Fusarium head blight (FHB) is a disease that poses a major challenge in cereal production that has important food and feed safety implications due to trichothecene contamination. In this study, the effect of stevioside—a glycoside found in the leaves of candyleaf (Stevia rebaudiana Bertoni)—was evaluated in vitro against Fusarium culmorum (W.G. Smith) Sacc., alone and in combination (in a 1:1 molar ratio) with polyphenols obtained from milk thistle seeds (Silybum marianum (L.) Gaertn). Different concentrations, ranging from 32 to 512 µg·mL⁻¹, were assayed, finding EC₅₀ and EC₉₀ inhibitory concentrations of 156 and 221 µg·mL⁻¹, respectively, for the treatment based only on stevioside, and EC₅₀ and EC₉₀ values of 123 and 160 µg·mL⁻¹, respectively, for the treatment based on the stevioside–polyphenol conjugate complexes. Colony formation inhibition results were consistent, reaching full inhibition at 256 µg·mL⁻¹. Given that synergistic behavior was observed for this latter formulation (SF = 1.43, according to Wadley’s method), it was further assessed for grain protection at storage, mostly directed against mycotoxin contamination caused by the aforementioned phytopathogen, confirming that it could inhibit fungal growth and avoid trichothecene contamination. Moreover, seed tests showed that the treatment did not affect the percentage of germination, and it resulted in a lower incidence of root rot caused by the pathogen in Kamut and winter wheat seedlings. Hence, the application of these stevioside–S. marianum seed extract conjugate complexes may be put forward as a promising and environmentally friendly treatment for the protection of cereal crops and stored grain against FHB.

中文翻译：

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对甜菊苷，水飞蓟种子提取物及其缀合物的镰刀菌的抗真菌活性。

镰刀菌枯萎病（FHB）是谷物生产中的一个重大挑战，由于天花粉污染，对谷物和饲料的安全性具有重要影响。在这项研究中，甜菊糖苷（一种在糖果叶（甜叶菊甜叶菊中）发现的糖苷）的效果在体外评估了单独或组合（摩尔比为1：1）对镰孢镰刀菌（WG Smith）Sacc。的影响。与从水飞蓟种子（Silybum marianum（L.）Gaertn）获得的多酚。测定了从32至512 µg·mL ^-1的不同浓度，发现EC ₅₀和EC ₉₀抑制浓度分别为156和221 µg·mL ^-1仅基于甜菊糖苷的治疗，基于甜菊糖苷-多酚共轭复合物的治疗的EC ₅₀和EC ₉₀值分别为123和160 µg·mL ^-1。菌落形成抑制结果一致，在256 µg·mL ^-1时达到完全抑制。考虑到后一种配方具有协同作用（根据Wadley的方法，SF = 1.43），因此可以进一步评估其在储存时的谷物保护作用，主要针对上述植物病原体引起的霉菌毒素污染，从而证实它可以抑制真菌的生长和繁殖。避免天花粉污染。此外，种子试验表明，该处理方法不影响发芽率，并且降低了病原体在Kamut和冬小麦幼苗中引起的根腐病发生率。因此，这些甜菊糖苷-S . marianum种子提取物结合物复合物的应用可能被提出作为一种有前途且对环境友好的处理方法，用于保护谷物和储藏谷物免受FHB的侵害。