Abstract
OBJECTIVES: Korean mint (Agastache rugosa; KM) is a medicinal plant of the Labiatae mint family that exerts a wide range of health benefits including anti-inflammatory and antioxidants. The beneficial health effects of KM have been associated with the presence of polyphenols. However, the bioavailability of KM is still poorly evaluated to understand how bioactive compounds are absorbed and reach systemic circulation. The objective of this study was to investigate how the dominant KM polyphenols are differently available in circulation in vitro and in vivo. METHODS: In a randomized, double-blind, crossover design, 10 healthy females consumed either placebo or KM extract. Blood samples have collected before and 15, 30, 60,120, 180, and 360 min for the analysis of serum polyphenol concentration by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). Additionally, the bioaccessibility of KM polyphenols was assessed after in vitro digestion using Caco-2 monolayers grown in permeable filter supports. RESULTS: The UPLC-MS/MS analysis showed the dominant components in the extract were rosmarinic acid (RA), acacetin (AC) and acacetin 7-glucoside (tilianin, TA). Following KM extract consumption, the absorption curve of RA, TA, and AC changed over 6 h. RA and TA were most abundant 2–3 h post-initial ingestion with a gradual decrease afterward. By contrast, the appearance of AC in serum was delayed to 2 h but continuously increased until 6 h post-ingestion. In vitro data with absorptive intestinal cells indicated that AC and TA gradually decreased in the apical side, and correspondent enrichments were found in the basal side. RA was not transported in quantifiable concentration. CONCLUSIONS: These findings suggest that KM polyphenols are readily available in circulation, providing a potential direct role in health benefits. FUNDING SOURCES: This research was supported by the BK21 FOUR (Fostering Outstanding Universities for Research) funded by the Ministry of Education (MOE, Korea) and the National Research Foundation of Korea (NRF).