Echinocandin

Echinocandins are a class of antifungals which act by preventing glucan synthesis pathway necessary for fungal cell wall formation.

Until now three echinocandins are approved for clinical use - Caspofungin, Micafungin and Anidulafungin.

A fourth echinocandin - Rezafungin is being developed.

• Caspofungin - Synthetically modified pneumocandin B0 of Glarea lozoyensis (Zalerion arboricola).

• Micafungin - Synthetic modification of cyclic hexapeptide FR901370 derived from Coleophoma empetri.

• Anidulafungin - Synthetic modification of echinocandin B0, produced by Aspergillus nidulans

Echinocandin is a non-competitive inhibitor of the enzyme β-(1,3)-glucan synthase.

β-(1,3)-glucan synthase is required for synthesis of β-( 1,3)-glucan from uridine diphosphate-glucose. β-(1,3)-glucan is a structural component of the fungal wall. Loss of β-(1,3)-glucan leads to the loss of cell wall integrity.

The affected cells lyse due to osmotic pressure.

Echinocandins also exhibit immunomodulatory activity – it unmasks/release glucans from the cell wall. This process enhances the phagocytic killing of fungus via dectin-1 receptor activation.

Some other antifungals (some in development) that act of fungal cell walls -