Phytochemical bioactivity, antibacterial and antioxidant profiling of B/nZVCu-M nanoparticles biosynthesized using Ocimum sanctum leaves extract

Abstract

Due to continuously increasing resistance to synthetic antibiotics, there is an urgent need to shift our focus toward natural antioxidant-based antibacterial products due to their vast chemical diversity which provide potent therapeutic effect and make the microbes unable to copy them for creating resistance. To address this problem, an enhanced method is herein implemented using aqueous/methanol extract of Ocimum sanctum leaves as a capping and reducing agent for the synthesis of Bentonite supported Copper-Metal nanoparticles (B/nZVCu-M NPs) (M: Ag/Ni). The average nanoparticle size and crystalline size was found to be 74$\pm 0.43$ nm with few agglomerations. The increase in surface area (40.329 m²/g) and low pore volume (0.10 cm³/g) indicates production of more active sites for better performance. B/nZVCu-Ag NPs (ZOI = 15.33 $\pm$ 0.58 mm) showed better antibacterial activity against Staphylococcus aureus as compared to B/nZVCu-Ni NPs (ZOI = 7.64 $\pm$ 0.58 mm). This study also reveals the MIC of B/nZVCu-Ag NPs with methanol extract to be more efficient as compared to B/nZVCu-Ni NPs. The IC₅₀ value of the B/nZVCu-Ag NPs and B/nZVCu-Ni NPs with aqueous extract was 43.80 mg/g and 45.54 mg/g. The IC₅₀ of the ascorbic acid was 31.39 mg/g. In this study the IC₅₀ value of the B/nZVCu-Ag NPs and B/nZVCu-Ni NPs are 125 $\pm$ 0.95 µg/ml and 134 $\pm$ 0.46 µg/ml (methanol extract). The statistical data analysis of this study proves to be significant at p < 0.05.