Comparison of Antioxidant Activities in Agastache Species

The Agastache species, members of the mint family (Labiatae), are native to Korea, India, China, and the USA and known to have significant amounts of phenolics and flavonoids such as tilianin, acacetin, agastachin, and rosmarinic acid. This plant species has proven antioxidant, antibacterial, antimicrobial, anti-aging, anti-inflammatory, and anti-cancer activities. The objective of this study was to investigate the variation in the antioxidant activities of 12 accessions between three different Agastache species (A. foeniculum, A. rugosa, and A. urticifolia). The antioxidant activities were measured by DPPH and ABTS radical scavenging activities. The relative antioxidant capacity index (RACI) was calculated to integrate different chemical methods of determining antioxidant activities and contents. A. urticifolia showed the highest (0.86) and A. rugosa the lowest (-1.49) RACI among the three species. The Pearson's correlation coefficients indicated that there were significant positive correlations between the antioxidant activities and total polyphenolic content. Hierarchical cluster analysis classified 12 accessions into three groups based on the antioxidant properties. This study provides insights into the variation in the antioxidant activities and content profiles between the Agastache species. The antioxidant properties of the three Agastache species observed from these results provide information for the development of these species as valuable functional foods and novel dietary ingredients.