Inhibitory effects of rooibos (Aspalathus linearis) against reactive carbonyl species and advanced glycation end product formation in a glucose-bovine serum albumin model and cookies

In thermally processed foods, several heat-induced toxicants are potentially formed due to the Maillard reaction, such as α-dicarbonyls and advanced glycation end products (AGEs). In the present work, we found that the methylglyoxal (MGO)-trapping and antiglycative activities of the herbal tea samples correlated strongly with their total phenolic and flavonoid contents. Among the tested herbal tea samples, rooibos exhibited the strongest MGO-trapping and antiglycative activities against AGEs formation. Aspalathin, orientin and isoorientin were further identified as the major bioactive compounds of rooibos that scavenged MGO to form the corresponding mono-MGO adducts. Moreover, the contents of dicarbonyls and AGEs in the cookie were remarkably reduced by fortification with rooibos. Altogether, our current findings suggested that rooibos might serve as a functional ingredient to reduce intake of dietary reactive carbonyl species (RCS) and AGEs from thermally processed foods, especially bakery products.