Evaluation of the functional properties of phenolic compound-rich European cranberrybush (Viburnum opulus L.): Biological activities, bioavailability, and safety

The aim of this study was to examine the functional properties of European cranberrybush (ECB) (Viburnum opulus L.) fruit containing high phenolic compounds, known for their beneficial health effects. Biological activities (antimicrobial, mutagenic, antimutagenic, antiproliferative activities) and bioavailability of ECB fruit juice extract were firstly assessed by in vitro assays. Then, ECB juice was used to evaluate the viability and growth performance of probiotic cultures in the formulated environments for potential use of a new whey-based functional beverage. Additionally, since ECB fruit juice was found to be strongly inhibitory against Listeria monocytogenes, antimicrobial effect of ECB fruit juice in milk-based environment with probiotics cultures was investigated by challenging in the presence of this pathogen. Finally, acute and subacute oral toxicities of ECB fruit extracts were evaluated in in vivo animal studies to establish a toxicity profile by detecting the LD50 and NOAEL. ECB extracts inhibited the growth of pathogens and spoilage microorganisms but showed a slight inhibitory effect on probiotics only at high concentrations. ECB extracts had no mutagenic activity and showed moderate levels (27.3%) of antimutagenic effect. ECB fruit juice induced antiproliferative effect on AGS cells in dose and time dependent manner. Total phenolic and anthocyanin contents of ECB extract remained after gastric digestion, but values decreased during intestinal digestion due to their low stability in alkaline conditions. Probiotic LAB maintained their viability in the presence of ECB juice added whey-based beverage resulting that utilization of whey powder could be an alternative medium for development of functional beverages. On the other hand, ECB juice was not inhibitory against L. monocytogenes when it was added in milk. Toxicity results showed that although ECB extract was not toxic after a single high dose exposure, consumption in high dose for a prolonged period showed toxicity on the liver, kidney, and adipose tissues. The LD50 was higher than 2000 mg/kg, whereas NOAEL was 500 mg/kg/day for long time consumption. Upon all these results, ECB juice shows potential use in functional food and nutraceutical industries.