Objective

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To evaluate the scientificity and feasibility of processing of Pinelliae Rhizoma by hot water washing （Tangxi）， and to provide reference for the development of related famous classical formulas.

Method

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Processing method of Pinelliae Rhizoma washed by hot water was established based on ancient Tangxi processing method， and the process conditions were optimized by single factor tests. The weight， moisture， ash， extract， total acid （calculated by succinic acid） contents and high performance liquid chromatography （HPLC） fingerprint of Pinelliae Rhizoma were compared before and after processing. In addition， the rabbit eye irritation test was conducted to evaluate the toxicity changes.

Result

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The processing method of Pinelliae Rhizoma washed by hot water was as following：washed by 4 times the amount of hot water at 80 ℃ for 10 times until clear water， transfused cross-section after incision， no or slight numbness in the mouth. The average moisture， ash， extract contents of Pinelliae Rhizoma washed by hot water were 9.34%， 1.71% and 4.22%， respectively. After being processed， the decline rates of weight and total acid content of Pinelliae Rhizoma were 7.49% and 43.31%. The HPLC fingerprint of Pinelliae Rhizoma before and after washing showed a decrease in all components， but there was no new chromatographic peak， and peak 9 （adenosine） reduced significantly. The results of rabbit eye irritation test showed that there was no obvious eye conjunctival irritation after washing， indicating that the toxicity of Pinelliae Rhizoma decreased obviously after washing.

Conclusion

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The established method of Pinelliae Rhizoma by Tangxi processing is stable and feasible， the aqueous extract of Pinelliae Rhizoma has no obvious eye conjunctival irritation after washing.