Background : Codonopsis lanceolata has been used in traditional medicines, as its roots contain several kinds of triterpenoid saponin with high medicinal values. This study was conducted to select an advanced extraction method in C. lanceolata root. Methods and Results : Four extraction methods including 70% MeOH reflux and solvent fraction (n-hexane, ethyl acetate, butanol, water), water saturated butanol reflux, boiling water, and ultrasonication (70% MeOH) were investigated for the determination of major lancemasides. The total contents of lancemasides were the highest of 2.80 ㎎/g in ultrasonication, followed by boiling water, MeOH reflux, and water saturated butanol reflux extraction, in that order. Lancemaseide A was the most abundant saponin in all treatments, followed by lancemaside G, aster saponin, lancemaside B, in that order. The content of lancemaside B was very low compared to lancemaside A. Although four types of saponins were confirmed in this study, the others saponin such as foetidissimoside A could not be quantified due to very low content. Ultrasonication was evaluated as optimal extraction method and further studies were conducted to determine the optimal condition. The result compared to dry methods of sample [freeze-drying and shade dry (< 60℃)] before ultrasonication was superior shade dry to freeze-drying. The extract time and temperature were the best in 2 hr, 64℃ treatment, respectively, although there was no significant statically. Conclusion : The ultrasonication method was evaluated as relatively simpler and more efficient method due to short extraction time, small solvent consumption relative to conventional reflux method.

Background : Recently, there have been dynamic researches conducted on stevia as natural sweetener subtitute for sugar, However, Researches related to harvest period and parts of plant in stevia are few. Therefore, this study was conducted to select optimum harvest time and parts by measuring the natural sweeteners contents and analyzing antioxidant materials and activity according to harvest times, parts of plant. Methods and Results : Stevia was cultivated in plastic house, The leaves were harvested from April to October and the stem were only harvest in July and September. Stevia leaves and stems were extracted using high temperature and pressure extraction: Dried stevia leaves of 5g were added by 100ml of distilled water equivalent to 20 times of dry weight, and the mixture were extracted by autoclave at 121℃ for 15min. The contents of Rebaudioside A and Stevioside of stevia leaves harvested from April to October showed a tendency to increase gradually from July to October as the temperature increased, but the contents of rebaudioside A and stevioside decreased slightly in August due to excessively high temperature. The extraction yield of stevia leaves were highest in October and September, and there was no significant difference in the other period. In the stevia stems, the extraction yield was lower than that of stevia leaves in general regardless of harvest time. Total phenolic contents and flavonoid contents according to harvest time showed little difference among treatment. Conclution : stevia leaves were better than stevia stems regarding the use of rebaudioside A and stevioside as natural sweeteners. Also, it was confirmed that the stevia leaves of July, September and October, except for the high temperature period of August, had superior in quality and quantity.