Abstract

Nanodelivery of bioactive compounds carried on nanoparticles has become a wide spread application in agro, food and biomedical research in the recent past. The aim of the study is to mount bioactive compounds onto Zinc oxide nanoparticles (ZnNP) and assess its properties. The ZnNPs were synthesized in bottom-up approach using Costus igneusbioactive compounds (CIBC). ZnNPs were characterized for nanoproperties that are surface plasmon resonance (SPR), particle size distribution and zetapotential. Bioactive properties of CIBC loaded ZnNP was evaluated using FT-IR, antimicrobial assay and antioxidant assay. Antifungal activity of the CIBC loaded ZnNPs were assessed for fungal species Aspergillus niger, Sclerotium sp, Rhizophus rolfzi, Aspergillus flavusagainst positive controls of 30μg 5mm discs of itraconazole (IZ) and ketoconazole (KZ). Antibacterial activity of CIBC loaded ZnNPs was assessed against bacteria species Bacillus subtilis, Streptomyces sp, Pseudomonas fluorescence and Staphylococcus aureususing disc diffusion methodand the results were compared with positive controls of 30μg 5mm discs of tetracycline (TCN), ampicillin (ACN), penicillin (PCN) and CMZ. SPR of the formed ZnNPs were recorded at 260nm using UV-Visible spectrophotometer. The average ZnNP particle size was 42.3nm at 90° scattering angle with monodisperse mode. Three different concentration of the ZnNP colloids were used (170ppm, 100pp and 80ppm). High zetapotential of -16.3mv at 25°C and a conductivity of 0.463ms/cm indicated the high stability of the nanoparticles. The presence of functional groups poly alcohols, carboxylic acids and benzene rings attached to the ZnNPs were identified using FT-IR analysis. CIBC loaded ZnNPs exhibited significant (p<0.05, Tukey’s HSD test) antifungal activity at 170ppm against Aspergillus nigerand Aspergillus flavus significant (p<0.05, Tukey’s HSD test) antibacterial activity at 170ppm against Streptomyces sp, Pseudomonas fluorescenceand Staphylococcus aureus. CIBC loaded ZnNPs showed 0.23μmol/ml trolox equivalents DPPH radical scavenging activity at 170ppm. Thus the results showed the significant potentials of CIBC loaded ZnNPs in biological applications as antimicrobial agents and bioactive compound carriers.

Keywords:Nanoparticles; Zinc; Costus igneus; Antimicrobial activity; Anti-oxidant assay