Research Article LC-MS based identification of secondary metabolites from marine antagonistic endophytic bacteria

Abstract

Halophytes occupy coastal and sub-coastal area of marine environment. They potential candidates for search of novel and new bacterial flora that have immense potential to yield novel therapeutic agents. Six different endophytic bacteria have been isolated from pneumatophores and roots of three halophytes (Salsola imbricata, Avicennia marina and Haplopeplis perfoliata) collected from western coastal area of Jeddah, Saudi Arabia. After testing against five fungal pathogens all were active against oomycetes fungal pathogens, Phytophthora capsici and Pythium ultimum. Molecular identification of the bacteria was done on the basis of 16S rRNA gene sequences which revealed 95.9–99.4% sequence identity to related type strains and were placed in four major genera and two major classes: Actinobacteria (Streptomyces and Nocardioides) and α-Proteobacteria (Inquilinus and Labrezia). Active metabolites of these six bacterial endophytes including EA61, EA83, EA85, EA87, EA97 and EA220 were identified by subjecting to chemical analyses using liquid chromatography-mass spectrometry (LC-MS). LC-MS analyses showed presence of different active compounds in the culture extracts of these isolates. Some of these metabolites are already reported as synthetic molecules and has diverse biological functions as antimicrobial, anti-inflammatory and anthelmintic compounds such as such as Sulfamethoxypyridazine, Sulfamonomethoxine, Sulfamerazine and Dimetridazole, Sulfadiazin