Digera muricata (L.) Mart. mediated synthesis of antimicrobial and enzymatic inhibitory zinc oxide bionanoparticles

Abstract

Abstract Herein, we report a simple and ecofriendly synthesis of ZnO nanoparticles (ZnO NPs) employing Digera muricata along with bioassay studies of synthesized NPs. The ZnO NPs obtained were indicated by a colour change from yellow to almost faint yellow giving whitish tinge and supported by the appearance of UV-Vis band at 373 nm and were characterized by using Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray (EDX), and scanning electron microscopy (SEM). The FT-IR spectrum confirmed the presence of biomolecules fabricated on ZnO NPs as indicated by the absorption bands at 1,378 for C–O  cm−1, and ZnO NPs were also evident from the absorption bands at 440 and 670 cm−1, the former being the result of symmetric vibration of hexagonal ZnO and the latter belonged to a very weak vibration of ZnO. Its surface morphology was confirmed by SEM, and the zinc and oxygen bonds were confirmed by EDX analysis giving sharp signals for Zn and oxygen with At% of 17.58 and 30.49, respectively. The antimicrobial activity of ZnO nanoparticles was determined by the agar well diffusion method against pathogenic bacterial and fungal strains using imipenem and miconazole as standards. The results reflected that ZnO NPs enhanced the activity of plant extracts against all employed algal (E. coli, S. faecalis, P. aeruginosa, K. pneumonia, S. aureus, and B. subtilis) and fungal (T. mentogrophytes, E. floccosum, A. niger, M. canis, and F. culmorum) strains. The antibacterial and antifungal activities of extracts were enhanced by the formation of ZnO NPs. The results indicated that Digera muricata extract contains effective reducing agents for green synthesis of Digera muricata fabricated ZnO NPs, which are more potent antimicrobial than the plant extract and showed almost similar inhibition against lipoxygenase, i.e., the IC50 value of 83.82 ± 1.15, comparable to the standard.