Purification and Characterization of Antifungal δ-Dodecalactone from Lactobacillus plantarum AF1 Isolated from Kimchi

The aim of this study was to purify and identify an antifungal compound from Lactobacillus plantarum AF1, which was isolated from kimchi. The antifungal compound was purified by solid-phase extraction and recycling preparative high-performance liquid chromatography, and its structure was elucidated by using gas chromatography-mass spectrometry (GC-MS). The active compound from L. plantarum AF1 was confirmed to be delta-dodecalactone (molecular weight, 198.3) by comparison of its gas chromatographic retention time with the mass spectrum of standard delta-dodecalactone. The MICs of delta-dodecalactone against various fungi and bacteria ranged from 350 to 6,250 mu g/ml. delta-Dodecalactone showed strong antifungal activity against molds Aspergillus fiavus, A. fumigatus, A. petrakii, A. ochraceus, A. nidulans, and Penicillium roqueforti. The three tested yeast strains of Candida albicans were more resistant than the molds. Antibacterial activity was evident but less potent than the antifungal activity. delta-Dodecalactone produced pleasurable (fruity) organoleptic characteristics. The results indicate the potential of the delta-dodecalactone produced by L. plantarum AF1 as a biopreservative and flavoring compound, as well as a biosafe remedy for candidiasis.