Phenolic Constituents of Extract From Mao Luang Seeds and Skin-Pulp Residue and Its Antiradical and Antimicrobial Capacities

The aim of the present study was to determine the total flavonoids, total anthocyanins, total phenolics, antioxidant and antimicrobial activity of Mao Luang seeds and skin–pulp residue. The seed and skin–pulp residues had total flavonoid content of 108.69 and 123.02 mg catechin (CE)/g fb, respectively. A high level of total anthocyanin content was detected in the skin–pulp residue, while the seeds had high total phenolic content. The individual flavonoids content of the Mao Luang seeds and skin–pulp residue consisted almost exclusively of (+)–CE and procyanidins. The seed extract exhibited the highest antiradical activity. Both of seed and skin–pulp residue extracts were active against all gram-positive bacteria except Streptococcus thermophilus American Type Culture Collection (ATCC) 19258, but exerted less inhibiting effect on the growth of the tested gram-negative bacteria. The activity of the methanolic extract of the seed was effective against Staphylococcus aureus ATCC 13150 and Streptococcus faecalis Thailand Institute of Scientific and Technological Research 459. PRACTICAL APPLICATIONS In this study, phenolic contents and its antioxidant and antimicrobial capacities in vitro of Mao Luang seeds and skin–pulp residue, an inedible waste product of juice and red wine manufactured, were researched. This study indicated that Mao Luang seeds and skin–pulp residue possess considerable amounts of phenolic compounds and significant radical-scavenging activity on stable 2, 2-diphenyl-1-picrylhydrazyl radicals and methanol extracts exhibited inhibitory activities against some of the microorganisms. Mao Luang seeds and skin–pulp residue could afford health benefits by preventing unwanted free radical-induced oxidative reactions. Mao Luang seeds and skin–pulp residue should be regarded as a valuable product and has potential as a value-added ingredient for food and dietary supplemental products for health promotion.