## 1 Introduction  
Nowadays, the rapid development and modern way of life worldwide, which is characterized by behaviors that support external factors, has led to the spread of many incurable diseases such as cardiovascular diseases, central nervous system problems, and cancer [1]. All these diseases are related to the presence of a large amount of free degenerative radicals inside the body, consequently causing the destruction of the body cells (oxidative stress) [2]. Hence, antioxidant agents that scavenge these free radicals and limit their destructive effects on the body cells remain the only solution. There are many antioxidant agents; however, antioxidants of natural origin are the best and safest way to combat and eliminate free radicals without harming the normal body cells [3]. Therefore, since ancient times, plants have been a significant source of effective compounds that act as cell guards to eliminate free radicals without harming other body cells. Extensive research has recently revealed the efficacy of many medicinal herbs in treating various modern diseases caused by free radicals [4]. Medicinal herbs contain many secondary metabolites, such as flavonoids, alkaloids, terpenes, and other phenolic compounds that work individually or synergistically to protect cells from harmful external factors. This leads to an increase in their lifespan and restoration of vitality [5]. Aromatic medicinal plants have biological properties that could be useful in the cosmetic, medical, and pharmaceutical fields [6]. Rutaceae, an essential plant family, is considered a source of a wide variety of secondary metabolites with antioxidant, antibacterial, antifungal, antihelmintic, spasmolytic, antitumor, antidepressant, analgesic, and anti-inflammatory activities [7]. The common Ruta species studied for their oil constituents and biological activities are _R. graveolens_, _R. chalepensis_, and _R. montana_[8]. _Ruta chalepensis_ L., commonly known as Shazab in Saudi Arabia, is a well-known member of the Rutaceae family and is commonly used in folk medicine to treat mental disorders, rheumatism, dropsy, neuralgia, fever, bleeding and menstrual issues, nervous disorders, and convulsions [9]. It has a strong aromatic odor and numerous biological activities, which could be attributed to the presence of different secondary metabolite classes such as saponins, flavonoids, triterpenes, and essential oils, additional to coumarins, phenols, and alkaloids [10]. The most important secondary metabolites in recent years have been essential oils extracted from natural sources, containing hydrocarbon compounds with hydrogenated, oxygenated, and dehydrogenated functional groups [11]. Most of these constituents are odorous mono or sesquiterpenoids found in various parts of the plant that evaporate at normal temperatures [12]. Many techniques are used to extract essential oil from aromatic plants, and the volume, percentage concentration, and many identified constituents vary. The headspace solid-phase microextraction (HS-SPME) technique is a relatively new advanced technique for volatile oil isolation. HS-SPME was constructed to isolate volatile constituents with a wide range of boiling points without forming artifacts, and the harmful organic solvents are not involved in the process [13]. Molecular docking is a time-efficient and cost-effective method used to explore the complexity of protein-ligand interactions, which helps design, synthesize, and discover therapeutically important drugs. It is used in protein engineering and medicinal chemistry as well as other biological and medicinal areas [14]. Many enzyme systems such as NADPH oxidase, cytochrome P450 reductase, nitric oxide synthases, and xanthine oxidase when inhibited will exhibit antioxidant and reactive oxygen scavenging potencies. To study the ability of the oil to inhibit NADPH oxidase enzymes, all compounds released from the GC-MS analysis were assessed, along with ascorbic acid, and docked against the NADPH oxidase enzyme.