Date of Completion

2025

Document Type

Research Project

Degree Name

Grade 12

Keywords

Tithonia diversifolia, green-synthesized silver nanoparticles, gram- positive bacteria, silver nitrate 2

Abstract

Antibacterial resistance is a major global problem for both developing and developed countries, urging the need to explore alternative antibacterial agents. Silver nanoparticles (AgNPs) synthesized from Tithonia diversifolia are known to exhibit antibacterial activity against gram-positive and gram-negative bacteria. However, studies on the antibacterial efficiency of AgNPs synthesized solely from its leaves, at varying concentrations, and against selected gram-positive bacteria: Methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecalis, remain limited. This study aims to address this gap by evaluating the potential of the synthesized T. diversifolia AgNPs to combat the selected gram-positive bacteria. The air-dried, powdered leaves were mixed with distilled water, filtered, and combined with silver nitrate to synthesize AgNPs. These were diluted with sterilized distilled water to 100%, 75%, 50%, and 25% concentrations, then tested via Kirby-Bauer disc diffusion assay. Zones of inhibition (ZOI) were measured after 24 hours incubation at 37 °C, and data were analyzed using one-way Analysis of Variance (ANOVA) and Tukey’s post hoc test at a 0.05 significance level. Results showed significant ZOI differences of AgNPs against MRSA and E. faecalis. Post hoc analysis confirmed significance across all bacteria, with 100% concentration exhibiting the largest ZOI. Though not yet equal to conventional antibiotics, its ability to disrupt the bacterial membranes of the antibiotic-resistant bacteria makes AgNPs promising for further development. The study suggests the potential of synthesized AgNPs as alternatives to conventional antibiotics, recommending further research on additional bacterial strains and optimization of synthesis to produce uniform nanoparticles for more accurate results.

First Advisor

Ramgie M. Bartolata, LPT

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