Alternarin A, a Drimane Meroterpenoid, Suppresses Neuronal Excitability from the Coral-Associated Fungi Alternaria sp. ZH-15

Alternarin A (1), a rearranged drimane meroterpenoid characterized by a thioglycerate moiety, was isolated together with two known analogues from the coral-associated fungi Alternaria sp. ZH-IS. Its structure was determined based on spectroscopic analysis, modified Mosher's method, and TDDFT/ECD calculations. In a primary cultured cortical neuronal network, compound 1 effectively inhibited the activity of spontaneous synchronous Ca2+ oscillations and 4-aminopyridine induced epileptic discharges in the low micromolar concentration range.