• Marwan Saad Azzubaidi Pharmacology Unit, Faculty of Medicine, Universiti Sultan Zainal Abidin Malaysia
  • Hussam Mizher Faculty of Pharmacy, International Islamic University Malaysia.
  • Ahmed Ghazi Alattraqchi Biochemistry Unit, Faculty of Medicine, Universiti Sultan Zainal Abidin Malaysia


Objective: The objectives of the current study were to confirm the blood pressure lowering effect of thymoquinone (TQ) and to investigate its mechanism through muscarinic and β-adrenergic receptors.

Methods: Mean arterial blood pressure (MAP) was recorded using the non-invasive blood pressure tail-cuff technique. A dose-response relationship was obtained after using 3 TQ doses (2.5, 5 and 10 mg/kg) intraperitoneally to 3 different groups (n =5) of adult rats under pentobarbital anesthesia. MAP was then measured for another 2 animal groups pretreated either with atropine (P-at) or propranolol (P-pro) followed by 10 mg/kg TQ.

Results: TQ produced a significant dose-dependent blood pressure and heart rate lowering effect. TQ-induced MAP reduction was significantly less pronounced in P-at (12±2.8 mmHg) than non-pretreated group (29±3.2 mmHg) with P<0.01. Conversely, TQ-induced MAP reduction in P-pro (28±3.4 mmHg) did not demonstrate a significant difference from the non-pretreated group (29±3.2 mmHg) with P>0.05.

Conclusion: This study confirms the dose-related hypotensive effect of TQ and provides an evidence for the traditional use of Nigella sativa for the treatment of hypertension. The mechanism of TQ-induced hypotension involves at least in part activation of vascular muscarinic receptors, but not β-adrenergic receptors.

Keywords: Thymoquinone, Atropine, Propranolol, Mean arterial pressure, Tail cuff, Cholinergic receptors, Adrenergic receptors, Heart rate


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How to Cite
Azzubaidi, M. S., H. Mizher, and A. G. Alattraqchi. “HYPOTENSIVE ACTIVITY OF THYMOQUINONE IN NORMOTENSIVE RATS AND ITS RECEPTOR MECHANISMS”. International Journal of Pharmacy and Pharmaceutical Sciences, Vol. 9, no. 8, Aug. 2017, pp. 216-8, doi:10.22159/ijpps.2017v9i8.16923.
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