Bioassay-guided isolation of potential bioactive constituents from pomegranate agrifood by-product

Food industries are yielding annually plentiful by-products worldwide, these concomitants could be an excellent source of natural functional ingredients. Hence, the antimicrobial and cytotoxic effects of pomegranate husk were examined and chromatographic analyzes were applied for isolation of the bioactive compounds. Lignans; isohydroxymatairesinol, punicatannin C, flavonoids; phloretin, quercetin glycoside, indolamine; punigratane, and phenolic acid; coutaric acid were identified for the first time from pomegranate pericarp, and their structures were elucidated by spectroscopic analysis. Compared to isolated compounds, which showed a weak cytotoxic effects, punicatannin C induced a moderate cytotoxic activity against HepG2 and MCF-7 cell lines. Phloretin and coutaric acid exhibited potent antimicrobial activity against Staphylococcus epidermidis, while punigratane possesses the most substantial antimicrobial effect on Micrococcus kristinae. In conclusion, pomegranate agrifood by-product; phloretin, punigratane, and coutaric acid display remarkable microbicide effects and could be used in medical, cosmetic, and food industries purposes as a safe, and economical alternative to synthetic agents.