This study was conducted to select the optimal extraction method of Codonopsis lanceolata saponin and to analyze saponin contents by harvesting time of Codonopsis lanceolata.
1. Determination of optimum extraction method of saponin lancemaside in Codonopsis lanceolata.
In order to investigate the lancemasides content depending on each extraction method, various extractions were performed: reflux (MeOH and BuOH), hot water, as well as ultrasonic bath (40KHz; continuous irradiation / interval irradiation) and ultrasonicator (20KHz) extractions. The result showed that the overall lancemasides content were the highest in ultrasonic bath (continuous irradiation) extraction, followed by ultrasonic bath (interval irradiation) > ultrasonicator > hot water > MeOH reflux > BuOH reflux extractions in that order.
When the extraction duration (1hr or 2hr) and the pulse (02/10, 06/10, or 10/10) of ultrasonic extraction (ultrasonicator) were varied, lancemasides content was the highest in 1hr extraction and 06/10 pulse. However, this level was higher when ultrasonic bath method was applied at 2hr and 54℃ than those extracted via ultrasonicator’s optimal condition at 1hr and 06/10. As a result, there was a need to determine the optimal extraction method of ultrasonic bath (continuous irradiation) by analyzing lancemasides content depending on sample dry method as well as extraction hour and temperature. The results indicated that lancemasides content was 4.7 times higher in shared drying method than freeze drying method. When the extraction duration was varied (1hr, 2hr, 3hr, and 4hr), although there was no significant statistical difference between 1hr and 2hr, lancemasides content was tendency in higher at 2hr. When extraction was performed at a varying degree of temperature from 34 to 70℃ with a 10℃ interval, the contents of lancemaside A (the main saponin ingredient of Codonopsis lanceolata) were the highest at 64℃.
Accordingly, the optimal extraction method of Codonopsis lanceolata saponin was ultrasonic (40KHz) extraction. As for the sample drying method prior to extraction, shade drying was more effective in lancemaside extraction than freeze drying. When applying the ultrasonic extraction method, the above result also verified that the effective duration of extraction was 2 hours and temperature at 64℃. Not only did the ultrasonic extraction method resulted in a higher level of saponin contents, but it also reduced extraction duration, cost, and labor more so in comparison with the reflux extraction and fruction, the widely used existing methods.
2. Analysis of lancemasides content by harvesting time in Codonopsis lanceolata.
In order to harvests date the lancemasides content and growth of plant (main branch, lateral branch, and leaves), and root harvest of Codonopsis lanceolata was carried out monthly from May to October. The result indicated that the later the harvesting time occurred, plant height and stem diameter showed a tendency to increase. Likewise, the later the harvesting time occurred, the growth rate of root fresh weight showed a tendency to increase slowly. As the temperature got cooler from september, cooler, it became significantly enlarged to increase in September and October.
The lancemasides content of Codonopsis lanceolata plant was the highest in May. After this peak, the later the harvesting time occurred, the lower the lancemasides content became. When analyzing the saponin contents of Codonopsis lanceolata plant in each part, it was the highest in main branch followed by leaves and lateral branch in that order. The lancemasides content was the highest in main branch regardless of harvesting time.
The lancemaside contents in roots, which is the underground part of Codonopsis lanceolata, had no significant difference depending on harvesting time. However, the later the harvesting time occurred, the more lancemasides content showed a tendency to increase.
Consequently, in plant of Codonopsis lanceolata, the lancemasides content was the highest in May, which is the initial growth period. And in root of Codonopsis lanceolata, the later the harvesting time occurred (September and October), the more lancemasides content showed a tendency to increase.