Fluorescence, Absorption, Chromatography and Structural Transformation of Chelerythrine and Ethoxychelerythrine in Protic Solvents: A Comparative Study

Developmental toxicity induced by chelerythrine in zebrafish embryos via activating oxidative stress and apoptosis pathways

Chelerythrine (CHE), a natural benzophenanthridine alkaloid, possesses various biological and pharmacological activities, such as antimicrobial, antitumor and anti-inflammatory effects. However, its adverse side effect has not been fully elucidated. Therefore, this study was designed to investigate the developmental toxicity of CHE in zebrafish. We found that CHE could lead to a notably increase of the mortality and malformation rate, while lead to reduction of the hatching rate and body length. CHE also could affect the normal developing processes of the heart, liver and phagocytes in zebrafish. Furthermore, the reactive oxygen species (ROS) and apoptosis levels were notably increased. In addition, the mRNA expressions of genes (bax, caspase-9, p53, SOD1, KEAP1, TNF-α, STAT3 and NF-κB) were significantly increased, while the bcl2 and nrf2 were notably inhibited by CHE. These results indicated that the elevation of ROS and apoptosis were involved in the developmental toxicity induced by CHE. In conclusion, CHE exhibits a developmental toxicity in zebrafish, which helps to understand the potential toxic effect of CHE.

A Study of the Mechanisms and Characteristics of Fluorescence Enhancement for the Detection of Formononetin and Ononin

In this work, the origins for the spectral difference between two isoflavones, formononetin (F) and ononin (FG), are revealed via a comparison study of the fluorescence molecular structure. The fluorescence enhancement of FG in hot alkaline conditions is reported for the first time. For F, there is almost no fluorescence under acidic conditions, but when the pH is >4.8, its fluorescence begins to increase due to the deprotonation of 7-OH. Under a pH between 9.3 and 12.0, the anionic form of F produces a strong and stable fluorescence. The fluorescence quantum yield (Yf) of F is measured to be 0.042. FG shows only weak fluorescence in aqueous solutions under a wide range of pH until it is placed in hot alkaline solutions, which is attributed to the cleavage reaction of the γ-pyrone ring in FG. The Yf of FG is determined to be 0.020. Based on the fluorescence sensitization methods of F and FG, the quantitative analysis and detection of two substances can be realized. The limit of the detections for F and FG are 2.60 ng·mL^-1 and 9.30 ng·mL^-1, respectively. The linear detection ranges of F and FG are 11.7~1860 ng·mL^-1 and 14.6~2920 ng·mL^-1, respectively. Although the structural relationship between F and FG is glycoside and aglycone, under hot alkaline conditions, the final products after the cleavage and hydrolysis reactions are essentially different. The different fluorescence characteristics between F and FG pave a way for further identification and a quantitative analysis of the corresponding components in Chinese herbal medicine.