Antioxidant and anticholinesterase effects of the ethanol extract, ethanol extract fractions and total alkaloids from the cultivated Ruta chalepensis

Abstract

Ruta chalepensis is a medicinal plant widely used in the folk medicine and have an interesting chemical composition of therapeutic interest. In the present work, we investigated the antioxidant activity of the ethanol extract, ethanol extract fractions, and total alkaloid extract of Ruta chalepensis using phosphomolebdenum, DPPH, ABTS, reducing power, CUPRAC, β-carotene bleaching and ferrous chelating assays. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition was also determined spectrophotometrically using Ellman's colorimetric method. The tested extracts showed a significant antioxidant activity by scavenging free radicals, protecting β-carotene from oxidation, and by acting as reducing and chelating agents. The antioxidant activity was found to be strongly correlated with the polyphenol levels. Butanol and ethyl acetate fractions with high contents of total phenolics, flavonoids, and flavonols exhibited the strongest antioxidant activity. The samples exhibited also an interesting inhibitory effect against AChE and BChE. Chloroform fraction was the most efficient among the fractions in both AChE and BChE inhibition with IC50 values of 41.14 ± 2.85 μg/ml and 79.56 ± 3.66 μg/ml respectively. Total alkaloids showed a strong inhibitory effect against the two enzymes (IC50 = 10.37 ± 0.83 μg/ml against AChE and 14.10 ± 0.68 μg/ml against BChE) comparable to that of galanthamine. These findings suggest a possible use of Ruta chalepensis as a potential source of bioactive molecules with anticholinesterase and antioxidant properties.