Joseph M. Agbedahunsi

Toxicity studies of Tithonia diversifolia A. Gray (Asteraceae) in rats

OBJECTIVE To investigate the toxicity of an ethanolic extract of the aerial parts of Tithonia diversifolia, used in Nigeria to treat malaria, in rats. MATERIALS AND METHODS A 70% ethanol extract was administered orally to adult Wistar rats at various dosages (400-1600 mg/kg) and the animals sacrificed and various organs examined at a range of times from 30 min up to 24 h after administration. RESULTS The studies showed a dose- and time-dependent toxic effect, which was reversible on the kidney and liver while there was no noticeable adverse effect on the morphology of the heart, spleen and brain. CONCLUSION A 70% ethanol extract of the aerial parts of Tithonia diversifolia, which had previously been shown to reduce parasitemia in mice infected with Plasmodium, displayed kidney and liver toxicity at the lowest dose tested. The use of this plant extract against malaria therefore raises concerns over its safety.

Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some selected Nigerian medicinal plants

As plantas podem ser uteis para estimular a memoria, bem como serem usadas para combater o envelhecimento. Vinte e duas plantas, de dezesseis familias, foram investigadas in vitro oara verificar sua atividade inibidora das enzimas acetilcolinesterase (AChE) e butirilcolinesterase (BuChE) pelo metodo espectrofotometrico de Ellman in situ e metodos de bioautografia utilizando fisostigmina como padrao. Pelo menos tres partes morfologicas de cada planta foram analisadas e a concentracao 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 acoes. 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 inibicao foi acima de 80%. Outras partes de algumas especies tambem foram seletivas, como as partes aereas 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 tuberculos 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 sao utilizadas como alimentos ou ingredientes alimentares na Nigeria e podem ser responsaveis pela baixa incidencia da doenca de Alzheimer no pais e desempenhar determinadas funcoes na mediacao da doenca.

Anticholinesterase constituents from the leaves of Spondias mombin L. (Anacardiaceae)

Spondias mombin has been used in traditional medicine for the management of several diseases, including memory loss. This study aimed to evaluate the cholinesterase inhibitory activity of the methanol extract of the leaves and its derived fractions, as well as carry out detailed phytochemical investigations leading to the isolation and characterization of bioactive compounds from the plant. The acetyl cholinesterase (AChE) and butyryl cholinesterase (BUChE) inhibitory activities were evaluated by colorimetric and thin-layer chromatography bioautographic assay techniques. The ethyl acetate fraction was most active against both enzymes, with percentage inhibition of 58.10 ± 1.08% and 52.66 ± 1.34% against AChE and BUChE, respectively. Three compounds, namely, botulin, campesterol and phytol, with IC50 of 0.88 μg/mL (AChE), 4.67 μg/mL (BuChE); 1.89 μg/mL (AChE), 4.08 μg/mL (BuChE) and 12.51 μg/mL (AChE), 23.89 μg/mL (BuChE), respectively, were isolated from the supernatant of the ethyl acetate fraction. The isolated cholinesterase inhibitory compounds correlate with the known memory-enhancing property of the plant and thus support one of its uses in ethnomedicine.

Ethnomedicinal survey of medicinal plants used in the management of sickle cell disorder in Southern Nigeria

ETHNOPHARMACOLOGICAL RELEVANCE The present study entails the medicinal plant species used to manage sickle cell disorder in Southern States of Nigeria. MATERIALS AND METHODS The ethnomedicinal information was gathered through multistage approach from three geopolitical zones of Southern Nigeria, which were purposively selected. Semi-structured questionnaires were administered on 500 respondents in 125 locations. The ethnomedicinal data collected were analyzed using quantitative value indices such as fidelity level (percentage) and use value. The information got was cross checked using literature search and other related materials. RESULT Five hundred respondents comprising 53.12% females and 46.88% males were observed. It was noted that 26.70% were illiterate while 73.30% had formal education. Seventy-nine percent is traditional healers, 27% herb traders and the other 4% are those who have awareness of sickle cell disease . One hundred and seventy five plant species belonging to 70 families, of which Fabaceae made up 26.76% and Euphorbiaceae 16.90% forming the highest occurrence. It was observed that leaves were the most common plant part used (69.10%) followed by root (15%) and stem bark (14%) in the preparation for sickle cell management. Majority (48.57%) of these plants were harvested from wild with 38.86% being trees. Citrus aurantifolia and Newbouldia laevis had highest use values of 0.69 and 0.64 respectively. Plants with the least use value (0.001) include Abrus canescens, Acacia xanthophloea, Aerva lanata and Axonopus compressus. The result of fidelity level values of the plant species for the management of Sickle Cell Disorder (SCD) revealed that Citrus aurantifolia had the highest value of 70.2% while Angraecum distichum and Axonopus compressus had the lowest Fidelity Level value of 0.18%. CONCLUSION The study revealed that people in the studied areas were well grounded in the medicinal plants used to manage sickle cell disease. This study reported for the first time 102 plant species having anti-sickling potentials with Fabaceae and Euphorbiaceae as the most dominant plant families. Many of the claimed plants were harvested from the wild showing threat thus providing needs for conservation of plants. The documented plants had high use value and fidelity level that provided quantitative and qualitative ethnomedicinal evaluation within and across the plant families. These give room for further scientific investigations in pharmacological profiles.

Evaluation of Some Salicylaldehyde-derived Baylis-Hillman Adducts and Coumarin Derivatives as Potential Antisickling Compounds

Abstract Some salicylaldehyde-derived Baylis-Hillman adducts and 3-(chloromethyl)coumarins have been synthesised and evaluated in vitro for their antisickling activities. The compounds were screened for inhibitory and reversal activity against mutated haemoglobin (HbSS) in red blood cells at four different concentrations (4 mg/mL, 2 mg/mL, 1 mg/mL and 0.5 mg/mL) as a measure of their antisickling potentials. Among the synthesized compounds, 6-chloro-3-(chloromethyl)coumarin 4d showed the highest inhibitory activity (83.75±1.90%), followed by 6-chlorocoumarin-3-methylsulfinic acid 5d (80.90 ±0.91%) and the least was tert-butyl-3-hydroxy- 3-(2-hydroxyphenyl)-2-methylenepropanoate 3a (33.33±1.86%). The results obtained from the reversal antisickling experiment showed that the percentage of sickle cells able to revert to the normal biconcave shape was dose dependent. Compound 5d had the highest reversal activity (66.49±1.39%) followed by 6-bromo-3- (chloromethyl)coumarin 4c (59.66±2.95) and 4d (55.50±1.95%) at 4 mg/mL. Compound 4c had higher reversal activity than the standard p-hydroxybenzoic acid at 2 mg/mL, 1 mg/mL and at 0.5 mg/mL. The 3-substituted coumarins 4a-d, and 5d had higher inhibitory antisickling activities than their Baylis-Hillman precursors 3a-d. Effect of 4a-d and 5d on the rate of polymerization of sickle cell heamoglobin was further studied spectrophotomerically using hemolysate of HbSS. The considerable inhibitory and reversal activities of these compounds make them good candidates for further antisickling studies.

In vitro antisickling and antioxidant properties of aqueous and ethanol extracts of fifty selected plants used in the management of sickle cell disorder in southern Nigeria

Sickle Cell Disease (SCD) is an ailment with enormous social and economic burden for patients and care givers. The study evaluated the in vitro antisickling and antioxidant properties of aqueous and ethanol extracts of fifty selected plants used in the management of sickle cell disease (SCD) with the aim of justifying their use in the management of the disease in southwestern Nigeria. Aqueous and 70% ethanol extracts of fifty (50) surveyed plants were subjected to in vitro antisickling activities and forty plants with above 50% activity levels in both inhibitory and reversal models were later tested for their antioxidant assay involving four tests namely DPPH, FRAP, Fe-chelating and total antioxidant content using standard methods. Significant mean values were separated using the Least Significant Difference at 0.05 % level of probability. Among all the plants with above 50% activity levels in both inhibitory and reversal models, three plants which are Gongronema latifolium , Cymbopogon citratus and Piper guineense had the highest value of 89.81, 89.72 and 84.48 % respectively in ethanol extracts. The least activity for both aqueous and ethanol extracts was found in Amaranthus spinosus and Amaranthus viridis . It can be inferred from the result of the study that 80 % the plants evaluated possessed high antisickling and antioxidant activities and may thus justified their use for the management of SCD in the South – West, Nigeria. Keywords: Sickle cell disease, antisickling, inhibition, reversal, antioxidant

Antimalarial Properties of Morinda lucida and Alstonia boonei on Sulphadoxine-Pyrimethamine and Curcuma longa on Quinine in Mice

The antimalarial activities of Morinda lucida (MLE), Alstonia boonei (ABE), Curcuma longa (CLE) at 12.5–400 mg kg−1, sulphadoxine-pyrimethamine (S-P), and quinine at 0.2–1.7 and 0.625–10 mg kg−1, respectively, were investigated in Plasmodium berghei–infected mice using the 4-d malaria test. Assessment of MLE plus S-P, ABE plus S-P, and CLE plus quinine was similarly done. Dose-dependent activities were noted with MLE, ABE, and CLE with chemosuppression values of 39.8–90.5, 0.2–74.8, and 34.6–78.4%, respectively. The combinations gave 1.8- to 2.5-fold greater chemosuppression than the individual drug/extracts. The efficacies of S-P and quinine were enhanced when combined with the extracts.