CHARACTERIZATION OF THE BIOACTIVE DIFFUSIBLE PIGMENT OF AN ACTINOMYCETE ISOLATED FROM PATAGONIAN SOIL

MARIA SOLEDAD VELA GUROVIC; NELDA LILA OLIVERA

Córdoba

Jornada; Reunión Internacional de Ciencias Farmacéuticas (RICIFA 2014); 2014

Actinomycetes comprise an enormous group of bacteria famous by its ability to produce antibiotics such as erythromycin, clindamycin, gentamycin among a huge amount of clinically successful antibiotics. It is known that the vast genomic potential of these bacteria has been underestimated. The key to unveil such metabolic productivity has not been cleared yet. However, some researchers suggest that changing the isolation and screening methods, the media and other production factors would lead to new metabolic diversity, and thus, new drug candidates for antibiotic therapy. The biodiversity of bacteria growing in Argentinean soils towards the production of antibiotics has not been explored yet. Here, we study the chemical composition of the antibacterial supernatant of Streptomyces sue01, an active strain isolated from Patagonian soils. This strain, identified by molecular methods as Streptomyces spp., was selected during a screening of antimicrobial producing strains as the most promising candidate from 60 isolates. Streptomyces SUE01 displayed a diffusible purple pigment and high antibacterial activity when grown in a medium supporting the production of potent antitumor antibiotics. After lyophilizing the active supernatant, a dark powder was obtained which was subjected to different extraction methods. The agar diffusion assay against Bacillus subtilis was used for monitoring the isolation steps and for assessing the potency of the lyophilized supernatant (156 ug/mL). The dark powder was extracted several times with methanol, yielding a blue-purple extract. Although both water soluble and methanol soluble fractions retained the activity, the 1HNMR profiles revealed differences on the chemical nature of the components. The HPLC chromatograms showed the presence of four main components in the methanol extracts. Two dimensional NMR experiments of this sample in D2O were performed revealing the presence of oxygenated carbons and double bonds with absence of alkylic components. These studies showed that the producing medium prompts the production of highly active metabolites of hydrophilic nature. Studies on dereplication will be further conducted with the aid of LC-MS techniques.