**Nidal Jaradat 1,\* and Nawaf Al-Maharik 2,\***


Received: 20 August 2019; Accepted: 19 October 2019; Published: 28 October 2019

**Abstract:** The present study aimed to identify the chemical constituents and to assess the in-vitro, antimicrobial, anticancer, antioxidant, metabolic enzymes and cyclooxygenase (COX) inhibitory properties of essential oil (EO) of *Stachys viticina* Boiss. leaves. The *S. viticina* EO was isolated and identified using microwave-ultrasonic and GC-MS techniques, respectively. Fifty-two compounds were identified, of which *endo*-borneol was the major component, followed by eucalyptol and epizonarene. The EO was evaluated against a panel of in-vitro bioassays. The EO displayed antimicrobial activity against methicillin-resistant *Staphylococcus aureus* (MRSA), *Escherichia coli* and *Epidermophyton floccosum*, with MIC values of 0.039, 0.078 and 0.78 mg/mL, respectively. The EO exhibited cytotoxicity against HeLa (cervical adenocarcinoma) and Colo-205 (colon) cancer cell lines with percentages of inhibition of 95% and 90%, for EO concentrations of 1.25 and 0.5 mg/mL, respectively. Furthermore, it showed metabolic enzyme (α-amylase, α-glucosidase, and lipase) inhibitory (IC50 = 45.22 ± 1.1, 63.09 ± 0.26, 501.18 ± 0.38 μg/mL, respectively) and antioxidant activity, with an IC50 value of 19.95 ± 2.08 μg/mL. Moreover, the *S. viticina* EO showed high cyclooxygenase inhibitory activity against COX-1 and COX-2 with IC50 values of 0.25 and 0.5 μg/mL, respectively, similar to those of the positive control (the NSAID etodolac). Outcomes amassed from this investigation illustrate that *S. viticina* EO represents a rich source of pharmacologically active molecules which can be further validated and explored clinically for its therapeutic potential and for the development and design of new natural therapeutic preparations.

**Keywords:** *Stachys viticina*; essential oil; cytotoxicity; antioxidant; antimicrobial; metabolic enzymes; cyclooxygenase
