In Vitro Antifungal and Antiviral Activities of γ-and δ-Lactone Analogs Utilized as Food Flavoring

Abstract

method and 96-well microbioassay system with a liquid culture system. These lactones fungicidally inhibited their growth because their minimum fungicidal concentrations were only 2 to 4 times that of their minimum inhibitory concentrations. Results obtained from their structure-fungicidal activity against two species of fungi were as follows: γ-lactones exhibit higher antifungal activity than δ-lactones; the antimicrobial effects of γ-lactones are intensified as the side chain length increases; massoialactone with an unsaturated δ-lactone ring gives a smaller minimum inhibitory concentration against the two types of fungi compared with γ-and δ-decalactones; and the (R)-forms of γ-undecalactone and γ-dodecalactone inhibit the growth of A. niger at smaller concentrations compared with the (S)-forms. Vaporized massoialactone inhibited the growth of the two fungi at 1.2μg/ml in a sealed vial, whereas the γ- and δ-decalactones exhibited no inhibition against the growth of the two fungi. Massoialactone arrested the oxygen consumption byC. albicansat 240 μM, suggesting that the antimicrobial mechanism responsible for massoialactone activity againstC. albicansmay be the inhibition of the respiratory system. The reproduction of influenza virus A was inhibited at 23 and 57% by massoialactone and δ-decalactone at 0.25 and 2.5 μg/ml, respectively.