Targeting SARS-CoV-2 nonstructural protein 15 endoribonuclease: an in silico perspective.

The newly emerged human coronavirus, SARS-CoV-2, had begun to spread last year and sparked worldwide. In this study, molecular docking is utilized to test some previously approved drugs against the SARS-CoV-2 nonstructural protein 15 (Nsp15). We screened 23 drugs, from which three (saquinavir, valrubicin and aprepitant) show a paramount predicted binding affinity (-9.1, -9.6 and -9.2 kcal/mol, respectively) against SARS-CoV-2 Nsp15. Moreover, saquinavir and aprepitant make nonbonded interactions with Leu201 in the active site cavity of Nsp15, while the drug valrubicin interacts with Arg199 and Leu201. This binding pattern may be effective against the targeted protein, leading to Nsp15 blockage and virus abolition. Additionally, the pharmacological properties of the screened drugs are known since they have been approved against different viruses.

A comparative study of biological potentiality and EAC cell growth inhibition activity of Phyllanthus acidus (L.) fruit pulp and seed in Bangladesh.

Medicinal plant-derived bioactive compounds have recently gained more interest in biological research as an important source of novel drug candidates. Phyllanthus acidus (L.) is a widely distributed herbal medicinal plant naturally used in Ayurvedic medicine in Bangladesh. The present study focused on exploring the biological potential as well as the inhibitory effect of EAC cell growth with a comparative analysis between Phyllanthus acidus fruit pulp and seed. Crude methanol extract of P. acidus (MEPA) fruit pulp and seed was assessed as DPPH and NO free radical scavengers. While Brine Shrimp lethality bioassay, the standard protocol of phytochemical screening and hemagglutination assay were performed successively to determine the toxic effect on normal cells, the identification of some crucial phytochemicals, and the existence of lectin protein. EAC (Ehrlich's Ascites Carcinoma) cell growth inhibition was determined by hemocytometer and morphological changes of EAC cells were observed by a fluorescence microscope using Swiss albino mice. The IC50 value of MEPA fruit pulp and seed was obtained as 57.159 µg/ml and 288.743 µg/ml respectively where minimal toxic effects on Brine Shrimp nauplii demonstrates that it is a good source of natural antioxidant compounds. Again, MEPA fruit pulp and seed-mediated effective agglutination of mouse blood erythrocyte strongly support the presence of lectin protein. Furthermore, MEPA fruit pulp and seed extract-treated EAC cells showed 65.71% and 28.57% growth inhibition respectively. The fluorescent microscopic examination of EAC cells treated with MEPA fruit pulp has shown more remarkable structural changes in the nucleus than that of seed. Based on the above findings, the present study reveals that MEPA fruit pulp can be considered as a novel biological candidate for the treatment of fatal diseases shortly.

Computational discovery of plant-based inhibitors against human carbonic anhydrase IX and molecular dynamics simulation.

Carbonic anhydrase IX (hCAIX) is a membrane-spanning metalloenzyme, encoded by CA9 gene, which can lead to various carcinomas if upregulated. Due to its overexpression in many cancer tissues, hCAIX has become a promising target for developing anticancer therapeutics. Furthermore, several classes of small-molecules have shown to inhibit the hCAIX expression. In this study, therefore, we screened (n = 42) plant-derived compounds to identify the most potent hCAIX inhibitors and to understand their interactions with hCAIX and drug candidacy through in silico approaches. Among all, only three compounds (i.e. fraxoside, scopolin, and xanthone,) provided higher binding affinity toward hCAIX protein as compared to the native ligand. In standard docking, scopolin showed -4.97 kcal/mol of binding energy with hCAIX while control ligand provided -4.45 kcal/mol. In precise docking, the highest binding affinity was found for fraxoside (-7.67 kcal/mol) as compared to -3.04 kcal/mol of the control. The Gibbs free energy (ΔG) of these potent leads was also consistent and in support of the docking studies. The binding interactions were also found to be stable in dynamics simulation. Furthermore, analysis of protein-protein interactions and co-expression revealed the possible association of CA9 gene with other tumorous genes, especially angiogenesis factor HIF1A which will most likely be affected by the identified inhibitors. With further experimental validation, therefore, these potential inhibitors could be effective against hCAIX protein, thereby, paving the way for prospective anticancer therapeutics.Communicated by Ramaswamy H. Sarma.

Methanolic Bark Extract of Abroma augusta (L.) Induces Apoptosis in EAC Cells through Altered Expression of Apoptosis Regulatory Genes.

Abroma augusta (L.), one of the herbal medicinal plants, is widely used for treatment of various maladies. The present study was initiated to determine the antioxidant, hemolytic, cytotoxicity, and anticancer activities of methanolic extract from the bark of the plant. The phytochemical screening was done by analyzing different phytochemicals present in the extract. We observed the presence of alkaloids, steroids, terpenoids, flavonoids, reducing sugars, and glycosides in the bark extract which showed the highest antioxidant capacity. Antioxidant potential of the methanolic extract was evaluated in vitro by DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging assay method. This extract showed prominent scavenging activity with IC50 value of 38.65 µg/ml. The hemolytic activity of the extract was evaluated at concentrations ranging from 250 to 1000 µg/ml. It was observed that the extract induced hemolysis percentage of 9.41% to 4.1%, which implies that the extract has no potent hemolytic activity. Cytotoxicity and anticancer activities were observed on Ehrlich ascites carcinoma (EAC) cells. In addition, the bark showed promising cytotoxicity with IC50 value of 329.41 µg/ml, and the study indicated that the extract was capable of inhibiting EAC cell growth by 75.5% when administered at 100 mg/kg/day body weight intraperitoneally for five consecutive days to Swiss albino mice. Morphological change of apoptotic cell was determined by fluorescence and optical microscopy. DNA fragmentation is another marker for apoptosis, and the bark extract-treated EAC cells showed smeared and fragmented DNA bands. Apoptosis correlated well with the upregulation of p53 and Bax and also with the downregulation of NF-κB and Bcl-2. Furthermore, activity and interaction of two A. augusta compounds were tested through molecular docking simulation study. In conclusion, our results suggest that A. augusta bark has the potential to be considered as an anticancer agent.