Characterization of novel antimicrobial compounds from mango (Mangifera indica L.) kernel seeds

The antimicrobial properties of mango seed kernel ethanol extract (MKE) were investigated. Minimum inhibitory concentrations (MICs) of the MKE against 18 species, of 43 strains, containing food-borne pathogenic bacteria were determined using the agar dilution method. The MKE had a broad antimicrobial spectrum, and was more active against gram-positive than gram-negative bacteria with a few exceptions. The antimicrobial activity of the MKE was stable against heat (121°C, 15 min), freezing (−20°C, 16 h) and pH treatment (pH 3–9) normally used in food processing. Chemical analysis showed that the MKE was composed of 79.5% polyphenol and 21.7% carbohydrate. The MKE was separated by reverse-phase HPLC with 10–30% acetonitrile linear gradient to characterize antimicrobial compounds. There were two fractions having antimicrobial activity; both peaks had maximum absorbance at 275 nm. These results indicated that the active component of the MKE was a type of polyphenol.