Endoperoxide antimalarials: development, structural diversity and pharmacodynamic aspects with reference to 1,2,4-trioxane-based structural scaffold

Mithun Rudrapal, Dipak Chetia Department of Pharmaceutical Sciences, Dibrugarh University, Dibrugarh, India Abstract: Malaria disease continues to be a major health problem worldwide due to the emergence of multidrug-resistant strains of Plasmodium falciparum. In recent days, artemisinin (ART)-based drugs and combination therapies remain the drugs of choice for resistant P. falciparum malaria. However, resistance to ART-based drugs has begun to appear in some parts of the world. Endoperoxide compounds (natural/semisynthetic/synthetic) representing a huge number of antimalarial agents possess a wide structural diversity with a desired antimalarial effectiveness against resistant P. falciparum malaria. The 1,2,4-trioxane ring system lacking the lactone ring that constitutes the most important endoperoxide structural scaffold is believed to be the key pharmacophoric moiety and is primarily responsible for the pharmacodynamic potential of endoperoxide-based antimalarials. Due to this reason, research into endoperoxide, particularly 1,2,4-trioxane-, 1,2,4-trioxolane- and 1,2,4,5-teraoxane-based scaffolds, has gained significant interest in recent years for developing antimalarial drugs against resistant malaria. In this paper, a comprehensive effort has been made to review the development of endoperoxide antimalarials from traditional antimalarial leads (natural/semisynthetic) and structural diversity of endoperoxide molecules derived from 1,2,4-trioxane-, 1,2,4-trioxolane- and 1,2,4,5-teraoxane-based structural scaffolds, including their chimeric (hybrid) molecules, which are newer and potent antimalarial agents. Keywords: endoperoxide, structural diversity, 1,2,4-trioxane, pharmacophore, pharmacodynamic, antimalaria

Ethnomedicinal plants used by traditional healers in East Godavari district of Andhra Pradesh, India

426-431An ethnomedicinal survey was carried out in 10 different villages of East Godavari district of Andhra Pradesh with an aim to document the information regarding folkloric uses of indigenous plant species. A total of 32 plant species belonging to 32 genera and 25 families were recorded, and enumerated along with their botanical name, family, local name, part(s) used, ethnomedicinal uses including their method of preparation, mode of administration and dosage. The reported plant species in the form of various traditional preparations are employed by the village people for the management as well as treatment of various ailments ranging from snake bite to fever

Design, molecular docking, drug-likeness, and molecular dynamics studies of 1,2,4-trioxane derivatives as novel Plasmodium falciparum falcipain-2 (FP-2) inhibitors

Despite significant progress made in drug discovery and development over the past few decades, malaria remains a life-threatening infectious disease across the globe. Because of the widespread emergence of drug-resistant strains of Plasmodium falciparum, the clinical utility of existing drug therapies including Artemisinin-based Combination Therapies (ACTs) in the treatment of malaria has been increasingly limited. It has become a serious health concern which, therefore, necessitates the development of novel drug molecules and/or alternative therapies to combat, particularly resistant P. falciparum. The objective of the present study was to develop 1,2,4-trioxane derivatives as novel antimalarial agents that would be effective against resistant P. falciparum. In our study, 15 new trioxane derivatives were designed by molecular modification of the 1,2,4-trioxane scaffold as possible antimalarial agents. Molecular modeling studies of trioxane derivatives were performed based on the CADD approach using Biovia Discovery Studio (DS) 2018 software. The protein-ligand docking study was performed against P. falciparum falcipain 2 (FP-2) using the simulation-based docking protocol LibDock by the flexible docking method. The assessment of drug-likeness, ADMET properties, and toxicity was also performed. Furthermore, the compounds CC3 and CC7, which showed the best binding affinity against the target P. falciparum FP-2, were investigated by molecular dynamics (MD) simulation studies followed by the calculation of MM-PBSA binding free energy of protein-ligand complexes using DS 2020. Results of the docking study showed that among the 15 compounds, three trioxane derivatives were found to possess promising binding affinity with LibDock scores ranging from 117.16 to 116.90. Drug-likeness, ADMET, and toxicity properties were found to be satisfactory for all the compounds. Among the 15 compounds, two compounds, namely CC3 and CC7, showed the highest binding affinity against FP-2 with LibDock score of 117.166 and 117.200, respectively. The Libdock score of the co-crystal inhibitor was 114.474. MD studies along with MM-PBSA calculations of binding energies further confirmed the antimalarial potential of the compounds CC3 and CC7, with the formation of well-defined and stable receptor-ligand interactions against the P. falciparum FP-2 enzyme. Additionally, the selectivity of trioxane hits identified as potential inhibitors of P. falciparum cysteine protease FP-2 was determined on human cysteine proteases such as cathepsins (Cat K and Cat L), which are host homologous. Finally, it was concluded that the newly designed 1,2,4-trioxane derivatives can be further studied for in vitro and in vivo antimalarial activities for their possible development as potent antimalarial agents effective against resistant P. falciparu

Formulation and Evaluation of Paracetamol Tablets using Coconut Oil as a Binder

Tablets are the medicament with suitable excipients. It comprises a mixture of active substances and excipients, usually pressed or compacted from a powder into a solid dose. The aim of this study was to formulate paracetamol tablets using Coconut oil as a binder in different concentrations (1%, 2%, 3%) and evaluate them with basic parameters. The granules manufactured using the binder had good flow property and compressibility. There are various examples of binders that can be used for tablet formulation. Here the efforts were made to formulate the paracetamol tablets by using coconut oil to check whether the tablet can be formulated and the other evaluation parameters for tablets, thereafter. Using coconut oil as a binder in the end gave satisfactory result as we could formulate a tablet with effective concentration of coconut oil with 1%.Theformulated tablets thereafter were evaluated for the characterization for granules to check such as flow property, bulk density, tap density etc.as well as the tablets were also evaluated for disintegration and dissolution as well.  Keywords: Paracetamol, Binder, Dry granulation, Excipients, Direct compression, Disintegration, Dissolutio

Dual synergistic inhibition of COX and LOX by potential chemicals from Indian daily spices investigated through detailed computational studies

Abstract Cyclooxygenase (COX) and Lipoxygenase (LOX) are essential enzymes for arachidonic acid (AA) to eicosanoids conversion. These AA-derived eicosanoids are essential for initiating immunological responses, causing inflammation, and resolving inflammation. Dual COX/5-LOX inhibitors are believed to be promising novel anti-inflammatory agents. They inhibit the synthesis of prostaglandins (PGs) and leukotrienes (LTs), but have no effect on lipoxin formation. This mechanism of combined inhibition circumvents certain limitations for selective COX-2 inhibitors and spares the gastrointestinal mucosa. Natural products, i.e. spice chemicals and herbs, offer an excellent opportunity for drug discovery. They have proven anti-inflammatory properties. However, the potential of a molecule to be a lead/ drug candidate can be much more enhanced if it has the property of inhibition in a dual mechanism. Synergistic activity is always a better option than the molecule's normal biological activity. Herein, we have explored the dual COX/5-LOX inhibition property of the three major potent phytoconsituents (curcumin, capsaicin, and gingerol) from Indian spices using in silico tools and biophysical techniques in a quest to identify their probable inhibitory role as anti-inflammatory agents. Results revealed the dual COX/5-LOX inhibitory potential of curcumin. Gingerol and capsaicin also revealed favorable results as dual COX/5-LOX inhibitors. Our results are substantiated by target similarity studies, molecular docking, molecular dynamics, energy calculations, DFT, and QSAR studies. In experimental inhibitory (in vitro) studies, curcumin exhibited the best dual inhibitory activities against COX-1/2 and 5-LOX enzymes. Capsaicin and gingerol also showed inhibitory potential against both COX and LOX enzymes. In view of the anti-inflammatory potential these spice chemicals, this research could pave the way for more scientific exploration in this area for drug discovery