ANTIMICROBIAL, INSECTICIDAL, AND ANTIRADICAL ACTIVITY OF SOLANUM VIRGINIANUM L. (SOLANACEAE)

  Objectives: The present study was conducted to determine antimicrobial, antiradical, and insecticidal activity of methanolic extract of the whole plant of Solanum virginianum L. (Solanaceae).Methods: Extraction of shade dried and powdered plant material was carried out by maceration process. Antibacterial and antifungal activities of extract were determined by agar well diffusion and poisoned food technique, respectively. Antiradical activity of extract was assessed by 1,1-diphenyl- 2-picrylhydrazyl (DPPH) and 2,2-azinobis 3-ethylbenzothiazoline 6-sulfonate (ABTS) free radical scavenging assays. Insecticidal activity, in terms of larvicidal activity, was evaluated against 2nd and 3rd instar larvae of Aedes aegypti.Results: The extract exhibited inhibitory activity against all bacteria. Gram-positive bacteria showed greater susceptibility to extract when compared to Gram-negative bacteria. The extract was effective in inhibiting the mycelial growth of all test fungi with marked activity against Curvularia sp. and Alternaria sp. The extract scavenged DPPH and ABTS radicals dose dependently with an inhibitory concentration value of 45.66 and 7.37μg/ml, respectively. The extract showed concentration-dependent larvicidal activity with high lethal activity observed against 2nd instar larvae with lethal concentration value of 0.82 mg/ml.Conclusion: In suitable form, the plant can be used as an effective agent against microbial infections and oxidative damage and to control insect vectors which transmit several diseases

Two Glycosylation Sites in H5N1 Influenza Virus Hemagglutinin That Affect Binding Preference by Computer-Based Analysis

Increasing numbers of H5N1 influenza viruses (IVs) are responsible for human deaths, especially in North Africa and Southeast Asian. The binding of hemagglutinin (HA) on the viral surface to host sialic acid (SA) receptors is a requisite step in the infection process. Phylogenetic analysis reveals that H5N1 viruses can be divided into 10 clades based on their HA sequences, with most human IVs centered from clade 1 and clade 2.1 to clade 2.3. Protein sequence alignment in various clades indicates the high conservation in the receptor-binding domains (RBDs) is essential for binding with the SA receptor. Two glycosylation sites, 158N and 169N, also participate in receptor recognition. In the present work, we attempted to construct a serial H5N1 HA models including diverse glycosylated HAs to simulate the binding process with various SA receptors in silico. As the SA-α-2,3-Gal and SA-α-2,6-Gal receptor adopted two distinctive topologies, straight and fishhook-like, respectively, the presence of N-glycans at 158N would decrease the affinity of HA for all of the receptors, particularly SA-α-2,6-Gal analogs. The steric clashes of the huge glycans shown at another glycosylation site, 169N, located on an adjacent HA monomer, would be more effective in preventing the binding of SA-α-2,3-Gal analogs

Comparative study of Levofloxacin and its amide derivative as efficient water soluble inhibitors for mild steel corrosion in hydrochloric acid solution

The influence of 8-fluoro-3-methyl-9-(4-methyl-piperazin-1-yl)-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid or levofloxacin (P1) and newly synthesized 8-fluoro-3-methyl-9-(4-methyl-piperazin-1-yl)-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid-(5-methyl-pyridin-2-yl)-amide (P2) on corrosion inhibition of mild steel in 0.5 M hydrochloric acid solution was studied using weight loss and electrochemical techniques. Inhibition efficiency of P1 and P2 increased with concentration and decreased with temperature in the concentration range 0.14--0.35 mM in the temperature range 303--333 K. Thermodynamic parameters for dissolution and adsorption process were studied. Increase in energy of activation after the addition of inhibitors indicated formation of barrier film which prevents charge and mass transfer. Free energy of adsorption showed that the type of adsorption was neither physical nor chemical but comprehensive. The adsorption of the P1 and P2 on the mild steel surface was found to obey the Langmuir isotherm. Impedance measurement showed that there is increase in the polarization resistance and decrease in double layer capacitance after the addition of inhibitors. From polarization study as the shift in corrosion potential is more than 85 mV, both P1 and P2 are anodic type of inhibitors. Scanning electron microscope images confirm the formation of inhibitory film on mild steel surface. Quantum chemical calculation results well correlated with experimental results. Lower values of energy gap, ionization potential and hardness, higher value of softness make P2 better inhibitor compared to P1