## 1 Introduction  
Food spoilage may be caused by physical, chemical, or microbiological mechanisms. Microbial spoilage is frequently due to spoilage bacteria, yeasts, or moulds' growth and/or metabolism [1; 2]. The chemical spoilage typically occurs when food exposure to oxygen triggers a chain of several chemical reactions involving lipids, fatty acids, and pigments and generates chemical compounds with undesirable biochemical properties, such as toxicity and unpleasant smell, taste, and colour [3]. These changes make foodstuff unacceptable or undesirable for consumption and, finally, generate food loss and waste [2]. The real economic losses generated by food spoilage are challenging to estimate. However, these losses represent a substantial financial burden assessed at 1.3 billion tonnes per year by FAO [4]. Consequently, to increase foodstuff quality, safety, and shelf-life without any adverse effect on their nutritional or sensorial properties, food additives such as preservatives and antioxidants have become indispensable for the food industry, mainly synthetic ones. In recent decades, there has been significant scientific progress concerning pharmacological studies of aromatic plants to identify and valorise natural extracts [5; 6]. This trend is concurrent with an increasing interest in identifying new sources of preservatives and antioxidants to replace synthetic food additives because of their potential carcinogenicity [7; 8]. A large plethora of plant extracts are also well known and researched for their antimicrobial potential. These extracts contain various compound classes such as terpen, polyphenolic compounds, flavonoids, various adelhydes, and ketones or alkaloids that disrupt bacteria activity by various mechanisms [9]. These mechanisms include key enzymes that play important roles in bacterial survival and proliferation and are frequently used as targets for novel antimicrobial drug design or for the determination of active antimicrobial agents' mechanisms of action using computational methods [10]; _Rutaceae_ family have been recognized for their economic value and also for the cultivated citrus fruits, timber, and essential oils (EOs), indicating a potential source of natural active principles [11; 12; 13]. One of the genera of _Rutaceae_ family plants investigated is the genus _Ruta_[13]. The genus _Ruta_ includes about 40 species of perennial shrubs and herbs distributed along the Mediterranean coast, the Balkan Peninsula, and Crimea [14]. In Romania, the _Ruta_ genus is represented by _Ruta gravelens_ L., _Ruta suaveolens_ D.C., and _Dicatamus albus_ L. [15]. Among the family members, _R. gravelens_ L. stands out for EO production [6]. Several studies report that oxygenated compounds (e.g., aldehydes, alcohols, and esters) are predominant in the _R. gravelens_ EOs (RGEO) isolated from leaves, fruits, flowers, stems, and roots [16]. In contrast, other investigations mention aliphatic compounds, especially ketones (2-undecanome and 2-nonanone), representing more than 50% of the total composition of RGEO [6; 14; 17]. These differences in the phytochemical profile of _R. gravelens_ may explain the anti-rheumatic, anti-diarrheic, anti-inflammatory, anti-febrile, antiulcer, anti-diabetics, and antimicrobial properties reported in the recent pharmacological trials [6; 18; 19]. To our knowledge, no investigation of the antioxidant properties of _R. gravelens_ has been previously reported. However, several studies report the in vitro antioxidant properties of the _Ruta montana_ and _Ruta calhepensis_. Still, no investigations report the _Ruta_ genus members' antioxidant activity in food systems. This research aimed to investigate: (i) the chemical composition of the EO isolated from the aerial parts of _R.