Valiollah Hajhashemi - Department of Pharmacology and Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
Behzad Zolfaghari - Department of Pharmacognosy, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
Pooya Amin - Department of Pharmacology and Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran

Objective: Several species of Pinus have shown anti-nociceptive and anti-inflammatory properties. This study was aimed to evaluate anti-nociceptive and anti-inflammatory effects of hydroalcoholic extract of bark and essential oil of leaves of P. eldarica in animal models.  Materials and Methods: Hydroalcoholic extract of bark and essential oil of leaves of P. eldarica were prepared and phenolic content and essential oil composition were analyzed using Folin-Ciocalteu method and GC/MS, respectively. Anti-nociceptive effect was assessed using acetic acid, formalin and hot plate tests in male Swiss mice (۲۵-۳۰ g) and for evaluation of anti-inflammatory activity, carrageenan test in male Wistar rats (۱۸۰-۲۰۰ g) and croton oil-induced ear edema in male mice, were used. Involvement of opioid, α۲-adrenergic, ۵-HT۳ receptors and adenosine triphosphate (ATP)-dependent K+ channels in pain relief was tested using naloxone, ondansetron, yohimbine and glibenclamide. Results: The total phenolic content of the extract in terms of gallic acid equivalent was ۴۰۴.۹±۷.۷ mg/g of the extract powder. P. eldarica hydroalcoholic extract (۲۰۰ and ۴۰۰ mg/kg) and essential oil (۱۰۰ and ۲۰۰ µl/kg) significantly (all, p <۰.۰۰۱) decreased pain behavior in acetic acid and formalin tests but not in hot plate test. The extract and essential oil suppressed edema in carrageenan and croton tests. Glibenclamide partially reversed the anti-nociceptive effect of hydroalcoholic extract while the other antagonists were ineffective. Conclusion: Hydroalcoholic extract of bark and essential oil of leaves of P. eldarica significantly decreased acute and chronic pain as well as inflammation. ATP-dependent K+ channels mediate a part of the observed anti-nociceptive effect.

Analgesic, Anti-inflammation, Herbal Medicine, Pinus eldarica