## 1 Introduction  
The synthesis of nanoparticles (NPs) has become a matter of great interest due to their different beneficial properties and applications in a variety of fields [1; 2; 3]. Several approaches have been proposed to generate metallic NPs, including electro-chemical, sonochemical, and photochemical processes; however, most of these methods suffer from the utilization of toxic, hazardous chemicals, and difficulty in purification [4; 5; 6].  
Green chemistry synthesis of NPs has recently received wide spread attention among physical and chemical synthesis processes for its emergence as a simple, speedy synthesis, inexpensive, eco-friendly, and size-controlling approach in the synthesis of metal NPs (MNPs) [3]. As a result of its growing popularity, there is an increased need to produce MNPs using biological systems such as bacteria [7], fungi [8], yeast [9], and plant extracts [3; 10; 11] as reducing and stabilizing agents. The latter synthetic procedure exemplifies a green approach. NPs produced by angiosperms, especially those medicinal in nature, are more stable, display a more speedy synthesis in the case of micro-organisms, reveal greater variation in shape and size and contain important reducing agents in comparison to those produced by other organisms [12; 13].  
Silver (Ag) has long been known to exhibit a strong antimicrobial, catalysis, and surface-enhanced Raman scattering; therefore, Ag-based compounds have been used extensively in numerous bactericidal applications [3; 14]. Since antibiotic resistance to the microorganisms become more common, and a continued preoccupation with health care expenses, researchers have tried to develop new resistance-free, cost-effective antimicrobial reagents [3]. The antimicrobial potential of Ag-based NPs has led to their incorporation in consumer, health-related, and industrial products [3; 15]. Moreover, due to its potential application to biological functions such as cancer therapy and imaging, AgNP biosynthesis has recently attracted considerable attention of researchers interested in the field [11; 14; 15].  
Although AgNP synthesis has already been reported in various plant seed extracts such as _Medicago sativa_[16], _Artocarpus heterophyllus_[17], _Jatropha curcas_[18], _Strychmos potatorum_[19], _Foeniculum vulgare_[20], _Silbyum marianum_[21], and _Syzygium cumini_[22], the field continues to receive attention due to the variety and high prospective of plants for producing NPs with different characteristics [11]. Additionally, the plant-based extracts of antioxidant-laden leaves, seeds, fruits, roots, and stems have been considered for use in the synthesis of AgNPs [10; 23].  
Originating from south Siberia and the Himalayan mountains, dragonhead (_Dracocephalum molavica_ L.) is a perennial, herbaceous plant belonging to the Lamiaceae family [1; 2]. Recent pharmacological studies have confirmed antioxidant, antiseptic, antibacterial, and carminative properties of the plant's essential oil [1], and the areal parts of _D. molavica_ are applied in traditional West Azerbaijan (Iranian) medicine for general diuretic, digestive, sedative, and antiemetic uses [2].  
Terpenoids are believed to take part in the reduction of Ag ions and the stabilization of following NPs [6]; therefore, we used _D. molavica_ seed extract as a reducing and stabilizing agent in the synthesis of AgNPs, with the intention of exploring its medicinal properties. As there appears to be no report concerning the synthesis of NPs using _D. molavica_ seed extract to date, the present study was designed to phytosynthesize AgNPs using _D. molavica_ seed extract, and to subsequently investigate the antimicrobial activities of synthesized NPs.