Chloroquine-resistant Malaria Research Articles

Frequency of chloroquine-resistant haplotype of Plasmodium falciparum (CVIET) in Ibadan, Southwest Nigeria 17 years post-chloroquine withdrawal

The replacement of chloroquine with artemisinin-based combination therapies (ACTs) for over a decade has had varying impacts on the ability of the malaria parasite to sustain its chloroquine resistance prowess in different malaria-endemic regions. We evaluated the frequency of Plasmodium falciparum chloroquine resistance transporter (PfCRT) mutations in Ibadan, Nigeria 17 years after the replacement of chloroquine with ACTs for malaria treatment. Fragments of PfCRT gene from genomic DNA of microscopically confirmed P. falciparum-infected patients were amplified and sequenced. There were 19% CVIET mutant and 81% CVMNK wild-type haplotypes on residues 72–76. A220S change were found in 16.7% of samples occurring concurrently with the CVIET haplotype, while a Q271E mutation occurred in a PfCRT wild-type isolate. The reduced prevalence of the PfCRT mutant alleles in this study compared to previous reports suggests a gradual disappearance of chloroquine-resistant malaria parasites following reduced drug pressure. It may also be a result of fitness demand on the parasites in attempts to evolve resistance against the current first-line regimen. However, evaluating the prevalence of other chloroquine resistance markers such as Plasmodium falciparum multidrug resistance 1 gene mutations in this population, and a more robust sample size will help to consolidate these findings.

Naringin and chloroquine combination mitigates chloroquine-resistant parasite-induced malaria pathogenesis by attenuating the inflammatory response

BackgroundMalaria, characterised by inflammation and multi-organ complications, needs novel chemotherapeutics due to the rise of drug-resistant malaria parasites, which is a serious health issue. Naringin (NGN), a flavanone glycoside (naringenin 7-O-neohesperidose), has a broad spectrum of pharmacological activities but its effect against malaria, alone and in combination, was not deeply investigated. PurposeTo assess the pharmacological efficacy of NGN alone and in combination with chloroquine (CQ) against a Plasmodium strain resistant to CQ and to elucidate its potential mode of action. MethodsThe anti-inflammatory potential of NGN was assessed in mouse microglial cells stimulated with hemozoin by analyzing inflammatory cytokines production. The anti-plasmodial potential of NGN was subsequently tested alone and in combination with CQ against the K1 strain of Plasmodium using the fixed ratio combination method. Further, we evaluated NGN's antimalarial efficacy against the CQ-resistant Plasmodium yoelii nigeriensis N67 strain (P. yoelii), both alone and in combination with CQ, by measuring parasitemia and survival rates. To comprehend the impact of NGN on malaria-induced inflammation in mice, we measured pro-inflammatory cytokines elevated by activated NF-кB signalling. These findings were supported by mRNA and immunohistochemical analyses of malaria-infected mice's liver and brain tissues. ResultsOur study demonstrated that NGN displayed anti-plasmodial activity, which was further augmented when combined with CQ. At 50 µM, NGN significantly reduced the elevation of pro-inflammatory cytokines in synthetic hemozoin-stimulated microglial cells. Compared to P. yoelii-infected mice, NGN (12.5 mg kg-1) significantly reduced parasitemia in mice, resulting in a survival period of up to 13 days. Survival improved by up to 20 days when NGN and CQ were given in combination. NGN, as revealed by immunohistochemical examination of brain and liver tissues, interfered with the NF-кB pathway, potentially reducing the elevation of pro-inflammatory cytokines (TNF-α, IL-1β, IL-18, IFN-γ, and IL-6). This was supported by the overexpression of inflammation-regulatory genes (TGFβ, Nrf2, HO-1, and iNOS) and the downregulation of inflammation-stimulating genes (NF-κB, NLRP3, and caspase-1). Histopathological analysis demonstrated the potential of NGN to restore liver and brain tissues to normal. The substantial decrease in the expression and production of ICAM-1 protein in the brain tissue implies the beneficial effects of NGN, pointing towards its potential for mitigating brain pathology. ConclusionThe findings of this study revealed NGN as a promising drug-like candidate for the management of CQ-resistant parasite-induced malaria pathogenesis for adjunctive therapy in combination with standard antimalarial drugs through its modulation of the NF-κB-mediated inflammation.

Antiplasmodial activity, in silico ADME and mammalian cell cytotoxicity of a synthetic protoberberine alkaloid, coralyne

Coralyne is a synthetic protoberberine alkaloid with anticancer activity and selectivity superior to that of berberine, its congener. As berberine is gifted with antiplasmodial activity, this study assessed the antiplasmodial activity of coralyne against erythrocytic stages of the malaria parasite in culture. Parasites were cultured by adopting the method described by Trager and Jensen in 1976. Following this, parasites were exposed at ring stage to increasing doses of coralyne to enable us compute the IC50. Further, given that berberine is a substrate of the efflux transporter permeability glycoprotein (P-gp), in silico techniques were used to study the pharmacokinetics of oral coralyne. Coralyne showed excellent potency (IC50Pf3D7: 0.52 µg/ml) against chloroquine sensitive strain and a little less potency (IC50PfINDO: 1.15 µg/ml) against the chloroquine resistant malaria parasite strain (Resistance index: 2.21). Further, with CC50HEK: >100 µg/ml, it was non-toxic to mammalian cells. However, in silico absorption, distribution, metabolism and excretion (ADME) studies predicts that like berberine, coralyne may also have poor oral bioavailability thus limiting its usefulness as an orally deliverable antimalarial agent. Given the negative impact of low bioavailability in the development of protoberberine alkaloids as antimalarials, synthesizing analogues of coralyne with nanomolar potency against the malaria parasite and improved oral pharmacokinetics may be a good strategy for the future.

Identifying inhibitors of β-haematin formation with activity against chloroquine-resistant Plasmodium falciparum malaria parasites via virtual screening approaches

The biomineral haemozoin, or its synthetic analogue β-haematin (βH), has been the focus of several target-based screens for activity against Plasmodium falciparum parasites. Together with the known βH crystal structure, the availability of this screening data makes the target amenable to both structure-based and ligand-based virtual screening. In this study, molecular docking and machine learning techniques, including Bayesian and support vector machine classifiers, were used in sequence to screen the in silico ChemDiv 300k Representative Compounds library for inhibitors of βH with retained activity against P. falciparum. We commercially obtained and tested a prioritised set of inhibitors and identified the coumarin and iminodipyridinopyrimidine chemotypes as potent in vitro inhibitors of βH and whole cell parasite growth.

Development of Novel Solid Nanostructured Lipid Carriers for Bioavailability Enhancement Using a Quality by Design Approach.

α, β-Arteether (ART) antimalarial drug is used to treat chloroquine-resistant malaria and cerebral malaria. The drug's solubility in water is relatively low (17μg/mL), and 40% of the drug degrades in the stomach, resulting in poor bioavailability. This article discusses the quality by design technique used forformulation development and optimization of nanostructured lipid carriers (NLCs). The ART-NLCs were made by solvent diffusion method. To develop solid NLCs, the NLCs were freeze-dried and encapsulated in enteric-coated capsule shells. The prepared NLCs showed particle size ranging between 156.8 ± 12nm while zeta potential ranging between - 26.1 ± 0.22mV. They also showed high encapsulation efficiency (> 85%) and an amorphous drug's lipid matrix state. Pharmacokinetic parameters of optimized formulation enhance oral bioavailability to 18.45%. These investigations demonstrated the superiority of NLCs for improvement of solubility as well as oral bioavailability of poorly water-soluble drugs.

Assessment of the activities of Chasmanthera dependens Hochst. combined with other plants on chloroquine-sensitive and chloroquine-resistant Plasmodium berghei

The prevalence of Plasmodium strains resistant to conventional monotherapy drugs has necessitated the need for more effective and affordable antimalarial agents. This study aimed at evaluating the antimalarial activities of some indigenous plants alone and in combination with chloroquine with a view to proffering herbal combination therapy as an alternative to the currently used antimalarial combination therapy. Extracts obtained separately from the decoctions of the roots of Chasmanthera dependens Hochst. (Menispermaceae), Vernonia amygdalina Delile (Asteraceae) and methanol extract of Sphenocentrum jollyanum Pierre (Menispermaceae) leaf were analysed by high resolution liquid chromatography-mass spectrometry and evaluated for repeated-dose oral toxicity in mice using standard protocols. Assessments of C. dependens and V. amygdalina with their combination were carried out on chloroquine-sensitive Plasmodium-infected mice with the 4-day chemosuppressive antimalarial test. Sphenocentrum jollyanum, C. dependens and their combinations with chloroquine (10 mg/kg) were assessed on chloroquine-resistant Plasmodium using the curative test model. The combination of C. dependens and V. amygdalina exhibited chemosuppression (71.1±3.7%) that was not significantly (p>0.05) different from chloroquine (80.1±1.9%). In the curative model, a significant parasite clearance (98.2%) was observed with the combination of C. dependens and chloroquine. The study concluded that the aqueous root extracts possessed potent antimalarial activity in chloroquine-sensitive malaria infection. It also revealed an additive interaction between C. dependens and chloroquine that could be further investigated as a herbal combination for chloroquine-resistant malaria.

Histopathological Changes in Kidneys of Developing Chick Embryo on Exposure to Artesunate

Introduction: Chick embryo is one of the most commonly used animals to study the adverse effects of various drugs for research purpose. In India, Malaria imposes incredible socio-economic burden on humankind. India reports approximately two million cases of malaria yearly, with large number of deaths. Surveys have demonstrated that the rates of treatment failure are higher than 50% due to Chloroquine resistance and poor efficacy of Sulphadoxine Pyrimethamine. Artesunate is a concentrate of Artemisia plant found in China, also called as Qinghaosu. It is a subordinate of a group of drugs artemisinin that have the most rapid action of all current drugs against Chloroquine resistant Plasmodium vivax and Plasmodium falciparum malaria. Aim: To understand the adverse effects of Artesunate on kidney of developing chick embryo. Materials and Methods: The present study was an experimental study which comprised of steps like selection and sampling of eggs in groups (control and experimental), selection and preparation of drug (dose titration), drug administration, incubation of eggs, manual hatching to obtain chick embryo, isolation of kidney, sectioning of kidney and staining for slide preparation, microscopical analysis of the slides. In this study, the fertilised eggs used were of White Leghorn chicken and were procured from King and King poultry farm Hapur, Uttar Pradesh, India. Hundred fertilised chicken eggs were divided into five experimental groups denoted by A, B, C, D, and E and five control groups denoted by a, b, c, d and e one for each experimental group respectively. Each experimental and control group had 10 eggs. Experimental groups A, B, C, D and E were exposed to artesunate with dose of 0.0004 mg, 0.0005 mg, 0.0006 mg, 0.0007 mg and 0.0008 mg respectively and control group a, b, c, d and e were treated with same concentration of normal saline as artesunate. The eggs were broken by scalpel on 18th day of incubation and chick embryos were obtained. The kidneys were removed sectioned, stained and studied using light and compound microscope. Results: Histopathological changes like tubular degeneration, vacuolation in the cytoplasm of epithelium lining of Proximal Convoluted Tubules (PCT) and Distal Convoluted Tubules (DCT), congestion in Glomeruli, haemorrhage in urinary space and mild lymphocytic infiltration were observed. Conclusion: Exposure to artesunate increases the risk of nephrotoxicity with increase of embryonic age.

Comparative in vivo antimalarial activities of aqueous and methanol extracts of MAMA powder - A herbal antimalarial preparation

Ethnopharmacological relevanceThe choice of extraction solvent is a significant consideration in ethnomedicine as optimal extraction could influence the bioactivity of the herbal medicinal product. Aim of studyThis study investigated the possible influence of the choice of solvents (methanol and water) for extracting MAMA Powder (MP) against Plasmodium berghei-infected mice to optimize its antimalarial activity and for developing other pharmaceutical dosage forms. Materials and methodsAqueous and methanol extracts of MP, obtained through the decoction and soxhlet methods, respectively, were subjected to liquid chromatography-mass spectroscopy (LC-MS) for their respective fingerprints. The antimalarial activities of the methanol and aqueous extracts (12.5–100 mg/kg) were evaluated orally using the chemosuppressive test model on chloroquine-sensitive Plasmodium berghei-infected mice. The methanol extract was subjected to the established infection and prophylactic antimalarial tests with chloroquine (10 mg/kg) and pyrimethamine (1.25 mg/kg) as positive controls, respectively. The aqueous extract was investigated in chloroquine-resistant P. berghei using the chemosuppressive (12.5–800 mg/kg) and established infection (25–400 mg/kg) antimalarial models. ResultsThe LC-MS fingerprints of both aqueous and methanol extracts revealed similar indole alkaloid contents. Chemosuppressive activity of the aqueous extract (75.3%) was significantly (p < 0.05) higher than the methanol extract (67.6%). In the chloroquine-resistant P. berghei infection experiments, the aqueous extract (400 mg/kg) exhibited significant parasite clearance (72%). ConclusionThe study concluded that the water extract with higher antimalarial activity could be optimized for chloroquine-resistant malaria and can thus facilitate the production of liquid and solid dosage forms.

SEARCH FOR BIOLOGICALLY ACTUVE SUBSTANCES WITH ANTIMICROBIAL AND ANTIBIOTIC POTENTIATING PROPERTIES AMOUNG MEMBERS OF THE GENUS ARTEMISIA AGAINTS THE MAIN PATHOGENS OF INFECTIOUS SKIN LESIONS

Abstract. Active components of the genus Artemisia show a wide range of antimicrobial effect against most bacterial pathogens. In addition, artemisin isolated from wormwood is used to treat chloroquine-resistant malaria. Antimicrobial and antibiotic-potentiating effects of eight aqueous ethanolic extracts (40 %, 70 % and 90 %) aerial part of the genus Artemisia aqueous against S. aureus and S. epidermidis strains with various types of resistance to macrolides, lincosamides, tetracyclines and fluoroquinolones isolated from outpatients with different forms of pyoderma have been researched with agar diffusion micromethod. Determination of effective antimicrobial concentrations of antimicrobials and test extracts against staphylococci have been performed with serial dilutions micromethod. The statistical program "Statistica", computer programs UTHSCSA Image Tool 3.0 and Microsoft Office Excel 2016 have been used for statistical processing of microbiological research results. The pronounced antimicrobial effect of the wormwood extract Artemisia dracunculus L. (MIC 125.0 - 250.0 μg/ml) against all S. aureus and S. epidermidis test strains has been established. Other studied extracts showed much weaker antimicrobial effect (MIC 1000.0 - 1500.0 μg/ml). It was found that the species of staphylococci and the phenotype of resistance of test strains do not affect antimicrobial activity of the studied extracts. We have found that there is no clear сorrelation between antimicrobial properties of the studied extracts and the phenotype of resistance of staphylococci test-strains. Extracts were equally effective against staphylococcal strains with low level of resistance by efflux of antimicrobial drug and skin isolates with chromosomal resistance. The greatest resistance to BAC of the studied extracts was showed by test strains with a high level of resistance to antibiotics of MLS-group and tetracycline, exhibiting sensitivity only to tarragon wormwood.&#x0D; Active components of 70, 90 % common mugwort extract Artemisia vulgaris L. (increase of the inhibition zone up to 117 – 142 %, p&lt;0.05) and southern wormwood extract (increase of the inhibition zone up to 50 – 59 % and 74 – 122 %, respectively, p&lt;0.05) showed dose-dependent synergistic interaction with erythromycin. Common mugwort extract (70 %) showed synergistic interaction with ¼ MIC of tetracycline (increase of the inhibition zone up to 100 %) against strains with combined resistance to all studied antimicrobials. For the study we used crude total extracts of medicinal plants (40 %, 70 % and 90 % ethanol), so we expect their significantly higher antimicrobial effect against staphylococcal strains while optimizing the extraction process and subsequent purification. It should be noted that 90 % aqueous ethanol extracts showed significantly better antimicrobial properties compared to 40 % and 70 % extracts. Active compounds of tarragon wormwood Artemisia dracunculus L. extract show pronounced antimicrobial effect against S. aureus and S. epidermidis strains, the main causative agents of infectious skin lesions, with different types of resistance to macrolides, lincosamides, tetracyclines and fluoroquinolones. Dose-dependent synergistic interaction with macrolides of common mugwort Artemisia vulgaris L. extracts and southern wormwood Artemisia abrotanum L. extract with macrolides (erythromycin) and tetracycline has been revealed.

Quinolinotriazole antiplasmodials via click chemistry: synthesis and in vitro studies of 7-Chloroquinoline-based compounds

Malaria is nowadays one of the most serious health concerns in a global scale and, although there is an evident increase in research studies in this area, pointed by the vast number of hits and leads, it still appears as a recurrent topic every year due to the drug resistance shown by the parasite exposing the urgent need to develop new antimalarial medications. In this work, 38 molecules were synthesized via copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) or “click” chemistry, following different routes to produce 2 different organic azides, obtained from a 4,7 dicholoquinoline, reacted with 19 different commercially available terminal alkynes. All those new compounds were evaluated for their in vitro activity against the chloroquine resistant malaria parasite Plasmodium falciparum (W2). The cytotoxicity evaluation was accomplished using Hep G2 cells and SI index was calculated for every molecule. Some of the quinoline derivatives have shown high antimalarial activity, with IC50 values in the range of 1.72-8.66 µM, low cytotoxicity, with CC50>1000 µM and selectivity index (SI) in the range of 20-100, with some compounds showing SI>800. Therefore, the quinolinotriazole hybrids could be considered a very important step on the development of new antimalarial drugs.

Could Artesunate Have a Positive Effect on the Neurological Complications Related to Infection When It Is Used in the Treatment of COVID-19?

Artesunate is a safe noncytotoxic drug with low side effects which is used in the treatment of chloroquine-resistant malaria. In addition to being an antimalarial drug, artesunate also has immunomodulatory, anticarcinogenic, and antiviral activity. There are in vivo and in vitro studies reporting that artesunate may have a positive effect on the treatment of COVID-19. Artesunate may be effective based on its effect on the anti-inflammatory activity, chloroquine-like endocytosis inhibition mechanism, and nuclear factor kappa B (NF-κB) signal pathway. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may cause neurological complications in addition to targeting the respiratory system. In this study, we have discussed the possible neuroprotective action mechanisms of artesunate. We think that systemic and intranasal topical artesunate administration may have a positive effect on neurological complications resulting from COVID-19.

Antimalarial agent artesunate induces G0/G1 cell cycle arrest and apoptosis via increasing intracellular ROS levels in normal liver cells.

Artesunate (ARS) has been shown to be highly effective against chloroquine-resistant malaria. In vitro studies reported that ARS has anticancer effects; however, its detrimental action on cancer cells may also play a role in its toxicity toward normal cells and its potential toxicity has not been sufficiently researched. In this study, we investigated the possible cytotoxic effects using normal BRL-3A and AML12 liver cells. The results showed that ARS dose-dependently inhibited cell proliferation and arrested the G0/G1 phase cell cycle in both BRL-3A and AML12 liver cells. Western blotting demonstrated that ARS induced a significant downregulation of cyclin-dependent kinase-2 (CDK2), CDK4, cyclin D1, and cyclin E1 in various levels and then caused apoptosis when the Bcl-2/Bax ratio decreased. Conversely, the levels of intracellular reactive oxygen species (ROS) were increased. The ROS scavenger N-acetylcysteine can significantly inhibit cell cycle arrest and apoptosis induced by ARS. Thus, the data confirmed that ARS exposure impairs normal liver cell proliferation by inducing G0/G1 cell cycle arrest and apoptosis, and this detrimental action may be associated with intracellular ROS accumulation. Collectively, the possible side effects of ARS on healthy normal cells cannot be neglected when developing therapies.

GC-MS Analysis of Bioactive Compounds of Artemesia annua and Assessment of its anti-proliferative activity against Human Cancer Cell Lines

Plant essential oil is found to possess many beneficial effects in the field of medicine. Especially essential oil derived from different species of plants is reported to have specific activity against cancer. Artemesiaannua is an annual herb belonging to Asteraceae family has been traditionally used for treating several ailments. It is a conventional medicinal plant used in the treatment of chloroquine-resistant and cerebral malaria. The major aim of this study was to evaluate the anticancer potential of this plant against cancer cell line. Hydro distilled volatile oil obtained from aerial parts of A.annua was analysed by GCMS. The majority of the compounds derived from essential oil of Artemesiaannua are monoterpenes and sesquiterpenes. Artemisinin, the active component of Artemesiaannua is a sesquiterpenoid lactone containing unusual endoperoxide bridge that shows remarkable activity against numerous tumour growth and metastases. The pleiotropic nature of artemisinin induces oxidative stress, anti-angiogenetic effect and apoptosis triggering on cancer cells. The anti-proliferative effect of essential oil derived from Artemesiaannua on human cancer cell lines like MCF-7, HT29 and AGS was done by MTT assay. Results shows the essential oil of artemisia annua have cytotoxic potential by inhibiting cell growth in a dose dependent manner. However, further investigations in isolating active cytotoxic components and understanding its molecular mechanisms will help in therapeutic management of cancer.

A CASE OF TROPICAL ILLNESS MANAGED IN THE MEDICAL ICU WITH AN INVESTIGATIONAL NEW DRUG

SESSION TITLE: Case Report Semifinalists 3 SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/21/2019 02:30 PM - 03:15 PM INTRODUCTION: Rates of international travel are increasing along with increasing exposure to tropical diseases. It is of importance to maintain knowledge of common tropical diseases and treatment options. CASE PRESENTATION: A 30-year-old male, who returned a week prior from admission, from a vocational trip to Nigeria. Patient presented with symptoms of headache, fever, nausea, vomiting, abdominal pain and diarrhea. Patient was septic but otherwise hemodynamically stable, with presenting labs demonstrating profound thrombocytopenia with low haptoglobin (table 1) and presence of malaria on Wright-Giemsa stain. Blood smear demonstrated 17% Plasmodium Falciparum paracitemia. The Center of Disease Control(CDC) was contacted. Patient was started on treatment with intravenous(IV) quinidine and doxycycline and admitted to the Medical Intensive Care Unit(MICU) for further monitoring. Due to lack of available IV quinidine to complete therapy the decision was made to transition to IV artesunate and continued on doxycycline. Hospital course remained uncomplicated with quick resolution of parasitic loads (<1%). DISCUSSION: Malaria with Plasmodium Falciparum occurring in certain geographical areas, including Nigeria, are categorized by the CDC as a chloroquine resistant. Four applicable pharmacological therapies are available in such cases: atovaquone-proguanil, artemether-lumefantrine, quinine in combination with doxycycline, tetracycline or clindamycin and mefloquine. Quinine is the only FDA approved IV medication for treatment of severe malaria. The CDC defines severe malaria by the presence of one of more specifically defined clinical signs and symptoms and/or parasitemia of >5%. Our patient was stratified into a category of severe malaria by presence of a paracitemia of 17%. Per CDC recommendations severe malaria should be treated with IV antimalarial medication. World Health Organization recommends artesunate over quinine therapy for severe malaria. The FDA has approved artesunate as an investigational option in certain individuals who qualify. CONCLUSIONS: Artesunate is an effective alternative treatment option for individuals with severe malaria. We demonstrate a case of successful treatment of severe chloroquine resistant plasmodium falciparum malaria with artesunate. Reference #1: Centers for Disease Control and Prevention. (2018). Treatment of Malaria: Guidelines For Clinicians (United States) Reference #2: Dilip R. Karnad, MD, Guy A. Richards, MD PhD, Gisele Sampaio Silva, MD, Pravin Amin, MD. Tropical diseases in the ICU: A syndromic approach to diagnosis and treatment. Journal of Critical Care 46(2018)119-126 DISCLOSURES: No relevant relationships by Shozab Ahmed, source=Web Response No relevant relationships by Monika Kakol, source=Web Response

Effects of Quinine, Quinidine and Chloroquine on Human Muscle Nicotinic Acetylcholine Receptors.

The genus Cinchona is known for a range of alkaloids, such as quinine, quinidine, cinchonine, and cinchonidine. Cinchona bark has been used as an antimalarial agent for more than 400 years. Quinine was first isolated in 1820 and is still acknowledged in the therapy of chloroquine-resistant falciparum malaria; in lower dosage quinine has been used as treatment for leg cramps since the 1940s. Here we report the effects of the quinoline derivatives quinine, quinidine, and chloroquine on human adult and fetal muscle nicotinic acetylcholine receptors (nAChRs). It could be demonstrated that the compounds blocked acetylcholine (ACh)-evoked responses in Xenopus laevis oocytes expressing the adult nAChR composed of αβ𝜀δ subunits in a concentration-dependent manner, with a ranked potency of quinine (IC50 = 1.70 μM), chloroquine (IC50 = 2.22 μM) and quinidine (IC50 = 3.96 μM). At the fetal nAChR composed of αβγδ subunits, the IC50 for quinine was found to be 2.30 μM. The efficacy of the block by quinine was independent of the ACh concentration. Therefore, quinine is proposed to inhibit ACh-evoked currents in a non-competitive manner. The present results add to the pharmacological characterization of muscle nAChRs and indicate that quinine is effective at the muscular nAChRs close to therapeutic blood concentrations required for the therapy and prophylaxis of nocturnal leg cramps, suggesting that the clinically proven efficacy of quinine could be based on targeting nAChRs.

Evaluation of Alangium lamarckii Bark for Antiplasmodial and Cytotoxic Constituents and Isolation of a Novel Tubulosine Analogue

Alangium lamarkii is traditionally used in India for the treatment of malaria. Partial activity guided-fractionation of the basic chloroform fraction of the methanolic extract of the bark led to the isolation of a novel tubulosine analogue, 10-demethyl-9'- N-methyltubulosine (1), for which the trivial name tubulosatine is suggested. In addition, the known A. lamarkii constituents, tubulosine (2), cephaeline and emetine were isolated as potent antiplasmodial and cytotoxic constituents, but 1 was up to 1000-fold less potent than the former alkaloids against both malaria parasites and human cancer cell lines. The compounds were active against both chloroquine-sensitive and chloroquine-resistant malaria parasites, but no selective toxicity was observed towards malaria parasites compared with cancer cells with any of the alkaloids. Further work to explore the basis for the relatively weak biological activities of 1 would be worthwhile. Betulinic acid, stigmasterol and its 3- O-glucoside were isolated from the neutral chloroform fraction of the methanolic extract.

Effects of quinine sulfate- an antimalarial drug on palatal growth in developing mice embryo: A histopathological study

Background: Malaria is one of the most common infectious and fatal diseases worldwide. Quinine sulfate is one of the antimalarial drug used to treat chloroquine resistant malaria and malaria falciparum.Aims and Objectives: The present study was designed to assess its developmental defects on mice palate.Materials and Methods: Thirty adult pregnant female Swiss albino mice were used in the present work. They were divided into five groups of six each. One control group (c) with 6 pregnant mice received normal saline orally from day 6 to 15 of gestation. Four treated groups of 6 pregnant mice each were formed. Treated groups T1, T2, T3 and T4 were administered Quinine sulfateorally with 50, 100, 200, 400 mg/kg bw/day from day 6 to 15 of gestation respectively.Results: No palatal abnormalities were observed histologically in the control and T1 treated group. However, varying degrees of clefting of the palate, from failure of elevation of the palatal shelves to failure of fusion in the midline were observed in the Quinine sulfate treated groups (T2, T3 &amp; T4).Conclusion: Quinine sulfate induced defects in the developing palate in the present study by disturbing the process of palatogenesis, which is characterized by incomplete growth, elevation or fusion of the palatal shelves.Asian Journal of Medical Sciences Vol.9(5) 2018 31-36

Reversal of Chloroquine Resistance of Plasmodium vivax in Aotus Monkeys.

Chloroquine-resistant (CQR) vivax malaria has emerged as a threat to the malaria elimination agenda. The objective of this study was to assess if a combination of chloroquine (CQ) and prochlorperazine was able to reverse CQ resistance of the Plasmodium vivax AMRU-1 strain from Papua New Guinea in infected Aotus monkeys. For this purpose, in two independent experimental drug efficacy trials, a total of 18 Aotus monkeys infected with blood obtained from donor animals were randomly assigned to treatment and control groups and orally administered CQ at 10 mg/kg or prochlorperazine at 20 mg/kg, alone or in combination, for five consecutive days. Reversal of CQR was achieved in animals that received the drug combination, whereas neither drug alone produced cures. This same drug combination reverses CQR in P. falciparum and could be an alternative for treatment in humans with chloroquine-resistant P. vivax infections.

In vitro evaluation of chloroquine-loaded and heparin surface-functionalized solid lipid nanoparticles

BackgroundUse of chloroquine, an otherwise safe and relatively affordable anti-malarial drug, was discontinued due to widespread prevalence of resistant parasites. Many entrant anti-malarial drugs for treatment of chloroquine resistant malaria raises the concerns of cost and safety among other challenges. Innovative ways of circumventing chloroquine resistance is of paramount importance. Such may include nanoparticulate delivery strategies and targeting. This study evaluated physicochemical properties and in vitro antiplasmodial activity of chloroquine encapsulated heparin functionalized solid lipid nanoparticles (CQ-Hep-SLNs) and non-heparin functionalized SLNs (CQ-SLN) against Plasmodium falciparum.MethodsThe modified double-emulsion solvent evaporation technique was used to prepare the nanoparticles. HPLC/UV was used to determine the in vitro drug release. The semi-automated micro-dilution technique was adapted in assessing the in vitro antiplasmodial activity to give drug concentration capable of inhibiting 50% of the P. falciparum (IC50), as a function of antiplasmodial efficacy.ResultsPrepared nanoparticles were below 500 nm in size with % drug loading (%DL) between 21 and 25% and encapsulation efficiency (%EE) of 78–90%. The drug-loaded SLN exhibited a biphasic drug release profile at pH 7.4, with an initial burst release during the first 24 h followed by sustained release in both formulations. Nanoformulated CQ-SLN (4.72 ± 0.14 ng/mL) and CQ-Hep-SLN (2.41 ± 0.27 ng/mL), showed enhanced in vitro antiplasmodial activities against chloroquine sensitive (D6) strain of P. falciparum, albeit with no activity against the chloroquine resistant W2 strain, compared to free CQ standard (5.81 ± 0.18 ng/mL).ConclusionsThese findings suggest that the nanoformulated drugs displayed enhanced anti-malarial activities against chloroquine sensitive (D6) strains of P. falciparum compared to the free CQ standard. There is some form of potential dual synergistic effect of CQ-loaded heparinized solid lipid nanoparticles (Hep-SLN), meaning that combining heparin and CQ in SLNs has beneficial effects, including potential for specific targeting of parasitized red blood cells as afforded by heparin. Thus, the study has produced SLNs nanoparticles that have superior in vitro activities than CQ on CQ-sensitive parasites.

Morphological and skeletal abnormalities induced by α/β arteether on developing chick embryo

Introduction: Malaria continues to be one of the India's leading public health problem.α/β artether is one of the most common antimalarial drug used worldwide to treat chloroquine resistant malaria and malaria falciparum. The present study was designed to assess the teratogenic effects of α/β artether on developing chick embryo. Material and Methods: The study was performed on 300 fertilized eggs of white leg horn chicken.The eggs were divided in to five experimental groups A, B, C, D, E having 30 eggs each and five control groups a,b,c,d,e one each for every experimental group respectively having 30 eggs each. On 5th day of incubation eggs from experimental groups A, B, C, D and E were exposed to α/β artether with dose of 0.00039 mg, 0.000585 mg, 0.00078 mg, 0.00097 mg and 0.00117 mg whereas the control groups were treated with same amount of normal saline. Results: The results showed growth retardation and some significant morphological abnormalities like scanty feathers, subcutaneous hemorrhage and skeletal abnormalities like poor ossification of the bones, kyphosis and lordosis. Discussion: The drug is toxic specially when used in higher dose and for a long period. At present there is no alternative drug available for the treatment of chloroquine resistant malaria and malaria falciparum except α/β artether. Therefore α/β artether and other artemisinins should be used only after establishment of proper diagnosis in recommended dose only not in higher dose and not for a long duration.