Melanin pigments extracted from horsehair as antibacterial agents.

Here we present the important findings related to biologically derived pigments for potential use as antibacterial agents. Melanin biopigments extracted from Equus ferus hair exhibit a homogeneous elliptical microstructure with highly ordered semicrystalline features. Spectroscopic analysis indicates that melanin contains a high degree of redox active catechol groups, which can produce reactive oxygen species. The antibacterial activity of melanins was tested by incubating Escherichia coli and Staphylococcus aureus with melanins. The results showed 100% bacterial growth inhibition within 4 h. This finding suggests that melanin pigments may serve as naturally occurring antibacterial agents with unique redox chemistry and reactive oxygen species generation capability.