Geldanamycin (1) had been isolated as a major compound from Streptomyces zerumbet W14; an endophyte of Zingiber zerumbet (L.) Smith. Two new geldanamycin derivatives; 17-(tryptamine)-17-demethoxygeldanamycin (2) and 17-(5-methoxytryptamine)-17-demethoxygeldanamycin (3) were synthesized and their antiviral activity was evaluated based on influenza virus propagation in embryonated chicken eggs and viral absorption by hemagglutination inhibition test. The findings indicated that these compounds inhibited viral propagation at concentration of 12.5 µg/ml. For the viral absorption, only compounds 2 and 3 inhibited hemagglutination at concentration of 50 µg/ml. The solubility of compounds 2 and 3 in water was 290 µM and 306 µM, higher than that of compound 1 about 1.91 and 2.01 times, respectively. The compounds 2 and 3 showed moderate cytotoxic activity on LLC-MK2 and Vero cells with IC50 values of >200.00 µg/ml. These results were expected to provide guides for the invention of tryptamine-geldanamycin hybrids to prevent influenza virus infection in viral absorption and viral propagation steps.
Key words: Antiviral activity, Endophytic Actinomycetes, Geldanamycin, Influenza virus, tryptamine-geldanamycin hybrids
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