Sensitive 3D7 Strain Research Articles

Design, in silico study, synthesis and evaluation of hybrid pyrazole substituted 1,3,5-triazine derivatives for antimalarial activity

ObjectivesMalaria is a significant global health challenge, particularly in Africa, Asia, and Latin America, necessitating immediate investigation into innovative and efficacious treatments. This work involves the development of pyrazole substituted 1,3,5-triazine derivatives as antimalarial agent. MethodsIn this study, ten compounds 7(a-j) were synthesized by using nucleophilic substitution reaction, screened for in silico study and their antimalarial activity were evaluated against 3D7 (chloroquine-sensitive) strain of P. falciparum. Key findingThe present work involves the development of hybrid trimethoxy pyrazole 1,3,5-triazine derivatives 7 (a–j). Through in silico analysis, four compounds were identified with favorable binding energy and dock scores. The primary focus of the docking investigations was on the examination of hydrogen bonding and the associated interactions with certain amino acid residues, including Arg A122, Ser A108, Ser A111, Ile A164, Asp A54, and Cys A15. The IC50 values of the four compounds were measured in vitro to assess their antimalarial activity against the chloroquine sensitive 3D7 strain of P. falciparum. The IC50 values varied from 25.02 to 54.82 μg/mL. ConclusionAmong the ten derivatives, compound 7J has considerable potential as an antimalarial agent, making it a viable contender for further refinement in the realm of pharmaceutical exploration, with the aim of mitigating the global malaria load.

Synthesis and Characterization of Phenylenediamine Side‐Chain‐Modified 4‐Aminoquinoline Mannich Bases and Evaluation of their in vitro Antimalarial Activity

AbstractTwelve novel compounds (Phenylenediamine side chain modified 4‐Aminoquinoline Mannich Bases) were synthesized and characterized by using a variety of analytical and spectroscopic methods. All the synthesized compounds were screened for in‐vitro antimalarial activity on 3D7 strain of Plasmodium falciparum. Synthesized compounds showed MIC values between 1.9 and 125 μg/ml in antimalarial screening (in‐vitro). Two compounds (MIC=1.9 μg/ml or 1.953 0.10 μM and 7.8 μg/ml or 2.200 0.08 μM) were found most potent against chloroquine sensitive 3D7 strain of Plasmodium falciparum which is comparable to standard drug chloroquine (MIC=0.4 μg/ml or 0.106 0.01 μM).

Microwave assisted synthesis, docking and antimalarial evaluation of hybrid PABA‐substituted 1,3,5‐triazine derivatives

AbstractA series of novel PABA‐substituted 1,3,5‐triazine derivatives were developed via microwave assisted synthesis and subsequently tested for antimalarial activity against chloroquine sensitive 3D7 strain of Plasmodium falciparum using chloroquine as standard. Antimalarial screening result showed that synthesized compounds exhibited IC50 in the range of 4.46 to 79.72 μg mL−1. Among the tested compounds, 4c and 4f showed significant antimalarial activity with low binding energies (BE) ‐172.32 and 160.41 kcal mol−1 via interacting with Arg122 through the involvement of COOH of the phenyl linked to 1,3,5‐triazine. In conclusion, these core scaffolds can be used for future antimalarial drug development.

Design and Discovery of 3,6-Substituted 1,2,4,5-Tetraoxanes as New Class of Falcipain-2 Inhibitors for Antimalarial Action

A new series of tetraoxanes were developed and screened for in vitro antimalarial activity against chloroquine sensitive strains of Plasmodium falciparum (3D7 and RKL-2) and chloroquine resistant strain of P. falciparum (RKL-9). Among the synthesized derivatives, few compounds showed mild to moderate activity against the parasites as compared to a standard drug. The test results revealed two compounds, 5a (3,3,6-trimethyl-1,2,4,5-tetraoxane) and 5k (3,3-dimethyl-6,6-diphenyl-1,2,4,5-tetraoxane) possessing significant activity against chloroquine sensitive 3D7 strain (IC50 = 1.953 ± 0.020 μg/mL) and RKL-2 strain (IC50 = 3.906 ± 0.010 μg/mL). At the same time, only compound 5j (3-methyl-3,6,6-triphenyl-1,2,4,5-tetraoxane) showed superior activity against chloroquine resistant RKL-9 strain (IC50 = 3.906 ± 0.006 μg/mL) in in contrast to all other derivatives of the set studied. In order to elucidate the vital drug interaction with falcipain-2 (FP-2), docking studies of potent ligands were performed.

Cowpea mosaic virus (CPMV) as a carrier vehicle for antimalarial drugs, modification and application

Globally more than 45% of the population is under the risk of malaria infection. In this presented work, three different compounds have been tested as anti-malarial agents with and without conjugation to the external surface of Cowpea mosaic virus (CPMV). The particle developed as a carrier of ferrocene (Fc) due to the resistance to commercially available antimalarial drugs. CPMV-Fc conjugate, in which 174 molecules are covalently bound to external surface carboxylates of the viral nanoparticle (VNP), shows the greatest inhibition toward proliferation of plasmodium falciparum compared to free ferrocene which has no activity as antimalarial agent. Fc also enhanced the activity of two different compounds of 4-aminochloroqunoline derivatives 3-((7chloroquinolin-4-yl) amino) propionic acid CQp and (7-chloroquinolin-4-yl) alanine CQ-ala, after its conjugation to CPMV-CQp and CPMV-CQ-ala in 82 and 134 molecules per particle respectively to give CPMV-CQ-p-Fc and CPMV-CQ-ala-Fc. The activity of each conjugated ferrocene has been evaluated with and without using biological material. In the case of biological material these compounds have been tested against both chloroquine sensitive strain 3D7 and chloroquine resistance strain Dd2 using the chloroquine as a standard antimalarial drug. The CPMV conjugate is targeted to the food vacuole parasite of the plasmodium falciparum cell, where the pH is dropped, drug carrier is degraded and the drug released.

Molecular docking, synthesis and in vitro antimalarial evaluation of certain novel curcumin analogues

The receptor protein PfATP6 has been identified as the common target of artemisinin and curcumin. The work was initiated to assess the antimalarial activity of six curcumin derivatives based on their binding affinities and correlating the in silico docking outcome with in vitro antimalarial screening results. A ligand library of thirty two Knoevenagel condensates of curcumin were designed and docked against PfATP6 protein and six compounds with the best binding scores were synthesized and screened for their antimalarial activity against the sensitive 3D7 strain of Plasmodium falciparum. ADME/Tox, pharmacokinetic and pharmacodynamic profiles of the designed compounds were analyzed and reported. 4-FB was found to have similar binding energy to the standard artemisinin (-6.75 and -6.73 respectively) while 4-MB, 3-HB, 2-HB, B, 4-NB displayed better binding energy than curcumin (-5.95, -5.89, -5.68, -5.35, -5.29 and -5.25 respectively). At a dose of 50 µg/mL all the six compounds showed 100% schizont inhibition while at 5µg/ml, five showed more than 75% inhibition and better results than curcumin. 4-FB showed the best activity with 97.8% schizonticidal activity. The in vitro results superimpose the results obtained from the in silico study thereby encouraging development of promising curcumin leads in the battle against malaria.

In vitro anti-malarial interaction and gametocytocidal activity of cryptolepine

BackgroundDiscovery of novel gametocytocidal molecules is a major pharmacological strategy in the elimination and eradication of malaria. The high patronage of the aqueous root extract of the popular West African anti-malarial plant Cryptolepis sanguinolenta (Periplocaceae) in traditional and hospital settings in Ghana has directed this study investigating the gametocytocidal activity of the plant and its major alkaloid, cryptolepine. This study also investigates the anti-malarial interaction of cryptolepine with standard anti-malarials, as the search for new anti-malarial combinations continues.MethodsThe resazurin-based assay was employed in evaluating the gametocytocidal properties of C. sanguinolenta and cryptolepine against the late stage (IV/V) gametocytes of Plasmodium falciparum (NF54). A fixed ratio method based on the SYBR Green I fluorescence-based assay was used to build isobolograms from a combination of cryptolepine with four standard anti-malarial drugs in vitro using the chloroquine sensitive strain 3D7.ResultsCryptolepis sanguinolenta (IC50 = 49.65 nM) and its major alkaloid, cryptolepine (IC50 = 1965 nM), showed high inhibitory activity against the late stage gametocytes of P. falciparum (NF54). In the interaction assays in asexual stage, cryptolepine showed an additive effect with both lumefantrine and chloroquine with mean ΣFIC50s of 1.017 ± 0.06 and 1.465 ± 0.17, respectively. Cryptolepine combination with amodiaquine at therapeutically relevant concentration ratios showed a synergistic effect (mean ΣFIC50 = 0.287 ± 0.10) whereas an antagonistic activity (mean ΣFIC50 = 4.182 ± 0.99) was seen with mefloquine.ConclusionsThe findings of this study shed light on the high gametocytocidal properties of C. sanguinolenta and cryptolepine attributing their potent anti-malarial activity mainly to their effect on both the sexual and asexual stages of the parasite. Amodiaquine is a potential drug partner for cryptolepine in the development of novel fixed dose combinations.

Evaluation of Novel α-(Acyloxy)-α-(Quinolin-4-yl) Acetamides as Antiplasmodial Agents.

Because of expanding resistance to efficient and affordable antimalarial drugs like chloroquine, the search is continuing for more effective drugs against this disease. In-vitro antiplasmodial activity and cytotoxicity of α-(acyloxy)-α-(quinolin-4-yl) acetamides on Plasmodiumfalciparum and structure-activity relationships of this new class of Passerini adducts is described. The in-vitro antiplasmodial activity of compounds was tested against chloroquine sensitive 3D7 strain. Toxicity of active compounds was investigated on HepG2 cell line. Compounds 1, 20 and 22 showed significant antiplasmodial activity with IC50 value of 1.511, 1.373 and 1.325 µM, respectively. The active compounds did not show noticeable toxicity when tested against HepG2 cell line. The present results bring essential elements which will be used for the synthesis of more active derivatives of α-(acyloxy)-α-(quinolin-4-yl) acetamides.

Cinnamoylated chloroquine analogues: A new structural class of antimalarial agents

A novel series of cinnamoylated chloroquine hybrid analogues were synthesized and evaluated as antimalarial agents. The trans cinnamic acid derivatives (3–8) were synthesized by utilizing substituted aldehydes and malanoic acid in DMF catalysed by DABCO. The final cinnamoylated chloroquine analogues (9–14) were synthesized by utilizing DCC coupling reagent. The amido chloroquine (17) was prepared from acid (16) and compound 2 in benzene using SOCl2 as chlorinating agent. The corresponding ester (15) was prepared from 2-hydroxy acetophenone and 2-bromoacetates in actonitrile in presence of K2CO3 as base followed by basic hydrolysis. The preparation of amide based chloroquine-chalcone analogues (18–22), were obtained by the combination of amido chloroquine (17) and aldehydes in 10% aq. KOH in methanol at room temperature. Further we prepared epichlorohydrin based chloroquine-chalcone analogues (25–28), by reacting the epoxide (24a, 24b and 24c) with 2 and methelenedioxy aniline. In vitro antimalarial activity against chloroquine sensitive strain 3D7, chloroquine resistant strain K1 of P. falciparum and in vitro cytotoxicity of compounds using VERO cell line was carried out. The synthesized molecules showed significant in vitro antimalarial activity especially against CQ resistant strain (K1). Among tested compounds, 13, 9 and 10 were found to be the most potent compounds of the series with IC50 value of 44.06, 48.04 and 59.37 nM against chloroquine resistant K1 strain.

Antiplasmodial β-triketones from the flowers of the Australian tree Angophora woodsiana

Chemical investigations of the MeOH extract of air dried flowers of the Australian tree Angophora woodsiana (Myrtaceae) yielded two new β-triketones, woodsianones A and B (1, 2) and nine known β-triketones (3–11). Woodsianone A is a β-triketone-sesquiterpene adduct and woodsianone B is a β-triketone epoxide derivative. The structures of the new and known compounds were elucidated from the analysis of 1D/2D NMR and MS data. The relative configurations of the compounds were determined from analysis of 1H–1H coupling constants and ROESY correlations. All compounds (1–11) had antiplasmodial activity against the chloroquine sensitive strain 3D7. The known compound rhodomyrtone (5) and new compound woodsianone B (2) showed moderate antiplasmodial activities against the 3D7 strain (1.84µM and 3.00µM, respectively) and chloroquine resistant strain Dd2 (4.00µM and 2.53µM, respectively).

Novel 2,3-Dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones: Synthesis and Biological Evaluation.

Herein we describe the synthesis and evaluation of a series of novel 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones for in vitro cytotoxicity against three human cancer cell lines as well as for potential antimalarial activity against the chloroquine-sensitive strain 3D7 of Plasmodium falciparum. The title compounds were prepared via PdCl2-mediated endo-dig cyclization of 2-aryl-8-(arylethynyl)-6-bromo-2,3-dihydroquinazolin-4(1H)-ones. The latter were prepared, in turn, via initial Sonogashira cross-coupling of 2-amino-5-bromo-3-iodobenzamide with aryl acetylenes followed by boric acid-mediated cyclocondensation of the intermediate 2-amino-3-(arylethynyl)-5-bromobenzamides with benzaldehyde derivatives. The 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones 4a–k were evaluated for potential in vitro cytotoxicity against the breast (MCF-7), melanoma (B16) and endothelioma (sEnd.2) cell lines. All of the compounds except 4h and 4i were found to be inactive against the three cancer cell lines. Compound 4h substituted with a 4-methoxyphenyl and 4-fluorophenyl groups at the 3- and 5-positions was found to exhibit significant cytotoxicity against the three cancer cell lines. The presence of phenyl and 3-chlorophenyl groups at the 3- and 5-posiitons of the pyrroloquinazolinone 4i, on the other hand, resulted in significant cytotoxicity against vascular tumour endothelial cells (sEnd.2), but reduced activity against the melanoma (B16) and breast cancer (MCF-7) cells except at higher concentrations. The 2,3-dihydro-1H-pyrrolo[3,2,1-ij]quinazolin-1-ones 4a–l were found to be inactive against the chloroquine sensitive 3D7 strain of Plasmodium falciparum.

Synthesis and antimalarial potential of some novel quinoline-pyrazolopyridine derivatives.

A series of 1-(4-methylquinolin-2-yl)-4,6-diaryl-1H-pyrazolo[3,4-b]pyridin-3-amine derivatives was synthesized by the reaction of 3-cinnamoyl-4-hydroxy-6-methyl-2H-pyran-2-ones with 2-chloro-4,6-diphenylnicotinonitrile analogues in the presence of 2-hydrazino-4-methyl quinoline and ethanol. The newly synthesized compounds were characterized by IR, 1H NMR and mass spectral data. The synthetic series of novel quinoline-pyrazolopyridine hybrids were screened for in vitro schizont maturation assay against chloroquine sensitive 3D7 strain of Plasmodium falciparum, from which the most five active analogues were further evaluated for in vivo 4-day suppressive test in Swiss albino mice. Among the series, 5p (containing 4-Cl substituent attached to both aryl ring) portrayed considerable potent antimalarial activity during in vitro as well as in vivo study.

Synthesis of New Chloroquine Derivatives as Antimalarial Agents

A series of hybrid molecules referred to as “reversed chloroquines” (RCQs) were designed, synthesized, and tested against chloroquine resistant strains of Plasmodium falciparum. The designed compounds contain bulky aromatic groups and chloroquine like nucleus linked with each other via two or three carbon alkyl linkers. Five compounds were designed based on the structure – activity relationship. These five compounds have been successfully synthesized, of which three compounds show significant antimalarial activity in vitro. A modification of the reversal agent (RA) like moiety was designed using substituted biphenyl groups. The aminoalkyl substitution of the heterocycle and tertiary aliphatic aminoalkyl nitrogen atom with two- or three-carbon bridges to the heteroaromatic nitrogen is required for potential “resistance reversal activity”. The synthesized compounds were screened for their in vitro antimalarial activity as characterized by the 50% inhibitory concentration (IC50), cytotoxic concentration (CC50), and selectivity index (SI). These compounds did not show any cytotoxic effect. One of these compounds (5), which contains two-carbon linker chain, unsaturation at position 2, and chlorine substituted biphenyls in RA-like moiety, was found to possess appreciable and promising in vitro antimalarial activity against the chloroquine sensitive 3D7 strain of P. falciparum.

In vitro antiplasmodial and HIV-1 neutralization activities of root and leaf extracts from Berberis holstii

The in vitro antiplasmodial activities and HIV neutralizing activities of six crude extracts from the leaves and roots of Berberis holstii were evaluated. The antiplasmodial activities were assessed against a chloroquine sensitive 3D7 strain of the malaria parasite, Plasmodium falciparum, and the HIV neutralizing activity were assessed against HBX2 and ZM53 pseudovirions. Parasite lactate dehydrogenase (pLDH) assay was used to measure parasite viability and Luciferase Reporter Gene assay was used to measure HIV neutralizing activity. The crude alkaloid extract of the roots showed the most potent anti-parasitic activity (IC50=0.17μg/mL) with a selectivity index (SI) of 701.2 while the DCM/MeOH extract also showed good activity (IC50=2.33μg/mL). The aqueous and total alkaloid extracts of the roots displayed significant anti-parasitic activity (IC50=3.64 and 3.85μg/mL, respectively). The aqueous extract of the leaves displayed good HIV neutralizing activity (IC50=5.84μg/mL) against the HXB2 pseudo virus. All the extracts tested displayed low cytotoxicity against TZM-bl cells.

Plasmodium falciparum: Assessment of Selectivity of Action of Chloroquine, Alchornea cordifolia, Ficus polita, and Other Drugs by a Tetrazolium-Based Colorimetric Assay

A tetrazolium-based colorimetric selective assay (MTT-based CSA) was developed to assess the selectivity of antimalarial drugs. This in vitro assay, unlike all others, measures the ability of drugs to indirectly protect red blood cells (RBCs) from Plasmodium-falciparum-induced destruction. Optimum incubation time and number of cells needed were 5 days and 23 × 106 RBCs per well, respectively. A parasitemia range of 0.375% to 3% was found to be suitable for this assay. The MTT-based CSA determined anti-P. falciparum strain DD2 activity of chloroquine at a higher 50% effective concentration (EC50) value (21.0 μg/mL) than the isotopic microtest (10.0 μg/mL). Artesunate and oxytetracycline achieved 90% effect against DD2 with minimal or no toxicity to RBCs. Against chloroquine sensitive strain 3D7, chloroquine and Alchornea cordifolia had EC50 values of 0.025 μg/mL and 4.9 μg/mL respectively, and selective index (SI) values of >2,000 and >69.4 μg/mL, respectively.

Synthesis and antimalarial activity evaluation of some isoquine analogues

The worldwide diffusion of resistance in malaria parasite, especially the Plasmodium falciparum, towards currently available drugs has become a major health and development challenges to human society. Isoquine, an isomeric analogue of amodiaquine, has been reported recently as a second generation lead compound for development of cost-effective and potentially safer alternative to amodiaquine which cause adverse effects including agranulocytosis and liver damage. In this study, a series of seven analogues of isoquine have been synthesized and subjected to in vitro antimalarial activity screening against the chloroquine sensitive 3D7 strain of Plasmodium falciparum. A simple two-step Mannich reaction was used to synthesize the compounds. All the seven compounds possessed little to moderate antimalarial activity. However, the analogues with aliphatic alcoholic amino group side chain having promising activity than the compounds with substituted aromatic ring side chain and compounds substituted with urea while analogues with heterocyclic ring side chain exhibits moderate antimalarial activity.

Synthesis of oxalamide and triazine derivatives as a novel class of hybrid 4-aminoquinoline with potent antiplasmodial activity

Frequency of malaria and its resistance to chemotherapeutic options are emerging rapidly. To counter this problem, a series of 4-aminoquinolines having oxalamide and triazine functionalities in the side chain were synthesized and screened for their antimalarial activities. Triazine derivative 48 found to be the most active against CQ sensitive strain 3D7 of Plasmodium falciparum in an in vitro assay with an IC 50 of 5.23 ng/mL and oxalamide derivative 13 showed an in vivo suppression of 70.45% on day 4 against CQ resistant strain N-67 of Plasmodium yoelii.

Synthesis of novel thiourea, thiazolidinedione and thioparabanic acid derivatives of 4-aminoquinoline as potent antimalarials

In search of new 4-aminoquinolines which are not recognized by CQR mechanism, thiourea, thiazolidinedione and thioparabanic acid derivatives of 4-aminoquinoline were synthesized and screened for their antimalarial activities. Thiourea derivative 3 found to be the most active against CQ sensitive strain 3D7 of Plasmodium falciparum in an in vitro model with an IC 50 of 6.07 ng/mL and also showed an in vivo suppression of 99.27% on day 4 against CQ resistant strain N-67 of Plasmodium yoelii.

Synthesis and bioevaluation of hybrid 4-aminoquinoline triazines as a new class of antimalarial agents

The emergence and rapid spread of chloroquine resistant strains of Plasmodium falciparum has dramatically reduced the chemotherapeutic options. Towards this goal, a series of new class of hybrid 4-aminoquinoline triazines were synthesized and screened against CQ sensitive strain 3D7 of P. falciparum in an in vitro model. Compounds 65 and 69 exhibited more than 99% suppression on day 4 and on day 6 post treatment, compound 69 showed impressive 99.11% suppression against CQ resistant strain N-67 of P. yoelii in an in vivo assay.

Antiplasmodial, β-haematin inhibition, antitrypanosomal and cytotoxic activity in vitro of novel 4-aminoquinoline 2-imidazolines

A novel series of 4-aminoquinoline-containing 2-imidazolines were synthesized via a one-pot 3-component condensation reaction of amine, aldehyde and isocyanoacetate. The products were obtained in high yield as well as purity and were evaluated directly against two strains of Plasmodium falciparum and Trypanosoma brucei. Compound was the most active across all parasites with ED(50) = 3.3 nM against a chloroquine (CQ)-sensitive 3D7 strain, ED(50) = 33 nM against a CQ-resistant K1 strain and ED(50) = 70 nM against T. brucei. Several compounds were able to inhibit formation of beta-haematin in vitro, suggesting haemozoin formation in the malaria parasite as a possible target. On the other hand, evaluation against a human KB cell line revealed that the compounds were generally non-cytotoxic to the host cells.