Biosynthesis, Characterization, and Biological Activities of Procyanidin Capped Silver Nanoparticles

• Main Authors: Umar M. Badeggi, Jelili A. Badmus, Subelia S. Botha, Enas Ismail, Jeanine L. Marnewick, Charlene W. J. Africa, Ahmed A. Hussein
• Format: Article
• Language: English
• Published: MDPI AG 2020-09-01
• Series: Journal of Functional Biomaterials
• Subjects: biosynthesis; procyanidins dimers; <i>Leucosidea sericea</i>; silver nanoparticles; phytoconstituents; antimicrobial
• Online Access: https://www.mdpi.com/2079-4983/11/3/66

In this study, procyanidin dimers and <i>Leucosidea sericea</i> total extract (LSTE) were employed in the synthesis of silver nanoparticles (AgNPs) and characterized by ultraviolet-visible (UV-Visible) spectroscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and dynamic light scattering (DLS) techniques. AgNPs of about 2–7 nm were obtained. DLS and stability evaluations confirmed that the AgNPs/procyanidins conjugates were stable. The formed nanoparticles exhibited good inhibitory activities against the two enzymes studied. The IC₅₀ values against the amylase enzyme were 14.92 ± 1.0, 13.24 ± 0.2, and 19.13 ± 0.8 µg/mL for AgNPs coordinated with LSTE, F1, and F2, respectively. The corresponding values for the glucosidase enzyme were 21.48 ± 0.9, 18.76 ± 1.0, and 8.75 ± 0.7 µg/mL. The antioxidant activities were comparable to those of the intact fractions. The AgNPs also demonstrated bacterial inhibitory activities against six bacterial species. While the minimum inhibitory concentrations (MIC) of F1-AgNPs against <i>Pseudomonas aeruginosa</i> and <i>Staphylococcus aureus</i> were 31.25 and 15.63 µg/mL respectively, those of LSTE-AgNPs and F2-AgNPs against these organisms were both 62.50 µg/mL. The F1-AgNPs demonstrated a better bactericidal effect and may be useful in food packaging. This research also showed the involvement of the procyanidins as reducing and capping agents in the formation of stable AgNPs with potential biological applications.