In vitro screening for acetylcholinesterase inhibition and antioxidant activity of medicinal plants from southern Africa

摘要

Objective:To determine the acetylcholinesterase inhibitory（AChE1） and antioxidant activity of the ethyl acetate and methanol extracts of 12 traditional medicinal plants used in the treatment of neurological disorders.Methods:AChEI activity was determined spectrophotometrically using the Ellman’s colorimetric method.Antioxidant activity was carried out by determining the ability of the extracts to scavenge 2,2-diphenyl-1-picryl hydrazyl（DPPH） and 2,2’-azinobis- 3-ethylbenzothiazoline-6-sulfonic acid（ABTS） radicals.The levels of total phenols,flavonoids and flavonols were determined quantitatively using spectrophotometric methods.Results:AChEI was observed to be dose-dependent.Lannea schweinfurthii（L.schweinfurthii）（Engl.） Engl.and Scadoxus puniceus（S.puniceus）（L.） Friis & I.Nordal.root extracts showed the lowest IC50 value of 0.000 3 mg/mL for the ethyl acetate extracts while Zanthoxylum davyi（Z.davyi）（I.Verd.） P.G. Watermann had the lowest IC50 value of 0.01 mg/mL for the methanol extracts in the AChEI assay. The roots of Piper capense（P.capense） L.f.,L.schweinfurthii,Ziziphus mucronata（Z.mucronata） Willd.,Z.davyi and Crinum bulbispermum（C.bulbispermum）（Burm.f.） Milne-Redh.& Schweick.showed noteworthy radical scavenging activity and good AChEI activity.Conclusions: Five plants show good antioxidant and AChEI activity.These findings support the traditional use of the plants for treating neurological disorders especially where a cholinesterase mechanism and reactive oxygen species（ROS） are involved.