Taxonomy, purification and chemical characterization of four bioactive compounds from new Streptomyces sp. TN256 strain

Abstract

A new actinomycete strain designated TN256, producing antimicrobial activity against pathogenic bacteria and fungi, was isolated from a Tunisian Saharan soil. Morphological and chemical studies indicated that strain TN256 belonged to the genus Streptomyces. Analysis of the 16S rDNA sequence of strain TN256 showed a similarity level ranging between 99.79 and 97.8% within Streptomyces microflavus DSM 40331(T) and Streptomyces griseorubiginosus DSM 40469(T) respectively. The comparison of its physiological characteristics showed significant differences with the nearest species. Combined analysis of the 16 S rRNA gene sequences (FN687758), fatty acids profile, and results of physiological and biochemical tests indicated that there were genotypic and phenotypic differentiations of that isolate from other Streptomyces species neighbours. These date strongly suggest that strain TN256 represents a novel species with the type strain Streptomyces TN256 (=CTM50228(T)). Experimental validation by DNA-DNA hybridization would be required for conclusive confirmation. Four active products (1-4) were isolated from the culture broth of Streptomyces TN256 using various separation and purification steps and procedures. 1: N-[2-(1H-indol-3-yl)-2 oxo-ethyl] acetamide 'alkaloid' derivative; 2: di-(2-ethylhexyl) phthalate, a phthalate derivative; 3: 1-Nonadecene and 4: Cyclo (L: -Pro-L: -Tyr) a diketopiperazine 'DKP' derivative. The chemical structure of these four active compounds was established on the basis of spectroscopic studies NMR and by comparing with data from the literature. According to our biological studies, we showed in this work that the pure compounds (1-4) possess antibacterial and antifungal activities.

In vivo antimalarial activity of the endophytic actinobacteria, Streptomyces SUK 10

“…In this study, the natural product gave an optical rotation of []D -138.2 (c = 1.0, EtOH) which was compatible with those isolated earlier from other Streptomyces strains (Jain et al, 1977). This diketopiperazine (DKP) derivative compound is naturally produced by many organisms and displays a wide diversity of structures and biological functions (Smaoui et al, 2012). This scenario suggests that Gancidin W may be a useful chemical entity for the discovery and development of new drugs.…”

Purification and identification of two antifungal cyclic dipeptides from Bacillus cereus subsp. thuringiensis associated with a rhabditid entomopathogenic nematode especially against Fusarium oxysporum

“…Cain et al 44 reported that cyclo(Pro-Tyr) exhibits no activity against strains of Micrococcus luteus, Mycobacterium smegmatis, Sacharomyces cerevisiae, Candida neoformans, Candida albicans and Aspergillus niger. Smaoui et al 45 reported the antimicrobial activity of Cyclo(Pro-Tyr) against Micrococcus luteus LB 14110, S. enterica ATCC43972 and Fusarium sp. Cyclo(Pro-Tyr) demonstrated inhibitory effects against bioluminescence by V. harveyi 46 .…”

Cyclopeptides from marine actinomycete Streptomyces sp. G261

“…This observation strongly suggested that the leucine unit of 1 was replaced by the 4hydroxyphenylanaline moiety in 5. Comparison with the literature, [10][11][12] compound 5 was identified as Cyclo-(Pro-Tyr). This cyclodipeptide had antibacterial activity against both Gram-positive and Gram-negative bacteria and antifungal property.…”