Antifungal Efficacy and Convenience of Krameria lappacea for the Development of Botanical Fungicides and New Alternatives of Antifungal Treatment

Abstract

The support of trends in agriculture with limited or restricted use of pesticides is linked to the difficulty of protection against pathogenic and toxigenic fungi. Therefore, it is a great challenge to find alternatives to these dangerous fungi. These alternatives include using safe antifungal plant substances of medicinal or aromatic plants as components of botanical pesticides. Within 69 plant species, only 13 were selected as potentially of interest. However, the species Krameria lappacea, whose extraction yield (economic factor) achieved 17.6% and minimum inhibitory concentrations (MIC50) 0.11–1.24 mg mL−1, was found to be enormously advantageous. Extraordinary efficacy on a set of dangerous filamentous fungi, comparable to expensive essential oils or active phenolic compounds, was demonstrated. In the most effective extract fraction, two main substances from the group of neolignans, analogues of kramerixin, were detected by using GC-MS and LC-MS analysis, and their molecular structure was determined. The advantage of K. lappacea was discussed on the basis of the mode of action and chemical properties of the detected neolignans. K. lappacea could be a suitable source for environmentally friendly preparations, thanks to its high yield in simple extraction, excellent antifungal activity, broad antifungal spectrum, harmlessness, and assumed lower volatility of active compounds.