Exploring the Impact of Standardized Melissa officinalis Extract and Key Phenolic Acids on the Contractility of Isolated Jejunum and Colon Segments in Pigs

Background: The rising global demand for animal protein necessitates sustainable and efficient livestock production. This study explored the effects of Melissa officinalis extract and its main phenolic acids on the motility of the swine jejunum and colon, with the aim of verifying its usefulness as a health-promoting feed additive. The trials were performed on isolated jejunum and colon preparations and verified the effects of Melissa officinalis extract and 3 phenolic acids (rosmarinic, chlorogenic, and lithospermic) on spontaneous and acetylcholine (ACh)-induced smooth muscle activity under isometric conditions. Results: The study revealed the antispasmodic effect of Melissa extract. The preparation reduced by about 50% the control contraction when used at the highest tested dose (0.1 mg/ml). The results suggest that rosmarinic acid contributes the most to the eventual effect on the plant. In contrast, chlorogenic acid was a potent myocontractile agent under all the studied conditions and models. Conclusions: The major outcome of the study is the confirmation of the utility of a standardized extract of lemon balm as an antispasmodic agent in jejunum and colon specimens challenged with ACh, i.e., the most important stimulatory neurotransmitter in the enteric nervous system. Owing to the lack of data revealing the effects of lemon balm extract and individual phenolic acids on spontaneous contractility, it is impossible to conclude indisputably about their contributions to the final effects on the plant. Nevertheless, this study highlights the potential of Melissa officinalis to modulate intestinal motility in pigs experiencing hypermotility disorders, mainly microbial infections.