Evaluation of the antioxidant activity of Annona muricata (Guyabano) mediated silver nanoparticles and Annona muricata ethanolic leaf extract

ANN THERESE S. SOBRETODO, MICA ANTONIA D. JAEN, RICHLYN JOY S. VILLALOBOS, and RAMON ANGELO N.
SINCO
Philippine Science High School – Western Visayas Campus, Brgy. Bito-on, Jaro, Iloilo City 5000, Department of Science and Technology – Science Education Institute, Philippines


Abstract
Silver nanoparticles (AgNPs) biosynthesized from various plant sources is an emerging material used for several applications. These may be used as antioxidants as several studies have focused on its ability to eliminate free radicals. Annona muricata (Guyabano) leaves are commonly known to possess such antioxidant properties due to its present bioactive compounds—thus becoming a suitable capping agent for AgNPs. The present study compared the antioxidant activity of A. muricata leaf extract, A. muricata mediated AgNPs, and commercially available AgNPs against ascorbic acid (positive control) and methanol (negative control) via DPPH Assay. Results show the leaf extract having the highest antioxidant activity after the positive control. This suggests that the plant extract can primarily be used as an antioxidant while the synthesized AgNPs do not contribute to its antioxidant property.

Keywords: Annona muricata, silver nanoparticles, antioxidant, DPPH Assay, biosynthesis


Evaluation of alanine-silver nanocomposites from biosynthesized silver nanoparticles

ANGELA JOYCE T. LOOT, MCXEL S. NUNAG, RASHEEN C. RABINO, and ARIS C. LARRODER
Philippine Science High School – Western Visayas Campus, Brgy. Bito-on, Jaro, Iloilo City 5000, Department of Science and Technology – Science Education Institute, Philippines



Abstract
Exposure to ionizing radiation damages the genetic material of living cells which may eventually become cancerous. Alanine- silver nanocomposites have recently been developed as a liquid detector for radiation dosimetry purposes. Despite this application, none have so far investigated the use of iosynthesized silver nanoparticles in the synthesis of alanine-silver nanocomposites. This study aimed to spectrophotometrically evaluate the interaction of biosynthesized silver nanoparticles and alanine in the formation of alanine-silver nanocomposites. The formation of silver nanoparticles was confirmed by ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM). The absorbance level of the alanine-silver nanocomposite solution was determined using UV-Vis spectroscopy. It was observed that the silver nanoparticles formed were spherical with a mean size of 27 nm. The interaction of alanine with silver nanoparticles yielded no visible color change. However, a trend of increasing absorbance level was observed. In conclusion, biosynthesized silver nanoparticles can be possibly used in the synthesis of alanine-silver nanocomposites. Further investigation on the effect of alanine to the size and morphology of silver nanoparticles is recommended.

Keywords: nanocomposite, biosynthesis, uv-vis spectroscopy, alanine, radiation dosimetry