ABSTRACT
Plant-based nanoparticles (NPs) are sustainable, eco-friendly alternative to conventional methods. These NPs offer excellent antibacterial properties, making them a promising avenue for producing effective antimicrobial agents. The emergence of antibiotics resistance has become a global health concern, thus the application of green synthesized nanoparticles. A total of five (5) samples of urine and stool were obtained from the Benin Medical Centre in Benin City, Edo State. The samples were immediately transported to Wellspring University Research Laboratory for microbiological analysis. For fresh utilization of Carica papaya and Bryophyllum pinnatum, the leaves were washed, weighed and crushed, and mixed with 100 ml of distilled water. The mixture was heated at 85 °C and 60 °C for 60 minutes. The synthesis of silver nanoparticles (AgNPs) and copper nanoparticles (CuNPs) was done following standard procedures: 5 ml and 1 ml of each plant extract were dispensed into 45 ml and 20 ml of AgNO3 and CuSO4 solutions, respectively, NPs were preliminarily validated by visually detecting the colour change from white and blue in the solution to yellow and light green, respectively. NPs were characterised using a UV-visible spectrophotometer at 300 nm and Fourier Transform infrared, following standard procedures. In vitro antimicrobial activity of plant-mediated NPs was investigated using five isolates: S. aureus, B. alvei, H. pylori, P. aeruginosa and E. coli. For the antibacterial activity, antibiotic discs, filter paper discs, and agar-well diffusion methods were applied. The antibiotic susceptibility test carried out showed that S. aureus and P. aeruginosa were resistant at 66.67 % to cefuroxime, cefexime, ofloxacin cefuroxime, ofloxacin and cefotaxime . While B. alvei, H. pylori and E. coli were 58.33 %, 50 %, and 41.67 % resistant respectively to the antibiotics they were tested with. However, the susceptibility rate was high. The MAR index of the isolates was greater than 0.2, indicating high-risk contamination sources where antibiotics are often used. The agar-well diffusion method showed 100 % inhibition of the isolates by plant-mediated NPs but no inhibition by the plant extract alone. This study has shown that plant-mediated NPs show promising antimicrobial activity, promoting sustainability and eco-friendliness. Further research is needed to evaluate safety and efficacy in clinical settings.
