Introduction Garlic (Allium sativum) is one of the oldest medicinal plants used by diferent cultures. Already in antiquity it was used for treatment and prevention of some diseases (1) . It has been shown that garlic has diferent applica- tions as an antimicrobial, (2) antitumor, (3) antithrombotic, hypolipidemic, antiarthritic, and hypoglycemic agent. (4,5) A wide range of mechanisms has been suggested for diferent efects of garlic. Its antitumor efect would be attributable to its antiproliferative action on carcinoma cells and its inhibitory activity on angiogenesis. (6) Also, aged garlic extract (AGE) can regulate immune cells as macrophages. AGE and its constituents are claimed to possess beneicial efects for prevention of atheroscle- rotic vascular diseases (7) which are thought to be at least partly due to its antioxidant properties, (8) suppression of CD36 expression and oxidized low-density lipoprotein (OxLDL) uptake into macrophages. (7) Our previous stud- ies also demonstrated that garlic enhances natural killer (NK) cell activity (9) and T-lymphocyte function (10) and sup- presses indoleamin 2,3-dioxygenase (IDO) expression. (11) A variety of compounds isolated from various prepara- tions have been identiied as being responsible for bio- logical efects of garlic. he garlic oil derivatives, diallyl sulide, diallyl disulide, and allyl methyl sulide have Immunopharmacology and Immunotoxicology, 2010, 1–7, Early Online Address for Correspondence: Zuhair Mohammad Hassan, Department of Immunology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran. E-mail: hasan_ZM@modares.ac.ir RESEARCH ARTICLE Efect of 14-kDa and 47-kDa protein molecules of age garlic extract on peritoneal macrophages Saeed Daneshmandi 1 , Monire Hajimoradi 1 , Hasan Namdar Ahmadabad 1 , Zuhair Mohammad Hassan 1 , Maryam Roudbary 2 , and Tooba Ghazanfari 3 1 Department of Immunology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran, 2 Department of Mycology, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran, and 3 Department of Immunology, Medical School, University of Shahed, Tehran, Iran Abstract Introduction: Garlic (Allium sativum), traditionally being used as a spice worldwide, has different applications and is claimed to possess beneficial effects in several health ailments such as tumor and atherosclerosis. Garlic is also an immunomodulator and its different components are responsible for different properties. The present work aimed to assess the effect of protein fractions of garlic on peritoneal macrophages. Materials and methods: 14-kDa and 47-kDa protein fractions of garlic were purified. Mice peritoneal macro- phages were lavaged and cultured in a microtiter plate and exposed to different concentrations of garlic pro- teins. MTT assay was performed to evaluate the viability of macrophage. The amount of nitric oxide (NO) was detected in culture supernatants of macrophages by Griess reagent and furthermore, the cytotoxicity study of culture supernatants was carried out on WEHI-164 fibrosarcoma cell line as tumor necrosis factor-α bioassay. Results: MTT assay results for both 14-kDa and 47-kDa protein fractions of stimulated macrophages were not significant (P > 0.05). Both 14-kDa and 47-kDa fractions significantly suppressed production of NO from macro- phages (P = 0.007 and P = 0.003, respectively). Cytotoxicity of macrophages’ supernatant on WEHI-164 fibrosar- coma cells was not affected by garlic protein fractions (P = 0.066 for 14-kDa and P = 0.085 for 47-kDa fractions). Conclusion: according to our finding, 14-kDa and 47-kDa fractions of aged garlic extract are able to suppress NO production from macrophages, which can be used as a biological advantage. These molecules had no cytotoxic effect on macrophages and do not increase tumoricidal property of macrophages. Keywords: Allium sativum; nitric oxide; MTT; TNF-α (Received 25 December 2009; revised 02 February 2010; accepted 09 February 2010) ISSN 0892-3973 print/ISSN 1532-2513 online © 2010 Informa UK Ltd DOI: 10.3109/08923971003690041 http://www.informahealthcare.com/ipi