After extracting Radix liquiritiae from Ether, Acetone by ethanol, it was further fractionated into. three R. liquiritiae fractions, (A), (B), and (C). With these fractions a series of experiments was conducted to find out the inhibitory action of these fractions on the bacterial growth as well as the increased potential in the bacterial resistance against these fractions and compared the same of Allium sativum fraction (A). Original Staph. aureus 209 P, PC, SM-resistant strains and PC-SM double resistant strain served as the bacterial materials. The results of the study are summarized in the following.
I. R. liquiritiae fraction (A) has been found to show the inhibitory action on the original strain of Staph. aureus 209 P and its drug resistant strains only, but (B) and (C) fractions show no effect on the bacteria. To other strains of bacteria the fractions (A), (B), and (C) do not show any inhibitory effect. However, R. liquiritiae fraction (A) shows its inhibitory action on the growth of Staph. aureus 209 P even at the concentration of 1/5 that of A. sativum fraction.
2. In the successive tissue culture of four strains, the original strain, PC, SM- drug resistant strains of Staph. aureus 209 p in the media containing R. liquiritiae fraction (A) and A. sativum fraction (A), it has been found that the increase in the resistance potential against A. sativum fraction (A) is considerably different between the original strain and the drug resistant strains of Staph. aureus 209 P, but that against R. liquiritiae fraction (A) is considerably potentiated in both the original and the drug resistant strains. In other words, at the tenth generation, the original strain shows the 6-fold resistance, while PC, SM-resistant strains 8-fold resistance and PC-SM double resistant strain 10-fold against A. sativum fraction (A). On the other hand, R. liquiritiae fraction (A) imparts the resistance to both the original strain and the drug resistant strains in the same degree, namely, only 3-fold resistance at the tenth generation of the successive tissue culture.