Chemical and Biological Investigations of Vietnamese cyanobacteria

• Main Author: Le Thi Anh Tuyet
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2010
• Subjects: Cyanonacteria; ddc:540; Antarctic; The Antarctic; Antarc*
• Online Access: https://epub.ub.uni-greifswald.de/frontdoor/index/index/docId/662; https://nbn-resolving.org/urn:nbn:de:gbv:9-000848-1; https://epub.ub.uni-greifswald.de/files/662/PhDthesis_19.7.2010_LeThiAnhTuyet.pdf

Chemische und biologische Untersuchungen Vietnamesischer Cyanobakterien Summary Cyanobacteria are a diverse and ancient group of photosynthetic prokaryotic organisms that can inhabit a wide range of environments including extreme conditions such as hot springs, desert soils and the Antarctic. They are abundant producers of natural products well recognized for their bioactivity and utility in drug discovery and biotechnology applications. Novel intracellular and extracellular compounds from various cultured and field cyanobacteria with diverse biological activities and a wide range of chemical classes have considerable potential for development of pharmaceuticals and other biomedical applications. However, cyanobacteria are still viewed as unexplored source of potential drugs. Especially the collections of cyanobacterial strains from South East Asia where biodiversity is high are still largely unexplored. Thus, we investigated twelve soil cyanobacterial strains isolated from soil samples collected from rice, cotton, and coffee fields in Dak Lak province of Vietnam and one marine strain, Lyngbya majuscula collected from Khanh Hoa province of Vietnam for the search for new compounds with antimicrobial and cytotoxic activities. From the 12 soil cyanobacterial strains, 48 extracts prepared with n-hexane, methanol, and water for biomasses and ethyl acetate for growth media were screened for antibacterial activity against Gram-positive bacteria (Bacillus subtilis ATCC 6051 and Staphylococcus aureus ATCC 6538) and Gram-negative bacteria (Escherichia coli ATCC 11229, Pseudomonas aeruginosa ATCC 27853). Of 48 extracts, 47.92% and 45.83% showed activity against Bacillus subtilis and Staphylococcus aureus, respectively, while 22.92% and 6.25% exhibited activity against Escherichia coli and Pseudomonas aeruginosa, respectively. All investigated cyanobacteria (12/12) showed antibacterial activity to at least one of the test organisms applied. Among the active extracts, extracts obtained from 5 cyanobacterial strains, ...