Abstract: Protein extracts from the seeds of different cultivars of hot pepper were screened for their antifungal activity against Aspergillus flavus in terms of inhibition zone diameter. The results showed that the seeds of all six cultivars investigated had inhibitory effects on the growth of A. flavus, and Guizhou lantern pepper seeds had the strongest antifungal effect of them. The conditions for extraction of antifungal proteins from the Guizhou Lantern cultivar were optimized as follows: EDTA buffer as the extraction solvent, solid-to-solvent ratio 1:5.05 (g/mL), extraction time 16.13 h, and ammonium sulfate saturation 81.15%, leading to an inhibitory zone diameter of 23.89 mm, which was 93.06% higher than that (12.34 mm) before optimization. In addition, the antifungal peptides from hot pepper seeds were separated and purified by dialysis, 10 kDa ultrafiltration and Sephadex gel chromatography. The purified antifungal peptide was found to be homogenous with a molecular mass of around 7.8 kDa by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

Key words: hot pepper seeds, antimicrobial peptides, extraction conditions, separation and purification