Linz-Buoy George

Ameliorative effect of curcumin on hepatotoxicity induced by chloroquine phosphate.

India is one of the most endemic areas, where malaria predominates and its control has become a formidable task. Chloroquine phosphate (CQ) on account of its rapid action on blood schizontocide of all the malarial parasite strains has become the most widely prescribed drug for prophylaxis and treatment of malaria. Toxicity of CQ is most commonly encountered at therapeutic and higher doses of treatment. Thus, the present study was undertaken to evaluate the protective effect of Curcumin, a herbal antioxidant obtained from Curcuma longa, on hepatic biochemical and histopathological status of CQ induced male mice. Swiss albino male mice were administered oral doses of CQ (100mg/kg body wt., 200mg/kg body wt. and 300mg/kg body wt.) and CQ+curcumin (300mg/kg body wt.+80mg/kg body wt.) for 45 days. A withdrawal of high dose treatment for 45 days was also studied. Administration of CQ brought about a significant decrease in Protein content with a decline in SDH, ATPase and ALKase activities, whereas ACPase activity was found to be significantly increased following CQ treatment. Antioxidant enzyme SOD registered a significant reduction as opposed to TBARS which was found to be elevated in a significant manner in the CQ treated groups as compared to control. Gravimetric indices (body weight and organ weight) declined significantly following CQ treatment. Administration of curcumin exhibited significant reversal of CQ induced toxicity in hepatic tissue. Protein content, SDH, ATPase, ALKase, ACPase, SOD, TBARS, body weight and organ weight were found to be comparable to that of control group after curcumin administration. Thus, obtained results led us to conclude the curative potential of curcumin against CQ induced hepatotoxicity.

Prioritization of active antimalarials using structural interaction profile of Plasmodium falciparum enoyl-acyl carrier protein reductase (PfENR)-triclosan derivatives

An empirical relationship between the experimental inhibitory activities of triclosan derivatives and its computationally predicted Plasmodium falciparum enoyl-acyl carrier protein (ACP) reductase (PfENR) dock poses was developed to model activities of known antimalarials. A statistical model was developed using 57 triclosan derivatives with significant measures (r = 0.849, q2 = 0.619, s = 0.481) and applied on structurally related and structurally diverse external datasets. A substructure-based search on ChEMBL malaria dataset (280 compounds) yielded only two molecules with significant docking energy, whereas eight active antimalarials (EC50 < 100 nM, tested on 3D7 strain) with better predicted activities (pIC50 ~ 7) from Open Access Malaria Box (400 compounds) were prioritized. Further, calculations on the structurally diverse rhodanine molecules (known PfENR inhibitors) distinguished actives (experimental IC50 = 0.035 μM; predicted pIC50 = 6.568) and inactives (experimental IC50 = 50 μM; predicted pIC50 = -4.078), which showed that antimalarials possessing dock poses similar to experimental interaction profiles can be used as leads to test experimentally on enzyme assays.

Structural Insights into the Theoretical Model of Plasmodium falciparum NADH Dehydrogenase and its Interaction with Artemisinin and Derivatives: Towards Global Health Therapeutics

It is a continuing quest to uncover the principal molecular targets of malarial parasites to understand the antimalarial activity and mechanism of action of artemisinin, a potent antimalarial. A series of parasite proteins are experimentally validated as potential targets, such as translationally controlled tumor protein (TCTP) and sarco/endoplasmic reticulum membrane calcium ATP-ase (SERCA). The present study addressed the development of a theoretical model of Plasmodium falciparum NADH dehydrogenase with inference from artemisinin in vivo inhibitory activity. We report here the predicted binding modes of artemisinin and its derivatives. The modeled protein resembled the structural architecture of flavoproteins and oxidoreductases, consisting of two Rossmann folds and dedicated binding sites for its cofactors. Docked poses of the ligand dataset revealed its interactions at or near the si face, indicating being activated. This may aid in generation of reactive oxygen species, thereby disrupting the membrane potential of parasite mitochondria and leading to the clearance from the blood. These observations open up new strategies for development of novel therapeutics, or improvement of existing pharmacotherapies against malaria, a major burden for global health.

Role of curcumin on chloroquine phosphate-induced reproductive toxicity.

The present study was conducted to screen the efficacy of curcumin against chloroquine phosphate (CQ)-induced reproductive toxicity in adult male Swiss albino mice. Animals were given oral doses of 100, 200, 300 mg/kg body weight (b.w.), and high dose of CQ (300 mg/kg b.w.) + curcumin (80 mg/kg b.w.) for 45 days. Animals of the withdrawal group were given high dose of CQ (300 mg/kg b.w.) for 45 days and, at day 46, were kept for another 45 days. Effects were observed on some key enzymes, such as alkaline phosphatase, which was found to be decreased, whereas acid phosphatase was increased and succinate dehydrogenase and adenosine triphosphatase were decreased. Oxidative parameters, such as superoxide dismutase declined, whereas thiobarbituric acid-reactive substances were found to be elevated. Protein level was also decreased. Gravimetric indices were also recorded. Results obtained indicated adverse effects of CQ in a dose-dependent manner. The presence of curcumin with CQ alleviated its toxic effects. Hence, it can be concluded that curcumin has beneficial influences and appears able to ameliorate CQ toxicity.

Antiproliferative Efficacy of Kaempferol on Cultured Daudi Cells: An In Silico and In Vitro Study

There is always a constant need to develop alternative or synergistic anticancer drugs with minimal side effects. One important strategy to develop effective anticancer agents is to investigate potent derived compounds from natural sources. The present study was designed to determine antiproliferative activity of Kaempferol using in silico as well as in vitro study. Docking was performed using human GCN5 (hGCN5) protein involved with cell cycle, apoptosis, and glucose metabolism. Cell viability and cytotoxicity on Daudi cells were evaluated by trypan blue and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in a dose and time dependent manner, respectively. The compound inhibited the proliferation and growth of the Daudi cells, through induced cell death. The pure compound proved lead inhibitors of cell proliferation, thus manifesting significant antiproliferative activity. The docking results revealed that Kaempferol exhibited binding interaction to hGCN5 protein. Further, molecular dynamics using the dock pose of hGCN5-Kaempferol complex were performed to understand the basic structural unit which lead to inefficiency in binding and, therefore, pronounced instability and its possible consequences of reduced binding affinity. The data obtained in this study indicates that Kaempferol is a promising compound leading to inhibition of Daudi cell growth and proliferation.

A Computational Approach towards the Understanding of Plasmodium falciparum Multidrug Resistance Protein 1

The emergence of drug resistance in Plasmodium falciparum tremendously affected the chemotherapy worldwide while the intense distribution of chloroquine-resistant strains in most of the endemic areas added more complications in the treatment of malaria. The situation has even worsened by the lack of molecular mechanism to understand the resistance conferred by Plasmodia species. Recent studies have suggested the association of antimalarial resistance with P. falciparum multidrug resistance protein 1 (PfMDR1), an ATP-binding cassette (ABC) transporter and a homologue of human P-glycoprotein 1 (P-gp1). The present study deals about the development of PfMDR1 computational model and the model of substrate transport across PfMDR1 with insights derived from conformations relative to inward- and outward-facing topologies that switch on/off the transportation system. Comparison of ATP docked positions and its structural motif binding properties were found to be similar among other ATPases, and thereby contributes to NBD domains dimerization, a unique structural agreement noticed in Mus musculus Pgp and Escherichia coli MDR transporter homolog (MsbA). The interaction of leading antimalarials and phytochemicals within the active pocket of both wild-type and mutant-type PfMDR1 demonstrated the mode of binding and provided insights of less binding affinity thereby contributing to parasites resistance mechanism.

Molecular interaction of selected phytochemicals under the charged environment of Plasmodium falciparum chloroquine resistance transporter (PfCRT) model

Phytochemicals of Catharanthus roseus Linn. and Tylophora indica have been known for their inhibition of malarial parasite, Plasmodium falciparum in cell culture. Resistance to chloroquine (CQ), a widely used antimalarial drug, is due to the CQ resistance transporter (CRT) system. The present study deals with computational modeling of Plasmodium falciparum chloroquine resistance transporter (PfCRT) protein and development of charged environment to mimic a condition of resistance. The model of PfCRT was developed using Protein homology/analogy engine (PHYRE ver 0.2) and was validated based on the results obtained using PSI-PRED. Subsequently, molecular interactions of selected phytochemicals extracted from C. roseus Linn. and T. indica were studied using multiple-iterated genetic algorithm-based docking protocol in order to investigate the translocation of these legends across the PfCRT protein. Further, molecular dynamics studies exhibiting interaction energy estimates of these compounds within the active site of the protein showed that compounds are more selective toward PfCRT. Clusters of conformations with the free energy of binding were estimated which clearly demonstrated the potential channel and by this means the translocation across the PfCRT is anticipated.

Ethnobotanical database based screening and identification of potential plant species with antiplasmodial activity against chloroquine-sensitive (3D7) strain of Plasmodium falciparum

Objective: To evaluate the antiplasmodial activity of aqueous-methanolic plant extracts of nine plant species selected, based on ethnobotanical data. Methods: Based on ethnobotanical database, the selected plants were tested for their antiplasmodial activity against chloroquine-sensitive (3D7) strain of Plasmodium falciparum. Qualitative tests and high performance thin layer chromatography analysis were carried out to explore the phytocomponents present in the plant extracts. 1,1-diphenyl-2-picrylhydrazyl antioxidant activity was also determined to check the antioxidant activity of the plant extracts. Results: Moringa oleifera (IC50: 3.906 μg/mL), Acalypha indica (IC50: 3.906 μg/mL), Hyptis suaveolens (IC50: 3.906 μg/mL), Mangifera indica (IC50: 4.150 μg/mL) and Averrhoa bilimbi (IC50: 4.881 μg/mL) showed very good antiplasmodial activity. Conclusions: Crude extracts of Mangifera indica and Hyptis suaveolens demonstrated the most efficacious antimalarial activity. A bioassay-guided fractionation of these extracts to identify the lead compound is proved to be useful. The results validate the traditional use of the selected plants as antimalarials.

Calotropis procera Extract Halts Plasmodium falciparum Transgression Through Red Blood Cell (RBC) Membrane

Aim: To evaluate the potential of Calotropis procera extracts in erythrocyte membrane stabilization with special emphasis on Plasmodium falciparum entry into RBCs. Place and Duration of Study: Department of Zoology, BMT and Human Genetics, University School of Sciences, Gujarat University, Gujarat, India, between December-2014 to December2015. Methodology: In this study, we evaluated the erythrocyte membrane stabilization properties of Calotropis procera leaf extracts. The aqueous and methanolic leaf extracts of Calotropis procera were screened for its phytochemical, antioxidant, erythrocyte membrane stabilization and subsequent antiplasmodial activity. The in vitro antiplasmodial activity was evaluated on Plasmodium falciparum chloroquine-sensitive (MRC2) and chloroquine-resistant (RKL9) strains. Results: In the present study, phytochemical analysis of aqueous extract has shown only the Original Research Article George et al.; IBRR, 6(2): 1-12, 2016; Article no.IBRR.27960 2 presence of flavonoids, triterpenoids, carbohydrates and phenolic compounds whereas the methanolic extract has shown the presence of all the phyto-components except saponins, oils and fats. Antioxidant activity of the extracts was measured by (DPPH•) radical scavenging assay. The methanolic extract of Calotropis procera showed more potent antioxidant activity when compared to aqueous extract. We observed an increased inhibition of entry of the parasites in relation to the concentration of both the extracts. Though enhanced stabilization effects were observed at higher concentrations of the methanolic extract, there was a steady membrane stabilizing property with the aqueous extract. The experimental evidence obtained in our study revealed that the methanolic extract of the leaves of C. procera, tends to be more effective in preventing the parasite entry into RBCs. Conclusion: Our finding confirms the importance of investigating the antimalarial activity of Calotropis procera which is used in traditional medicine. Overall, the methanolic extract of Calotropis procera appeared to be the best candidate and will be further investigated for their erythrocyte membrane stabilization and antiplasmodial properties of the individual isolated compounds, alone and in combinations.