In this paper, we reported the isolation and structural elucidation of six secondary metabolites Cyclo-(Pro-Trp) (1), Cyclo-(Pro-Met) (2), Cyclo-(Pro-Val) (4), N-acetyltryptamine (3), uridine (5), and 2- phenylacetic acid (6) from the cultures broth of Micromonospora sp. (strain G044). | Journal of Science and Technology 55 (3) (2017) 251-257 SECONDARY METABOLITES FROM MICROMONOSPORA SP. (G044) Cao Duc Tuan1, 3, Truong Bich Ngan1, Doan Thi Mai Huong1, *, Vu Thi Quyen1, Le Thi Hong Minh1, Brian Murphy2, Chau Van Minh1, Pham Van Cuong1, * 1 Institute of Marine Biochemistry-VAST, 18, Hoang Quoc Viet, Cau Giay, Ha Noi, Viet Nam 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, Viet Nam * Email: doanhuong7@ Received: 24 August 2016; Accepted for publication: 28 December 2016 ABSTRACT In the course of our screening program, the EtOAc extract of a Micromonospora sp. (strain G044) from sponge Tethya aurantium of the sea of Côtô - Thanh Lân exhibited antimicrobial activity against Enterococcus faecalis, Bacillus cereus and Candida albicans. In this paper, we reported the isolation and structural elucidation of six secondary metabolites Cyclo-(Pro-Trp) (1), Cyclo-(Pro-Met) (2), Cyclo-(Pro-Val) (4), N-acetyltryptamine (3), uridine (5), and 2phenylacetic acid (6) from the cultures broth of Micromonospora sp. (strain G044). The structures of 1 – 6 were determined by analyses of MS and 2D NMR data. All compounds were evaluated for their antimicrobial activity against a panel of clinically significant microorganisms. Compound 1 inhibited Escherichia coli with a MIC value of 128 µg/ml. Keywords: Micromonospora sp., marine microorganisms, antimicrobial activity, Cyclo-(ProTrp), Cyclo-(Pro-Met), Cyclo-(Pro-Val). 1. INTRODUCTION Sponges have been the focus of many studies as they have proved to be a rich source of biologically active secondary metabolites. Since the discovery of spongothymidine and spongouridine in the early 50's [1], a large number of biologically active compounds were isolated from marine sponges and their associated microorganisms [2]. The chemical diversity of sponge-derived products is remarkable and their .
