Anti-peroxyl radical quality and antibacterial properties of rooibos infusions and their pure glycosylated polyphenolic constituents

• Published in: Molecules (Basel, Switzerland) Switzerland), 2013-09, Vol.18 (9), p.11264-11280
• Main Authors: Simpson, Madeline J, Hjelmqvist, Daisy, López-Alarcón, Camilo, Karamehmedovic, Nadja, Minehan, Thomas G, Yepremyan, Akop, Salehani, Baback, Lissi, Eduardo, Joubert, Elizabeth, Udekwu, Klas I, Alarcon, Emilio I
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Antimicrobial agents; antioxidant capacity; Antioxidants; Apigenin - chemistry; Apigenin - isolation & purification; Apigenin - pharmacology; Aspalathus - chemistry; bacteria; Beverages; Chalcones - chemistry; Chalcones - isolation & purification; Chalcones - pharmacology; Cocoa; E coli; Escherichia coli - drug effects; Farmaceutiska vetenskaper; Flavonoids - chemistry; Flavonoids - isolation & purification; Flavonoids - pharmacology; Free Radical Scavengers - chemistry; Free Radical Scavengers - isolation & purification; Free Radical Scavengers - pharmacology; Glucosides - chemistry; Glucosides - isolation & purification; Glucosides - pharmacology; glycosylated polyphenols; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Microbial Sensitivity Tests; Mikrobiologi inom det medicinska området; ORAC indices; Oxidation; Oxidative stress; Peroxides; Plant Extracts - chemistry; Plant Extracts - isolation & purification; Plant Extracts - pharmacology; Polyphenols; Polyphenols - chemistry; Polyphenols - isolation & purification; Polyphenols - pharmacology; Quercetin - analogs & derivatives; Quercetin - chemistry; Quercetin - isolation & purification; Quercetin - pharmacology; rooibos infusions; Rutin - chemistry; Rutin - isolation & purification; Rutin - pharmacology; Staphylococcus aureus - drug effects; Staphylococcus epidermidis - drug effects; Tea
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules180911264

The anti-peroxyl radical quality of two aqueous rooibos infusions and solutions of their most abundant glycosylated polyphenols was evaluated using pyrogallol red and fluorescein-based oxygen radical absorbance ratios. It was observed that the artificial infusions, prepared using only the most abundant polyphenols present in rooibos and at concentrations similar to those found in the natural infusions, showed greater antioxidant quality than the latter infusions, reaching values close to those reported for tea infusions. Additionally, the antimicrobial activity of the natural and artificial infusions was assessed against three species of bacteria: Gram (+) Staphylococus epidermidis and Staphylococcus aureus and Gram (-) Escherichia coli. When compared to the natural infusions the artificial beverages did not demonstrate any bacterostatic/cidal activity, suggesting that the antibacterial activity of rooibos is related to compounds other than the glycosylated polyphenols employed in our study.