Antifungal and antioxidant activities of heartwood, bark, and leaf extracts of Robinia pseudoacacia

Abstract

Different solvent fractions (Fs) of water:methanol (1:1 v/v) of heartwood, bark, and leaf extracts of Robinia pseudoacacia were evaluated for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method; the antifungal activity against the mycelial growth of Trametes versicolor fungus was also determined. The most active fractions were analyzed for their chemical composition using gas chromatography-mass spectrometry (GC/MS). At higher concentrations (0.016 mg/mL), the values of antioxidant activity were 92.3%, 92.5%, 50.6%, 93.4%, and 96.6%, for heartwood F7 (ethyl acetate fraction), bark F7 (ethyl acetate fraction), leaves F9 (methanol fraction), BHT, and vitamin C, respectively. Among the fractions and concentrations of extracts from heartwood, F7 at 12.5 ppm led to the lowest growth of T. versicolor (22.00 mm); F7 of the bark extract showed good antifungal activity, with lower mycelia growth values reached 11.33, 11.33, and 13.00 mm at concentrations of 12.5, 25, and 50 ppm, respectively. For leaf extracts, F9 showed good antifungal activity at all concentrations, where the values of mycelial growth were 26.00, 25.33, and 28.33 mm at concentrations of 12.5, 25, and 50 ppm, respectively. These results indicated that the fractions of R. pseudoacacia can be a valuable and economic resource for use in antioxidant activity or as an antifungal activity against the growth of T. versicolor.