The present invention disclose a simple biogenic method for the synthesis of multiple nanoparticles( Fe, Mg, Ca, Ag) and Zn, Ce, Si (quantum dots)/nanoparticles using aqueous extract of Cajanus cajan leaf under mild environment at ambient temperature. The sizes of synthesized nanoparticles which include quantum dots generated by this method were characterized by transmission electron microscopy (TEM). The generated nanoparticles reaction mixture including quantum dots showed enhanced antioxidant activity as compared to extract of Cajanus cajan most probably due to formation of antioxidant nanoparticles. The synthesized quantum dots also mimic catalase and hence can be utilized in various domains of biomedical applications including diagnostics.
