The change in the color of reaction mixture to yellowish brown or dark brown
after mixing a plant extract and silver nitrate is a general characteristic of silver
nanoparticles biosynthesis. In our initial experiments assaying A. absinthium aqueous
extract with AgNO3, reaction mixtures started turning brown within 30 minutes and it
continued turning darker with time (Figure 1a). The reaction mixture with 1:1 (v/v) ratio
of each reactant turned darker more rapidly, compared to the rest of reaction mixtures.
However, no color change was observed with the plant extract or AgNO3 alone under the
same conditions.