26-week repeated oral dose toxicity study of UP446, a combination of defined extracts of Scutellaria baicalensis and Acacia catechu, in beagle dogs.

The needs for relatively safe botanical alternatives to relieve symptoms associated to arthritis have continued to grow in parallel with the ageing population. UP446, a standardized bioflavonoid composition from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu, has been used as over the counter joint care dietary supplements and a prescription medical food. Significant safety data have been documented in rodents and human for this composition. Here we evaluated the potential adverse effects of orally administered UP446 in beagle dogs following a 26-week repeated oral dose toxicity study. UP446 at doses of 250, 500 and 1000 mg/kg/day were administered orally to beagle dogs for 26 weeks. A 4-week recovery group from the high dose (1000 mg/kg) and vehicle treated groups were included. No morbidity or mortality was observed for the duration of the study. No significant differences between groups in body weights, food consumption, ophthalmological examinations, electrocardiograms, urinalysis, hematology, clinical chemistry, organ weights, gross pathology and histopathology were documented. Emesis, loose feces and diarrhea were noted in both genders at the 1000 mg/kg treatment groups. These clinical signs were considered to be reversible as they were not evident in the recovery period. In conclusion, the no-observed-adverse-effect-level (NOAEL) of UP446 was considered to be 500 mg/kg/day both in male and female beagle dogs.