American Journal of BioScience 2015; 3(2-1): 23-26 Published online April 21, 2015 (http://www.sciencepublishinggroup.com/j/ajbio) doi: 10.11648/j.ajbio.s.2015030201.15 ISSN: 2330-0159 (Print); ISSN: 2330-0167 (Online) Screening of Antioxidant and Antimicrobial Properties of the Syzygium jambos L. Mst. Marium Begum 2 , Majidul Haque 1 , Md. Reyad-ul-Ferdous 5 , Moynul Hasan 3 , Hasan Tarek 3 , Md. Noor-A-Alam 3 , Md. Belal Hossain 3 , Md. Nazir Uddin 3 , Taslima Begum 4 , Choudhury Mahmood Hasan 1, * 1 Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Dhaka, Dhaka-1000, Bangladesh 2 Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Dhaka, Dhaka-1000, Bangladesh 3 Department of Pharmacy, Dhaka International University, Dhaka-1213, Bangladesh 4 Department of Pharmacy, Primeasia University, Dhaka-1213, Bangladesh 5 Department of Pharmaceutical Sciences, North South University, Dhaka-1229, Bangladesh Email address: cmhasan@gmail.com (C. M. Hasan), rockyreyad@yahoo.com (M. R. Ferdous) To cite this article: Mst. Marium Begum, Majidul Haque, Md. Reyad-ul-Ferdous, Moynul Hasan, Hasan Tarek, Md. Noor-A-Alam, Md. Belal Hossain, Md. Nazir Uddin, Taslima Begum, Choudhury Mahmood Hasan. Screening of Antioxidant and Antimicrobial Properties of the Syzygium jambos L. American Journal of BioScience. Special Issue: Pharmacological and Phytochemicals Investigation. Vol. 3, No. 2-1, 2015, pp. 23-26. doi: 10.11648/j.ajbio.s.2015030201.15 Abstract: Syzygium jambos (L.) Alstone belonging to the Myrtaceae family have been investigated for evaluation of their biological activities namely antioxidant and antimicrobial activity. The n-hexane, carbon tetrachloride, chloroform, aqueous soluble fractions of methanolic extract as well as crude methanolic extract of stem barks of Syzygium jambos were evaluated for their free radical scavenging activity. The methanolic extract and aqueous soluble fractions of stem barks of Syzygium jambos exhibited significant antioxidant activity with the IC 50 value of 36.36 μg/ml and 44.744µg/ml respectively whereas chloroform, carbon tetrachloride and hexane soluble fraction of stem barks exhibited mild antioxidant activity with the IC 50 value 191.018, 257.102, 414.79 μg/ml respectively. The crude extract, along with n-hexane, carbon tetrachloride and chloroform partitionates of the crude extract of Syzygium jambos were screened for their antimicrobial activity against a wide range of both gram-positive and gram-negative bacteria by the disc diffusion method. The results obtained were compared with that of a standard antibiotic, ciprofloxacin. All the fractions of Syzygium jambos exhibited mild activity against most of the test organism. Keywords: Syzygium jambos, Medicinal Plant, Identification, Anti-oxidant, Antimicrobial Activity 1. Introduction In the plant kingdom there is a remedy for every disease [1] . Two hundred and fifty years ago, there were few or no synthetic medicines. The plants were the main source of drugs for the world's population. Today, 75% of the world's population, the poor 3/4 ths , still relies on those plants and other tools of traditional medicine [2] . Plants have provided a source of inspiration for novel drug compounds, as plant derived medicines have made large contributions to human health and well-being [3] . The number of higher plant species (angiosperms and gymnosperms) on this planet is estimated at 250,000 [4] , with a lower level at 215,000 [5] and an upper level as high as 500,000 [6,7] . Of these, only about 6% have been screened for biologic activity, and a reported 15% have been evaluated phytochemically [8] . Chemical diversity of secondary plant metabolites that results from plant evolution may be equal or superior to that found in synthetic combinatorial chemical libraries. Success in natural products research is conditioned by a careful plant selection, based on various criteria such as chemotaxonomic data, ethnomedical information, field observations or even random collection. One main strategy in the isolation of new leads consists of the so-called bioactivity-guided isolation, in which pharmacological or biological assays are used to target the isolation of bioactive compounds [9] . The work described in this dissertation is an attempt to