AKOMOLAFE, OLUWATOBI AYOBAMI and Covenant University, Theses Masters (2024) GREEN SYNTHESIS OF SILVER NANOPARTICLES USING Nymphaea nouchali (Burm.) LEAF EXTRACT: ANTIMICROBIAL AND ANTIDIABETIC EVALUATION. Masters thesis, Covenant University.
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Abstract
The field of nanotechnology is gaining interest in science today; hence, there is a need to take this advantage in combating drug resistance by disease-causing microorganisms and finding alternative routes for antidiabetic treatment in humans. Moreover, the safety of the environment and humans has been an issue of concern as the method of producing nanoparticles poses a toxicity challenge. Thus, the green synthesis that engages sustainable biodiversity is considered a substitute, as the method produces less toxic nanoparticles especially for biomedical applications compared with the orthodox syntheses. This study evaluated the antimicrobial and antidiabetic potential of Nymphaea nouchali extract and its corresponding silver nanoparticles (AgNPs). Successive extraction was carried out on the plant via cold extraction method on a polarity scale using n-hexane, followed by ethyl acetate, and methanol yielding NLH, NLE, and NLM, respectively. Qualitative analysis was conducted to detect secondary metabolites in the leaf extract. In green chemistry, a hot maceration method was employed to prepare an aqueous extract of Nymphaea nouchali leaf, which was then used as a reducing agent in the synthesis of AgNPs. The UV-visible double spectrophotometer was used to monitor the reaction. FTIR, SEM-EDAX, XRD, XRF, and GC-MS techniques were used to analyze the nanoparticles that were prepared. Furthermore, the following test microorganisms were used for the antimicrobial assay: gram-negative bacteria- Escherichia coli, Pseudomonas aeruginosa, Salmonella sp.; gram-positive bacterium Staphlococcus aureus; Fungi-Candida albicans, and Aspergillus niger. An in-vitro assay targeting α-amylase activity was used for the antidiabetic evaluation. Noticeable colour change informed the nanoparticle formation, which was preliminarily confirmed with an appearance of surface plasmon resonance (SPR) around 450 nm using UV-visible spectrophotometer. The following peaks and functional groups were identified with FTIR, 3398 cm-1 (O-H), 2925 cm-1 and 2855 (C-H), 1703 cm-1 (C=O), and 1043 cm-1 (C-O). From the sensitivity testing, Nymphaea nouchali displayed the highest inhibition, even more than the control, against all the test organisms except Candida albicans. AgNPs inhibited the growth of E. coli, Salmonella sp., S. aureus, and A. niger. In the antidiabetic assay, N. nouchali and AgNPs inhibited α-amylase at IC50 value 204.48 mg/mL and 408.67 mg/mL, respectively. Hence, from this study, both N. nouchali extract and AgNPs are potential antibacterial, antifungal, and antidiabetic drug candidates.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Silver nanoparticles, N. nouchali, green chemistry, antimicrobial, antidiabetic, α-amylase |
| Subjects: | Q Science > QD Chemistry Q Science > QH Natural history > QH301 Biology R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Chemistry |
| Depositing User: | Patricia Nwokealisi |
| Date Deposited: | 23 Sep 2024 15:07 |
| Last Modified: | 23 Sep 2024 15:07 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/18430 |
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