Phenolic composition and anticholinesterase, antioxidant, antifungal and antibiotic modulatory activities of Prockia crucis (Salicaceae) extracts collected in the Caatinga biome of Ceará State, Brazil

IntroductionA phytochemical and biological activity investigation was performed in extracts of Prockia crucis P. Browne ex. L., Salicaceae, occurring in the Caatinga biome.MethodsEthanol extracts of leaves and bark were analysed by high performance liquid chromatography (HPLC) and evaluated for anti-Candida activity, as well as testing for fluconazole-modifying activity. In addition, antioxidant activity was assayed by the DPPH free radical scavenging method and acetylcholinesterase (AChE) inhibitory activity was determined.ResultsSignificant growth of acetylcholinesterase inhibition zones was observed with both extracts, which was comparable to the standard physostigmine, indicating potential activity against Alzheimer's disease. Good antioxidant action was found with EC50 values of 47.731 μg/mL for bark extract and 137.64 μg/mL for leaf extract. HPLC analysis of the extracts showed the presence of gallic acid and luteolin mainly in the bark and the more kaempferol and coumarin in the leaves. Using the microdilution method, fungal strains of Candida albicans, C. krusei and C. tropicalis showed a minimum inhibitory concentration ≥1024 μg/mL. In the test of fluconazole modulation against multiresistant Candida clinical isolates, there was a clear synergism of both extracts on the C. tropicalis strain when combined with fluconazole. A significant antagonistic effect of the bark extract on C. albicans was observed for P. crucis, showing no potentiation of the antifungal effect when fluconazole was used in combination with the natural product.ConclusionsThe extracts of P. crucis demonstrated an interesting antioxidant, anti-AChE and antibiotic modulatory activities, and due probably to the active phenolic compounds.