[Mechanism of interaction between chrysin and leptin].

The study of interaction mechanism between chrysin and leptin was investigated by various spectroscopic techniques and atom force microscope. The ultraviolet spectrum presents a red shift in 200-220 nm after chrysin upon. And there is a structure alternative showed in 270 nm when the concentration ratio of chrysin and leptin in 10-15. From the fluorescence spectrum, it was found that chrysin could combine with leptin in physiological condition. The binding constant (Ka) values, at 298 K and 310 K, were (0.41±0.05)×106 and (3.26±0.46)×106 L·mol⁻¹, and the binding site number were 1.02±0.04 and 0.51±0.01, respectively. The atom force microscope results showed that the dimension of leptin molecules became more swollen after binding with chrysin because of the hydrophobicity. These results demonstrate that the mechanism of chrysin and leptin interaction could play a role in leptin adjust in human body, and it could provide a new aspect for the study of obesity treatment.

[Effect of paeoniflorin and menthol on membrane fluidity, Na⁺-K⁺-ATPase activity and Ca²âº-ATPase activity during transport of puerarin in Calu-3 cell].

The aim of this research is to investigate the effects of paeoniflorin and menthol on the physiological function of Calu-3 cell membrane during the transport of puerarin. Calu-3 cell was used as the in vitro cell model to simulate nasal mucosa tissues, and the cell membrane fluidity, Na⁺-K⁺-ATPase activity and Ca²âº-ATPase activity were detected by fluorescence recovery after photobleaching(FRAP) and ultramicro enzyme activity testing, in order to explore the mechanism of compatible drugs on promoting puerarin transport. The results showed that when puerarin associated with low, middle and high concentration of menthol or both paeoniflorin and menthol, the fluorescence recovery rate was increased significantly, while Na⁺-K⁺-ATPase activity had no significant change and Ca²âº-ATPase activity was enhanced significantly as compared with puerarin alone. Therefore, it was concluded that menthol had the abilit of promoting the transport and the mechanism might be related to increasing membrane fluidity and activating Ca²âº-ATPase.