Phytochemicals from native plants of the Argentine coast with fungicidal potential

STEGMAYER, M.I.; ALVAREZ, N.; RUIZ, V.E.; FERNÁNDEZ, L.N.; FAVARO, M.A.; DERITA, M.

San Pedro (Buenos Aires)

Simposio; VIII International Symposium on Biofumigation.; 2024

INTA EE San Pedro

The most common and destructive fungal diseases in oranges, strawberries, and peaches are caused by fungi of the genera Penicillium, Botrytis, Colletotrichum, Rhizopus, and Monilinia, respectively. Synthetic fungicides are used to control these pathogens, but market demands regarding their residue limits have led to minimizing their use and seeking replacement alternatives. The general objective of this work was to evaluate products extracted from native plants of the Litoral region for their fungicidal capacity against fruit pathogens. The study summarizes the evaluation of 120 extracts/essential oils/pure molecules obtained from 52 plant species that were fungicidal or fungistatic against some of the mentioned pathogens, using in vitro and ex vivo assays. At least one type of extract from each plant species and all evaluated essential oils showed fungistatic or fungicidal activity against some of the fungi under study. The most active plant extracts were selected for bio-guided fractionation and isolation of the compounds responsible for the activity. The following compounds were isolated: Polygodial (1) from Persicaria acuminata; Pinostrobin (2) and Flavokawin B (3) from Polygonum stelligerum; and Solidagenone (4) from Solidago chilensis. A phytochemically standardized extract of P. acuminata was subjected to ex vivo assays on oranges, strawberries, and peaches inoculated with different pathogens, obtaining comparable results to commercial fungicides in all cases. Cytotoxicity assays against Huh7 liver cells showed that natural products were less cytotoxic than commercial fungicides Carbendazim and Imazalil. It is concluded that phytochemicals have great potential for controlling postharvest diseases in Argentina's fruit production; however, further studies on the standardization of actives in extracts, dosages, and application technologies are needed.