Evaluation of storage stability and safety of hypoglycemic Pueraria-Ophiopogon tea

Pueraria-Ophiopogon tea (POT), a hypoglycemic green tea-based functional food product, is mainly mixed with Pueraria, Ophiopogon and green tea, and supplemented with Ganoderma and American ginseng. This study aimed to demonstrate the storage stability and safety of POT for further utilization and development. POT was evaluated for the accelerated stability test during storage at 37 ± 1 °C and 75% relative humidity for 3 months via senses, pesticide residue level, physicochemical indexes and microbiological indexes. The safety of POT was measured using the acute oral toxicity test, repeated dose 30-day oral toxicity test and genotoxic test. POT has high active ingredient content and an excellent physicochemical profile during the accelerated storage tests. In the acute oral (20000 mg/kg) and repeated dose 30-day oral toxicity study (2500 mg/kg; 5000 mg/kg; 10000 mg/kg), the treatment of POT did not produce significant changes in the physiological, biochemical, hematological, and histopathological parameters. Further, there was no evidence of genotoxicity of POT in the in vivo micronucleus test, the sperm abnormality test and the in vitro Ames test. The results concluded that the oral approximate lethal doses of POT were > 20000 mg/kg and the no observed adverse effect level of POT was 10000 mg/kg/day in mice and rats. This study suggests that POT could be considered a stable and safe hypoglycemic alternative strategy and provides a framework for evaluating the safety and stability of herb tea.