In vitro and in vivo antiplasmodial activity of Colombian plants against human malaria Plasmodium falciparum

Andrographolide (AND), the diterpene lactone compound, was purified by HPLC from the methanolic fraction of the plantAndrographis paniculata. The compound was found to have potent antiplasmodial activity when tested in isolation and in combination with curcumin and artesunate against the erythrocytic stages ofPlasmodium falciparum in vitroandPlasmodium bergheiANKAin vivo. IC50s for artesunate (AS), andrographolide (AND), and curcumin (CUR) were found to be 0.05, 9.1 and 17.4 μM, respectively. The compound (AND) was found synergistic with curcumin (CUR) and addictively interactive with artesunate (AS).In vivo, andrographolide-curcumin exhibited better antimalarial activity, not only by reducing parasitemia (29%), compared to the control (81%), but also by extending the life span by 2-3 folds. Being nontoxic to thein vivosystem this agent can be used as template molecule for designing new derivatives with improved antimalarial properties.

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ChemInform Abstract: 4-Thiophenoxy-2-trichloromethylquinazolines Display in vitro Selective Antiplasmodial Activity Against the Human Malaria Parasite Plasmodium falciparum.

ChemInform ◽

10.1002/chin.201209176 ◽

2012 ◽

Vol 43 (9) ◽

pp. no-no

Author(s):

Patrice Vanelle ◽

et al. et al.

Keyword(s):

Plasmodium Falciparum ◽

Malaria Parasite ◽

Antiplasmodial Activity ◽

Human Malaria Parasite ◽

Human Malaria ◽

Parasite Plasmodium ◽

Parasite Plasmodium Falciparum

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4-Thiophenoxy-2-trichloromethyquinazolines display in vitro selective antiplasmodial activity against the human malaria parasite Plasmodium falciparum

Bioorganic & Medicinal Chemistry Letters ◽

10.1016/j.bmcl.2011.06.113 ◽

2011 ◽

Vol 21 (19) ◽

pp. 6003-6006 ◽

Cited By ~ 27

Author(s):

Pierre Verhaeghe ◽

Aurélien Dumètre ◽

Caroline Castera-Ducros ◽

Sébastien Hutter ◽

Michèle Laget ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Malaria Parasite ◽

Antiplasmodial Activity ◽

Human Malaria Parasite ◽

Human Malaria ◽

Parasite Plasmodium ◽

Parasite Plasmodium Falciparum

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4-Chlorothymol Exerts Antiplasmodial Activity Impeding Redox Defense System in Plasmodium falciparum

Frontiers in Pharmacology ◽

10.3389/fphar.2021.628970 ◽

2021 ◽

Vol 12 ◽

Author(s):

Saurabh Kumar ◽

Pooja Rani Mina ◽

Ravi Kumar ◽

Anirban Pal ◽

Ateeque Ahmad ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Survival Time ◽

Redox Balance ◽

Antimicrobial Activities ◽

Antiplasmodial Activity ◽

Mean Survival Time ◽

Hemolytic Assay ◽

Thymol Derivatives

Malaria remains one of the major health concerns due to the resistance of Plasmodium species toward the existing drugs warranting an urgent need for new antimalarials. Thymol derivatives were known to exhibit enhanced antimicrobial activities; however, no reports were found against Plasmodium spp. In the present study, the antiplasmodial activity of thymol derivatives was evaluated against chloroquine-sensitive (NF-54) and -resistant (K1) strains of Plasmodium falciparum. Among the thymol derivatives tested, 4-chlorothymol showed potential activity against sensitive and resistant strains of P. falciparum. 4-Chlorothymol was found to increase the reactive oxygen species and reactive nitrogen species level. Furthermore, 4-chlorothymol could perturb the redox balance by modulating the enzyme activity of GST and GR. 4-Chlorothymol also showed synergy with chloroquine against chloroquine-resistant P. falciparum. 4-Chlorothymol was found to significantly suppress the parasitemia and increase the mean survival time in in vivo assays. Interestingly, in in vivo assay, 4-chlorothymol in combination with chloroquine showed higher chemosuppression as well as enhanced mean survival time at a much lower concentration as compared to individual doses of chloroquine and 4-chlorothymol. These observations clearly indicate the potential use of 4-chlorothymol as an antimalarial agent, which may also be effective in combination with the existing antiplasmodial drugs against chloroquine-resistant P. falciparum infection. In vitro cytotoxicity/hemolytic assay evidently suggests that 4-chlorothymol is safe for further exploration of its therapeutic properties.

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Insights Gained fromP. falciparumCultivation in Modified Media

The Scientific World JOURNAL ◽

10.1155/2013/363505 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 7

Author(s):

Sanjay A. Desai

Keyword(s):

Plasmodium Falciparum ◽

Basic Research ◽

Culture Conditions ◽

Parasite Growth ◽

Human Malaria ◽

Parasite Culture ◽

Comparison Of Results ◽

Modified Media

In vitrocultivation ofPlasmodium falciparum, the agent of severe human malaria, has enabled advances in basic research and accelerated the development of new therapies. Since the introduction ofin vitroparasite culture nearly 40 years ago, most workers have used a medium consisting of RPMI 1640 medium supplemented with lipids and hypoxanthine. While these standardized conditions yield robust parasite growth and facilitate comparison of results from different studies, they may also lead to implicit assumptions that limit future advances. Here, I review recent studies that used modified culture conditions to challenge these assumptions and explore parasite physiology. The findings are relevant to understandingin vivoparasite phenotypes and the prioritization of antimalarial targets.

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Stable Artesunate Resistance in A Humanized Mouse Model of Plasmodium falciparum

10.5772/intechopen.100381 ◽

2021 ◽

Author(s):

Sheetal Saini ◽

Rajinder Kumar ◽

Rajeev K. Tyagi

Keyword(s):

Plasmodium Falciparum ◽

Combination Therapy ◽

Malaria Infection ◽

Artemisinin Resistance ◽

Antimalarial Drugs ◽

Humanized Mouse ◽

Humanized Mouse Model ◽

Human Malaria

Plasmodium falciparum, the most devastating human malaria parasite, confers higher morbidity and mortality. Although efforts have been made to develop an effective malaria vaccine, stage- and species-specific short-lived immunity crippled these efforts. Hence, antimalarial drug treatment becomes a mainstay for the treatment of malaria infection in the wake of the unavailability of an effective vaccine. Further, there has been a wide array of antimalarial drugs effective against various developmental stages of P. falciparum due to their different structures, modes of action, and pharmacodynamics as well as pharmacokinetics. The development of resistance against almost all frontline drugs by P. falciparum indicates the need for combination therapy (artemisinin-based combination therapy; ACT) to treat patients with P. falciparum. A higher pool of parasitemia under discontinuous in vivo artemisinin drug pressure in a developed humanized mouse allows the selection of artesunate resistant (ART-R) P. falciparum. Intravenously administered artesunate, using either single flash doses or a 2-day regimen, to the P. falciparum-infected human blood chimeric NOD/SCID.IL-2Rγ−/− immunocompromised (NSG) mice, with progressive dose increments upon parasite recovery, was the strategy deployed to select resistant parasites. Parasite susceptibility to artemisinins and other antimalarial compounds was characterized in vitro and in vivo. P. falciparum has shown to evolve extreme artemisinin resistance as well as co-resistance to antimalarial drugs. Overall, the present information shall be very useful in devising newer therapeutic strategies to treat human malaria infection.

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Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100162132 ◽

1990 ◽

Vol 48 (3) ◽

pp. 914-915

Author(s):

D.J.P. Ferguson ◽

A.R. Berendt ◽

J. Tansey ◽

K. Marsh ◽

C.I. Newbold

Keyword(s):

Plasmodium Falciparum ◽

Red Blood Cells ◽

Blood Cells ◽

Umbilical Vein ◽

Cell Types ◽

Amelanotic Melanoma ◽

Cytoplasmic Process ◽

Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

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Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro

Blood ◽

10.1182/blood.v76.6.1250.1250 ◽

1990 ◽

Vol 76 (6) ◽

pp. 1250-1255 ◽

Cited By ~ 36

Author(s):

S Whitehead ◽

TE Peto

Keyword(s):

Plasmodium Falciparum ◽

Growth Inhibition ◽

Antimalarial Activity ◽

Clinical Malaria ◽

Inhibitory Effect ◽

Parasite Development ◽

And Control ◽

Speed Of Onset

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.

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In vitro and in vivo inhibition of malaria parasite infection by monoclonal antibodies against Plasmodium falciparum circumsporozoite protein (CSP)

Scientific Reports ◽

10.1038/s41598-021-84622-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Merricka C. Livingstone ◽

Alexis A. Bitzer ◽

Alish Giri ◽

Kun Luo ◽

Rajeshwer S. Sankhala ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Monoclonal Antibodies ◽

Disease Burden ◽

Vaccine Candidate ◽

Specific Binding ◽

Circumsporozoite Protein ◽

Target Epitope ◽

Selection Of

AbstractPlasmodium falciparum malaria contributes to a significant global disease burden. Circumsporozoite protein (CSP), the most abundant sporozoite stage antigen, is a prime vaccine candidate. Inhibitory monoclonal antibodies (mAbs) against CSP map to either a short junctional sequence or the central (NPNA)n repeat region. We compared in vitro and in vivo activities of six CSP-specific mAbs derived from human recipients of a recombinant CSP vaccine RTS,S/AS01 (mAbs 317 and 311); an irradiated whole sporozoite vaccine PfSPZ (mAbs CIS43 and MGG4); or individuals exposed to malaria (mAbs 580 and 663). RTS,S mAb 317 that specifically binds the (NPNA)n epitope, had the highest affinity and it elicited the best sterile protection in mice. The most potent inhibitor of sporozoite invasion in vitro was mAb CIS43 which shows dual-specific binding to the junctional sequence and (NPNA)n. In vivo mouse protection was associated with the mAb reactivity to the NANPx6 peptide, the in vitro inhibition of sporozoite invasion activity, and kinetic parameters measured using intact mAbs or their Fab fragments. Buried surface area between mAb and its target epitope was also associated with in vivo protection. Association and disconnects between in vitro and in vivo readouts has important implications for the design and down-selection of the next generation of CSP based interventions.

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