Dequalinium

G01AC05

G - Genito urinary system and sex hormones

D - Dermatologicals

R - Respiratory system

QG - Genito urinary system and sex hormones

QD - Dermatologicals

_In vitro_, dequalinium possesses antimicrobial activity against gram-positive and gram-negative bacteria, yeasts, and protozoa. Dequalinium has a rapid bactericidal and fungicidal action. The antiparasitic and antiviral properties of dequalinium have also been noted. For example, dequalinium can bind to the membrane-proximal external region (MPER) of the spike envelope of the human immunodeficiency virus HIV-1. As with other quaternary ammonium compounds similar to dequalinium, gram-positive bacteria are more sensitive to dequalinium than gram-negative bacteria. The bactericidal and fungicidal effects of dequalinium can occur within 30 to 60 minutes. According to _in vitro_ studies, the minimal inhibitory concentration (MIC) for dequalinium against relevant vaginal pathogens ranges from 0.2 to ≥ 1024 µg/mL. There is evidence that dequalinium exhibits anticancer activity in human leukemia cells: dequalinium induces a cytotoxic effect by altering redox balance, downregulating Raf/MEK/ERK1/2 and PI3K/Akt signalling pathways, and promoting apoptosis of leukemic cells. Dequalinium was also shown to block small conductance Ca²⁺-activated K⁺ channels, called SK channels, which are often expressed in some cancer cells to play a role in cell proliferation and migration. One study showed that dequalinium reduced macrophage motility in mice, inhibiting macrophage infiltration of irradiated tumours and attenuating local metastasis. Interestingly, dequalinium was shown to modulate and induce self-oligomerization of alpha-synuclein, a synaptic protein known to cause aggregates in several neurodegenerative disorders. This finding highlights the neuroprotective actions of dequalinium; however, further investigations are warranted as dequalinium is a neurotoxic agent.

Dequalinium has multiple modes of action. Dequalinium absorbs into the bacterial cell surface and diffuses through the cell wall, disrupting bacterial cell permeability. It is taken up by the bacteria rapidly. Once in the bacteria, dequalinium denatures proteins involved in the respiratory chain and glycolysis of bacteria, interfering with bacterial cell metabolism and ribosomal protein synthesis. By inhibiting bacterial F1-ATPase, dequalinium inhibits mitochondrial ATP synthesis and blocks glucose metabolism. These molecular actions ultimately deplete bacterial energy sources. As dequalinium accumulates in the mitochondria, it is considered a mitochondrial poison. Dequalinium can also precipitate nucleic acids, as it can intercalate one of its quinoline chromophores between DNA base pairs. Depending on the drug concentration, dequalinium can lyse the bacterial cell by promoting osmotic imbalance.