**1. Introduction**

People since ancient times have been using plant secondary metabolites in their daily life for the treatment of a wide range of diseases, as food preservatives and flavoring, and to annihilate insects. The World Health Organization has estimated that around 80% of the world population rely on plant extracts for their medication [1]. With time, synthetic chemicals have replaced plant secondary metabolites as the former provide early results. However, most synthetic drugs have various side effects and may cause many serious human health problems, therefore strategies have been implemented to replace synthetic drugs with plant secondary metabolites due to their ability to protect human body against oxidative damage and their great positive impact on human health [1–3]. Nowadays, due to the growing public awareness about the probable harmful effects of synthetic additives and the tendency of consumers to use natural foods, the use of natural bioactive compounds is witnessing

significant growth [4]. Due to the wide prevalence of cancer worldwide, there is an essential and urgent need for a search for new anticancer medications [5]. In fact, majorities of used antitumor drugs are derived from natural sources [6].

The essential oils extracted from plants have been used in traditional medicine for the treatment and prevention of various diseases, in cosmetics, foods, and food supplements in addition to dental practice and hygiene products [7,8].

*Stachys* (Lamiaceae family) is a large genus of herbs and shrubs containing around 300 species, widely spread in the temperate regions, especially in the Irano-Turanian and Mediterranean areas. Recently, several studies have documented anti-inflammatory, cytotoxic, antioxidant, immune system booster and antimicrobial properties of the extracts from a number of *Stachys* species [9].

*Stachys viticina* Boiss. is a perennial herbaceous shrubby plant that can reach a height of 100 cm, with multiple branches, grey-colored and erect stems. The upper leaves are crenate, while the lower ones are large, oblong-ovate and verticillaster. In traditional medicine, various *Stachys* species have been utilized as anti-inflammatory, antimicrobial, anti-diarrheal, wound healing and astringent remedies. In addition, they were used to treat ulcers, cough, sclerosis of the spleen and genital tumors [10,11].

It is worth mentioning that the chemical constituents of *S. viticina* EO, as well as its biological and pharmacological properties, haven't been reported. Thus, the current study was designed to investigate the chemical composition of the EO extracted from *S. viticina* leaves. Additionally, the antioxidant, anticancer, antimicrobial, metabolic enzyme (α-amylase, α-glucosidase, and lipase) and cyclooxygenase (COX) inhibitory properties of *S. viticina* EO was assessed.

#### **2. Results**

#### *2.1. Phytochemical Composition of S. viticina Essential Oil*

In accord with our ability and experience in the isolation and identification of natural products from plants, as well as in assessing their biological activities, we decided to study the chemical components of *S. viticina* EO, as well as their biological effects, in the hope to finding new drug leads from natural sources. The isolation procedure was carried out using a microwave-ultrasonic apparatus. The phytochemical composition was identified and estimated using GC-MS. The obtained yield of the EO was 1.72 ± 0.97%. GC-MS analyses indicated the presence of 52 phytochemical compounds in *S. viticina* EO, of which *endo*-borneol was the major component, followed by eucalyptol and epizonarene, as revealed in Table 1 and Figure S1.

#### *2.2. Antioxidant and Metabolic Enzymes Inhibitory Activity*

The inhibitory activity of *S. viticina* EO against oxidation and metabolic enzymes (α-amylase and α-glucosidase and lipase) was assessed using standard biomedical assays. The results showed that *S. viticina* essential oil has α-amylase and α-glucosidase inhibitory activities, with IC50 values of 45.22 ± 1.1 and 63.09 ± 0.26 μg/mL, respectively.

As indicated in Table 2 and Figures S2–S5, the EO displayed antioxidant and antilipase activities with IC50 values of 19.95 ± 2.08 and 501.18 ± 0.38 μg/mL, respectively.


#### **Table 1.** *S. viticina* leaves EO phytochemical composition.


**Table 2.** The metabolic enzymes inhibitory and the antioxidant activities IC50 values of *S. viticina* essential oil compared with the required positive controls.
