Scientific connotation of decocting method "taking when fragrance volatilized fiercely" for Yinqiao Powder based on dynamic changes of volatile components during decocting process / 中草药

ABSTRACT

Objective: To establish a method for the determination of three main volatile components (menthone, menthol, and pulegone) in Yinqiao Powder (YQP) distillate and provide the evidence for elucidating the scientific connotation of its traditional decocting method "taking when the fragrance volatilized fiercely". Methods: YQP distillates with different decocting time were prepared to study the dynamic changes of chemical components during decocting process. GC-MS was used to analyze the volatile components qualitatively and determine the contents of menthone, menthol, and pulegone in YQP distillate. Results: GC-MS total ion chromatograms of YQP volatile oil included 26 peaks, of which the relative contents of 14 peaks were greater than 1.5%, mainly from Forsythiae Fructus, Menthae Haplocalycis Herba, and Schizonepetae Herba. With the extension of the boiling time, the evaporation rates of menthone, menthol, and pulegone all increased to maximum and then decreased gradually. When boiling for 5-10 min, the maximum average evaporation rates of menthone, menthol, and pulegone were 13.77, 147.74, and 31.26 ìg/min, respectively. When boiling for 0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-40, 40-50, 50-60, 60-80, 80-100, and 100-120 min, the average evaporation rates of total three volatile components were 160.23, 192.77, 120.71, 70.85, 54.01, 42.41, 30.36, 17.87, 14.98, 10.01, 7.79, and 7.58 ìg/min, respectively. Conclusion: The evaporation rates of menthone, menthol, and pulegone in YQP are heavily influenced by decocting time. The fragrance is volatilized fiercely at about 5 min after boiling, while the average evaporation rates of menthone, menthol, and pulegone are high, so after boiling for 5-10 min, menthone, menthol, and pulegone were evaporated a lot. The fragrance gets weak after 15 min of boiling, the average evaporation rates of menthone, menthol, and pulegone are decreasing heavily. It is suggested that the traditional decocting method has some scientific foundation.