Enzyme inhibitory and antioxidant activities of Viburnum tinus L. relevant to its neuroprotective potential

Abstract

In vitro neuroprotective activity of the extracts of Viburnum tinus L. was investigated via inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and tyrosinase (TYRO) by microtitre plate assays. Their antioxidant activity was tested using 2,2-diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), super oxide (SO), and nitric oxide (NO) radical-scavenging activities, ferric ion-chelation capacity, ferric- (FRAP), and phosphomolybdenum-reducing antioxidant power (PRAP) assays. Total phenol and flavonoid content of the extracts was determined spectrophotometrically. The branch-ethyl acetate and fruit-methanol extracts exerted potent anticholinesterase effects (66.4 ± 0.65% to 97.7 ± 0.47%), while the fruit-methanol extract had the highest TYRO inhibition (47.0 ± 0.68%). The methanol extracts showed higher activities in most of the antioxidant tests. All the extracts displayed notable NO-scavenging effects (47.5 ± 5.03% to 74.5 ± 1.80%). Only the fruit-ethyl acetate extract quenched SO radical (38.4 ± 1.01%) at 500 μg ml(-1). Our data indicate that the fruit and branch extracts of V. tinus may provide potential neuroprotection.