Antimicrobial activity and chemical differences between the two chemotypes of rhubarbs / 药学学报

Through our pre-investigation and literature analysis, it was found that rhubarb could be categorized into two types, chrysophanol-type and rhein-type, based on the proportion of the two constituents in the total content of anthraquinones after acid hydrolysis. In this paper, the antimicrobial activities of chrysophanol-type and rhein-type rhubarbs against Staphylococcus aureus were compared with microcalorimetric analysis, in order to illustrate the bioactive differentiability between the two chemotypes. For the aim to display the distinction of chrysophanol and rhein percentage in total anthraquinones, the sampling volume was regulated to make the total anthraquinones equivalent, thus, the antimicrobial difference was only attributed to the difference of chemotypes. The results indicated that the antimicrobial difference between the two chemotypes was confirmable labeled at the biothermokinetic parameters of S. aureus growth affected by the rhubarb samples. The growth rate constant (k1) of the first exponential phase for the growth of S. aureus affected by the rhein-type rhubarb was significantly lower than that of chrysophanol-type (P<0.01), which suggested stronger antimicrobial activity of rhein-type rhubarb than that of chrysophanol-type. However, the antimicrobial activities of rhein-type rhubarbs were not positively correlated to the contents of rhein. It suggested that the antimicrobial activity of rhubarb might be related to some unknown components which were of same accumulating pattern of rhein. The findings in present study provided some experimental evidence on categorizing rhubarb into two chemotypes through the difference of antimicrobial activity on S. aureus by microcalorimetric analysis and, further, offered references to revision of the commercial specification of rhubarb from chemical view.

COLD and HOT nature of Coptis & Evodia and their prescriptions investigated with diet restriction/cold-water swimming mice models / 药学学报

To establish a new method to evaluate the COLD and HOT nature of Coptis & Evodia and their prescriptions Zuojinwan and Fanzuojinwan. Physical models of mice were established by diet restriction with cold-water swimming (weak model, WM) and fed with high protein animal feeds (strong model, SM). An instrument with cold and hot pads was used to investigate the variation of temperature tropism among SM and WM groups of mice affected by drugs. Meanwhile, the oxygen consumption and activity of adenosine triphosphatase (ATPase) were detected, in order to investigate the mechanism of energy metabolism which might be affected by these drugs. The results showed that the drug effects gradually changed in an order of "Coptis-->Zuojinwan--> Fanzuojinwan-->Evodia". In detail, Coptis increased the remaining rate (RR) of mice on hot pad, decreased oxygen consumption and ATPase activity (n=6, P < 0.01 or P < 0.05), while Evodia performed inversely; which indicated the COLD nature of Coptis and HOT nature of Evodia, and confirmed with their traditional definition in medicinal works. In conclusion, the methods applied in this work, can objectively and directly express the nature disparity between the two herbs and predict the tendency of changes of the nature of their combination, which brings a new approach in investigation of the nature theory of traditional Chinese medicine.

Effect of processing on the chemical contents and hepatic and renal toxicity of rhubarb studied by canonical correlation analysis / 药学学报

In this article, canonical correlation analysis was used to explore the relationship between the toxicity-attenuating effect and the variation of chemical contents in rhubarb caused by processing. With quasi-acute toxicity test, the difference of hepatic and renal toxicity to mice with the processed materials of rhubarb was researched. The chemical contents of anthraquinones and tannins in rhubarb were measured by UV-vis spectrophotometry and high performance liquid chromatography. The results showed that there were toxic effects to liver and kidney in mice after repeated intragastric administration of rhubarb and its processed materials for 14 days at a dosage of 76 g x kg(-1). The toxic effect of processed materials was much lower than crude drug. With canonical correlation analysis, the sequence of the hepatic and renal toxicity of chemical contents in rhubarb were found as follows: total anthraquinone glycosides (AQGs) > tannins (Tns) > total anthraquinones (AQs); aloe-emodin (AE) > physcione (Ph) > rhein (Rn) > emodin (Ed) > chrysophanol (Ch) and AEG > PhG > ChG > EdG > RnG of glycosyl-anthraquinone. It could be concluded that processing would attenuate the toxicity of crude drug of rhubarb. The toxicity-attenuating effect might be correlated to the decline of the contents of both anthraquinone glycosides and tannins, especially the aloe-emodin glycoside and physcione glycoside. The results also suggested that the serum alanine aminotransferase (ALT) and creatine (CREA) would be useful to monitor the hepatic and renal toxicity of rhubarb.