In vitro screening for acetylcholinesterase inhibition and antioxidant activity of medicinal plants from southern Africa.
OBJECTIVE
To determine the acetylcholinesterase inhibitory (AChEI) 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 IC(50) 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 IC(50) 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.
Department of Pharmacology, School of Medicine, University of Pretoria, South Africa.
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Adewusi
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Steenkamp
D000085:Acetates; D000110:Acetylcholinesterase / Q000378:metabolism*; D000353:Africa, Southern; D052160:Benzothiazoles / Q000037:antagonists & inhibitors; D001713:Biphenyl Compounds / Q000037:antagonists & inhibitors; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D003124:Colorimetry; D004305:Dose-Response Relationship, Drug; D005419:Flavonoids / Q000032:analysis; D044948:Flavonols / Q000032:analysis; D005609:Free Radicals / Q000037:antagonists & inhibitors; D005638:Fruit / Q000737:chemistry; D006801:Humans; D020128:Inhibitory Concentration 50; D000432:Methanol; D010636:Phenols / Q000032:analysis; D010851:Picrates / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors; D012997:Solvents; D013053:Spectrophotometry / Q000379:methods; D013451:Sulfonic Acids / Q000037:antagonists & inhibitors
D000085:Acetates; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D002800:Cholinesterase Inhibitors; D005419:Flavonoids; D044948:Flavonols; D005609:Free Radicals; D010636:Phenols; D010851:Picrates; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D012997:Solvents; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C007650:ethyl acetate; C004931:1,1-diphenyl-2-picrylhydrazyl; D000110:Acetylcholinesterase; D000432:Methanol