Oladipo I.C.1*, Adewole K. H.1 and Ogunsona S. B.1

Nanotechnology, the science of manipulating matter at atomic level has paved way for many innovative ideas in all areas. In this research, the green synthesis of gold nanoparticles from Strophanthus hispidus and some of its biomedical applications were evaluated. The aqueous extract of Strophanthus hispidus was employed in the mediation of gold nanoparticles, the reaction resulted in deep purple colour colloidal suspension formation after 15 minutes of photo-activation. The colloidal suspension was subjected to characterization using UV-Vis spectroscopy, FTIR, EDX and TEM. The UV-Vis spectrum of the AuNPs displayed strong peak at 552 nm. The FTIR showed broad peaks at 3417.98, 2918.40, 2359.02, 2000.25, 1766.85, 1622.19, 1384.94 and 1097.53 cm-1 which are attributed to the involvement of sugar, alkaloids and proteins in the AuNPs synthesis and stabilization. Gold was the prominent metal observed in the EDX analysis while the TEM micrograph showed spherical particles whose sizes are between 10.90 and 34.63 50nm.The AuNPs showed antifungal activities of 87.6, 70.1, 72.5, 82.8 and 51.8% against Aspergillus flavus, Aspergillus niger, Fusarium poae, Fusarium solani and Penicillium avenatum respectively at 50 µl /ml. The AuNPs showed significant antioxidant properties of 90.96, 88.09, 85.23 and 84.47% at 50, 100, 150 and 200µl/ml against DPPH. The AuNPs showed a significant angiotensin converting enzyme (ACE) inhibitory activities of 60.88 ± 3.100% at concentration of 50µg/ml. Conclusively, this study has established the relevance of Strophanthus hispidus leaf aqueous extract in the bio-fabrication of eco-friendly gold nanoparticles. The nanoparticles showed significant antifungal properties which could be useful in the production of eco-friendly fungicides, and also its antihypertensive properties have proven its drug improvement potentials, also the antioxidant activity of the gold nanoparticles could be useful in combating against oxidative stress.

Keywords : Eco-friendly, gold nanoparticles, antioxidant, antifungal, anti-hypertensive.

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