By Bridget Zagrobelny, Andrew Eigenfeld

Faculty Mentor: Dr. Lynn Lewis

Abstract

The human gastrointestinal tract hosts a diverse microbial ecosystem essential for regulating digestion, immune response, metabolism, and neurological function. Recent research has identified polyphenols, particularly anthocyanins found in dark red and purple fruits, as potential dietary compounds capable of supporting beneficial gut bacteria. This project investigates whether anthocyanin-rich fruit extracts act as prebiotics by stimulating the growth of Lactobacillus plantarum, a probiotic species associated with gut health. In order to evaluate, an in vitro growth assay was conducted using cherry, black currant, and Aronia berry extracts at low, medium, and high concentrations in MRS broth. L.plantarum cultures were incubated under aerobic conditions and monitored over 15 hours using spectrophotometric analysis at 600 nm. Results indicate that exposure to anthocyanin extracts did not significantly stimulate the growth of L. plantarum compared to the control; however, no inhibitory effects were observed either. These findings suggest that while anthocyanin-rich extracts do not enhance L. plantarum proliferation under the conditions tested, they also do not interfere with its growth, indicating a neutral interaction. As the gut continues to emerge as a key regulator of human health, understanding even subtle microbial responses to common dietary compounds provides critical insight for future research in maintaining microbial balance and overall well-being.