核桃楸乙醇提取物的稳定性

采用常规提取法浸提核桃楸叶、树皮和外果皮,以胡桃醌降解率作为评价指标(胡桃醌测定采用高效液相色谱法),考察温度、pH值和光照等因素对核桃楸乙醇提取物稳定性的影响:随着温度升高,核桃楸乙醇提取物中的胡桃醌降解率增大,稳定性降低;pH值在4~8之间时,核桃楸乙醇提取物稳定性好,pH=2和pH=10时,稳定性差;温度升高或pH值变化时,核桃楸乙醇提取物中的胡桃醌降解具有一级反应的特征;强光照射时,核桃楸乙醇提取物稳定性差,胡桃醌降解具有零级反应的特征。核桃楸树皮乙醇提取物的稳定性大于核桃楸叶,核桃楸叶乙醇提取物的稳定性大于核桃楸外果皮。

Stability of Alcohol Extracts from Juglans mandshurica

The effects of extraction temperature, pH value and light intensity on the stability of the alcohol extracts from the leaves, bark and green peel of Juglans mandshurica Maxim. were studied using the degradative rate of juglone determined by HPLC method as the evaluation index. Results show that the stability of the extracts decreases and the degradative rate of juglone increases with extraction temperature increasing. The stability of the extracts is poorer at pH value of 2 or 10, while it is better at pH values ranging from 4 to 8. The degradation of juglone is characterized by first-order reaction at varying pH values and increasing temperatures. The stability of the extracts is weak under high light intensity, and the degradation of juglone is characterized by zero-order reaction. The stabilities of the extracts show bark>leaves>green peel.