Saccharopolytide A, a new cyclic tetrapeptide with rare 4-hydroxy-proline moieties from the deep-sea derived actinomycete Saccharopolyspora cebuensis MCCC 1A09850.

A genome mining analysis on the deep-sea derived actinomycete Saccharopolyspora cebuensis MCCC 1A09850 indicated its potential to produce polypeptides. Accordingly, a systematic chemical investigation was conducted, which resulted in the isolation of one new cyclic tetrapeptide (saccharopolytide A, 1) and two known polyketides (2, 3) along with six other miscellaneous compounds (4‒9). Mainly by analysis of the 1D, 2D NMR and MS data, the chemical structure of saccharopolytide A was established as cyclo-(l-Leu-4-hydroxy-l-Pro-l-Phe-4-hydroxy-l-Pro). All isolates were evaluated for anti-allergic and anti-tumor bioactivities. Indol-3-carbaldehyde (4) showed weak anti-allergic effect with IC50 value of 55.75 µg/mL. And 2 showed weak anti-proliferative activity against Hela and H1299 tumor cell lines. Our results consolidate the potential of deep-sea-derived microorganisms to produce structurally interesting compounds.

[Secondary metabolites from a deep-sea-derived actinomycete Micrococcus sp. R21].

To investigate cytotoxic secondary metabolites of Micrococcus sp. R21, an actinomycete isolated from a deep-sea sediment (-6 310 m; 142 degrees 19. 9' E, 10 degrees 54. 6' N) of the Western Pacific Ocean, column chromatography was introduced over silica gel, ODS, and Sephadex LH-20. As a result, eight compounds were obtained. By mainly detailed analysis of the NMR data, their structures were elucidated as cyclo(4-hydroxy-L-Pro-L-leu) (1), cyclo(L-Pro-L-Gly) (2), cyclo( L-Pro-L-Ala) (3), cyclo( D-Pro-L-Leu) (4), N-ß-acetyltryptamine (5), 2-hydroxybenzoic acid (6), and phenylacetic acid (7). Compound 1 exhibited weak cytotoxic activity against RAW264. 7 cells with IC50 value of 9.1 µmol x L(-1).