Ellagic acid is ubiquitous in plants and is considered as a potential candidate for antioxidant and antineoplastic drugs. However, ellagic acid has poor solubility and precipitates easily even after initial solubilization. Improvement of its bioavailability has been a concern of pharmaceutical industry. It was found that storage in Sanlejiang oral liquid at low temperature keeps its stability. Ellagic acid is anomalous in a way that is easily soluble at low temperatures but precipitates at high temperatures. In order to reveal the mechanism of this phenomenon and develop precipitation prevention and control strategies, ellagic acid in Sanlejiang oral liquid was stored at high, medium and low temperatures for three months. The changes of composition and phase state of the whole system during storage were systematically tracked and studied by means of precipitation amount or morphology, HPLC chemical profile of supernatant versus precipitates, and comprehensive characterization of physical phase state. The results show that the amount of precipitation at low temperature is only 1/3 of that at normal room temperature. As the temperature rises, the sedimentation increases sharply. HPLC analyses of supernatant versus precipitates revealed that ellagic acid precipitation originated from two ways:chemical degradation and physical deposition. The chemical sedimentation is related to the hydrolysis of tannins under acidic condition, forming chebulagic acid and corilagin. Physical sedimentation is related to the decrease of the association degree and viscosity of polyphenol colloids when temperature rises. This study elucidated the stability mechanism of ellagic acid in liquid preparations of TCM, and provided the mechanistic basis for efficient utilization and solution prepartion of ellagic acid.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |