Green Synthesis, Characterization and In Vitro Antioxidant Activity of Silver Nanoparticles from Aqueous Candle Bush (Senna alata) Leaf Extract
Keywords:
Green synthesis, AgNPs, Characterization, TEM, SEM, XRDAbstract
Green synthesis of AgNPs has become a preferred method over chemical and physical approaches because it is eco-friendly, cost-effective, and avoids the use of toxic chemicals. Senna alata, commonly known as Candle Bush, is a medicinal plant widely used in traditional medicine for treating skin infections, diabetes, and inflammatory diseases. This study assesses the phytochemical content and antioxidant activity of Senna alata leaf extract, which is used in the environmentally friendly manufacture of silver nanoparticles. Both qualitative and quantitative phytochemical screening revealed a high concentration of bioactive chemicals, with the main ingredients being flavonoids (638.88 ± 4.45 mg/100 g), tannins (665.45 ± 10.29 mg/100 g), and phenols (941.32 ± 10.56 mg/100 g). The biosynthesized AgNPs have been characterized by various analytical techniques such as TGA/DTA, TEM, SEM, and EDS. TEM analysis revealed spherical nanoparticles within the size range of 2.70–6.37 nm. TGA confirmed good thermal stability up to a temperature of 400°C. SEM showed the structures to be of irregular porosity with sizes varying between 100 nm and 9 μm, whereas EDS showed silver as the major constituent (50.58 wt %). Antioxidant activity was evaluated by DPPH and ABTS assays. The nanoparticles demonstrated higher DPPH radical scavenging activity (IC50: 0.129 mg/mL) than that of the crude extract (IC50: 0.134 mg/mL), while showing similar ABTS radical scavenging activities (IC50: 0.943 and 0.954 mg/mL, respectively). These results indicated that S. alata-mediated synthesis of AgNPs is a very promising eco-friendly approach toward developing nanoparticles with improved antioxidant properties that can be useful in pharmaceutical and biomedical applications.
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Copyright (c) 2025 Ceasar Williams Onojah, Rotimi A. Larayetan, Kingsley Makoji Omatola, Amanabo Monday Adegbe, Sunday Abah, Arome Abu, Gloria Nwamaka Aningo, Oluranti Olagoke Ogunmola (Author)

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