ISSN: 2320-1924 Narges Eskandari Roozbahani. Department of Pharmacology, School of Veterinary Medicine, Shiraz University, P.O. Box 1731, Shiraz 71345, Iran, E-mail: neskandari32@yahoo.com JOURNAL OF PHARMACEUTICAL AND BIOLOGICAL SCIENCES (Available online at http://www.jpabs.com/) THE EFFECT OF AQUEOUS EXTRACT OF GARLIC ON FORMALIN-INDUCED PAIN IN MALE RATS. Narges Eskandari Roozbahani 1 *, Javad Sajedianfard 2 , Negar Karimaghaie 2 , Hamid Rajaian 1 1 Department of Pharmacology, School of Veterinary Medicine, Shiraz University, P.O. Box 1731, Shiraz 71345, Iran 2 Department of Physiology, School of Veterinary Medicine, Shiraz University, P.O. Box 1731, Shiraz 71345, Iran Received: 13 Sep 2014/ Accepted: 15 Oct 2014/ Published online: 25 Oct 2014 © JPABS – 2014 ABSTRACT : Garlic, belongs to the Liliaceae family and Allium sativum species and is native to Asia. Various health benefits, such as reducing blood glucose, cholesterol and blood pressure, beneficial effects on the cardiovascular system, coagulation disorders and antioxidative effects have been recognized since ancient times. It has also been used to treat respiratory and gastrointestinal diseases. In addition, it is effective used against parasitic, viral, bacterial and fungal infections. Moreover, it has been used to relieve rheumatic pains. The aim of this study was to evaluate the analgesic effect of aqueous extract of garlic (AEG) in the formalin test as an experimental model of acute and chronic chemical pain. Forty two male Wistar rats (250±30 g) were used and pain was induced via injection of 2.5% formalin into the rat’s hind paw and pain behaviors were monitored for one hour. The analgesic effect of AEG, with doses of 5 and 2.5 ml/kg via intraperitoneal injection were assessed in formalin test after 15 and 30 min. Analgesic effect of intraperitoneal and oral administration of AEG, during 30 min before formalin test, was also investigated. Results showed that various doses of AEG significantly (P<0.05) reduced pain showing a maximum effect with a dose of 2.5 ml/kg administered 15 min before formalin test. AEG with a dose of 2.5 ml/kg in 15 min before induction of pain has a good pain reliefing effect in formalin test both in acute and chronic phases in the rat. Key Words: Garlic, Pain, Analgesia, Formalin test, Rat. INTRODUCTION: Pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage that causes person to react to eliminate the painful stimulus. 1,2 Nociceptors, can convert a range of stimuli to receptor potential which in turn initiates an efferent action potential. 3 Injury release prostaglandins and bradykinin which activate nociceptors, followed by a release of substance P and Calcitonin Gene Related Peptide. 4 Garlic belongs to the Liliaceae family, Allium sativum species and is native to Asia. The major part of this plant that is used as drug is the “Bullb”. 5 Raw garlic homogenate is the major preparation of garlic and is essentially the same as aqueous extract of garlic (AEG). 6 Allicin is thought to be the principal bioactive compound present in AEG. When garlic is chopped or crushed, allinase enzyme is activated and acts on alliin to produce allicin. 7 Active sulfur contains compounds of garlic are responsible for different biological functions such as antidiabetic, antibiotic, lipid lowering, fibrinolytic effect 8 , antiviral 9,10 , antibacterial 11 , antifungal 12,13 , antiparasitic 14,15 antioxidative 16,17 , prevent or treat of cardiovascular and several metabolic diseases 18,19,20 , atherosclerosis 21,22,23 , hyperlipidemia 19 , platelet aggregation 24,25,26 , hypertension and diabetes RESEARCH ARTICLE