Relationship between the Number of Carbon Chains and the Antifungal Activity of 9-Straight Chain Alkylated Acridine Derivatives

Abstract

The entire series of 9-straight chain alkylated acridine derivatives which are acridine (1, C0) -9-n-octiylacridine (9, C8) except C0 were synthesized and C0 was purchased. The relationship between the number of carbon chains on 9-straight chain alkylated acridine derivatives and their antifungal activity toward Aspergillus niger at pH 3.7, 5.2 and 7.0 was investigated by the paper disc method. The degrees of the antifungal activity of the tested compounds were estimated in terms of both initial strength (IS), which was obtained by measuring the diameter of the inhibition zone around each paper disc with the tested compound after 3 days incubation, and durability of the antifungal activity (DF). The diameter of inhibition zone (16.5mm) of 4-chloro-m-cresol at pH 5.2 after 3 days incubation at 25t was used as a control for the antifungal activity to be defined as f =100. The DF was estimated by the period until inhibition zone disappeared or f value after 10 days incubation when inhibition zone was observed continuously. Though the regularly relationship between the number of carbon chain and the antifungal activity was not consequently found, the existence of optimum number of the carbon chain at each tested pH was suggested. That is, the ranking of IS and DF were as follows.IS;pH3.7 : C7 (8) >C6 (7), C5 (6) >C8 (9), C4 (5) >C0 (1), C1 (2), C2 (3), C3 (4)pH5.2 : C0 (1) >C4 (5) >C5 (6) >C3 (4) >C7 (8), C1 (2) >C2 (3) >C8 (9) >C6 (7)pH7.0 : C0 (1) >C1 (2) >C4 (5) >C3 (4) >C5 (6) >C6 (7) >C7 (8) >C8 (9) >C2 (3) DF;pH3.7 : C7 (8) >C5 (6) >C6 (7) >C4 (5) >C8 (9) >C1 (2) >C0 (1) >C2 (3), C3 (4)pH5.2;C4 (5) >C5 (6) >C7 (8) >C6 (7) >C8 (9) >C3 (4) >C0 (1) >C1 (2) >C2 (3)pH7.0 : C7 (8) >C6 (7) >C8 (9) >C5 (6) >C1 (2) >C0 (1) >C2 (3), C3 (4), C4 (5)