[Study on antipyretic effect of rhubarb on rats and its antipyretic ingredients].

A combination of LC-MS technology and activity evaluation was used to identify the antipyretic ingredients in rhubarb. The rat model of fever was established with dried yeast and then was administered ethanol extract and different polar fractions of rhubarb. Next, the anal temperature of these rats was measured and recorded at 0.5, 1, 2, 3, 4 and 5 h after administration, and the inhibition rate of each part on the rise of body temperature was calculated. The inhibition rate is higher and the antipyretic effect is better. The chemical composition of the effective fraction was analyzed with UPLC-ESI-Orbitrap-MS/MS technology. Compared with the model group, the increase of body temperature of ethanol extract group all reduced at each measurement time especially after 3 h, and the inhibition rate were 38.7%(P<0.05), 78.2%(P<0.01) and 72.4%(P<0.01) at 3 h, 4 h, and 5 h after administration, respectively. Both n-butanol and water fraction showed some antipyretic activity in the early stage, with the inhibition rate of 28.1%(P<0.01) and 24.9%(P<0.05) at 1 h after administration, respectively, while other fractions were not active. Thirty-three and twelve compounds were identified from n-butanol and water fraction by LC-MS/MS analysis, respectively, including ten tannins, fifteen anthraquinone glycosides, four anthrone glycosides, one phenolic glycoside, one naphthaline derivative, one anthraquinone and one sucrose. These results revealed that rhubarb had antipyretic activity on rats, and tannin and anthraquinone glycosides were the main active ingredients inside.