Biogenic synthesised Zinc oxide nanoparticles by using the marine bacterial pigment (Melanin) and its antioxidant and in-vitro anticancer activity

Abstract

This study aimed to explore the biogenic synthesis of zinc oxide nanoparticles (ZnO NPs) using melanin isolated from marine bacteria and evaluate their antioxidant and anticancer activities. The objectives included isolating melanin from Actinoalloteichus sp obtained from mangrove grounds, synthesizing Melanin ZnO NPs, characterizing their physicochemical properties, assessing antioxidant activity, and investigating their impact on SK-MEL-28 cell line apoptosis. The primary aim of this research was to investigate the biogenic synthesis of Melanin ZnO NPs and evaluate their potential as antioxidants and anticancer agents. Isolate melanin from marine bacteria (Actinoalloteichus sp). Biogenically synthesized Melanin ZnO NPs and their physicochemical properties were characterized. Evaluate the antioxidant activity of Melanin ZnO NPs using the DPPH radical scavenging method. Assessment of the in vitro anticancer activity of Melanin ZnO NPs against SK-MEL-28 cells. Apoptotic induction of Melanin ZnO NPs on SK-MEL-28 cells using AO/EB staining. Melanin isolation involved collecting sediment samples from mangrove grounds (Pichavaram and Parangipettai) using a core sampler for microbiological analysis. Melanin ZnO NPs were synthesized by incorporating melanin into zinc acetate dihydrate, followed by NaOH addition and subsequent purification. Characterization employed UV-visible, XRD, FT-IR, EDX, FE-SEM, and HR-TEM analyses. Antioxidant activity was assessed using the DPPH radical scavenging method, while in-vitro anticancer activity was determined by MTT assay against SK-MEL-28 cells. Apoptotic induction was evaluated through AO/EB staining. Melanin ZnO NPs were successfully synthesized and characterized, confirming their nanoscale nature and crystalline structure. The antioxidant activity revealed a concentration-dependent decrease compared to ascorbic acid, while in-vitro anticancer activity demonstrated a dose-dependent inhibition against SK-MEL-28 cells. AO/EB staining provided insights into the apoptotic induction of Melanin ZnO NPs on SK-MEL-28 cells. The biogenic synthesis of Melanin ZnO NPs presents a potential avenue for cancer therapy, as indicated by their significant in-vitro anticancer activity. However, their antioxidant efficacy may be limited compared to standard antioxidants. Further studies are needed to elucidate underlying mechanisms and validate these findings in vivo for comprehensive therapeutic assessment.