Isolation and Purification of Antifungal Compounds from the Green Microalga Chlorella vulgaris

The current study aimed to purify antifungal compounds from Chlorella vulgaris extracts, fractions, sub-fractions and pure compounds against different strains of mycotoxigenic fungi. Antifungal activity was conducted using disc diffusion assay, TLC-bioautography and Minimum Inhibitory Concentration (MIC). Isolation, purification and structure elucidation of antifungal compounds were carried out using column chromatography, Thin Layer Chromatography (TLC), UV-Vis spectrophotometer, Gas Chromatography–Mass Spectrometry (GC-MS), and Nuclear Magnetic Resonance (NMR). C. vulgaris Diethyl Ether Extract (DEE) showed the highest antifungal activity against all tested fungi with inhibition zone from 11.5 to 21.9 mm. By fractionation of DEE, Fraction F3 (chloroform:methanol, 50:50) and F5 (methanol 100%); sub-fraction CF3-10 and CF5-10 exhibited antifungal activity against all tested fungi. Two pure compounds, hydroxyphenophytin B and hexadecanoic acid methyl ester, with antifungal activity were isolated from CF3-10 and CF5-10, respectively. C. vulgaris DEE and isolated compounds can be used as promising antifungal agents from natural sources against mycotoxigenic fungi at post-harvest or storage stages.