Antifungal and phytotoxic activities of flavonoids from Caatinga green propolis

Caatinga green propolis, derived from Mimosa tenuiflora, represents a recently characterised Brazilian propolis type rich in flavonoid constituents with broad biological activities. In this study, 12 flavonoids were isolated from the hydroalcoholic extract of Caatinga green propolis and evaluated for their phytotoxic and antifungal potential. Phytotoxic activity was assessed against Lactuca sativa, Agrostis stolonifera and Lemna paucicostata, revealing moderate to significant growth inhibition, particularly for 7-O-methyleriodictyol and penduletin. Antifungal activity was evaluated against Colletotrichum fragariae using TLC bioautography, where methylquercetin, sakuranetin and cirsimaritin exhibited the strongest inhibitory effects. These results demonstrate that flavonoids contribute significantly to the biological properties of Caatinga green propolis and identify specific compounds with promising phytotoxic and antifungal activities, expanding current knowledge on this distinctive propolis type and support its potential as a source of natural products for plant protection and weed management.