histatins

Histatins are a family of small, histidine-rich, cationic peptides found in human saliva. They are produced by the salivary glands and contribute to the mouth’s innate immune defenses. The family includes several members, notably histatin-1, histatin-2, histatin-3, histatin-5, and histatin-7, with histatin-5 being the most extensively studied for antifungal activity.

Histatins exhibit antimicrobial properties, with histatin-5 displaying strong activity against Candida species, especially Candida albicans. They also have activity against a range of other oral microbes and may influence biofilm formation and wound healing in the oral mucosa. These peptides exist in saliva as active forms, often generated by proteolytic processing of larger precursor proteins within the glands.

Mechanisms of action are not fully understood and may be multifaceted. Proposed modes include interactions with microbial membranes due to their cationic, histidine-rich nature, uptake into fungal cells, and subsequent disruption of intracellular processes such as mitochondrial function and energy production. Metal ion binding and interference with metal homeostasis may also contribute to antimicrobial effects.

Physiological and clinical relevance centers on the role of histatins in protecting oral tissues from infection and aiding healing. They have attracted interest for potential therapeutic uses, including treatment of oral candidiasis and the development of stable peptide analogs. Limitations for clinical application include proteolytic degradation in saliva and variability in peptide activity among individuals.