Cyanidin 3-O-glucoside and other anthocyanins affect enniatins production in Fusarium avenaceum

Fusarium Head Blight (FHB), caused by various Fusarium species, is a major threat to global cereal production. F. avenaceum is an important FHB pathogen producing enniatin mycotoxins. While several studies have explored the antifungal and anti-mycotoxigenic potential of different phenolic compounds, the effects of anthocyanins (pigments abundant in plants including certain cereals) remain poorly understood. This study explored the effects of anthocyanins on F. avenaceum conidial germination, fungal biomass and enniatins production. In vitro assays revealed that while anthocyanidins (cyanidin, delphinidin) inhibited conidial germination, cyanidin 3-O-glucoside and delphinidin 3-O-glucoside increased fungal biomass. Notably, cyanidin 3-O-glucoside and delphinidin consistently reduced enniatins production (A1, B and B1), whereas delphinidin 3-O-glucoside primarily reduced enniatin A1. These contrasting effects can likely be ascribed to presence or absence of the glycosylated moiety, distinct degradation pathways, and the influence of anthocyanins on fungal gene expression, including the regulation of key genes involved in enniatin biosynthesis and oxidative homeostasis. Furthermore, the study examined the concurrent effects of cyanidin 3-O-glucoside and ferulic acid, another plant phenolic compound. When combined, ferulic acid stabilized cyanidin 3-O-glucoside, preserving its anti-mycotoxin activity, while antifungal potential of ferulic acid was abrogated, highlighting the complex interactions between these compounds. These findings provide valuable insights into the potential of anthocyanins as natural anti-mycotoxin agents and suggest an optimization of their use for mycotoxin control.