Safety assessment of European cranberrybush (Viburnum opulus L.) fruit juice: Acute and subacute oral toxicity

European cranberrybush (ECB) (Viburnum opulus L.) fruits are abundant in phenolic compounds associated with various health benefits. However, the toxicity and safety of ECB juice have not been systematically studied. In the present study, acute and subacute oral toxicities of ECB fruit juice were evaluated on Sprague-Dawley rats and BALB/c mice to establish a toxicity profile. In acute tests, a single administration of 2000 mg/kg body weight of extract to rats exhibited no clinical signs of toxicity or mortality, indicating that the lethal dose (LD50) was over 2000 mg/kg. In subacute tests, repeated administration for 28 days at 0 (control), 500, and 2000 mg/kg doses of extract in mice did not display adverse clinical signs or deaths. However, in the 2000 mg/kg subacute group, platelet counts were significantly high, which correlated with histopathological analyses revealing that ECB extract at 2000 mg/kg was toxic to the kidney, liver, and adipose tissue. The NOAEL value of ECB extract was found as 500 mg/kg/day, but further sub-chronic and chronic toxicity studies are warranted to comprehensively evaluate the long-term safety implications. The study's results emphasize the importance of considering the dosage of dietary supplements containing high levels of phenolic compounds over an extended period to avoid potential cumulative effects from prolonged consumption of high doses.