Marine microbiology is one of the most promising fields in the study of bioactive natural products. As a renewable source, high diversity and the capacity to supply new metabolites of great pharmaceutical importance, marine microorganisms have proven to be efficient producers of unmatched structures with peculiar mechanisms of action1. This paper reports the chemical study of the hexane phase from ethyl acetate (EtOAc) extract of the bacteria BRB081 recovered from sediments collected at Araçá beach, São Sebastião – SP (23°48’54.4’’S; 45°24’26.7’’W). The isolated cultures were grown on A1 liquid medium and extracted with EtOAc. Crude extract showed cytotoxic activity against human adenocarcionma cells (HCT-116) and its chemical profile was evaluated by HPLC-MS and NMR. Subsequently, the crude extract (3.74g) was partitioned with hexane (484.3mg), chloroform (1.87g) and methanol (1.09g). Chloroform phase showed higher cytotoxic activity and was previously studied furnishing surugamides2. Hexane phase showed significant activity against HCT-116 and MCF-7 cells proliferation (41%) and (46%) respectively and its chemical composition was investigated. Derivatization of this phase was carried out with pyridine and BSTFA (N,O-bis-(trimethylsilyl)-trifluoroacetamide) for GC-MS analysis. The chemical composition of hexane phase was elucidated by mass spectra and through comparison with literature data. From this analysis, 86.75% of the extract was identified as phenylcarboxylic acids and fatty acids (Table 1). Among the components, the phenylacetic acid was found as the major compound (56.41%) on the extract. The phenylacetic acid has been described in literature as an excellent antimicrobial agent tested against plant and human pathogens3, however its antitumoral activity was not evaluated yet. The non-identified compounds (13.25%) in the hexane phase are branched fatty acids containing between 15 and 18 carbon atoms in the structure, although their structures could not be unambiguously determined by MS data.
Table 1. Compounds identified by CG-MS in hexane phase of EtOAc extract from marine bacteria
Peak Name C:insaturation Relative Percentual (%)
1 Phenylacetic acid - 56.41
2 4-Phenylbutanoic acid - 1.32
3 Tetradecanoic acid C14:0 1.11
4 Pentadecanoic acid C15:0 7.73
5 (Z)-Hexadec-9-enoic acid C16:1 3.38
6 Hexadecanoic acid C16:0 8.83
7 Heptadecanoic acid C17:0 6.50
8 Octadecanoic acid C18:0 1.47
Total Identified 86.75

Acknowledgments: Grant 2015/17177-6, São Paulo Research Foundation (FAPESP), CAPES and CNPq.
References:
1Costa-Lotufo, L.V.; Wilke, D.V.; Jimenez, P.C.; Epifanio, R.A. Quim. Nova, 32: 703-716, 2009.
2Takada, K.; Ninomia, A.; Naruse, M.; Sun, Y.; Miyazaki, M.; Nogi, Y.; Okada, S.; Matsunaga, S. J. Org. Chem. 78:6746–6750, 2013.
3Kulshreshtha, G.; Velusamy, P. Minerva Biotecnologica, 24: 29-36, 2012.