In the search for antiviral cyclopeptides against influenza A virus, five unprecedented Caryophyllaceae-type cyclopeptides ( 1 – 5 ) were isolated from the leaves of Melicope pteleifolia . Their chemical structures and absolute configurations were unambiguously determined by means of advanced Marfey’s analysis and comprehensive spectroscopic analyses including two-dimensional nuclear magnetic resonance and MS/MS fragmentation. Interestingly, compounds 3 – 5 contain an unusual heterocycle, a 3a-hydroxypyrroloindole moiety, which was biosynthetically formed by a nucleophilic cyclization from the least abundant amino acid, tryptophan, precursor and has aroused a great interest in the aspect of chemical diversity and biological activity. All isolates ( 1 – 5 ) were evaluated for their protective effects against influenza A viruses H1N1 and H9N2 in MDCK cells. All isolated cyclopeptides exhibited strong anti-influenza activity, especially against H1N1. Compound 3 showed the most potent CPE inhibition effect, which was stronger than that of the positive control ribavirin against H1N1, with an EC_{50} (μM) of 2.57 ± 0.45 along with higher selectivity.
Melicopteline A-E, Unusual Cyclopeptide Alkaloids with Antiviral Activity against Influenza A Virus from Melicope pteleifolia
[Category] 신종인플루엔자,
[Source] pubmed
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