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RESUMO: "Atividade inibitória da acetilcolinesterase e butirilcolinesterase de algumas plantas medicinais da Nigéria". As plantas podem ser úteis para estimular a memória, bem como serem usadas para combater o envelhecimento. Vinte e duas plantas, de dezesseis famílias, foram investigadas in vitro oara verificar sua atividade inibidora das enzimas acetilcolinesterase (AChE) e butirilcolinesterase (BuChE) pelo método espectrofotométrico de Ellman in situ e métodos de bioautografia utilizando fisostigmina como padrão. Pelo menos três partes morfológicas de cada planta foram analisadas e a concentração de ensaio foi de 42,5 µg/mL. Algumas plantas foram ativas em ambas as enzimas, embora com algumas partes mais ativas que outras. A casca da raiz de Spondias mombin apresentou a maior atividade as duas enzimas, 64,77% para AChE e 83,94% para BuChE. Outras partes das plantas selecionadas apresentaram boa seletividade em suas ações. As plantas seletivamente ativos contra AChE foram as casca do caule e casca da raiz de Alchornia laxiflora (41,12%), e casca da raiz de Callophyllum inophyllurn (56,52%). As folhas de C. jagus (74,25%), folhas de Morinda lucida (40,15%), folhas e casca do caule de Peltophorum pterocarpum (49,5% e 68,85%, respectivamente), physiostigmine inibiu 90,31%. Em geral, atividades melhoras foram apresentadas contra BuChE. Folhas, casca da raiz e casca do caule Bombax bromoposenze foram particularmente ativos. A inibição foi acima de 80%. Outras partes de algumas espécies também foram seletivas, como as partes aéreas de Antiaris africana, Cissampelos owarensis (78,96%), folhas e casca do caule de Combretum molle (90,42% e 88,13%, respectivamente), casca da raiz e de tubérculos de Dioscorea dumentorum (mais de 87%), folhas de G cola, cascas de raiz de Markhamia tomentosa, casca do caule de Pycnanthus angolensis e folhas de Tetrapleura tetraptera. A maioria destas plantas são utilizadas como alimentos ou ingredientes alimentares na Nigéria e podem ser responsáveis pela baixa incidência da doença de Alzheimer no país e desempenhar determinadas funções na mediação da doença.Unitermos: Plantas medicinais, acetilcolinesterase, butrilcolinesterase, perda da memória. ABSTRACT:Plants have been found to be useful as memory enhansers as well as antiaging. Twenty two of such plants from sixteen families were investigated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities using the in vitro Ellman's spectrophotometric and in situ bioautographic methods with physostigmine as standard. At least three morphological parts were examined for each of the plants investigated and the test concentration was 42.5 μg/ mL. Some plants were active on both enzymes though with some morphological parts being more active than others. The root bark of Spondias mombin showed the highest activity to the two enzymes; 64.77% and 83.94% on AChE and BuChE respectively. Other plant parts of the selected plants exhibited some remarkable selectivity in their actions. Those selectively active against...

Khaya grandifoliola (Welw) CDC (Meliaceae) is widely used in WestAfrica for the treatment of fever. The dried powdered stem-bark of the plant was extracted with various solvents. The resulting extracts and column purified fractions therefrom were tested for their antimalarial properties using Plasmodium berghei berghei for in vivo antimalarial determinations and Plasmodium falciparum for in vitro antiplasmodial activities. The n-hexane extract, the crude and purified fractions gave the most active antimalarial activities with about 91% chemosuppression in vivo and IC 50 values of 1.4 µg/ml (for multi-drug resistant clone) or 0.84 µg/ml (for Nigerian P. falciparum isolates). These values were comparable to those observed with the reference drug chloroquine diphosphate. The stem-bark was dried in a hot-air oven at 60°C and powdered. The powdered stem-bark (110 g each) was extracted with water by direct boiling to obtain a decoction, and using a Soxhlet apparatus for 72 h. Also separately, the powdered stem-bark (110 g) was successively extracted by Soxhlet with n-hexane, chloroform, ethyl acetate and distilled water. Then four 110 g each samples were separately extracted with n-hexane, chloroform, ethyl acetate and methanol. All the solvent-derived extracts were concentrated in vacuo at 40°C; 60°C was used for the aqueous extracts. The aqueous extracts were finally lyophilized to give yields of 7.2 and 12.0% for the decoction and Soxhlet-derived aqueous extract respectively. The lyophilized extracts were redissolved in water and partitioned successively with n-hexane, chloroform and ethyl acetate, which gave the following yields: 0.67 (NH), 2.67 (KGC) and 6.7% (KGE), respectively. The aqueous phase residue (KGW) gave 20% yield. The nhexane partitioned fraction (NH) was chromatographed on a column of silica gel (60-120 mesh, 20 g). The column was eluted successively at 2 ml/min with n-hexane (100%, 1 l); chloroform: n-hexane (1:1, 1.5 l); chloroform (100%, 0.5 l) and finally washed with methanol (100%, 1 l). The column eluate was monitored by TLC and functions having similar components were pooled yielding three major groups coded NH-1, NH-2 and NH-3. These were examined by TLC using silica-gel GF245 and chloroform: methanol (9:1) as solvent system. NH-1 gave a light-yellow oil (Rf 0.80) in petroleum spirit: CHCI 3 (9:1). NH-2 and NH-3 produced multiple spots.