Relationship between total phenolic content, antioxidant potential, and antiglycation abilities of common culinary herbs and spices.

Advanced glycation endproducts and oxidative stress contribute to the pathogenesis of diabetic complications. The total phenolic content (TPC), antioxidant, and antiglycation properties of crude ethanolic extracts of 10 common culinary herbs and spices from Mauritius were investigated in vitro. Fluorescence at 370 nm/440 nm was used as an index of albumin glycation. Allium sativum had the highest TPC (3.1 mg GAE/mL), whereas Allium cepa L. showed the highest radical scavenging capacity (72%) and Zingiber officinale had the most potent ferric-reducing antioxidant power (FRAP; 2.99 mg AAE/mL). In contrast, Thymus vulgaris and Petroselinum crispum had the most potent antiglycation activity with IC(50) values of 21.8 and 200 mg/mL, respectively. There was no significant correlation between TPC (r=0.001), FRAP (r=0.161), and the antiglycation activity (r=0.034) for the extracts studied. Therefore, the results showed that antiglycation properties of plant-derived extracts cannot always be attributed to their phenolic content or antioxidant potential.