二鹽基脂肪酸類の腐敗菌、腸チフス菌及びコレラ菌に對する殺菌作用

抄録

Attention was called in my previous works^(1)(2)(3) to the bactericidal action of monobasic fatty acids on Staphylococcus pyogenes aureus, Proteus vulgaris, Bacillus typhosus and Vibrio cholerae.
In the present paper is given an extension of my observations on the same kinds of bacteria with the same methods⁽⁴⁾ but using dibasic fatty acids instead. Incidentally monobasic and dibasic fatty acids are herein compared in this connexion.
The results obtained may be summarized as follows: - (1) Among the dibasic fatty acids of the same molecular concentration, oxalic acid (C₂) tops the list in the strength as bactericide, and malonic acid (C₃) comes the next. With increase in the number of C-atoms the bactericidal activity of the acids in question suddenly falls down from malonic acid on until C₆ acid is reached but it goes up gradually henceforth.
(2) The bactericidal action of anions is not observable in those dibasic fatty acids with 2 to 6 C-atoms, but it is the case with those having more than 6 C-atoms.
(3) Dibasic, monobasic, unsaturated, and monobasic saturated fatty acids having 2 or 3 C-atoms stand in descending order of bactericidal activity when tested with respective acids having the same number of C-atoms and the same concentration. This is chiefly due to the difference of pH values. The above-mentioned order is reversed with those having the same concentration but containing 5 or more than 5 C-atoms. Such seems to be caused by undissociated molecules of these acids.
(4) The already mentioned 3 kinds of the acids are graded as weak, strong, stronger in their bactericidal capacity when compared at the same pH-value, due to the difference of molecular concntration of each.
(5) Neither increase nor decrease in the number of carboxyl group in the acids in question is accompanied by any change in strength as bactericide.