In vitro fermentation of rosmarinic acid and lemon balm (Melissa officinalis L., Lamiaceae) extract by probiotic microorganisms

Rosmarinic acid (RA) represents a phenolic compound with numerous proven health benefits. However, peroral application limits its effectiveness, due to degradation occurring inside digestive tract. The aim of the research was to investigate in vitro stability of RA under the fermentative activity of microorganisms present in intestinal microbiota.Pure compound and lemon balm extract were used as sources of RA, while the source of microorganisms were 11 commercially available probiotics containing preparations. The concentrations of RA before and after fermentation were determined by high performance liquid chromatography (HPLC-DAD). Reduction of RA's content was significant in some of used probiotics, ranging from approximately 20% to total 100% in case of pure compound use. In cases of use of same probiotic supplement, decrease in RA's content is higher in case of lemon balm extract. The bacterial strain found responsible for higher extent of degradation was Lactobacillus helveticus. During fermentation process, various metabolites can be formed, including caffeic and ferulic acid, while other compounds detected in lemon balm's extract were also susceptible to microbial fermentation.Rosmarinic acid degrades extensively during fermentation by microorganisms present in intestinal flora. This compound is more stable in pure samples than in complex matrix of extract.(c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

Rosmarinic acid (RA) is a phenolic compound with proven health benefits, but its effectiveness is limited when taken orally due to degradation in the digestive tract. This study investigated the stability of RA under intestinal microbiota fermentation. Pure compound and lemon balm extract were used as sources of RA, and commercially available probiotics were used as sources of microorganisms. RA's content decreased significantly in some probiotics, ranging from approximately 20% to total degradation when using the pure compound. The bacterial strain Lactobacillus helveticus was found to be responsible for extensive degradation. RA is more stable in pure samples than in complex extract matrix.