No abstract

Dengue is a Flavivirus infection transmitted through mosquitoes of the Aedes genus, which is known to occur in over 100 countries of the world. Dengue has no available drugs for treatment; CYD-TDV is the only vaccine thus far approved for use by a few countries in the world. In the absence of drugs and a widely approved vaccine, attention has been focused on plant-derived compounds to the discovery of a potential therapeutic for DENV. The present study aimed to determine, in silico, the binding energies of the steroidal saponins, melongosides, to NS2B-NS3 activator protease of DENV-2, which plays an essential role in the viral replication. The blind molecular docking studies carried out gave binding energies (ΔG = −kcal/mol) of melongosides B, F, G, H, N, O, and P as 7.7, 8.2, 7.6, 7.8, 8.3, 8.0, and 8.0, respectively. All the melongosides interacted with the NS3 protease part of NS2B-NS3. Melongosides B, F, and N showed interactions with His51, while melongoside G interacted with Asp75 of NS3, to be noted, these are important amino acid residues in the catalytic site of the NS3 protease. However, the 200 ns molecular dynamic simulation experiment indicates significant stability of the protein-ligand interactions with the RMSD values of 2.5 Å, thus suggesting a better docking position and no disruption of the protein-ligand structure. Taken together, melongosides need further attention for more scientific studies as a DENV inhibitory agent, which if proven, in vivo and in clinical trials, can be a useful therapeutic agent against at least DENV-2.

The objective of the present study includes the evaluation of the antidiarrheal properties of the methanol extracts of Litsea deccanensis Gamble (MELD) bark, Litsealancifolia (Roxb.) Hook. f. MELL),Litseaglutinosa Gamble (MELG) and Litsea monopetala Roxb. (MELM) leavesin Swiss albino mice. The antidiarrheal activity was evaluated by measuring percentage inhibition of diarrheal feces, total fecal output, gastrointestinal motility and by using peristaltic indices. Castor oil was used to induce diarrhea in the experimental animal. The experiments were carried out by using three different doses (100, 200, and 400 mg/kg body weight) of these four plant extracts. The number of wet feces and total weight of the feces were significantly (p < 0.05) and dose-dependently reduced by all the plant extracts and this effect was comparable with standard drug. MELD, MELL, MELG and MELM extracts at dose of 400 mg/kg body weight demonstrated diarrheal inhibition by 43.55%, 45.16%, 32.26% and 41.94%, respectively while it was 98.39% for the standard loperamide. Percentage (%) of fecal output for MELD, MELL, MELG and MELM extracts at the dose of 400 mg/kg were 40.14%, 62.27%, 64.06%, 46.26%, respectively.The gastrointestinal motility induced by castor oil was also reduced noticeably (p < 0.05) by all the plant extracts with the increasing doses. The percentage inhibition of gastrointestinal motility at the dose of 400 mg/kg were 26.26%, 33.22%, 32.36% and 22.52% for the MELD, MELL, MELG and MELM extracts respectively, while it was 27.56% for loperamide. In most cases, all the plant extracts can reduce the peristaltic indices which were comparable to control. The obtained results from this study revealed that the methanol extracts of four different species of Litsea found in Bangladesh may have antidiarrheal potential. It also provides the basis for the traditional use of these plants to treat diarrhea.

A preliminary in vitro acid neutralizing capacity test of twelve traditional Ayurvedic antacids were performed in this study. Five traditional preparations of ash of conch shell, ash of oyster, ash of pearl, limestone, and ash of cowrie showed high acid neutralizing capacity similar to standard antacid combination of Al(OH) 3 and Mg(OH) 2. Among these the ash of conch shell found the highest acid neutralizing capacity. The ash of tamarind and ash of Achyranthus aspera showed moderate acid neutralizing capacity. The acid neutralizing capacity of red ochre; ash of iron; mixture of niter, alum and ammonium chloride; saltpeter; and ash of mica found below the USP 23 limit.

The recent coronavirus (known as COVID-19 or SARS-CoV-2) has created a pandemic of unheard proportions affecting virtually every country and region of the world. As of April 15, 2020 the virus has resulted in over 2 million infections, and over 100,000 deaths and has brought world economic activities to a standstill, and has led to social isolation and massive unemployment with possible economic recessions on an unprecedented scale around the corner. Till now, the virus shows no signs of abatement. Also till now, scientists have not been able to come out with an effective drug or vaccine against the virus. This review attempts to give a comprehensive view of the origin of the virus, the mode of its entry and infecting human beings, and further discusses the possibility of new drugs and vaccines against the virus.