Antimicrobial and antioxidant potentials of biosynthesized colloidal zinc oxide nanoparticles for a fortified cold cream formulation: A potent nanocosmeceutical application

Nanocosmeceuticals are promising applications of nanotechnology in personal care industries. Zinc oxide is an inorganic material that is non-toxic and skin compatible with self-cleansing and microbicidal properties. Herein, exploitation of colloidal zinc oxide nanoparticles (ZnONps) as potent biomaterial for a topical formulation of cosmetic and dermatological significance is employed. ZnONps were green synthesized using environmentally benign Adhatoda vasica leaf extract and characterized by UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HR-TEM) and energy-dispersive X-ray spectroscopy (EDX). The results reveal that the biosynthesized ZnONps exhibit an absorption peak at 352nm. XRD and HR-TEM analyses confirm the hexagonal wurtzite structure of ZnONps with particle size of about 10nm to 12nm. Elemental analysis by EDX confirms the presence of zinc and oxygen. Zeta potential of -24.6mV affirms the stability of nanoparticles. The antibacterial and antifungal activities of biosynthesized ZnONps exhibit mean zone of inhibition from 08.667±0.282 to 21.666±0.447 (mm) and 09.000±0.177 to 19.000±0.307 (mm) respectively, in a dose-dependent manner. The IC₅₀ value exerted from the antioxidant activity of ZnONps is found to be 139.27μgmL^-1. ZnONps infused cold cream formulation of microbicidal and antioxidant properties was further tested against clinical skin pathogens. The nano-based cold cream exhibited significant inhibitory action against Candida sp., which showed resistance against a commercial antifungal cream (2%). Therefore, this study demonstrates the exploitation of ZnONps as promising colloidal drug carriers in cosmeceuticals that can significantly alleviate human skin infections and oxidative stress induced cellular damage.