for these particular compounds further strengthened our hypothesis. Here, in this series, compound 5f having unsubstituted acetophenone part and a furan moiety linked to oxadiazole ring emerged as the most potent compound and results were found to be comparable to that of the most potent compound (indole bearing) of previous series. Additionally, depending on the available literature, compounds (5a–r) were tested for their antileishmanial potential. Compounds 5a, 5c and 5r demonstrated dose-dependent killing of the promastigotes. Their IC50 values were found to be 33.3 ± 1.68, 40.1 ± 1.0 and 19.0 ± 1.47 μg/mL respectively. These compounds (5a, 5c and 5r) also had effects on amastigote infectivity with IC50 of 44.2 ± 2.72, 66.8 ± 2.05 and 73.1 ± 1.69 μg/mL respectively. Further target validation was done using molecular docking studies. Acute oral toxicity studies for most active compounds were also performed.

Investigation of antiplasmodial efficacy of lupeol and ursolic acid isolated from Ficus benjamina leaves extract

This study emphasizes on the investigation of antiplasmodial activity of triterpenoids isolated from Ficus benjamina leaves. An unsaponified fraction of petroleum ether extract of plant leaves was subjected to silica gel column chromatography which led to the isolation of two known triterpenoids; namely ursolic acid and lupeol. These compounds were evaluated for antiplasmodial activity by schizont maturation inhibition assay using 3D7 Plasmodium strains. Both, ursolic acid and lupeol were found to exhibit significant antiplasmodial effect with an IC50 value of 18 µg/ml and 3.8 µg/ml, respectively. This study further confirms the traditional role of Ficus benjamina plant in the treatment of malaria which may be attributed to ursolic acid and lupeol.

Bioassay Guided Fractionation and in vitro Anti-plasmodial Activity of Ficus deltoidea and Ficus benjamina

Background: Malaria is infectious vector born disease affecting 212 million people belonging to 97 countries globally in the year 2016. Although this number has reduced progressively from last one decade but recent failure of currently available antimalarial drug therapy has accentuated the urgent need to explore different novel approaches in Anti-plasmodial drug discovery. Objective: The aim of the present study was to evaluate the Anti-plasmodial activity of traditional medicinal plants Ficus deltoidea and Ficus benjamina. Materials and Methods: Crude petroleum ether and hydro alcoholic extract of both the plant species were evaluated for Anti-plasmodial activity by schizont maturation inhibition assay using 3D7 plasmodium strains. Results: It was observed that petroleum ether extract of F. benjamina leaves showed most promising inhibitory effect on the growth of schizonts with IC50 14.5 μg/ml. Bio-assay guided fractionation of petroleum ether extract of F. benjamina led to the hexane and chloroform fraction with high Anti-plasmodial activity (IC50 4.0 μg/ml and IC50 7.8 μg/ml respectively). Further, phytochemical investigation of F. benjamina indicated the presence of various valuable phytochemicals belonging to class of steroids, terpenoids and phytosterols. Conclusion: This study has revealed the Anti-plasmodial activity of F. deltoidea and F. benjamina for the first time. Significant Anti-plasmodial activity and preliminary phytochemical studies of F. benjamina indicates its rich chemical diversity which make this plant a good candidate for isolating new molecule that could serve as new lead in Anti-plasmodial drug discovery.

Synthesis of pyrazole acrylic acid based oxadiazole and amide derivatives as antimalarial and anticancer agents

Depravity of malaria in terms of morbidity and mortality in human beings makes it a major health issue in tropical and subtropical areas of the globe. Drug counterfeiting and non-adherence to the treatment regimen have significantly contributed to development and spread of multidrug resistance that has highlighted the need for development of novel and more efficient antimalarial drugs. Complexity associated with cancer disease and prevalence of diversified cell populations vindicates highly specific treatment options for treatment of cancer. Resistance to these anticancer agents has posed a great hindrance in successful treatment of cancer. Pondering this ongoing situation, it was speculated to develop novel compounds targeting malaria and cancer. Moving on the same aisle, we synthesized pyrazole acrylic acid based oxadiazole and amide derivatives using multi-step reaction pathways (6a–x; 6a′–h′). Schizont maturation inhibition assay was employed to determine antimalarial potential. Compound 6v emerged as the most potent antimalarial agent targeting falcipain-2 enzyme. Anticancer activity was done using sulforhodamine B assay. Compounds 6b′ and 6g′ demonstrated promising results against all the tested cell lines. Further, Microscopic view clearly indicated formation of apoptotic bodies, chromatin condensation, shrinkage of cells and bleb formation. Validation of the results was achieved using molecular docking studies. From the obtained results, it was observed that cyclization (oxadiazole) favored antimalarial activity while non-cyclized compounds (amides) emerged as better anticancer agents.

In vitro antioxidant and antimalarial activities of leaves, pods and bark extracts of Acacia nilotica (L.) Del.

BackgroundThe emergence of drug resistant malaria is threatening our ability to treat and control malaria in the Southeast Asian region. There is an urgent need to develop novel and chemically diverse antimalarial drugs. This study aimed at evaluating the antimalarial and antioxidant potentials of Acacia nilotica plant extracts.MethodsThe antioxidant activities of leaves, pods and bark extracts were determined by standard antioxidant assays; reducing power capacity, % lipid peroxidation inhibition and ferric reducing antioxidant power assay. The antimalarial activities of plant extracts against Plasmodium falciparum parasites were determined by the 48 h schizont maturation inhibition assay. Further confirmation of schizonticide activity of extracts was made by extending the incubation period up to 96 h after removing the plant extract residues from parasites culture. Inhibition assays were analyzed by dose-response modelling.ResultsIn all antioxidant assays, leaves of A. nilotica showed higher antioxidant activity than pods and bark. Antimalarial IC50 values of leaves, pods and bark extracts were 1.29, 4.16 and 4.28 μg/ml respectively, in the 48 h maturation assay. The IC50 values determined for leaves, pods and bark extracts were 3.72, 5.41 and 5.32 μg/ml respectively, after 96 h of incubation. All extracts inhibited the development of mature schizont, indicating schizonticide activity against P. falciparum.ConclusionA. nilotica extracts showed promising antimalarial and antioxidant effects. However, further investigation is needed to isolate and identify the active components responsible for the antimalarial and antioxidant effects.

Screening and In Vitro Evaluation of Potential Plasmodium falciparum Leucyl Aminopeptidase Inhibitors.

Plasmodium falciparum leucyl aminopeptidase (PfA-M17) regulates the intracellular pool of amino acids required for the growth and development of parasites. Thus, PfA-M17 is a promising target for anti-malarial drug development. In the present study, structure-based drug design was used to identify novel PfA-M17 inhibitors, which were subsequently validated by in vitro PfA-M17 and human LAP3 enzyme inhibition assay. A library of 3,147,882 compounds was screened using receptor-based virtual screening against the active site of PfA-M17, and three levels of accuracy were used: high-throughput virtual screening, gridbased ligand docking with energetics (Glide standard precision) and Glide extra precision. Seventeen screened compounds were selected and tested in the rPfA-M17 enzyme inhibition assay. Of these nine compounds were found to be effective inhibitors. To test the target activity, all nine PfA-M17 inhibitors were tested against rhLAP3, the human homolog of PfA-M17. One compound (compound 2) was found to be moderately effective against PfA-M17 (Ki = 287 μM) with limited inhibitory activity against hLAP3 (Ki of 4,464 μM). Subsequently, induced fit docking and pharmacophore modelling were used to further understand more precise ligand-protein interactions in the protein-inhibitor complexes. Among the 9 effective PfA-M17 inhibitors, 5 compounds were found effective in the P. falciparum schizont maturation inhibition (SMI) assay. A good correlation (r =0.83) was observed between the rPfA-M17 enzyme inhibition concentration and SMI assay.

Plasmodium vivax drug resistance genes; Pvmdr1 and Pvcrt-o polymorphisms in relation to chloroquine sensitivity from a malaria endemic area of Thailand.

The aim of the study was to explore the possible molecular markers of chloroquine resistance in Plasmodium vivax isolates in Thailand. A total of 30 P. vivax isolates were collected from a malaria endemic area along the Thai-Myanmar border in Mae Sot district of Thailand. Dried blood spot samples were collected for analysis of Pvmdr1 and Pvcrt-o polymorphisms. Blood samples (100 μl) were collected by finger-prick for in vitro chloroquine susceptibility testing by schizont maturation inhibition assay. Based on the cut-off IC50 of 100 nM, 19 (63.3%) isolates were classified as chloroquine resistant P. vivax isolates. Seven non-synonymous mutations and 2 synonymous were identified in Pvmdr1 gene. Y976F and F1076L mutations were detected in 7 (23.3%) and 16 isolates (53.3%), respectively. Analysis of Pvcrt-o gene revealed that all isolates were wild-type. Our results suggest that chloroquine resistance gene is now spreading in this area. Monitoring of chloroquine resistant molecular markers provide a useful tool for future control of P. vivax malaria.

Monitoring of clinical efficacy and in vitro sensitivity of Plasmodium vivax to chloroquine in area along Thai Myanmar border during 2009-2010

BackgroundIn Thailand, the proportion of Plasmodium vivax infection has become equal to Plasmodium falciparum. Reports of a trend of gradual decline of in vitro sensitivity of P. vivax to chloroquine in some areas of the country, together with accumulating evidences of chloroquine resistance P. vivax in other parts of the world, emphasize the need for closely and continuously monitoring clinical efficacy in conjunction with in vitro sensitivity of P. vivax isolates.MethodsThe study was conducted at Mae Tao clinic for migrant workers, Tak Province during March 2008 - August 2009. A total of 130 patients (17 Thais and 113 Burmeses; 64 males and 66 females) with mono-infection of P. vivax malaria, aged between 15-60 years and weighing more than 40 kg, were included in the study. Patients received treatment with chloroquine (2,000 mg chloroquine phosphate over three days) and the anti-relapse drug primaquine (15 mg for 14 days). In vitro sensitivity of P. vivax isolates was evaluated by schizont maturation inhibition assay.ResultsAll patients showed satisfactory response to treatment. The cure rate was virtually 100% within the follow-up period of 42 days. Neither recurrence of P. vivax parasitaemia nor appearance of P. falciparum occurred during the investigation period. In vitro data showed a stable sensitivity of chloroquine in this area since 2006. Geometric mean and median (95% CI) values of IC50 for chloroquine were 100.1 and 134.7 (1.1-264.9) nM, respectively.ConclusionIn vivo results suggest that the standard regimen of chloroquine was still very effective for the treatment of blood infections with P. vivax in the Thai-Myanmar border area. In vitro sensitivity data however, raise the possibility of potential advent of resistance in the future. Regular monitoring of the chloroquine sensitivity of P. vivax is essential to facilitate the early recognition of treatment failures and to expedite the formulation of appropriate changes to the drug policy.

Assessment of in vitro sensitivity of Plasmodium vivax fresh isolates

Objective To compare the applicability of the SYBR Green–I assay with the standard schizont maturation assay, for determination of sensitivity of Plasmodium vivax ( P. vivax) to chloroquine and a new antifolate WR 99210. Methods The study was conducted at Mae Tao Clinic for migrant workers, Tak Province during April 2009 to July 2010. A total of 64 blood samples (1 mL blood collected into sodium heparinized plastic tube) were collected from patients with mono–infection with P. vivax malaria prior to treatment with standard regimen of a 3-day chloroquine. In vitro sensitivity of P. vivax isolates was evaluated by schizont maturation inhibition and SYBR Green–I assays. Results A total of 30 out of 64 blood samples collected from patients with P. vivax malaria were successfully analyzed using both the microscopic schizont maturation inhibition and SYBR Green–I assays. The failure rates of the schizont maturation inhibition assay (50%) and the SYBR Green–I assay (54%) were similar ( P=0.51). The median IC 10s, IC 50s and IC 90s of both chloroquine and WR99210 were not significantly different from the clinical isolates of P. vivax tested. Based on the cut–off of 100 nM, the prevalences of chloroquine resistance determined by schizont maturation inhibition and SYBR Green–I assays were 19 and 11 isolates, respectively. The strength of agreement between the two methods was very poor for both chloroquine and WR99210. Conclusions On the basis of this condition and its superior sensitivity, the microscopic method appears better than the SYBR Green–I Green assay for assessing in vitro sensitivity of fresh P. vivax isolates to antimalarial drugs.

In vitro antiplasmodial and antimicrobial potential of Tagetes erecta roots

Context: Among strategies to combat malaria, the search for newer antimalarial compounds is a priority. Traditionally, Tagetes erecta Linn. (Compositae) has been used for the treatment of various diseases and ailments including malaria.Objective: Five successive extracts (petroleum ether, chloroform, ethyl acetate, methanol and aqueous) of the roots of T. erecta and a new bithienyl compound, 2-hydroxymethyl-non-3-ynoic acid 2-[2,2']-bithiophenyl-5-ethyl ester from the roots of the plant, were evaluated for in vitro antiplasmodial activity against chloroquine sensitive and resistant strains of Plasmodium falciparum. The extracts were also tested for in vitro antimicrobial activity against seven microbial strains.Materials and methods: The antiplasmodial screening was carried out using the schizont maturation inhibition assay. Preliminary antimicrobial screening was carried out using the agar well assay followed by determination of minimum inhibitory concentration (MIC) using two-fold serial dilutions.Results: Among all the extracts tested, the ethyl acetate fraction exhibited significant antiplasmodial efficacy with the 50% inhibitory concentrations (IC50) of 0.02 and 0.07 mg/mL against the chloroquine sensitive and resistant strains of Plasmodium falciparum respectively. The new bithienyl compound also showed significant schizonticidal activity against both chloroquine sensitive and resistant strains of Plasmodium falciparum with the IC50 values of 0.01 and 0.02 mg/mL. Additionally, all extracts exhibited significant antimicrobial activity against three Gram-positive and two Gram-negative bacterial and two fungal strains with MIC values ranging between 12.5-100 µg/mL.Discussion: The new bithienyl compound was profoundly able to arrest the ring stages of the malarial parasites thereby exerting its antiplasmodial effect.Conclusion: The observations provide support for the ethnobotanical use of the plant.

In vitro Anti Plasmodial Activity of Enicostemma littorale

Problem statement: Malaria is a prevalent disease in India. The proble m of drug resistance is worsening. Hence, new effective and a ffordable antimalarial drugs are very much needed. The long-established use of quinine and the more re cent introduction of artemisinin as highly effectiv e anti malarials demonstrate that plant species are a n important resource for the discovery of new anti malarial agents. Approach: Majority of the plants belonging to Gentianaceae fa mily were proven as good antimalarials containing swertiamarin as a com mon marker. Enicostemma littorale (Gentianaceae) is also known from traditional knowl edge for treatment of visham jwara and is rich in swertiamarin amongst all of the plants belonging to same family. In view of this, initial screening ha d been undertaken. Our laboratory had also been worki ng on the same for its antidiabetic activity. Results: This was first report to demonstrate anti plasmodi al activity of Enicostemma littorale (Gentianaceae) against Plasmodium falciparum . Methanolic extract of plant and swertiamarin isol ated from it showed promising results in vitro in schizont maturation inhibition assay having IC 50 of 529.045 and 12 µg mL -1 respectively. We also reported a simple and rapid method for isolation of swertiamarin which was applicable at commercial scale. Conclusion: The present study represented the potential antimalarial action of plant and its active phytoconstituent, may give new lead to researchers in field of antimalarial drug discovery .

In Vitro Anti-plasmodial activity of Trigonella foenum-graecum L.

Developing countries, where malaria is one of the most prevalent diseases, still rely on traditional medicine as a source for the treatment of this disease. For the present study, Trigonella foenum-graecum L. (fenugreek) were collected from Coimbatore, Tamilnadu, India. The test plant has been used in India by traditional healers for the treatment of fever as well as other diseases. The active principle was extracted out in different solvent systems to assess the anti-plasmodial potential, with an aim that they can further be utilized to formulate drugs. In vitro anti-plasmodial assay of the extracted fractions of fenugreek leaves was carried out using laboratory adapted chloroquine sensitive and resistant Plasmodium falciparum isolates. Schizont maturation inhibition assay was adopted to analyze the potential of the extracts. Ethanol extract (50%) seemed to possess profound anti-plasmodial activity with IC50 value of 8.75 ± 0.35 µg ml−1 and 10.25 ± 0.35 µg ml−1 against chloroquine sensitive and resistant P. falciparum isolates, respectively. Among the investigated six fractions of the plant extracts, two were found to have significant anti-plasmodial activity with IC50 values <10 µg ml−1, namely ethanol and butanol extracts. Two extracts chloroform and ethyl acetate showed moderate activity with IC50 values ranging from 10 to 20 µg ml−1, and the other two extracts, hexane and water appeared to be inactive with IC50 values >85 µg ml−1. In addition, preliminary phytochemical screening of the various extracts indicated the presence of alkaloids, saponin, tannin like phenolic compounds, flavonoids and steroids.