Comparative investigation on physicochemical, biological, and cytotoxicity of magnesium oxide prepared by chemically mediated and green synthesis using the bark of Cassia absus Linn

•The first report of the synthesis of MgO nanoparticles using bark extract of Cassia absus Linn.•Particle size was reduced and the nanorod morphology was observed.•Improved free radical scavenging activity and enhanced antimicrobial activity were observed.•A sustained and slow antibiotic release profile and improved fibroblast viability were noticed. The MgO nanoparticles were synthesized from the bark extract of Cassia absus Linn. and the chemical method. The green synthesized and chemically synthesized MgO nanoparticles were confirmed from the XRD and FTIR analysis. The green synthesized MgO showed reduced particle size and nanorods morphology whereas the chemically synthesized samples showed nanoflake morphology. The phenolic components present in the green synthesized MgO nanoparticles aided in the improved antioxidant properties and the improved surface area of MgO nanoparticles resulted in the slow and sustained drug release (10 % delay) which could be an attractive property in the delivery of the antibiotics. The sample is non-cytotoxic and the zebrafish embryo mortality rate is much lesser than that of the chemically synthesized MgO nanoparticles. The fibroblast viability was enhanced in the green synthesized MgO nanoparticles; therefore, the MgO nanoparticles could be used in drug delivery systems and tissue engineering applications.