Abstract
A new alkaloid, 2-(furan-2-yl)-6-(2S,3S,4-trihydroxybutyl)pyrazine (1), along with 12 known compounds, 2-(furan-2-yl)-5-(2S,3S,4-trihydroxybutyl)pyrazine (2), (S)-4-isobutyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (3), (S)-4-isopropyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (4), (4S)-4-(2-methylbutyl)-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (5), (S)-4-benzyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazine-6-carbaldehyde (6), flazin (7), perlolyrine (8), 1-hydroxy-β-carboline (9), lumichrome (10), 1H-indole-3-carboxaldehyde (11), 2-hydroxy-1-(1H-indol-3-yl)ethanone (12), and 5-(methoxymethyl)-1H-pyrrole-2-carbaldehyde (13), were isolated and identified from the fermentation broth of an endophytic actinomycetes, Jishengella endophytica 161111. The new structure 1 and the absolute configurations of 2–6 were determined by spectroscopic methods, J-based configuration analysis (JBCA) method, lactone sector rule, and electronic circular dichroism (ECD) calculations. Compounds 8–11 were active against the influenza A virus subtype H1N1 with IC50 and selectivity index (SI) values of 38.3(±1.2)/25.0(±3.6)/39.7(±5.6)/45.9(±2.1) μg/mL and 3.0/16.1/3.1/11.4, respectively. The IC50 and SI values of positive control, ribavirin, were 23.1(±1.7) μg/mL and 32.2, respectively. The results showed that compound 9 could be a promising new hit for anti-H1N1 drugs. The absolute configurations of 2–5, 13C nuclear magnetic resonance (NMR) data and the specific rotations of 3–6 were also reported here for the first time.
Highlights
Mangroves, unique forest ecosystems found mainly in the tropical and subtropical intertidal regions, represent a rich biological diversity and a high population of actinomycetes [1,2]
Pyrazine alkaloids from marine organisms exhibited cytotoxic and antimicrobial activities [17,18,19,20,21], three of which were identified from the mangrove plant [22] and fungi [23,24]. β-Carbolines, as a type of natural indol alkaloids, displayed cytotoxic [25], antiviral [26,27], antimicrobial [28], antiparasitic [29], and antithrombotic activities [30]
The EtOAc extract of the fermentation broth of J. endophytica 161111 was subjected to extensive chromatographic separations over silica gel, RP-18, Sephadex LH-20 and high performance liquid chromotography (HPLC) to yield the new compound 1 and the known compounds 2–13
Summary
Unique forest ecosystems found mainly in the tropical and subtropical intertidal regions, represent a rich biological diversity and a high population of actinomycetes [1,2]. From these actinomycetes, many bioactive compounds such as cytotoxic streptocarbazoles A and B have been obtained [3]. Pyrazine alkaloids from marine organisms exhibited cytotoxic and antimicrobial activities [17,18,19,20,21], three of which were identified from the mangrove plant [22] and fungi [23,24]. Pyrrololactones that had been reported as the volatile components of the roasted roots of Cichorium intrybus [8] were not identified from the marine organisms
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
