^aEmergency Room, Ayvaclk Hospital, Yeni Hastane Street, 17860 Ayvaclk,

Çanakkale, Türkiye

^bFaculty of Medicine Department of Medical Biology, Çanakkale Onsekiz Mart University, 17020 Çanakkale, Türkiye

Mosses are one of the oldest land plants that constitute the second largest group of the plant kingdom, are found in almost every region, have known therapeutic effects, are rich in secondary metabolites, can withstand harsh climatic conditions and thirst for a long time. Volatile extracts of Hypnum cupressiforme Hedw. were analyzed by gas chromatography-mass spectrometry in this study, and the presence of 18 different phytocompounds was determined as secondary metabolites. Using these extracts, silver nanoparticles (AgNPs) were synthesized using a green synthesis method. The AgNPs that were created were characterized. The extracts and AgNPs were tested for antibacterial, antibiofilm, antioxidant, mutagenic, and DNA-cleavage activity. The tests revealed no evidence of mutagenicity. Antibiofilm and antibacterial activity of AgNPs against P.

vulgaris, P. aeruginosa, and E. faecalis were demonstrated. Both oxidatively and hydrolytically, H. cupressiforme the extract was found to have higher antioxidant properties and high DNA cleavage activity.