Bioactive 2(1H)-Pyrazinones and Diketopiperazine Alkaloids from a Tunicate-Derived Actinomycete Streptomyces sp.
AbstractAs a part of our ongoing effort to allocate marine microbial bioactive leads, a tunicate-derived actinomycete, Streptomyces sp. Did-27, was investigated. Three new 2(1H)-pyrazinones derivatives, (S)-6-(sec-butyl)-3-isopropylpyrazin-2(1H)-one (1), (S)-3-(sec-butyl)-6-isopropylpyrazin-2(1H)-one (2) and (S)-6-(sec-butyl)-3-isobutylpyrazin-2(1H)-one (3), together with the known (1H)-pyrazinones analogues deoxymutaaspergillic acid (4), 3,6-diisobutyl-2(1H)-pyrazinone (5) and 3,6-di-sec-butyl-2(1H)-pyrazinone (6), and the diketopiperazine alkaloids cyclo(6-OH-d-Pro-l-Phe) (7), bacillusamide B (8), cyclo(l-Pro-l-Leu) and cyclo(l-Pro-l-Ile) (10) were isolated from this strain. The structures of the compounds were determined by study of their one- and two-dimensional NMR spectra as well as high-resolution mass spectral determinations. Compound 4 was reported previously as a synthetic product, while compound 6 was reported as 2-hydroxy-3,6-di-sec-butylpyrazine. Herein, we report the complete NMR data for compounds 4 and 6. The compounds were evaluated for their cytotoxic activities against three cell lines. Compound 5 showed potent and selective activity against HCT-116 cell line with IC50 of 1.5 μg/mL, while 1–10 showed variable cytotoxic activities against these cancer cell lines. These results provide further understanding about the chemistry and bioactivities of the alkylated 2(1H)-pyrazinone derivatives. View Full-Text
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Shaala, L.A.; Youssef, D.T.A.; Badr, J.M.; Harakeh, S.M. Bioactive 2(1H)-Pyrazinones and Diketopiperazine Alkaloids from a Tunicate-Derived Actinomycete Streptomyces sp.. Molecules 2016, 21, 1116.
Shaala LA, Youssef DTA, Badr JM, Harakeh SM. Bioactive 2(1H)-Pyrazinones and Diketopiperazine Alkaloids from a Tunicate-Derived Actinomycete Streptomyces sp.. Molecules. 2016; 21(9):1116.Chicago/Turabian Style
Shaala, Lamiaa A.; Youssef, Diaa T.A.; Badr, Jihan M.; Harakeh, Steve M. 2016. "Bioactive 2(1H)-Pyrazinones and Diketopiperazine Alkaloids from a Tunicate-Derived Actinomycete Streptomyces sp.." Molecules 21, no. 9: 1116.
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