Extracts with antifungal activity against Botrytis cinerea from potato industry waste

Potato tuber (Solanum tuberosum L.) is the fourth most important agricultural product after wheat, rice, and maize. Fresh potatoes or processed potato products generate large amount of by-products, such as peel, leaves, and stems. In peel and leaf potato, organic acids, amino acids, phenolic acids, flavonoids, iridoids, oxylipins, glycoalkaloids among other compounds have been identified. In this work, potato leaves were used to extract compounds with antifungal activity against the phytophatogenic fungus Botrytis cinerea. Solvents with different polarities were used to extract bioactive compounds from potato leaves. The purification of bioactive compounds from leaf extracts from S. tuberosum was performed in various chromatographic steps, obtaining a bioactive fraction with at least two compounds. Based on the spectroscopic and thin-layer chromatographic data analysis, it can be suggested that this active fraction would have a terpenoid and an aromatic compound. This fraction inhibited the mycelial growth of B. cinerea with an ED50 of 4.3 mg L−1. The unpurified extracts showed only pro-oxidant activity; however, the bioactive fraction did not show pro-oxidant or antioxidant effects. The results of this work suggest that potato by products can be used in the production of biofungicides to control to B. cinerea.