2009 Kyung Hee University Press 277 Oriental Pharmacy and Experimental Medicine 2009 9(4), 277-284 www.opem.org OPEM In vitro anti-oxidant activity of the leaves of Dillenia indica Moni Rani Saha 1 , Md Ashraful Alam 1, * , SM Raquibul Hasan 1 , Raushanara Akter 1 , Md Mokarram Hossain 1 , Ehsanul Hoque Mazumder 2 and Md Sohel Rana 2 1 Department of Pharmacy, Stamford University, Bangladesh; 2 Jahangirnagar University, Saver, Dhaka, Laboratory of Pharmacognosy and Pharmacology, Department of Pharmacy, Stamford University, Bangladesh Received for publication April 22, 2008; accepted April 29, 2009 SUMMARY The methanol extract of Dillenia indica was tested for antioxidant activity as determined by free radical scavenging of DPPH radical scavenging assay, reducing power, total antioxidant capacity measured by phosphomolybdenum method, total phenolic content and total flavonoids content determination assays. The extract showed significant activities in all antioxidant assays compared to the standard antioxidant in a dose dependent manner. In DPPH radical scavenging assay the IC value of the extract was found to be 100.53 μg/ml while ascorbic acid has the IC value 58.92 μg/ml. Dillenia indica extract showed strong reducing power and total antioxidant capacity. Moreover, methanol extracts also possess high amount of phenolics and flavovonoids and expressed as gallic acid and rutin equivalent respectively. The remarkable activities exhibited in reactive oxygen species scavenging may attributed to the high amount of hydrophilic phenolics present in Dillenia indica. Key words: Dillenia indica; DPPH; Total antioxidant capacity; Reactive oxygen species INTRODUCTION Endogenous free radicals such as superoxide, nitric oxide and hydroxyl free radicals are produced in the human body, everyday. In recent years, oxygen- derived free radicals have been reported to be closely involved in many biological symptoms such as inflammation, cancer, atherosclerosis, and coronary heart disease (Kourounakis et al., 1999; Gulcin et al., 2002). To prevent or delay the oxidation process, addition of antioxidants to foods is the most extensively used method. Although synthetic antioxidants such as butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertbutylhydroquinone (TBHQ) have been commonly used as antioxidants in foods for years, their safety has long been questioned (Branen, 1975; Ito et al., 1983). However BHT and BHA have been suspected of being responsible for liver damage and carcinogenesis (Grice, 1986; Wichi, 1988; Hettiarachchy et al., 1996). This has led to an increased interest in natural antioxidants (Braca et al., 2002; Gyamfi and Aniya, 2002; Kayano et al., 2002; Lim et al., 2002). The plant under investigation is a tree Dillenia indica belonging to the family Dilleniaceae. The fruit of Dillenia indica is said to possess tonic and laxative properties and is used of abdominal pain. The bark and leaves are astringent (Ghani, 2003). Alcoholic extract of the leaves of Dillenia indica had been reported to possess CNS depressant activities in mice (Ghani, 2003). Seeds of Dillenia indica showed antimicrobial activity (Ghani, 2003). Fruits of Dillenia indica also possessed antioxidant activity *Correspondence: Md Ashraful Alam, Department of Pharmacy, Stamford University, Bangladesh. E-mail: sonaliagun@yahoo.com DOI 10.3742/OPEM.2009.9.4.277