BAC chemicals may block brain hormone production

Benzalkonium chloride (BAC) is a common cleaning agent that can also act as a preservative in many everyday items. Recent research shows that BAC can interfere with an enzyme called 5α‑reductase 1, which is essential for turning testosterone into dihydrotestosterone (DHT) in the brain. The study tested different BAC molecules, each with a chain of carbon atoms ranging from one to eighteen. The experiments used several techniques: measuring the amounts of testosterone and DHT by liquid chromatography, watching how the molecules bind to the enzyme with surface plasmon resonance (SPR), and simulating their interactions on a computer. Results revealed that BAC molecules with ten or more carbon atoms could significantly slow the enzyme’s activity. The longest chain, C18, was the strongest blocker: it needed only about 10 µM to cut human enzyme activity in half, while it required roughly 34 µM for the rat version.SPR data showed that C18 sticks to the enzyme tightly, with a binding strength of 6. 4 µM and a slow release rate, meaning once it attaches it stays put for a while. Further tests indicated that BAC molecules do not simply block the active site; instead they compete with NADPH, a helper molecule for the enzyme, and act as mixed or non‑competitive inhibitors. When living cells were exposed to BAC components with 12–18 carbon atoms, the production of DHT dropped sharply at concentrations between 10 and 100 µM. Statistical analysis linked the potency of inhibition to physical properties like hydrophobicity (LogP), size, and flexibility. A 3D pharmacophore model highlighted that oily, non‑polar interactions are key to the blocking effect. Computer docking studies mapped how BAC molecules sit inside the enzyme’s NADPH pocket, using a mix of van der Waals forces, hydrogen bonds, and charge contacts. Together these findings suggest that BAC could act as an endocrine disruptor by hindering neurosteroid synthesis, potentially leading to neurological issues. The research was supported by a regional science foundation, which had no influence on the study’s design or conclusions.