Comparative fungicidal activity of a new quaternary ammonium salt, N-alkyl-N-2-hydroxyethyl-N,N-dimethylammonium butyl phosphate and commonly used disinfectants

Abstract

We synthesized a new quaternary ammonium salt, N-alkyl-N-2-hydroxyethyl-N,N-dimethylanimonium butyl phosphate (ABP) that does not precipitate in the presence of anionic surfactants by incorporating a paired butyl phosphate anion into cationic surfactants. ABP showed much greater bactericidal activities and antirusting effects than benzalkonium chloride (BAC). In this study, the fungicidal effects of ABP were evaluated in comparison with common disinfectants [BAC, chlorhexidine digluconate (CHX) and alkyldiaminoethylglycine hydrochloride (ADE)]. Fungicidal effects were evaluated in 10 strains of 6 fungal species, namely, 3 Candida albicans, 2 Candida tropicalis, 1 Candida parapsilosis, 1 Aspergillus niger, 2 Aspergillus terreus, and 1 Trichophyton rubrum. ABP and BAC showed the same effects on 2 C. tropicalis and C. parapsilosis, and similar effects on 3 C. albicans, with slight differences among the strains. ABP showed quick fungicidal effects against A. niger and 2 A. terreus of molds in 30 min at 0.1% and in 15 min at 0.2 and 0.4%, but BAC showed slow effects against A. niger at 1 h and 2 A. terreus at 30 min at 0.2 and 0.4%, respectively. There is one factor which may have caused this difference: the former had a butyl phosphate anion and the latter had a chloride anion as a counter ion. BAC, CHX and ADE needed 24 h to cause notable effects on A. niger at 0.1% and 1 h at 0.2%. The new synthetic anti-rust ABP is considered to have sufficient fungicidal effects that are comparable to those of BAC, CHX and ADE.