Study of the extraction, purification and antidiabetic potential of ursolic acid from Cornus officinalis Sieb. et Zucc.

Dawei Gao, Na Li, Qingwang Li, Jian Li, Zengsheng Han, Yusheng Fan and Zhiwei Liu

Background: Cornus officinalis Sieb. et Zucc. (CSZ) has been used in traditional Chinese medicine for over 1000 years, owing to its immunoregulation, antishock, antiarrhythmia, antioxidation and antidiabetes properties. The purpose of this study was to optimize the extraction method of ursolic acid (UA), and to find the main hypoglycemic ingredient of CSZ, then evaluate the toxicity of UA isolated from CSZ. Methods: UA was extracted by the methods of ethanol infusion, methanol infusion, refluent ethanol and sonication from CSZ; solvent extraction and macroporous resin column chromatography were used for purification; thin-layer chromatography and visible spectrophotometry were applied for the qualitative and quantitative identification. UA isolated from CSZ in the 100 and 200 mg/kg body weight doses was administered to alloxan-induced diabetic mice to determine the hypoglycemic effects. Results: The yield was the highest using ultrasonic extraction and macroporous resin purification. UA isolated from CSZ had a significant hypoglycemic effect compared with the diabetes control mice since day 10 (p < 0.05 or 0.01). The result of LD50 test and single-cell gel electrophoresis demonstrated that UA was not toxic. Conclusion: These results indicated that ultrasonic extraction was best among these extraction methods. Meanwhile, UA isolated from CSZ is the main hypoglycemic ingredient, and resulted in a good hypoglycemic effect in alloxan-induced diabetic mice. UA was testified to be nontoxic in the LD50 test (in vivo) and single-cell gel electrophoresis (in vitro).