Powder technology covers many fields from medicine to material science. Especially easy synthesis of nano- and micro-sized particles and low-cost synthesis with non-toxic chemicals are essential. The ability to design nanoparticles according to the application area and desired features is an advantage for many applications. Nanoparticles biosynthesis is under research due to broad biomedical practise. To synthesize of silver nanoparticle from the plant extract, Corylus avellana (Hazelnut) leaves were utilized for bioreduction of silver nitrate. The plant extract is thoroughly mixed with silver nitrate solution, studied the synthesis of nanoparticles using UV-Vis spectroscopy. The nanoparticles were characterized by SEM and XRD-Pattern. XRD analysis proved that the size range of the nanoparticles was 32 nm. Scanning microscope images also demonstrate nanoparticles having spherical shape and a mean size between 9 nm and 50 nm. The antibacterial effect of AgNPs obtained from hazelnut leaves demonstrated antibacterial effect against all tested bacteria strains. The results demonstrated that the plant extract acts as a good bioreductant for the production of silver nanoparticles. This compound was good inhibitor of the a-glycosidase, human carbonic anhydrase I and II isoforms, and cholinesterase enzymes. The results were obtained with Ki values of 12.84 +/- 0.41 mu M for alpha-glycosidase, 27.94 +/- 3.77 mu M for hCA I, 36.12 +/- 6.03 mu M for hCA II, 47.05 +/- 6.83 mu M for BChE, and 53.94 +/- 7.55 mu M for AChE, respectively. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.