Prospecting Anticancer Compounds in Actinomycetes Recovered from the Sediments of Saint Peter and Saint Paul's Archipelago, Brazil

Abstract

Saint Peter and Saint Paul's Archipelago is a collection of 15 islets and rocks remotely located in the equatorial Atlantic Ocean. In this particular site, the present project intended to assess the biodiversity and biotechnological potential of bacteria from the actinomycete group. This study presents the first results of this assessment. From 21 sediment samples, 268 strains were isolated and codified as BRA followed by three numbers. Of those, 94 strains were grown in liquid media and submitted to chemical extractions with AcOEt (A), BuOH (B), and MeOH (M). A total of 224 extracts were screened for their cytotoxic activity and 41 were significantly active against HCT-116 cancer cells. The obtained IC values ranged from 0.04 to 31.55 μg/ml. The HR-LC/MS dereplication analysis of the active extracts showed the occurrence of several known anticancer compounds. Individual compounds, identified using HR-MS combined with analysis of the AntiMarin database, included saliniketals A and B, piericidins A and C and glucopiericidin A, staurosporine, N-methylstaurosporine, hydroxydimethyl-staurosporine and N-carbamoylstaurosporine, salinisporamycin A, and rifamycins S and B. BRA-199, identified as Streptomyces sp., was submitted to bioassay-guided fractionation, leading to isolation of the bioactive piericidins A and C, glucopiericidin, and three known diketopiperazines, cyclo(l-Phe-trans-4-OH-l-Pro), cyclo(l-Phe-l-Pro), and cyclo(l-Trp-l-Pro).

Marine Bacteria from Rocas Atoll as a Rich Source of Pharmacologically Active Compounds

“…The cytotoxic activity evaluation of the ethyl acetate extract obtained from each strain showed that 26 crude extracts were considered cytotoxic at 50 µg/mL (Figure 1a), while nine were also active at 5 µg/mL (Figure 1b). These numbers are similar to those obtained from other studies performed with marine bacteria recovered from sediments collected at Atlantic islands [20,21]. In a previous work that investigated culturable actinomycetes isolated from sediments collected at the Saint Peter and Saint Paul Archipelago, 268 strains were isolated from 21 sediment samples, while 94 strains were selected for cytotoxicity analysis of their crude extract against HCT-116 cell lines [20].…”

“…In a previous work that investigated culturable actinomycetes isolated from sediments collected at the Saint Peter and Saint Paul Archipelago, 268 strains were isolated from 21 sediment samples, while 94 strains were selected for cytotoxicity analysis of their crude extract against HCT-116 cell lines [20]. Among them, 26 strains produced cytotoxic extracts, and the chemical analysis by liquid chromatography-mass spectrometry (HPLC-MS/MS) suggested the production of known cytotoxic compounds, such as staurosporines and piericidins [20].…”

Streptomyces nigra sp. nov. Is a Novel Actinobacterium Isolated From Mangrove Soil and Exerts a Potent Antitumor Activity in Vitro

“…LC-MS/MS combined with UV data and database analyses are used to confirm the structure of compounds of interest ( Ferreira et al, 2016 ). A variety of diketopiperazines from strain 452 T were detected using LC-MS/MS and analyzed by comparing with data in the Human Metabolome Database 5 .…”

Anticancer Potential of Compounds from the Brazilian Blue Amazon

“…Among culturable actinobacteria isolated from sediments collected therein, 268 strains were isolated and 94 were tested for cytotoxicity of their extracts, from which 26 produced cytotoxic extracts. Chemical analysis by HPLC-MS/MS suggested the production of known cytotoxic compounds, such as staurosporines and piericidins and, interestingly, saliniketals and rifamycins [150]. The latter class of compounds are typical natural products synthesized by bacteria of the Salinispora genus.…”

“…Another strain recovered from the SPSPA that gave a cytotoxic extract, Streptomyces sp. BRA199, was subjected to a bioassayguided fractionation to yield piericidin A and 3 diketopiperazines [150]. Although the first compound was not particularly assessed therein for bioactivity, piericidins are widely known as potent cytotoxins, originally isolated from actinobacteria, especially from Streptomyces sp.…”