Fungicidal and anti-aflatoxin activity of four meroterpenoids isolated from Arnebia euchroma root

Meroterpenoids are naturally occurring bioactive compounds derived from terpenoids. Isolation and structure elucidation of four meroterpenoids from Arnebia euchroma root confirmed as arnebinol A–D have been conducted and their antifungal and anti-aflatoxigenic activities against Aspergillus flavus have been investigated. Scanning electron microscopy revealed that after treating A. flavus with arnebinol A–D at ≥200 mg/L, the conidia with phialides appeared wrinkled and compressed, the cell wall was damaged, and mycelial growth was entirely inhibited. Arnebinol D could inhibit A. flavus aflatoxin production and reduce ergosterol levels. The present experiments confirmed the antifungal activity of arnebinol D and provided evidence for the potential use of these natural compounds against fungi.