Abstract
| - The aim of the present study was to evaluate which structural elements of the vanillin molecule areresponsible for its observed antifungal activity. MICs of vanillin, its six direct structural analogues,and several other related compounds were determined in yeast extract peptone dextrose broth againsta total of 18 different food spoilage molds and yeasts. Using total mean MICs after 4 days of incubationat 25 °C, the antifungal activity order was 3-anisaldehyde (1.97 mM) > benzaldehyde (3.30 mM) >vanillin (5.71 mM) > anisole (6.59 mM) > 4-hydroxybenzaldehyde (9.09 mM) > phenol (10.59 mM)> guaiacol (11.66 mM). No correlation was observed between the relative antifungal activity of thetest compounds and log Po/w. Furthermore, phenol (10.6 mM) was found to exhibit a greater activitythan cyclohexanol (25.3 mM), whereas cyclohexanecarboxaldehyde (2.13 mM) was more active thanbenzaldehyde (3.30 mM). Finally, the antifungal order of isomers of hydroxybenzaldehyde andanisaldehyde was found to be 2- > 3- > 4- and 3- > 2- > 4-, respectively. In conclusion, the aldehydemoeity of vanillin plays a key role in its antifungal activity, but side-group position on the benzenering also influences this activity. Understanding how the structure of natural compounds relates totheir antimicrobial function is fundamentally important and may help facilitate their application asnovel food preservatives. Keywords: Aldehyde; molds; natural antimicrobials; structure−function; vanillin; yeasts
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