Browsing by Author "Botha, Subelia"
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Item Functional metal oxides synthesized using natural extracts from waste maize materials(Elsevier, 2021) Nwanya, Assumpta Chinwe; Botha, Subelia; Ezema, Fabian I.We show in this article the possibilities of employing an environmentally friendly, uncomplicated, economical and sustainable green synthesis technique effected by natural extracts from waste maize (zea mays lea) materials to synthesize some functional transition single metal oxide nanoparticles (NPs). Copper oxides (Cu2O and CuO), zinc oxide (ZnO), nickel oxide (NiO), chromium oxide (Cr2O3), iron oxide (Fe2O3) and cadmium oxide (CdO) were successfully synthesized using this facile method. Structural characterizations by X-ray diffraction (XRD) for the various oxides show the phases and space groups corresponding to their individual structures. Images from the high resolution transmission electron microscope (HRTEM) revealed various shapes and sizes of the obtained nanoparticles. Results from the attenuated total reflection-Fourier transform infrared (ATR-FTIR) revealed different kinds of functional groups present in the synthesized metal oxide nanoparticles. We showed that the phytochemicals in the natural extracts obtained from the waste materials from Zea mays lea plant is pivotal to the bio-reduction, stabilization and chelation of the metal oxide nanoparticles.Item The potential of chalcone-capped gold nanoparticles for the management of diabetes mellitus(Surfaces and Interfaces, 2021-08) Pearce, Brendon; Benjeddou, Mongi; Botha, Subelia; Omolaja, Akinfenwa, A; Omuruyia, Sylvester, I; Badmus, Jelili, A; Ismail, Enas; Marnewick, Jeanine; Ekpob, Okobi, E; Hussein, Ahmed, ASearching for new natural bioactive capping agents represent an urgent priority in the green synthesis of metal nanoparticles. Additionaly, the biosaftey of metal nanparticles is a major concern especially in medical applications. Recently, the use of pharmacollogicaly active natural products as capping agents has been deployed to avoid toxic effects during the nanoparticles preparation and to enhance their drugability compared with convential drugs. Helichrysum foetidum is a South African medicinal plant used in folk medicine for the treatment of different human pathologies, and it is known to contain a variety of bioactive compounds. Herein, the total extract and two pure chalcones, helichrysetin and helichrysin, isolated from the same plant were successfully used to synthesize quasi-monodispersed gold nanoparticles in the size range of 2–12 nm. The bio-evaluation of samples indicated that the AuNP/capping agent conjugates are biostable, and have different biological profiles from the total extract/pure compounds. The enzymatic inhibition assays showed significant inhibition by the total extract, helichrysetin and their gold nanoparticles. Interestingly, a similar activity was observed for glucose uptake in HEK293 treated cells. On the other hand, all the tested samples relatively demonstrated no cytotoxicity when tested against the HaCaT keratinocytes. In conclusion, the study demonstrated potential enhancement of glucose uptake in mammalian kidney cells, and inhibition of carbohydrate-hydrolysing enzymes by green synthesized gold nanoparticles of H. foetidum. It also provides a therapeutic appraisal of AuNPs/chalcones conjugate towards the development of antidiabetes drugs derived from H. foetidum and its gold nanoparticles.