The Antioxidant Activity of Allylpyrocatechol is Mediated via Decreased Generation of Free Radicals Along With Escalation of Antioxidant Mechanisms Debjani Sarkar, 1,# Sunanda Kundu, 1 Soumita De, 1 Chellaram Hariharan, 2 Piu Saha, 1 Alak Manna, 1 Subrata Chattopadhyay 3 and Mitali Chatterjee 1 * 1 Department of Pharmacology, Institute of Postgraduate Medical Education & Research, 244 B Acharya JC Bose Road, Kolkata 700020, India 2 Microbiology Division, Central Drugs Laboratory, 3 Kyd Street, Kolkata 700016, India 3 Bio-Organic Division, Bhabha Atomic Research Centre, Mumbai 400085, India Allylpyrocatechol (APC) is responsible for the antiinflammatory activity exhibited by the methanolic extract of leaves of Piper betle. As antiinflammatory compounds may display antioxidant properties and vice versa, we investigated the antioxidant effect of APC. APC effectively reduced phorbol-myristate-acetate-induced generation of reactive oxygen species and superoxide in murine peritoneal macrophages as well as inhibited Escherichia-coli-induced phagocytic activity of macrophages. Furthermore, pBluescript SK + plasmid DNA damage induced by addition of sodium ascorbate was attenuated by APC as it inhibited transformation of the supercoiled form to a relaxed form. In addition, APC increased the enzymatic (catalase) and nonenzymatic (GSH) antioxidant components of murine macrophages. Taken together, APC exhibited an antioxidant activity which was mediated both via decreased generation of free radicals along with increase in cellular antioxidants. Copyright © 2012 John Wiley & Sons, Ltd. Keywords: allylpyrocatechol; catalase; DNA damage; GSH; phagocytosis; reactive oxygen species. INTRODUCTION Oxidative stress is defined as an imbalance between pro- oxidants and antioxidants, leading to disruption of redox signaling culminating in cellular damage (Droge, 2002 and ref. therein). The pro-oxidants include reactive oxygen species (ROS) that are generated through an incomplete reduction of oxygen molecules especially during respiration. They manifest detrimental results by virtue of their reaction with cellular components like the cell wall, lipid membranes, mitochondria, and DNA (Droge, 2002 and ref. therein). The generation of ROS gets amplified in several pathophysiological conditions such as inflammation, immunological disorders, and exposure to UV or radiation (Chan et al., 1999). Gener- ally, a redox balance is maintained by the presence of antioxidants and comprise of an enzymatic and a none- nzymatic component (Halliwell, 2006). The enzymatic antioxidant components comprise catalase, superoxide dismutase, GSH peroxidase, GSH reductase, ascorbate oxidase, and glucose 6 phosphate dehydrogenase (Bandyopadhyay et al., 1990) among others, whereas the nonenzymatic system comprises GSH, vitamin A, vitamin C, vitamin E, various iron chelators, melatonin, etc. (Reiter et al., 1995). Piper betle (Piperaceae), a perennial climber, has its ethnomedicinal properties traceable to Sanskrit litera- ture as early as 3000 BC, and in more recent years, its cytoprotective, radioprotective, antimicrobial, antifun- gal, antiinflammatory and antioxidant activities (Sarkar et al., 2008 and ref. therein) have been scientifically validated. The antiinflammatory activity of P. betle has been attributed to allylpyrocatechol (APC), a phytoconstituent present in ethanolic extract of leaves of P. betle (Sarkar et al., 2008), which has also been shown to inhibit Fe(II)-induced lipid peroxidation (Rathee et al., 2006). As ROS, independently or in combination, can aggravate the inflammatory response (Halliwell, 2006; Speranza et al., 2010), it may be extra- polated that antiinflammatory compounds may also display antioxidant properties and vice versa. Accordingly, this study was undertaken to determine the antioxidant activity of APC. MATERIALS AND METHODS Materials All chemicals were obtained from Sigma Aldrich (St. Louis, Missouri, USA) except nitroblue tetrazolium (NBT), potassium hydroxide, 5,5′-dithio-bis (2-nitro- benzoic acid) (DTNB, Sisco Research Laboratories, * Correspondence to: Mitali Chatterjee, Department of Pharmacology, Institute of Postgraduate Medical Education & Research, 244 B Acharya JC Bose Road, Kolkata 700020, India. E-mail: ilatim@vsnl.net # Department of Zoology, Barasat Government College, 10 KNC Road, Barasat, 24 Pgs. (N) Kolkata 700124, India PHYTOTHERAPY RESEARCH Phytother. Res. (2012) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/ptr.4720 Copyright © 2012 John Wiley & Sons, Ltd. Received 01 February 2012 Revised 29 March 2012 Accepted 13 April 2012