Browsing by Author "A J F N, Sobral"

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ANTIOXIDANT (IN VITRO), ANTIDIABETIC (IN VITRO) AND PHOTOCATALYTIC ACTIVITY OF COSTUS SPECIOSUS LEAF EXTRACT ASSISTED CS-AG-TIO2 COMPOSITES
(Springer, 2019-10-24) C, Surya; N A A, John; V, Pandiyan; P, Amutha; A J F N, Sobral; B, Krishnakumar
The researchers have currently targeted bio-synthesis nanoparticles (NPs) and their potential applications toward bio and photocatalytic field. The in vitro antidiabetic activity of noble metal modified TiO2 is really scare in literature. In the present work, green synthesis of CS-Ag nanoparticles was achieved through Costus speciosus (Crape ginger, an Indian ornamental plant, has long been medicinally used in traditional systems of medicine) leaf extract, and followed by solvothermal synthesis of CS-Ag-TiO2 composites. The prepared nanocomposites effectively utilized for in vitro antioxidant, in vitro antidiabetic study and azo dye AB 1 degradation under visible light.
BICL3-MODIFIED PERLITE AS AN EFFECTIVE CATALYST FOR SELECTIVE ORGANIC TRANSFORMATIONS: A GREEN PROTOCOL
(Springer, 2019-05-05) K, Brindha; P, Amutha; B, Krishnakumar; A J F N, Sobral
A new perlite supported Bismuth Chloride (BiCl3) was used as an efcient heterogeneous catalyst for the synthesis of heterocyclic compounds viz., quinoxalines and dihydropyrimidinones. Fourier-transform infrared spectroscopy (FT–IR), scanning electron microscopy, energy dispersive spectra, X-ray difractometry, thermogravimetric analysis and Brunauer–Emmett–Teller surface area analytical techniques were employed to characterize the prepared catalyst. Initially, the catalytic activity of the prepared BiCl3-Perlite was tested towards synthesis of simple quinoxaline derivatives at room temperature. The efect of solvent in the preparation of quinoxaline was also examined. The formed products were confrmed by their physical (melting point) and spectral data (FT–IR, 1 H and 13C-NMR). In order to implement the activity of the BiCl3-Perlite catalyst, a multicomponent reaction was adopted for synthesis of dihydropyrimidinones under solvent free conditions in a micro oven. The use of recyclable heterogeneous solid acid catalyst makes the reaction simple with minimum chemical waste, shorter reaction time, easy workup and products in good yield.
COSTUS SPECIOSUS LEAF EXTRACT ASSISTED CS-PT-TIO2 COMPOSITES: SYNTHESIS, CHARACTERIZATION AND THEIR BIO AND PHOTOCATALYTIC APPLICATIONS
(Elsevier, 2019-11-05) C, Surya; N A A, John; V, Pandiyan; S, Ravikumar; P, Amutha; A J F N, Sobral
The antioxidative and antidiabetic properties of Costus speciosus leaf extract assisted nanoparticles (CS–Pt modified TiO2) were compared with pristine TiO2 NPs along with standard ascorbic acid (AA). CS-Pt nanoparticles were synthesized through bioreduction process and supported on titanium dioxide semiconductor. Costus speciosus (CS) leaf extract was used as reducing and capping agent. Initially, CS-Pt nanoparticles synthesis was carried out with ethanolic extract of CS, later, two different wt% of CS-Pt supported TiO2 were prepared through sol-gel cum solvothermal process. The prepared materials have been characterized using different characterization techniques such as XRD, FT-IR, Raman, SEM, HR-TEM, EDS, DRS, PL and XPS measurements. CS-Pt-TiO2 nanocomposites showed well dispersion of Pt nanoparticles on TiO2 surface. The prepared materials have been effectively utilized for in-vitro antioxidant and in vitro antidiabetic activity. Moreover, the photocatlytic activity of the materials has been tested toward NBB degradation under visible light. CS-Pt NPs modified TiO2 composites show better activity when compared with pristine TiO2 in all cases.