Assessment of enzyme inhibitory and antioxidant activities of lignans from Taxus baccata L.
Phytochemical investigations of Taxus baccata L. by successive chromatographic methods resulted in the isolation of the lignans lariciresinol (1), taxiresinol (2), 3'-demethylisolariciresinol-9'-hydroxyisopropylether (3), isolariciresinol (4), and 3-demethylisolariciresinol (5) as well as taxoids. Compounds 1-5 were evaluated for their acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and lipoxygenase (LOX) inhibitory activities, which play a role in the pathogenesis of Alzheimer's disease (AD), by in vitro spectrophotometric methods, while they were also screened for their antioxidant capacity in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferrous ion-chelating effect, and ferric-reducing antioxidant power (FRAP) at 125, 250, 500, and 1000 microg ml(-1). All compounds exhibited a moderate inhibition against both BChE and LOX, whereas they were inactive towards AChE. The compounds displayed a great scavenging activity against DPPH especially at 500 and 1000 microg ml(-1). Besides, they were found to exert noteworthy reducing antioxidant power on ferric ions. In particular, the FRAP of compounds 2 (3.552 +/- 0.02), 4 (3.021 +/- 0.71), and 5 (3.533 +/- 0.01) were as high as that of the reference chlorogenic acid (3.618 +/- 0.01) at 1000 microg ml(-1). None of the compounds exhibited chelating ability against ferrous ions.
Kucukboyaci
Nurgun
N
Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey. nurgun@gazi.edu.tr
Orhan
Ilkay
I
Sener
Bilge
B
Nawaz
S Ahmad
SA
Choudhary
M Iqbal
MI
D000544:Alzheimer Disease / Q000188:drug therapy / Q000503:physiopathology; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology / Q000627:therapeutic use; D002091:Butyrylcholinesterase / Q000187:drug effects / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000302:isolation & purification* / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000302:isolation & purification / Q000494:pharmacology; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D020946:Taxus / Q000737:chemistry*; D014421:Turkey
D000975:Antioxidants; D002800:Cholinesterase Inhibitors; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D016859:Lipoxygenase Inhibitors; D002091:Butyrylcholinesterase