ACETYLCHOLINESTERASE INHIBITORY ACTIVITY WITH METHANOLIC EXTRACT FROM PSYCHOTRIA CAPILLACEA (RUBIACEAE)
impairment, which is associated with the cholinergic deficiency, and a form of treatment is to restore
acetylcholine neurotransmitters colinégicos (Ach). Published reports show promising results with
acetylcholinesterase (AChE) inhibitors considerably increasing the concentration of Ach neurotransmitter
in the brain of patients diagnosed with the disease1. Psychotria capillacea (Rubiaceae) popularly known
as "coffee", is a woody shrub native of forests in southern Brazil2. Psycotria genus plants have been the
target of several pharmacological studies to evaluate the acetylcholinesterase activity due to the presence
of alkaloids and iridoids. The aim of this study was to evaluate the acetylcholinesterase activity of the
methanol extract from P. capilacea of the leaves. Methods: P. capillacea leaves were collected in
Dourados – MS. The methanol extract was obtained by cold maceration with methanol and subsequent
evaporation of the solvent. For the evaluation of acetylcholinesterase activity in vitro, the euthanasia of
male Wistar rats was performed to the removal of the brain (cortex, cerebellum, hippocampus and
striatum), and homogenized separately in buffer Tris-HCl 10 mmol, pH 7.2 with saccharose 160 mmol
(1:10, p/v). The AChE activity in the homogenized was determined by the method of Ellman et al. (1961)3.
The assay medium containing DTNB 1.04 mmol and potassium phosphate buffer 24 mmol pH 7,2 was
incubated for 2 minutes at 30°C with 25 mL of sample (methanol extract 0.5 mg/mL) and the reaction
started by the addition of acetylthiocholine (Ach) 0,83mmol.L-1. The reaction product was determined at
412 nm with 2 min, and the specific activity (SA) was expressed in µmol by hydrolyzed acetylcholine (µmol
AchH.h-1.mg de proteína-1). The protein concentration from the homogenized samples was determined
by Coomasine Blue method (Bradford, 1976) using bovine serum albumin as standard4. Results: The
methanol extract of P. capillacea tended to change the AChE in the brain cortex (SA= 3.11 µmol AchH.h-
1.mg de protein-1), hippocampus (SA= 3.11 µmol AchH.h-1.mg de protein-1) and striatum (SA= 1.16 µmol
AchH.h-1.mg de protein-1). The sample not showed alteration in AChE activity in brain structures of the
cerebellum. Discussion and Conclusion: P. capillacea demonstrated inhibitory effect on
acetylcholinesterase, being responsible for degrading the neurotransmitter ACh. However, it is necessary
to keep studying ex vivo model to be able to characterize it as an inhibitor of AChE.
MORAIS, S.M; LIMA, K.S.B. ; SIQUEIRA, S.M.C. ; CAVALCANTI, E.S.B. ; SOUZA, M.S.T.
; MENEZES, J.E.S.A. ; TREVISAN, M.T.S. Correlação entre as atividades antiradical, antiacetilcolinesterase e teor de fenóis totais de extratos de plantas medicinais de farmácias vivas.
Rev. Bras. Pl. Med., Campinas, v.15, n.4, p.575-582, 2013.
FORMAGIO, A. S. N.; VOLOBUFF, C. R. F.; SANTIAGO, M.; CARDOSO, C. A. L.; VIERA,
M. C.; PEREIRA, Z. F. Evaluation of Antioxidant Activity, Total Flavonoids, Tannins and Phenolic
Compounds in Psychotria Leaf Extracts. Antioxidants, v.3, p.745-757. 2014.
ELLMAN, G. L.. A new and rapid colorimetric determination of acetylcholinesterase
activity. Biochemical Pharmacology, v. 7, p. 88-95, 1961.
BRADFORD, M. M. A rapid and sensitive method for quantitation of microgram
quantities of protein utilizing the principle of protein-dye binding. Analytical Biochemistry, v.72,
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