ABSTRACT
Theoretical studies on the adsorption, sensibility, and reactivity of a boron nitride nanocage decorated with Au, Cu, Ni, Os, Pt, and Zn metals as a biosensor material were carried out for the adsorption of carboplatin by applying the density functional theory computation at the B3LYP-GD3BJ/def2svp level of theory. All the optimized structures, as well as the calculations as regards the studied objective including electronic properties, geometry optimization parameters, adsorption energy studies, natural bond orbital analysis, topology studies, sensor mechanistic parameters, and thermodynamic properties (ΔG and ΔH), were investigated herein. As a result, the noticeable change in the energy gap of the studied surfaces when interacting with carboplatin accounted for the surfaces' reactivity, stability, conductivity, work function, and overall adsorption ability, implying that the studied decorated surfaces are good sensor materials for sensing carboplatin. Furthermore, the negative adsorption energies obtained for interacting surfaces decorated with Cu, Ni, Os, and Zn suggest that the surface has a superior ability to sense carboplatin as chemisorption was seen. Substantially, the geometric short adsorption bond length after adsorption, thermodynamically spontaneous reactions, and acceptable sensor mechanism results demonstrate that the investigated surfaces have strong sensing characteristics for sensing carboplatin.
ABSTRACT
Orthosiphon stamineus is considered an important traditional folk medicine. In this study ethanol and aqueous extracts of O. stamineus were evaluated in vitro for their antioxidant, antimicrobial as well as for their immunomodulatory properties on human peripheral blood mononuclear cells (PBMCs). The DPPH radical scavenging method was used for the determination of antioxidant activity, while the antibacterial efficacy was investigated by both disc diffusion method and Minimum Inhibitory Concentration (MIC) against four bacterial strains (Gram-positive and Gram-negative). Furthermore, the immunomodulatory potential of the extracts was investigated through the MTT assay. Aqueous extract of O. stamineus exhibited significant free radical scavenging activity with IC50 50 9.6 µg/mL, whereas the IC50 for the ethanol extract was 21.4 µg/mL. The best antimicrobial activity was shown by the aqueous extract of O. stamineus against Staphylococcus aureus, with inhibition zone of 10.5 mm and MIC value 1.56 mg/mL. Moreover, the results observed from the MTT assay showed that both plant extracts stimulated the PBMCs proliferation in vitro in a concentration-dependent manner, but the aqueous extract has remarkable activity against PBMCs. These findings indicate that O. stamineus showed high antioxidant activity and may be considered as an immunomodulatory agent.
