Investigation of Antifungal and Anticancer Property of Zinc Oxide Nanoparticles Prepared Through Bioinspired Synthesis Using Endophytic Streptomyces Derived from Halophyte Salicornia brachiata Roxb

Zinc oxide nanoparticles (ZnO-NPs) are recognized as highly promising materials with applications in diverse fields, from therapeutics to agriculture. Hence, the present study aimed to biosynthesize ZnO-NPs employing the endophytic Streptomyces sp. 4VPT5-9 isolated from the halophytic plant Salicornia brachiata and evaluate the biological activity against plant pathogen Fusarium oxysporum NCIM 1008 and human breast (MDA-MB-231) and colorectal cancer (HCT-116) cell lines. The cell-free supernatant of the strain 4VPT5-9 was used as a greener attempt for the biosynthesis of ZnO-NPs. Biosynthesized ZnO-NPs exhibited an absorption peak at 287 nm. The hexagonal crystalline structure of the biosynthesized ZnO-NPs was validated through X-ray diffraction studies. These biosynthesized ZnO-NPs exhibited an irregular shape and varied in size, ranging between 120 and 150 nm with d-spacing value 0.26 nm. Moreover, FI-IR analysis showed different absorption peaks confirming the presence of different functional groups and formation of biosynthesized ZnO-NPs. XPS analysis confirmed the presence of Zn(II)O at different varied bending energies. The antifungal assay revealed that biosynthesized ZnO-NPs showed a pronounced inhibitory zone (12 mm) and the least MIC value of 60 µg/mL against plant pathogen F. oxysporum NCIM 1008. Moreover, the biosynthesized ZnO-NPs showed significant anticancer activity against MDA-MB-231 human breast cancer and HCT-116 human colorectal cell lines in a dose- and time-dependent manner. From this study, it is evident that an eco-conscious approach could pave a novel path for biosynthesis of ZnO-NPs through a halophytic plant-associated actinomycetes.