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The current pandemic Covid-19 brought about by a newly emerged and highly infectious virus named as Sars-CoV-2 as a worldwide danger, has infected more than 600 million people and number of deaths are continuously rising day by day. Till date there are no medications accessible for treatment. All over the world scientists and researchers are involved in the study of this emerged virus and its lifecycle. Structures of proteins in the life cycle of virus has been revealed in RCSB PDB (Research Collaboratory for Structural Bioinformatics Protein Data Bank) by researchers. Citrus fruits are used to treat many distresses of humans. Literature survey shows that it has various activities. Our research work is meant to identify the phytoconstituents which are having phenolic composition and good antiviral and antioxidant properties from citrus fruits against Covid-19 proteins (spike binding domain with ACE2 receptor and spike binding domain with Main protease) and to know its in-silico molecular basis. In this study, about 25 compounds from citrus fruits which is having a good antiviral and antioxidant properties and also phenolic composition were employed for molecular docking analysis, molecular dynamic simulation studies and ADME studies. Based on present study 2 compounds from Citrus fruits acted well against the Covid-19 proteins. The MD simulations were employed to identify Hesperidin and Procyanidin B2 as hit compounds. Further ADME analysis were studied for top 2 compounds, these compounds can be further taken for in-vitro studies to know the effective activity against Covid-19. HIGHLIGHTS Citrus fruit phytochemicals are fascinating core, which shows an excellent anti-viral, anti-inflammatory and antioxidant properties The SARS-CoV-2 is newly emerged and highly infectious virus, has infected more than 600 million people and number of deaths are continuously rising day by day Molecular docking analysis, Molecular dynamics simulation ADME studies was carried out Compound Hesperidin and Procyanidin B2 showed a good inhibitory activity against SARS-CoV-2 proteins GRAPHICAL ABSTRACT

In the current scenario, nanoparticle synthesis has been fascinated by biogenic approaches than the chemical methods. However, reproducibility of the source stands essentially in nanoparticle synthesis. Nanoparticle synthesis by fungi has more advantages such as the potential for bioaccumulation, immunity towards toxicity, relatively easier to handle, simpler in synthesis and downstream processing. In this study, biogenic copper nanoparticles (CuNPs) were embedded within graphene oxide-chitosan (GO-CS) polymer to endure the biocompatibility and toxicological effects on both normal and cancer cells. The characteristics of the copper nanoparticles/graphene oxide-chitosan (CuNPs/GO-CS) nanocomposites was found to be superior to the GO-CS. This is evident from the results obtained from X-ray diffraction technique, UV-visible spectroscopy, atomic force microscope, fourier transform infrared spectroscopy, fluorescence spectroscopy, confocal laser scanning microscope and scanning electron microscopy. The synthesized new copper nanoparticles/graphene oxide-chitosan (CuNPs/GO-CS) nanocomposites were studied for their anti-bacterial activity against Escherichia coli MTCC 443 and anti-cancer activity on breast cancer MCF7 cell lines.

Prolonged cancer cell survival, acquiring drug resistance, and secondary cancer development despite chemotherapy are the major challenges during cancer treatment, whose underlying mechanism still remains elusive. In this study, low-doses of chemotherapeutic drugs (LDCD) - doxorubicin (DOX), etoposide (ETOP), and busulfan (BUS) were used to ascertain the effect of residual concentrations of drugs on breast cancer cells. Our results showed that exposure to LDCD caused significant induction of ROS, early signs of apoptosis and accumulation of cells in S and G2-M phases of the cell cycle in MCF-7 and MDA-MB-231 cell lines. Under drug-free recovery conditions, a decrease in the number of apoptotic cells and an increase in the number of colonies formed were observed. Analysis of the molecular mechanism showed lower expression of cleaved products of caspase 3, 9, PARP and occurrence of DNA strand breaks in recovered cells compared to LDCD-treated cells, suggesting incomplete cell death activation and survival of cells with genomic damage after therapeutic insult. Thus, LDCD induces defective apoptosis in cancer cells allowing a small population of cells to escape from cell cycle check points and survive with accumulated genetic damage that could eventually result in secondary cancers that warrants further studies for better therapeutic strategies.

The polymer-cobalt(III) complexes, [Co(bpy)(dien)BPEI]Cl3 · 4H2O (bpy = 2,2'-bipyridine, dien = diethylentriamine, BPEI = branched polyethyleneimine) were synthesized and characterized. The interaction of these complexes with human serum albumin (HSA) and bovine serum albumin (BSA) was investigated under physiological conditions using various physico-chemical techniques. The results reveal that the fluorescence quenching of serum albumins by polymer-cobalt(III) complexes took place through static quenching. The binding of these complexes changed the molecular conformation of the protein considerably. The polymer-cobalt(III) complex with x = 0.365 shows antimicrobial activity against several human pathogens. This complex also induces cytotoxicity against MCF-7 through apoptotic induction. However, further studies are needed to decipher the molecular mode of action of polymer-cobalt(III) complex and for its possible utilization in anticancer therapy.

The interaction of surfactant-cobalt(III) complexes [Co(bpy)(dien)TA](ClO4)3 · 3H2O (1) and [Co(dien)(phen)TA](ClO4)3 · 4H2O (2), where bpy = 2,2'-bipyridine, dien = diethylenetriamine, phen = 1,10-phenanthroline and TA = tetradecylamine with human serum albumin (HSA) under physiological conditions was analyzed using steady state, synchronous, 3D fluorescence, UV/visabsorption and circular dichroism spectroscopic techniques. The results show that these complexes cause the fluorescence quenching of HSA through a static mechanism. The binding constant (Kb ) and number of binding-sites (n) were obtained at different temperatures. The corresponding thermodynamic parameters (∆G°, ∆H° and ∆S°) and Ea were also obtained. According to Forster's non-radiation energy transfer theory, the binding distance (r) between the complexes and HSA were calculated. The results of synchronous and 3D fluorescence spectroscopy indicate that the binding process has changed considerably the polarity around the fluorophores, along with changes in the conformation of the protein. The antimicrobial and anticancer activities of the complexes were tested and the results show that the complexes have good activities against pathogenic microorganisms and cancer cells.