Anogeissus leiocarpus (DC.) Guill. & Perr. (Combretaceae): A review of the traditional uses, phytochemistry and pharmacology of African birch.

Anogeissus leiocarpus (DC.) Guill. & Perr. belongs to the family Combretaceae and is used both by African traditional medical practitioners and livestock rearers to treat diseases such as African trypanosomiasis, animal diarrhoea, asthma, cancer, cough, diabetes, dysentery, erectile dysfunction, fever, giardiasis, helminthiases, meningitis, menstrual disorders, monkeypox, oral infections, poliomyelitis, sickle cell anaemia, snake bites, toothache, urinary schistosomiasis, and yellow fever. Some of these activities have been associated with the presence of polyphenols in the plant which include ellagic acid derivatives, flavonoids, stilbenes, tannins, and triterpenes. Several bioactive molecules have been identified from A. leiocarpus. These include the main active constituents, ellagitannins, ellagic acid derivates, flavonoids and triterpenes. Pharmacological studies have confirmed its antibacterial, antifungal, antihyperglycemic, antihypertensive, antimalarial, antioxidative, antiparasitic, antitumour and anti-ulcer effects. The stem bark has been investigated mainly for biological activities and phytochemistry, and it is the most mentioned plant part highlighted by the traditional users in ethnomedicinal surveys. In vitro and in vivo models, which revealed a wide range of pharmacological actions against parasites causing helminthiasis, leishmaniasis, malaria and trypanosomiasis, have been used to study compounds from A. leiocarpus. Because of its uses in African traditional medicine and veterinary practices, A. leiocarpus has received considerable attention from researchers. The current review provides a comprehensive overview and critical appraisal of scientific reports on A. leiocarpus, covering its traditional uses, pharmacological activities and phytochemistry.

Antidiabetic and antioxidant potential of total extract and supernatant fraction of the roots of Anogeissus leiocarpus in HFD-fed and Streptozocin -induced diabetic rats.

The aim of this study was to evaluate the antidiabetic properties of hydro alcoholic extract and supernatant fraction of the roots of Anogeissus leiocarpus, a plant used by traditional healers to treat Diabetes mellitus. Diabetes mellitus was induced by a single intraperitoneal administration of Streptozocin to Sprague Dawley rats under a fructose-enriched fat diet. Diabetic rats were treated with 500 mg/kg of total extract and 100 mg/kg of supernatant. The antidiabetic activity was assessed by measuring blood glucose level, lipid profile, insulin and biochemical parameters together with the antioxidant potential. The administration of total extract and supernatant exhibited significant decrease (p < 0.01) of the blood glucose level in the diabetic rats after 7 days of treatment compared to the diabetic rats. A significant reduction in the serum concentrations of cholesterol (19.7 %) and triglycerides (56.7 %) was observed in the treated diabetic rats. The levels of insulin did not differ across all the groups. However, compared to diabetic rats, HOMA-IR (Homeostasis Model Assessment for Insulin-resistance) and HOMA-ß (Homeostasis Model Assessment for ß cell function) showed a statistical decrease in insulin resistance and an increase in pancreatic ß cell function in the treated diabetic rats. Moreover, total extract and supernatant significantly increased GSH level and decreased lipid peroxidation because of their antioxidant properties. In comparison, the supernatant fraction exerted stronger antidiabetic and antioxidant effects than the total extract. Hence, the roots of Anogeissus leiocarpus are a potent antidiabetic agent that can be developed as an alternative medicine for diabetes and its complications.

Elevated serum sialic acids, a potent biomarker of alloxan-induced type 1 diabetes in dogs by ethanolic extract of Anogeissus leiocarpus.

OBJECTIVES: This study investigated serum sialic acids for a predictive and diagnostic biomarker of diabetes mellitus (DM) in dogs and its prognostic value with ethanolic extract of Anogeissus leiocarpus. DESIGN: Four groups of 3 dogs were used; non-diabetic controls (ND), diabetic-untreated (DU), diabetic insulin-treated (DI) and diabetic extract-treated (DE). Free serum sialic acids (FSSA) and erythrocyte surface sialic acids (ESSA) were assayed in all groups, pre-and post-induction of hyperglycaemia and results were presented as means ± standard error of means (SEM) and subjected to ANOVA using Tukey's post-hoc tests with GraphPad Prism® statistical package. RESULTS: FSSA increased in DU and plateaued at third week (61.8 ± 0.41 µg/ml), (P < 0.002) with additional 38.2 µg/ml (62%) generated, coinciding with hyperglycaemia. FSSA of DI increased but declined to 22.3 ± 1.55 µg/ml. Extract of Anogeissus leiocarpus effectively modulated FSSA in DE as increased value declined to 21.4 ± 0.78 µg/ml. Pre-induction DU ESSA (8.27 ± 0.11 µg/ml) significantly (P < 0.002) decreased by third week (2.33 ± 1.49 µg/ml), coinciding with hyperglycaemia. Strong negative correlation coefficient (r = -0.92) occurred between DU's FSSA and ESSA and ND (P < 0.03). Sialic acid expression in dog's insulin dependent diabetes mellitus (IDDM) is 18% lower than normal. Extract of A. leiocarpus restored ESSA completely. ESSA cleaved in DU, 5.94 µg/ml (72%), could not account for the extra FSSA (32.26 µg/ml); liver and kidneys are contributors. CONCLUSION: FSSA predicts canine DM.

Antihyperlipidemic and antioxidant properties of hydro-alcoholic extracts from Anogeissus leiocarpus (Combretaceae).

Anogeissus leiocarpus (Combretaceae) is a medicinal plant used in Togo to treat diabetes mellitus and others diseases. The present study was undertaken to evaluate the antihyperlipidemic and antioxidant activities of total extract and fractions of roots of Anogeissus leiocarpus. The antihyperlipidemic activity of the total extract and the supernatant was performed in vivo by the fructose overload test in ICR mice. Antioxidant potential was determined in vitro by methods based on scavenging of DPPH∗, total antioxidant capacity and reducing power. After the screening, phenolic compounds and flavonoids were evaluated by the well-known colorimetric assay using respectively Folin-Ciocalteu reagent and aluminium chloride. The results obtained showed that the total extract and the supernatant significantly reduced the serum and liver levels of triglycerides and hence the level of VLDL-Cholesterol compared to hyperlipidemic mice. In vitro the total extract and fractions had the ability to scavenge free radicals, to reduce metal and possessed strong total antioxidant activity. Phytochemical screening revealed the presence of polyphenols, flavonoids, alkaloids, tannins and saponosides in the extract and fractions. And the supernatant fraction contained more polyphenolic compounds than others. From this study, it is concluded that the total extract and fraction of Anogeissus leiocarpus possessed strong antihyperlipidemic, antioxidant properties and were riched in polyphenols, which can be used in the treatment of diabetes mellitus' complications. Hence, the supernatant fraction was the most biologically active.

Anogeissus leiocarpus attenuates paroxetine-induced erectile dysfunction in male rats via enhanced sexual behavior, nitric oxide level and antioxidant status.

Sexual dysfunction is a side effect of the antidepressant drug paroxetine. Anogeissus leiocarpus is a medicinal plant with a wide range of biological activities which include antioxidant and antiulcer properties. With these in mind, we investigated the effect of Anogeissus leiocarpus stem bark extract on paroxetine-induced sexual dysfunction in male Wistar rats. Forty-two adult male Wistar rats were divided into seven experimental groups: normal control, PAR (10 mg/kg), PAR + sildenafil (5 mg/kg), ALE (50 and 100 mg/kg) and PAR + ALE (50 and 100 mg/kg). The experiment lasted for 21 days, after which the rats were subjected to sexual behavioral test. Various biochemical assays (phosphodiesterase-5, arginase, acetylcholinesterase, nitric oxide and MDA) were carried out on the penile tissue homogenate. From our findings, paroxetine significantly altered sexual behavior in male rats and increased phosphodiesterase-5, arginase and acetylcholinesterase activities with a concomitant decrease in nitric oxide level. Furthermore, paroxetine altered antioxidant status which revealed by increased MDA level and reduced thiol level. However, treatment with Anogeissus leiocarpus stem bark extract reversed the altered sexual behavior in male rats and boosted antioxidant status. In addition, administration of Anogeissus leiocarpus stem bark extract resulted in a significant attenuation of phosphodiesterase-5, arginase and acetylcholinesterase activities in paroxetine-induced rats. In view of the aforementioned findings, Anogeissus leiocarpus could be considered a promising natural agent in erectile dysfunction management.

An aqueous extract of the Anogeissus leiocarpus bark (AEAL) induces the endothelium-dependent relaxation of porcine coronary artery rings involving predominantly nitric oxide.

BACKGROUND: Anogeissus leiocarpus is a Sahel tree traditionally used by the residents of Burkina Faso for its antihypertensive properties. In this study, experiments were conducted to evaluate whether an aqueous extract of the Anogeissus leiocarpus (AEAL) trunk bark induces a vasorelaxant effect on porcine coronary artery rings and to investigate the underlying mechanism. METHODS: AEAL-induced relaxations were assessed using porcine coronary artery rings suspended in organ chambers. The phosphorylation levels of Src, Akt and endothelial nitric oxide synthase (eNOS) were assessed in a primary endothelial cell culture by Western blot. The reactive oxygen species (ROS) formation was assessed using dihydroethidine. RESULTS: In porcine coronary artery rings, AEAL at 0.1-300 µg/mL induced endothelium-dependent relaxations, which were inhibited in the presence of inhibitors of nitric oxide (NO) and the endothelium-derived hyperpolarization pathways. Moreover, the AEAL-induced NO-mediated relaxations were significantly reduced by the inhibitors of Src and PI3-kinase as well as by the membrane-permeant ROS scavengers. In cultured porcine coronary artery endothelial cells, treatment with AEAL is associated with an intracellular generation of ROS. Moreover, the AEAL induced the phosphorylations of Akt (Ser473), eNOS (Ser1177) and a transient phosphorylation of Src (Ser17) in a time-dependent manner. CONCLUSIONS: These findings indicate that AEAL is a potent inducer of endothelium-dependent NO-mediated relaxations in porcine coronary arteries through the redox-sensitive Src/PI3-kinase/Akt pathway-dependent activation of eNOS.

A comparative assessment of antiproliferative properties of resveratrol and ethanol leaf extract of Anogeissus leiocarpus (DC) Guill and Perr against HepG2 hepatocarcinoma cells.

BACKGROUND: Epidemiological and experimental evidences have shown cancer as a leading cause of death worldwide. Although the folklore use of plants as a reliable source of health-restoring principles is well-documented, the search for more of such plants that are active against diseases, such as cancer, continues. We report here a laboratory-based evidence of the relevance of an ethanol leaf extract of Anogeissus leiocarpus (A2L) in comparison with resveratrol, a natural polyphenol, in cancer therapy. METHODS: The quantitative assessment of flavonoid and phenolic contents involved quercetin and gallic acid as standards, respectively were determined using spectrophotometry. Cytotoxicity was determined fluorometrically using propidium-iodide-staining method. Antioxidant status, adenosine triphosphate (ATP) levels, caspase activities and mitochondrial integrity were assessed using fluorometry/luminometry. RESULTS: The antioxidant assay demonstrated that A2L possesses a strong antioxidant capacity as compared with the reference compounds, ascorbic acid and butylated hydroxytoluene. This is further buttressed by the significantly high level of phenolics obtained in the quantitative assessment of the extract. A 72-h post-treatment examination indicated that both A2L and resveratrol modulate the proliferation of HepG2 liver carcinoma cells in a time- and concentration-dependent manner. Determination of the total nuclei area, propidium-iodide negative and positive nuclei areas all further buttress the modulation of cell proliferation by A2L and resveratrol with the indication that the observed cell death is due to apoptosis and necrosis at lower and higher concentrations of treatments respectively. At lower concentrations (0.39-3.13 µg/mL), resveratrol possesses higher tendencies to activate caspases 3 and 7. Bioenergetically, both resveratrol and A2L do not adversely affect the cells at lower concentrations (0.39-6.25 µg/mL for resveratrol and 12.5-100.0 µg/mL for A2L) except at higher concentrations (12.5-25.0 µg/mL for resveratrol and 200-800 µg/mL for A2L) which are more pronounced in A2L-treated cells. Furthermore, the antioxidant status of HepG2 cells is not perturbed by resveratrol as compared with A2L. Assessment of 24-h post-treatment mitochondrial function shows that resveratrol is not mitotoxic as compared with A2L which exhibits mitotoxicity at its highest concentration. CONCLUSIONS: Taken together, findings from this study showed that A2L possesses strong antiproliferative activity and its prospect in the management of hepatocellular carcinoma deserves further investigation.

In vitro inhibition of phosphodiesterase-5 and arginase activities from rat penile tissue by two Nigerian herbs (Hunteria umbellata and Anogeissus leiocarpus).

BACKGROUND: Anogeissus leiocarpus and Hunteria umbellata have been reportedly used in traditional medicine for the management of erectile dysfunction (ED). However, the scientific basis for their use has not been well established. Therefore, this study was designed to investigate the inhibitory effects of water extractable phytochemicals of H. umbellata and A. leiocarpus on phosphodiesterase-5 (PDE-5) and arginase as well as pro-oxidants induced lipid peroxidation in rat penile tissue. METHODS: The effects of the extracts on important enzymes (PDE-5 and arginase) linked with ED and pro-oxidants (Fe2+ and sodium nitroprusside) induced lipid peroxidation were investigated. Also, radicals scavenging and metal chelating abilities were determined. In addition, phenolic contents were determined and characterized using HPLC. RESULTS: The results showed that both extracts inhibited PDE-5 and arginase activities in a dose-dependent manner. Inhibitory property of A. leiocarpus (IC50 - 174.19 µg/mL) was significantly better (p<0.05) than that of H. umbellata (IC50 - 537.72 µg/mL) in PDE-5 assay. The extracts were potent inhibitors of arginase than PDE-5, and these extracts were equally potent in inhibiting arginase. Furthermore, Fe2+ and sodium nitroprusside caused a significant increase in malondialdehyde content; however, both extracts reduced malondialdehyde level in concentration-dependent manner. It is noteworthy that both extracts scavenged radicals (OH* and ABTS*) and chelated Fe2+. HPLC analysis revealed abundance of rutin, chlorogenic acid, gallic acid, caffeic acid, and quercetin, among others. CONCLUSIONS: The ability of the extracts to inhibit PDE-5, arginase and pro-oxidant induced lipid peroxidation, and chelate metal might suggest their folkloric use for the management of ED.

Methanol Extract from Anogeissus leiocarpus (DC) Guill. et Perr. (Combretaceae) Stem Bark Quenches the Quorum Sensing of Pseudomonas aeruginosa PAO1.

Background: Due to its extensive arsenal of virulence factors and inherent resistance to antibiotics, Pseudomonas aeruginosa is a threat particularly in immunocompromised patients. Considering the central role of quorum sensing in the production of virulence factors, inhibition of bacterial communication mechanism constitute an opportunity to attenuate pathogenicity of bacteria resistant to available antibiotics. Our study aimed to assess the anti-quorum sensing activity of Anogeissus leiocarpus, traditionally used in Burkina Faso, for the treatment of infected burn wounds. Methods: Investigations were carried out on methanol extract from A. leiocarpus stem bark. The reporter strains Chromobacterium violaceum CV026 and P. aeruginosa PAO1 derivatives were used to evidence any interference with the bacterial quorum sensing and expression of related genes. P. aeruginosa PAO1 was used to measure the impact on pyocyanin production. Results: At a sub-inhibitory concentration (100 µg/mL), A. leiocarpus methanol extract quenched the quorum sensing mechanism of P. aeruginosa PAO1 by down-streaming the rhlR gene, with a subsequent reduction of pyocyanin production. Moreover, the antioxidant polyphenols evidenced are able to reduce the oxidative stress induced by pyocyanin. Conclusion: The antioxidant and anti-quorum sensing activities of A. leiocarpus stem bark could justify its traditional use in the treatment of infected burn wounds.

Studies of the antitrypanosomal and toxicological properties of Anogeissus leiocarpus (Dc.) Guill. & Perr. (Combretaceae) and Vitellaria paradoxa C. F. Gaertn (Sapotaceae) in mice / Estudios de las propiedades antitripanosómicas y toxicológicas de Anogeissus leiocarpus (Dc). Guill. & Perr. (Combretaceae) y Vitellaria paradoxa C. F. Gaertn (Sapotaceae) en ratones

African animal trypanosomosis (AAT) is a disease of concern with ravaging effects on the health of both animals and livestock in tropical Africa. This study investigates the anti-trypanosomal activities of Anogeissus leiocarpus (ALE) and Vitelleria paradoxa (VPE) stem bark extracts and also determines the toxicological profile of the active plant, with a view to establishing the anti-trypanosomal potential and safety of the plants. Laboratory mice (19 g – 26 g) and rats (140 g – 165 g) obtained from the Animal house, Faculty of Pharmacy, OAU, Ile-Ife were used for the study. The animals were treated according to the standard set criteria for animal use and care. VPE showed neither trypanocidal nor trypanostatic activities while ALE was found to be trypanostatic at 62.5 and 125 mg/kg body weight. However, the partitioned aqueous fraction of ALE was found to demonstrate comparable anti-trypanocidal effect as Diminal (standard agent). In conclusion, the ethanolic extract of A. leiocarpus possesses antitrypanosomal effect through the relative suppression or delay in parasite establishment in trypanosome-infected mice. The toxicological study of A. leiocarpus stem bark extract revealed that it is relatively safe for use in cattle and other grazing animals.

La tripanosomiasis africana de los animales es una enfermedad de preocupación que causa estragos sobre la salud de los animales y el ganado en África tropical. Este estudio investiga las actividades anti-tripanosomal de Anogeissus leiocarpus (ALE) y Vitelleria paradoxa (VPE) del tallo y extractos de corteza. También determina el perfil toxicológico de la planta activa, con el fin de establecer el potencial anti-tripanosomal y la seguridad de las plantas. Ratones de laboratorio (19 g - 26 g) y ratas (140 g - 165 g) obtenidos del Bioterio de la Facultad de Farmacia de la OUA, se utilizaron para el estudio. Los animales fueron tratados de acuerdo con los criterios estándar establecido para el uso y cuidado de animales. VPE mostró actividades no tripanocidas ni tripanostáticas mientras que en ALE se encontró que era tripanostático a 62,5 y 125 mg/kg de peso corporal. Sin embargo, se encontró que la fracción acuosa de ALE demostró un efecto anti-tripanocida comparable como Diminal (agente estándar). En conclusión, el extracto etanólico de A. leiocarpus posee efecto sobre tripanosomas a través de la supresión relativa o retraso en la creación de parásitos en ratones infectados con tripanosomosis. El estudio toxicológico del extracto de corteza del tallo A. leiocarpus reveló que es relativamente seguro para su uso en el ganado y otros animales de pastoreo.

In vitro evaluation of the antioxidant potential, phenolic and flavonoid contents of the stem bark ethanol extract of Anogeissus leiocarpus.

Plant-derived antioxidants with free radical scavenging activities can be relevant as chemopreventive agents against the numerous diseases associated with free radicals and reactive oxygen species. Some phytoconstituents possess antioxidant activities in biological systems. On this basis, we evaluated the antioxidant potential, and determined the total phenolic and flavonoid contents of the ethanol extract of the stem bark of Anogeissus leiocarpus [EESAL]. Antioxidant assays carried out include: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, phosphomolybdate, ß-carotene bleaching, ferric reducing, and hydroxyl radical scavenging activities. Results of DPPH assay showed no significant difference (p < 0.001) between EESAL and butylated hydroxyanisole [BHA], while EESAL exhibited a significantly (p < 0.001) higher activity than BHT [butylated hydroxytoluene]. Phosphomolybdate method recorded a total antioxidant capacity of 190.00 ± 70.53 µg butylated hydroxytoluene equivalents [BHTE]/mg dry extract, while ß-carotene bleaching assay gave percent antioxidant activities of both EESAL and BHT as 81.46±1.62 and 80.90±1.39 respectively. Ferric reducing abilities of both EESAL and ascorbic acid increased in a concentration-dependent manner with EESAL displaying a significantly (p < 0.001) higher reductive activity than vitamin C. EESAL displayed a significantly higher hydroxyl radical scavenging activity as compared with BHT at the lowest concentration with no significant difference at the highest concentration. Total phenolic and flavonoid contents of EESAL were obtained as 608.10 ± 2.12 µg GAE/mg and 78.96 ± 3.37 µg QE/mg respectively. Taken together, the free radical scavenging and antioxidant activity of EESAL is likely due to its high phenolic content with complementary effects of the flavonoid components.

Endothelium-independent and endothelium-dependent vasorelaxation by a dichloromethane fraction from Anogeissus Leiocarpus (DC) Guill. Et Perr. (Combretaceae): possible involvement of cyclic nucleotide phosphodiesterase inhibition.

Many traditional medicinal herbs from Burkina Faso are used to treat arterial hypertension (HTA). Among them, Anogeissus leiocarpus (A. Leiocarpus) which is well known and widely used in Burkina traditional medicine. Herein we assess the effects of dichloromethane fraction from A. leiocarpus stem bark (ALF), selected as the most active on cyclic nucleotide phosphodiesterases (PDEs) and characterized its specificity towards purified vascular PDE1 to PDE5 isoenzymes and study its effects on a vascular model. ALF potently and preferentially inhibits (IC50=1.6 ± 0.6 µg/mL) the calmodulin-dependent phosphodiesterase PDE1, being mainly present in vascular smooth muscle and preferentially hydrolyses cGMP. In the same range (IC50 =2.8 ± 0.2 µg/ml) ALF inhibits PDE2, a cGMP-activated enzyme that is only present in endothelial cells and hydrolyses both cAMP and cGMP. PDE5, which specifically hydrolyses cGMP and which mainly contributes to cGMP hydrolysis is also potently inhibited by ALF (IC50=7.6 ± 3.5 µg/ml). The potencies of ALF on cAMP hydrolyzing isoenzymes was lesser, being more effective on PDE4 (IC50= 17.6 ± 3.5 µg/ml) than on PDE3 (60.9 ± 1.8 µg/ml). Since the major effect of ALF were against cGMP hydrolysis and since cGMP is implicated in endothelium-dependent relaxation, the endothelium-dependent vasorelaxation was studied on isolated porcine coronary arteries rings pre-contracted with U46619. The endothelium-dependent vasorelaxation is significantly inhibited by N(ω)-nitro-L-arginine (LNA 300 µmol/L, an inhibitor of endothelial NO synthase), but not affected by charybdotoxin (CTX, 100 nM) plus apamin (APA, 100 nM) (two inhibitors of EDHF-mediated responses). The combination of 4-aminopyridine (4-AP, 1 mmol/L, inhibitor of voltage-dependent potassium channels, Kv) plus baryum (Ba(2+), 30 µmol/L, inhibitor of the potassium channels with entering correction, Kir) plus ouabain (3 µmol/L, inhibitor of ATPase Na(+)/K(+) channels) partially inhibits endothelium-independent vasorelaxant effect. This endothelium-independent relaxant effect was also sensitive to combination of 1H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin1-one (ODQ, 10 µM, soluble guanylyl cyclase inhibitor) and N-[2-(p-Bromocinnamylamino)ethyl]-5-isoquinoline sulfonamide dihydrochloride (H89, 100 nM, Protein Kinase A inhibitor). Taken together, these results indicate that ALF is a powerful vasodilator modulated by the formation of NO from endothelium, but also act by directly relaxing the vascular smooth muscle cells, by inhibiting cGMP hydrolyzing PDEs (PDE1, PDE2 and PDE5) and to a lesser extend on cAMP degradation (PDE3 and PDE4), cAMP and cGMP being second messengers involved in vascular relaxation.

Cytotoxic activity of aqueous extracts of Anogeissus leiocarpus and Terminalia avicennioides root barks against Ehrlich ascites carcinoma cells.

OBJECTIVES: Folkloric claims on the use of a mixture of Anogeissus leiocarpus and Terminalia avicennioides root barks in tumor management exist without scientific evidence. This study aimed at investigating the phytochemical constituents and in vitro antiproliferative activity of these plants and their mixture. MATERIALS AND METHODS: Phytochemical screening was carried out on the aqueous extracts after which various concentrations (0 to 1 000 µg/ml) were incubated with Ehrlich ascites carcinoma cell lines for 3 and 24 hours. RESULTS: The extracts contained alkaloids, tannins, flavonoids, phenolics, saponins, phlobatannins, and terpenes. The separate extracts and their 1:1 mixture significantly (P<0.05) decreased the computed percentage viability of the cell lines in a dose- and time-dependent manner. CONCLUSIONS: The antiproliferative activity may be due to the presence of the bioactive compounds in the extracts and has a potential in the management of tumor.

Centrifugal partition extraction in the pH-zone-refining displacement mode: an efficient strategy for the screening and isolation of biologically active phenolic compounds.

Centrifugal partition extraction (CPE) was developed for the first time in the pH-zone-refining mode to fractionate a crude bark extract of the African tree Anogeissus leiocarpus Guill. & Perr. (Combretaceae). The fractionation process was performed at a flow rate of 20mL/min using a biphasic solvent system composed of methyl tert-butyl ether/acetonitrile/water (4:1:5, v/v/v) in the ascending mode. Sodium hydroxide (40mM) and trifluoroacetic acid (30mM) were used as retainer and displacer agents, respectively. In a single run of 67min, 3g of the initial crude extract were successfully separated into fractions selectively enriched in ionizable triterpenes, ellagic acid derivatives and flavonoids. The antioxidant potential of the initial crude extract, isolated compounds and fraction pools was also evaluated by using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) stable free radical scavenging assay, providing an interesting view about the effect of the degree of substitution of ellagic acid derivatives on their radical scavenging activity. This study will demonstrate that centrifugal partition extraction used in the pH-zone-refining mode can be proposed as an efficient strategy for the rapid screening of natural phenolic compounds.

In vitro anthelmintic effect of Anogeissus leiocarpus (DC.) Guill. & Perr. leaf extracts and fractions on developmental stages of Haemonchus contortus.

The anthelmintic effect of acetone leaf extract and fractions of Anogeissus leiocarpus was investigated to determine the relative efficacy of the components as anthelmintic against Haemonchus contortus (Rudolphi). The fractions were obtained by solvent-solvent group separation of the leaf extract. The fractions were evaluated for ovicidal and larvicidal activity by egg hatch inhibition assay and larval development viability assay. Best-fit LC(50) values for egg hatch test were 0.360, 0.316, 0.093, 0.219 and 0.196 mg/ml for the crude acetone extract, hexane, chloroform, butanol, and 35% water in methanol fractions, respectively. While the best-fit LC(50) values for larval development and viability test were 0.509, 0.162, 0.186, 0.288 and 0.130 mg/ml for the crude acetone extract, hexane, chloroform, butanol, and 35% water in methanol fractions, respectively. The 35% water in methanol fractions was the more active on larvae, although differences in activity between fractions were not significant (p>0.05). A. leiocarpus leaf extracts could find application in anthelmintic therapy in veterinary practice.

An antifungal Property of Crude Plant Extracts from Anogeissus Leiocarpus and Terminalia Avicennioides

Chloroform, ethanolic, methanolic, ethyl acetate and aqueous root extracts of Anogeissus leiocarpus and Terminalia avicennioides were investigated in vitro for antifungal activities against Aspergillus niger, Aspergillus fumigatus, Penicillium species, Microsporum audouinii and Trichophyton rubrum using radial growth technique. The plant extracts inhibited the growth of all the test organisms. The minimum inhibitory concentration (MIC) of the extracts ranged between 0.03µg/ml and 0.07µg/ml while the minimum fungicidal concentration ranged between 0.04µg/ml and 0.08µg/ml. Anogeissus leiocarpus appears to be more effective as an antifungal agent than Terminalia avicennioides. Ethanolic extracts of the two plant roots were more effective than the methanolic, chloroform, or aqueous extracts against all the test fungi