RESUMO
In the thermal analysis, the pyrolysis characteristics of crude Kansui Radix, alcohol extract of Kansui Radix, petroleum ether extract, chloroform extract, ethyl acetate extract, n-butanol extract, and licorice vinegar were analyzed with simulated air (N₂-O₂ 4:1) as the carrier gas, at a temperature increase rate of 10 °C·min⁻¹ and a volume flow rate of 60 mL·min⁻¹, respectively. The results showed that due to the different polarity of the extraction solvent, the type and quantity of the chemical components contained in each polar part were different, and with the increase in the amount of solid powder of licorice, the peak of the maximum heat loss rate occurred in advance. For petroleum ether, chloroform, and ethyl acetate fractions, (157.40±1.06), 3.50, (25.83±1.66) °C in advance respectively, but the weight loss rate of the chloroform fraction was increased by (2.62±5.19) °C, while decreased by (33.90±1.72), (19.28±1.11) °C for the petroleum ether and ethyl acetate fractions. So we can conclude that with the addition of licorice, the pyrolysis rate of the petroleum ether and chloroform fractions in the toxic part of Kansui Radix was increased; the temperature point at the peak of the maximum weight loss rate was decreased, and the ethyl acetate fraction (effective part) showed a decrease in temperature rising process, but its overall ratio of weight loss and weight loss rate were relatively small, retaining the effect of medicinal ingredients. This proved the mechanism of licorice system Kansui Radix on attenuating toxicity after processing and the scientificity and rationality of licorice system Kansui Radix. At the same time, as the proportion of glycyrrhizin was increased, the peak of the maximum heat loss rate of petroleum ether, chloroform and ethyl acetate fractions occurred in advance; the peak temperature was decreased, with easy pyrolysis. Among them, the thermogravimetric rate of the mixture of petroleum ether and chloroform fractions (10:1) was relatively large, with a low peak temperature, while ethyl acetate fraction showed opposite results. This conclusion has certain guiding significance for the ratio of gansui to licorice.