Abstract
M.Sc. (Nanoscience)
Plant phytochemicals have been under extensive research because of their preferable properties. Phytochemicals are phenolic compounds which may vary structurally which distinguish their intended applications. They possess anti-oxidant activities which have been a good requirement for treatment against certain ailments which include cancer. The anti-oxidant properties of phytochemicals are capable of relieving stress from cells by scavenging on reactive oxygen species or free radicals. The use of antioxidants has been in use for decades since it is in the human diet, hence extraction of these compounds for medical applications may be ideal since no significant side effects have been reported upon normal consumption. The effectiveness of anti-oxidants possessed by plant phytochemicals depends on the type of phytochemicals, their structural composition and the concentration. Research has uncovered the use of anti-oxidants as reducing agents for the synthesis of metallic nanoparticles for various applications. The synthesis has been found to be cost effective and amenable to optimization for preferred applications. This study describes the synthesis of gold nanoparticles by flavonoids; Sigmoidin A, Sigmoidin B isolated from Erythrina species and Durmillone isolated from Griffoniana species. The natural compounds have been fully characterized by UV-Vis, NMR and FT-IR. The compounds and their relative synthesized AUNPs were tested for anti-cancer activities against Normal Kidney Fibroblasts (BHK 21) and colorectal carcinoma (HCT 116) cell line.
A modified tuckervich method was used to synthesize AuNPs which were further characterized by UV-Vis, DLS, TEM, EDX and FT-IR. The synthesis was successful as was observed by a colour change of chloroauric solution from golden yellow to pink-wine red colours. The assumed presence of AuNPs in solution was determined by UV-Vis which measured 595.9nm for Sigmoidin A, 554.5nm for Sigmoidin B and 531nm for Durmillone. These maximum wavelengths of absorption by the AuNPs synthesized by all three flavonoids are characteristic of AuNPs as reported by literature. Average particle size, dispersity and zeta potential values of the synthesized AuNPs were determined by DLS. Properties of Sigmoidin A-AuNPs as per DLS results were 0.143 PDI, 64.8 d.nm and 0.170 mV which mean that the AuNPs were not aggregated but not stable as per the zeta potential value. Sigmoidin B-AuNPs properties by DLS were 0.443 Pdi, 34.4 d.nm and -0.0772 mV which meant that the nanoparticles were monodispersed but not stable as per the zeta-potential. Durmillone-AuNPs properties were 0.153 PDI, 32.7 d.nm and 0.0549 mV which...