Progress in Chemical and Biochemical Research Journal homepage: http://www.pcbiochemres.com/ Original Research Article Green Synthesis and Biological Assessments of Silver Nanoparticles Using the Plant Extract of Crataegus sinaica Boiss. Fruits Omar A. EL-Shahaby 1 , Fikry M. Reicha 2 , Maged Mohamed Nabil Aboushadi 1 , Mustafa M. El-Zayat 3 * 1 Botany Department, Faculty of Science, Mansoura University, ET-35516, Mansoura, Egypt. 2 Physics Department, Faculty of Science, Mansoura University, ET-35516, Mansoura, Egypt. 3 Unit of Genetic Engineering and Biotechnology, Faculty of Science, Mansoura University, ET-35516, Mansoura, Egypt. INTRODUCTION The study of the synthesis of silver nanoparticles is increasingly interesting because of their inhibitory effect against several microbial strains [1]. Silver is well known in medicine for its wide range of applications, for instance, antibacterial activity against many pathogenic strains [2,3]. Many fairly expensive chemical and physical approaches, supposedly dangerous for the environmen t and impact various biological risks. There is a continuous search for inexpensive and eco-friendly routes for the synthesis of nanoparticles, using microorganisms [4,5] and plant extracts [6]. Green synthesis is a preferable method because of the slower kinetics, which offers better handling, controlling the growth and stabilization of the crystals. The eco-friendly technique to obtain the A R T I C L E I N F O Crataegus sinaica Boiss is a hawthorn plant that was found as a hybrid of two species, C. azarolus and C. monogyna, which grows vastly in the mountains of the Protectorate of St. Catherine, South Sinai, Egypt. The fruits of the plant are rich in primary and secondary metabolites, for instance reducing, total sugars, flavonoids, and phenols as demonstrated by the phytochemical analysis. The aqueous extract of the fruits of the plant was used to prepare the silver nanoparticles by green method, in which the reducing and total sugars facilitate the preparation step as they act as reducing and stabilizing agents. The nanoparticles of the plant were efficiently synthesized through mixing Crataegus sinaica fruits aqueous extract with silver nitrate solution at room temperature following the predetermined procedures for nanoparticle preparation. The prepared nanoparticles were identified by means of spectroscopic and analytical measurements i.e. UV-vis, IR, TEM, and zeta sizer- zeta analyzer. The extract of the fruits of the plant and its silver nanoparticles were assessed as antimicrobial and antioxidant agents, in which the nanoparticle solution displayed the more potent activities against the diverse microbial species and potent antioxidant agent than the aqueous extract. Article history: Submitted: 2020-02-03 Revised: 2020-02-20 Accepted: 2020-04-12 Published: 2020-04-23 Manuscript ID: PCBR-2002-1080 K E Y W O R D S Crataegus sinaica Green synthesis Phenolic & flavonoid contents; Biological assessments. * Corresponding author: Mustafa M. El-Zayat Tel number: +201066061042, E-mail: mzayat2001@yahoo.com DOI: 10.33945/SAMI/PCBR.2020.2.3 © 2020 by SPC (Sami Publishing Company) A B S T R A C T G R A P H I C A L A B S T R A C T Progress in Chemical and Biochemical Research 2020, 3(2), 105-113