Nine compounds (1-9) were isolated and characterized from the culture broth of the marine bacteria Micromonospora sp. (strain G068), which was isolated from sediment collected at Co To – Quang Ninh. Their structures were determined by spectroscopic analysis including MS, 1D NMR and 2D NMR, as well as by comparison with reported data in the literature. All compounds were evaluated for their antimicrobial activities against a panel of . Compounds 1, 6, and 9 selectively inhibited Escherichia coli with MIC values of 128, 128 and 64 μg/mL, respectively. | Journal of Science and Technology 54 (2C) (2016) 465-471 SECONDARY METABOLITES PRODUCED BY MARINE BACTERIRUM MICROMONOSPORA SP. (G068) Cao Duc Tuan1, 3, Vu Van Chien1, Pham Thi Hang1, Nguyen Quoc Vuong1, Doan Thi Mai Huong1, *, Le Thi Hong Minh1, Brian Murphy2, Chau Van Minh1, Pham Van Cuong1 1 Institute of Marine Biochemistry-VAST, 18, Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam 2 3 University of Illinois at Chicago, 700 S Halsted, Chicago, Illinois, USA Hai Phong University of Medicine and Pharmacy, 72A, Nguyen Binh Khiem, Ngo Quyen, Hai Phong, Vietnam * Email: doanhuong7@ Received: 15 May 2016; Accepted for publication: 28 October 2016 ABSTRACT Nine compounds (1-9) were isolated and characterized from the culture broth of the marine bacteria Micromonospora sp. (strain G068), which was isolated from sediment collected at Co To – Quang Ninh. Their structures were determined by spectroscopic analysis including MS, 1D NMR and 2D NMR, as well as by comparison with reported data in the literature. All compounds were evaluated for their antimicrobial activities against a panel of clinically significant microorganisms. Compounds 1, 6, and 9 selectively inhibited Escherichia coli with MIC values of 128, 128 and 64 μg/mL, respectively. Keywords: Micromonospora sp., marine microorganisms, antibacteria, norharman, cyclic dipeptide. 1. INTRODUCTION Marine microorganisms have been important targets to study in recent years because of their production of novel metabolites which represent various biological properties such as antiviral, antitumor or antimicrobial activities. These secondary metabolites serve as model systems in discovery of new drugs [1 - 4]. In the research for bioactive metabolites from marine bacteria, we examined the extract of the culture broth of the marine Micromonospora sp. (G068 strain). During our screening program, the EtOAc extract of this strain exhibited antimicrobial activity against a Gram negative (Escherichia coli - ATCC25922) .
