Stability of Rosmarinic Acid in Aqueous Extracts from Different Lamiaceae Species after in vitro Digestion with Human Gastrointestinal Enzymes
Zoran Zorić1, Joško Markić2, Sandra Pedisić1, Viljemka Bučević-Popović3, Ivana Generalić-Mekinić4, Katarina Grebenar4 and Tea Kulišić-Bilušić4*
1Faculty of Food Technology and Biotechnology, Centre in Zadar, P. Kasandrića 6, HR-23000 Zadar, Croatia
2University Hospital of Split, Spinčićeva 1, HR-21000 Split, Croatia
3Faculty of Science, Department of Chemistry, University of Split, Teslina 12, HR-21000 Split, Croatia
4Faculty of Chemistry and Technology, University of Split, Teslina 10, HR-21000 Split, Croatia
Article history:
Received December 16, 2014
Accepted October 22, 2015
Key words:
rosmarinic acid, in vitro digestion, stability, human gastrointestinal enzymes, Lamiaceae species
Summary:
The present study compares the gastrointestinal stability of rosmarinic acid in aqueous extracts of thyme, winter savory and lemon balm with the stability of pure rosmarinic acid. The stability of rosmarinic acid was detected after two-phase in vitro digestion process (gastric and duodenal) with human gastrointestinal enzymes. The concentration of rosmarinic acid in undigested and digested samples was detected using HPLC-DAD. Results showed that gastrointestinal stability of pure rosmarinic acid was significantly higher than that of rosmarinic acid from plant extracts after both gastric and intestinal phases of digestion. Among plant extracts, rosmarinic acid was the most stable in lemon balm after gastric (14.10 %) and intestinal digestion phases (6.5 %). The temperature (37 °C) and slightly alkaline medium (pH=7.5) did not affect the stability of rosmarinic acid, while acid medium (pH=2.5) significantly decreased its stability (≥50 %). In addition, the stability rate of rosmarinic acid is infl uenced by the concentration of human gastrointestinal juices.
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