Cameroonian Medicine Research Articles

In Vitro Anti-Inflammatory and In Vivo Antiarthritic Activities of Aqueous and Ethanolic Extracts of Dissotis thollonii Cogn. (Melastomataceae) in Rats.

Dissotis thollonii Cogn. (Melastomataceae) is a tropical plant widely used in traditional Cameroonian medicine to relieve and treat many pathologies. It is widespread in the western region where it is used to treat typhoid fever, gastrointestinal disorders, and inflammatory diseases. The purpose of this study is to scientifically demonstrate the anti-inflammatory and antiarthritic properties of the aqueous and ethanolic extracts of the leaves of Dissotis thollonii. The anti-inflammatory properties were evaluated in vitro by inhibition tests for cyclooxygenase, 5-lipoxygenase, protein denaturation, extracellular ROS production, and cell proliferation; while antiarthritic properties were evaluated in vivo in rats using the zymosan A-induced monoarthritis test and the CFA-induced polyarthritis model. This study shows that aqueous and ethanolic extracts at a concentration of 1000 μg/ml inhibit the activity of cyclooxygenase (47.07% and 63.36%) and 5-lipoxygenase (66.79% and 77.7%) and protein denaturation (42.51% and 44.44%). Similarly, both extracts inhibited extracellular ROS production (IC50 = 5.74 μg/ml and 2.96 μg/ml for polymorphonuclear leukocytes, 7.47 μg/ml and 3.28 μg ml for peritoneal macrophages of mouse) and cell proliferation (IC50 = 16.89 μg/ml and 3.29 μg/ml). At a dose of 500 mg/kg, aqueous and ethanolic extracts significantly reduce edema induced by zymosan A (69.30% and 81.80%) and CFA (71.85% and 79.03%). At the same dose, both extracts decreased sensitivity to mechanical hyperalgesia with 69.00% and 70.35% inhibition, respectively. Systemic and histological analyzes show that both extracts maintain the studied parameters very close to normal and greatly restored the normal architecture of the joint in animals. Dissotis thollonii would therefore be a very promising source for the treatment of inflammatory diseases.

In vitro Antisalmonellal and Antioxidant Activities of Leaves Extracts of Tectona grandis L. F. (Verbenaceae)

Aim: Study aimed to evaluate the in vitro antisalmonellal and antioxidant properties of Tectona grandis, a medicinal plant commonly used in traditional Cameroonian medicine for the treatment of typhoid fever.
 Study Design: In vitro Antimicrobial and antioxidant analyses of plant extract using established protocols.
 Place and Duration of Study: Plant materiel collection at Loum (Moungo Division, Littoral region of Cameroon), identification at the National Herbarium of Cameroon, extraction of plant and all analyses at the Research Unit of Microbiology and Antimicrobial Substances, Department of Biochemistry, University of Dschang-Cameroon, between August 2018 and April 2019.
 Methodology: In vitro antisalmonellal activity of Tectona grandis extracts was evaluated by the liquid microdilution method as well as their antioxidant activity using by standard methods of H2O2 trapping, FRAP, DPPH radical trapping and OH radical trapping. Quantification test of total phenols and flavonoids and phytochemical screening of extract were also done.
 Results: The results showed that most of the Tectona grandis extracts had minimal inhibitory concentrations (MICs) ranging from 64 to 1024 μg/mL. Ethanolic extract, 70% ethanol extract and aqueous decoction are the most effective compared to aqueous extracts with activities between 64 and 128 μg/mL on the bacteria tested. Antioxidant tests showed that all extracts except macerated and aqueous infused extracts exhibited high DPPH trapping activities. The antioxidant activities of the extracts are proportionally linked in most cases to their flavonoid and total phenol contents at a concentration of 200 µg/mL. Aqueous decoction showed better H2O2 trapping activity at concentrations less than or equal to 25 µg/mL.
 Conclusion: These results show that the ethanolic extract and decocted aqueous of Tectona grandis leaves can be used as an alternative to treat salmonellosis.

Veterinary pharmacovigilance in sub-Sahara Africa context: a pilot study of adverse reactions to veterinary medicine in Cameroon

BackgroundSub-Saharan African market is highly affected by counterfeit veterinary drugs. Though these counterfeit and non-compliance of drugs can induce adverse effects during their utilization, there is no monitoring system of veterinary medicines. The present pilot study was carried out in Cameroon to identify and describe suspected cases of adverse reactions to veterinary drugs in animals and / or humans as well as inefficacy of veterinary drugs. The methodology involved a descriptive cross-sectional survey of 67 actors in the veterinary medicine sector in Cameroon.ResultsA total of 74/120 (62%) cases of suspected adverse effects and or lack of efficacy of veterinary drugs in animals and 46 (38%) cases of adverse reactions in humans were identified. Antiparasitics were the most incriminated therapeutic class in animals (61%) and human (56%). Adverse reactions were reported in dogs (44%) and poultry (24%) while drug inefficacy was most observed in poultry (47%). According to animal health professionals, levamisole (24%) and ivermectin (16%) were identified to be responsible for the adverse effects and that the highest level of inefficacy was most frequently reported for oxytetracycline (29%). The main adverse reactions were systemic (22%), gastrointestinal (20%) and neurological (13%) disorders.ConclusionThe results of this study showed that misuse and circulation of poor quality as well as lack of efficacy of veterinary drugs is very common in Cameroon. Adverse reactions were observed in animals and humans. Therefore, the establishment of a national veterinary pharmacovigilance system based on solid legal bases is essential for a continuous assessment of the risks-benefits effects of veterinary drugs marketed in Cameroon.

Preventive effects of aqueous extract of the whole plant of Eleusine indica (Linn) Gaertn. (Poaceae) against L-NAME induced nephrotoxicity in rat

Background: The entire plant of Eleusine indica is used in Cameroonian folk medicine to treat several diseases including renal problems. We investigated the preventive effects of Eleusine indica aqueous extract (EIAE) against L-NAME induced renal damages in rats. Methods: Animals were divided into a control group (0.9 % saline, 10 mL/kg, ip) and 4 experimental groups. The rats in the negative control group received L-NAME (30 mg/kg, ip). The positive group was treated with losartan (12.5 mg/kg, per os) and L-NAME while the two last groups received EIAE (100 mg/kg or 200 mg/kg, per os) and LNAME injection. After 60 days of treatment, blood pressure was measured; lipid profile, kidney and some oxidative stress parameters were evaluated. Results: Intraperitoneal injection of L-NAME induced a significant elevation in blood pressure, of total cholesterol, triglycerides and LDL-c, with a significant reduction of HDL-c levels as compared to the control groups. Nephrotoxicity was evidenced by significant elevation in serum levels of creatinine, urea and K+ , accompanied by a significant reduction of Na+ and GFR as compared to controls. Catalase, GSH and nitrites were significantly decreased in L-NAME injected group. L-NAME solution gave simultaneously with Eleusine indica prevented the rise of blood pressure, improve lipid profile, kidney function and antioxidant defenses. Conclusion: These results confirm the nephroprotective effects of Eleusine indica aqueous extract and highlight its protective properties in L-NAME-induced renal failure and its antioxidant capacities against kidney damages.

Evaluation of anti-onchocercal activity of pseudopalmatine, a quaternary protoberberine alkaloid of Enantia chlorantha (Syn. <i>Annickia chlorantha</i>)

As part of our efforts towards identifying and subsequently developing lead compounds from medicinal plants of Cameroon to combat neglected tropical diseases, we embarked to phytochemically investigate Enantia chlorantha (Syn. Annickia chlorantha). The rationale for choosing this plant is its numerous uses in folk medicine in Cameroon and other parts of Africa. In Cameroon the quaternary protoberberine alkaloids, columbamine (2), palmatine (3) and jatrorrizine (4) have been isolated from the stem back and combined to produce a phytomedicine (HEPAZOR®) used in the treatment of viral hepatitis. An alkaloidal extraction of the methanolic extract of the stem bark of the plant was carried-out and this afforded yellow amorphous solids whose structure was obtained using routine nuclear magnetic resonance spectroscopy (NMR), high pressure liquid chromatography coupled to an electrospray mass spectrometer (HPLC-ESI-MS) and comparison with literature. The compound was identified as pseudopalmatine (1), a quaternary protoberberine alkaloid. Preliminary screening of the compound on both adult and juvenile worms of Onchocerca ochengi, a close relative of Onchocerca volvulus, the parasite responsible for human onchocerciasis (river blindness), showed that compound (1) was inactive at a concentration of 500 μg/mL on the adult worms, but inhibited microfilariae motility completely at this same concentration and by 50 % at 250 μg/mL and was thus considered active. While this work to the best of our knowledge constitutes the first report on the anti-onchocercal activity of quaternary protoberberine alkaloids in general and pseudopalmatine (1) in particular isolated from E. Chlorantha, it has however opened a window for further investigation of the anti-onchoceral activity of this class of compounds. Key words: anti-onchocercal, pseudopalmatine, alkaloid, Enantia chlorantha

The anti-arthritic and anti-inflammatory activities of aqueous extract powder bark of Anthocleista schweinfurthii Gilg (Loganiaceae)

Aqueous extract bark of Anthocleista schweinfurthii (ASE) was investigated for anti-arthritic, anti-inflammatory activities and phytochemicals screening. Phytochemical screening was carried out according, to LC-MS procedures, the anti-inflammatory effect of ASE was evaluated in vitro inhibition of 15-lipoxygenase (15-LOX) enzyme and proteinase inhibiting action assays. The anti-arthritic activity was performed according to the Bovine Serum Albumin (BSA) test. The chemical composition of ASE showed that it was mainly composed of isocyanate, biphenyltriol, methoxyflavanone, soscoparin and glucopyroside. In the anti-inflammatory assays, ASE showed selective inhibition of 15-lipooxygenase with IC50 value of and moderate activity against the inhibition of proteinase action with IC50 value of L. Both the methods showed that the ASE posses good anti-inflammatory activity. ASE had strong in vitro anti-arthritic activity with IC50 of , the positive control Diclofenac had IC50 value of The result of this study justified the use of this plant in traditional Cameroonian medicine in the treatment of inflammation. ASE may offer a new source of potential therapeutic agents for the effective treatment of arthritis and inflammation. 
 
 Keywords: Anthocleista schweinfurthii, phytochemical screening, anti-arthritic activity, anti-inflammatory activity, 
 

Antioxidant Activities of <i>Dichrocephala integrifolia</i> (Linn.f.) O. Kuntze (Asteraceae) in a Mice Model of D-Galactose-Induced Oxidative Stress and Accelerated Aging

Dichrocephala integrifolia is a plant widely used in folk medicine in Africa to treat central nervous diseases such as dementia. In the present study, we evaluated the effect of the leave’s decoction of Dichrocephala integrifolia against D-galactose-induced neurotoxicity, oxidative stress and accelerated aging in mice. D-galactose (100 mg/ kg sc), was chronically injected daily to mice during 42 consecutive days after pretreatment with distilled water (10 ml/kg) or the decoction of D. integrifolia (35; 87.5; 175 or 350 mg/kg p.o) or vitamin C (100 mg/kg p.o). Following behavioral tasks (Open Field, Elevated Plus Maze and Morris Water Maze), animals were sacrificed on day 43 and their brains were used to evaluate some biochemical parameters of oxidative stress (malondialdehyde, nitrite oxide and reduced glutathione) and for histopathological assessments. The results of this study showed that a pretreatment of animals with the decoction of D. integrifolia at the doses of 87.5 and 175 mg/kg significantly (p˂0.05) reversed learning deficits, recall of memories and oxidative stress induced by D-galactose. The decoction of D. integrifolia also prevented neurogeneration in the dentate gyrus induced by D-galactose. These results indicated that D. integrifolia possesses neuroprotective effects against D-galactose-induced senescence, probably due to its antioxidant capacities and this can at least explain the wide use of this plant in traditional medicine in Cameroon in the prevention and treatment of dementia.

Screening of some Cameroonian Medicinal Plants against Bacterial and Yeasts involved in Gastrointestinal Disorders

The present study was designated to evaluated the antimicrobial activities of methanol and ethyl acetate extracts of Carcia arereh, Nelsonia canescens, Ficus thonningu, Bryophillum pinnatum, Cyclosorus striatus, Euphorbia cordifolia, Euphorbia hirta, Erygium foetidum and Mimosa pudica. The selected plants species are used as traditional folk medicine in Cameroon for the treatment of various diseases. Thiazolyl blue tetrazolium bromide colorimetric assay was used to evaluate the antimicrobial activity against 16 microbial species. Preliminary phytochemical screening of plant sample was also carried out. Alkaloids and anthraquinones were the most frequent secondary metabolite in the tested plant extracts. The MIC values obtained ranging from 32 to >1024

Antihypernociceptive and antioxidant effects of Petersianthus macrocarpus stem bark extracts in rats with complete Freund's adjuvant-induced persistent inflammatory pain.

Background Petersianthus macrocarpus (P. Beauv.) Liben (Lecythidaceae) is a plant used in Cameroonian folk medicine to cure ailments such as inflammation and pain. Previous work showed that aqueous (AEPM) and methanol (MEPM) extracts from the stem bark of P. macrocarpus possess acute analgesic activities. The present study evaluates whether the same extracts could inhibit persistent hyperalgesia induced by complete Freund's adjuvant (CFA) in rats. Methods Inflammatory pain was induced by intraplantar injection of CFA into the left hind paw of Wistar rats. AEPM and MEPM were administered either acutely or chronically by the oral route at the doses of 100 and 200 mg/kg/day. The mechanical hyperalgesia was tested using an analgesimeter, while the locomotion activity at the end of experiment was evaluated with an open-field device. Nitric oxide (NO), malondialdehyde (MDA) and superoxide dismutase (SOD) contents were assayed in the brain and spinal cord of rats subjected to 14 days chronic treatment. Results AEPM and MEPM at both doses significantly (p<0.001) inhibited the acute and chronic mechanical hyperalgesia induced by CFA. Although not significant, both extracts increased the mobility of CFA-injected animals. AEPM significantly (p<0.01) reduced the level of nitrate at 100 mg/kg, MDA at 200 mg/kg and significantly (p<0.05) increased the SOD in the spinal cord. MEPM significantly increased the SOD content and reduced the MDA concentration in the brain but had no effect on the nitrate. Conclusions AEPM and MEPM exhibit acute and chronic antihyperalgesic activities. In addition, both extracts possess antioxidant properties that might strengthen their chronic antihyperalgesic effects.

Antifilarial Activity of Cucurbita pepo ovifera var ovifera (Cucurbitaceae) on Onchocerca ochengi Adult Worms

One of the strategies for developing novel pharmaceutical drugs is to use natural sources such as plants for therapeutic treatment. Plant extracts are a cocktail of compounds which act synergically and can improve treatment effectiveness, reduce therapeutic duration and resistance. The ethanolic extracts of leaves and seeds of Cucurbita pepo ovifera var ovifera from Sudano-Guinean and Sudano-Sahelian zones of Cameroon were evaluated on the cattle parasite nematode Onchocerca ochengi. Worms were incubated with different concentrations of the plant extracts in RPMI-1640 supplemented with streptomycin and gentamicin. Mortality at 37°C was monitored after 24, 48 and 72 h. Ivermectin was used as positive control and DMSO as negative. Plant extracts from the two ecological zones showed anthelminthic activities on O. ochengi after 72 h with LC50 varying from 20 to 1090 µg /mL. The highest antifilarial activity in Sudano-Guinean zone was obtained with leave extract of C. pepo ovifera (LC50 of 20 µg/mL), while highest antifilarial activity in Sudano-Sahelian zone was obtained with seed extracts of the plant with LC50 value of 17 µg/mL after 72 h. These results show that anthelmintic activity depends on the part of the plant and the ecological zones. Additionally, the plant is not toxic. These results on the ethanolic extracts of leaves and seeds of C. pepo ovifera var ovifera confirmed the use of this plant in traditional medicine in Cameroon to treat disease due to nematodes. The plants could be used as alternative anthelmintic to fight against Human and Bovine onchocerciasis

Antibacterial activities of the methanol extract, fractions and compounds from Elaeophorbia drupifera (Thonn.) Stapf. (Euphorbiaceae)

BackgroundElaeophorbia drupifera (Thonn.) Stapf. (Euphorbiaceae) is used in Cameroonian folk medicine to treat several ailments including bacterial-related diseases such as skin infections. In this study, the methanol extract from the leaves (EDL), fractions (EDLa-d), sub-fractions EDLc1-7 and EDLc31-35 as well as isolated compounds were tested for their antimicrobial activities against a panel of Gram-negative and Gram-positive bacteria including multidrug resistant (MDR) phenotypes.MethodsThe broth microdilution method was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the above samples; column chromatography was used for the fractionation and purification of the leaves extract whilst the chemical structures of compounds were determined using spectroscopic techniques.ResultsPhytochemical investigation lead to the isolation of a mixture (1:3) of stigmasterol and β-sitosterol (1 + 2), euphol (3), sitosterol-O-β-D-xylopyranoside (4), 3,3′,4′-tri-O-methylellagic acid (5), a mixture (1:1) of afzelin and quercetin-3-O-β-D-xylopyranoside (6 + 7), 3,3′,4′-tri-O-methylellagic acid 4-O-β-D-glucopyranoside (8), ellagic acid-4-O-β-xylopyranoside-3,3′,4′-trimethyl ether (9) from EDLc. Crude extract and fractions displayed selective activities with MIC values ranged from 32 to 1024 μg/mL for EDL against 84.9% of the 33 tested bacteria, 93.9% for EDLc, 69.7% for EDLb, 33.4% for EDLa and 0.03% for EDLd. MIC values ranged from 16 to 1024 μg/mL were obtained with EDLc3 and EDLc4 on all tested bacteria meanwhile other sub-fractions displayed selective activities. MIC value of 32 μg/mL was obtained with fractions EDLa against Escherichia coli AG100, EDLc against Enterobacer aerogenes ATCC13048 and EA298. For sub-fractions obtained from EDLc, the lowest MIC value of 16 μg/mL was recorded with EDLc3 against Staphylococcus aureus MRSA11. A corresponding value of 8 μg/mL against Providencia stuartii NAE16 was recorded with EDLc33 obtained from further fractionation of EDLc3. EDLc3 had MIC values below 100 μg/mL against all tested bacteria. Compound 5 as well as the mixture (1:1) of 6 and 7 inhibited the growth of all the tested bacteria with MICs ranged from 64 to 256 μg/mL.ConclusionElaeophorbia drupifera is a potential source of phytomedicine to tackle MDR bacteria. Sub-fraction EDLc3 was more active than all isolated compounds and deserves further investigations to develop natural drug to combat Gram-negative, Gram-positive bacteria and otherwise MDR phenotypes.

Anticonvulsant activity of an active fraction extracted from Crinum jagus L. (Amaryllidaceae), and its possible effects on fully kindled seizures, depression-like behaviour and oxidative stress in experimental rodent models

Ethnopharmacological relevanceThe leaf extract of Crinum jagus L. (Amaryllidaceae) is widely used in traditional Cameroonian medicine as antiepileptic remedy and for the treatment of convulsion, depression and mood disorders associated with epilepsy. Aim of the studyHence, this study was conducted to evaluate the effects of an active fraction extracted from the leaves of Crinum jagus against seizures, depression-like behaviour and oxidative stress in pentylenetetrazole (PTZ)-induced kindling in mice. Materials and methodsBioactive-guided fractionation of the leaf extract of Crinum jagus by using 70mg/kg PTZ-induced convulsions in mice, afforded a potent anticonvulsant fraction (flavonol kaempferol; C4.4). The effects of C4.4 on 30mg/kg PTZ-induced kindling, kindling-induced depression like-behaviour and oxidative stress was evaluated. Mice were injected PTZ (30mg/kg, i.p.) once every alternate day (48±1h) until the development of kindling. Depression was assessed using tail suspension test and forced swim test while the oxidative stress parameters were estimated in the whole brain at the end of experiments. Mice were submitted to the rota-rod task and open-field test in order to assess any non-specific muscle-relaxant or sedative effects of C4.4. Acute toxicity of C4.4 was also assessed in mice. ResultsConvulsions-induced by 70mg/kg PTZ were strongly antagonized by C4.4. Oral administration of C4.4 significantly increased the latency to myoclonic jerks, clonic seizures as well as generalized tonic-clonic seizures, improved the seizure mean stage and decreased the number of myoclonic jerks in PTZ-kindled mice. The data indicated also that C4.4 significantly reduced the immobility times in the tail suspension test and the forced swim test. This active fraction has also antioxidant properties by decreasing the lipid peroxidation, and augmenting endogenous antioxidant enzymes in brain. C4.4 administered (12.5–50mg/kg) did not alter the locomotion of animals in the open-field or rotarod tests, which suggest a lack of a central depressant effect. The animals did not exhibit any acute toxicity to C4.4 at the therapeutic doses. ConclusionThese results suggest that pretreatment with C4.4 ameliorates convulsions-induced by PTZ, protects mice against kindling development, depression-like behaviour and oxidative stress in PTZ-kindled mice. These finding provides scientific rationale for the use of Crinum jagus extracts for the amelioration of epilepsy observed in traditional medicine in Cameroon.

Extracts of Feretia apodanthera Del. demonstrated anticonvulsant activities against seizures induced by chemicals and maximal electroshock

Extracts of Feretia apodanthera Del. (Rubiaceae) have been extensively used in traditional Cameroonian medicine to treat a variety of diseases, including some neurological disorders. The present study was aimed to tests the anticonvulsant properties of the aqueous extract and the alkaloid fraction of the stem barks of Feretia apodanthera. The anticonvulsant investigation was carried out against bicuculline-, picrotoxin-, pentylenetetrazol-, Methyl-β-carboline-3-carboxylate-, N-Methyl-D-aspartate-, 4-aminopyridine-, and maximal electroshock-induced seizures or turning behavior in mice. The aqueous extract protected mice against bicuculline-, picrotoxin-, pentylenetetrazol-, Methyl-β-carboline-3-carboxylate-, N-methyl-D-aspartate −, 4-aminopyridine- and maximal electroshock-induced seizures or turning behavior. Also, N-Methyl-D-aspartate-, 4-aminopyridine- and maximal electroshock- induced seizures or turning behavior, were significantly antagonized by the alkaloid fraction (80mg/kg) from Feretia apodanthera. The total protection of mice provided by the aqueous extract against convulsions induced by pentylenetetrazol or picrotoxin was anagonized by flumazenil, a specific antagonist of the benzodiazepine site in the GABAA receptor complex.The aqueous extract of Feretia apodanthera (but not the alkaloid fraction) increased the brain GABA content and inhibited the GABA transaminase activity.In conclusion, Feretia apodanthera was revealed possessing anticonvulsant effects in mice, likely via the GABAergic neurotransmission.

ANXIOLYTIC - LIKE PROPERTIES OF Hallea ciliata IN MICE.

Background:The aim of the present study was to evaluate the anxiolytic properties of the decoction of stem bark of Hallea ciliate in mice. The decoction of Hallea ciliata is used in traditional medicine in Cameroon to treat diseases like anxiety disorders, fever, infantile convulsions and malaria.Materials and Methods:Stress induced hyperthermia, elevated plus maze, open field and hole-board tests were used. Four different doses of the decoction were administered to mice and their effects were compared to the effects of diazepam and vehicle. Phytochemical characterization of the decoction revealed the presence of alkaloids, flavonoids, tannins and saponins.Results:Administration of Hallea ciliata resulted in a significant decrease of stress induced hyperthermia in mice at the doses of 29.5, 59 and 118 mg/kg. In the elevated plus maze test, Hallea ciliata increased the number of entries and the percentages of entries and time into the open arms, and reduced the number of entries and the percentages of entries and time into the closed arms. In the hole-board test, Hallea ciliata increased the number of both head-dipping and crossing and decreased the latency to the first head-dips and rearing. The decoction of Hallea ciliata and diazepam increased locomotion in the open field test.Conclusion:The number of rearing and the mass of fecal boli produced were decreased in mice treated with decoction and diazepam. In conclusion, the results indicated that decoction of Hallea ciliata has anxiolytic-like properties in mice and could potentially be used for anxiety treatment.

English

The leaves of Dorstenia mannii are used in traditional medicine in Cameroon and other African countries for the treatment of infectious diseases like malaria, skin rashes and stomach disorders. To substantiate this folkloric claim, the crude methanol extract and fractions from the leaves of D. mannii were investigated for their antifungal activity. The crude methanol extract was prepared from powdered dried leaves of the D. mannii. A portion was subjected to flash liquid chromatography on silica gel to afford test fractions. All test samples were screened for major groups of phytochemicals.Test samples and nystatin (reference) were evaluated for antifungal activity on ten yeasts using agar disc diffusion and broth microdilution methods. The qualitative analysis of crude methanol extract and fractions of D. mannii leaves revealed the presence of flavonoids, phenols, steroids and cardiac glycosides. In agar disc diffusion assay, seven of the ten pathogenic fungal strains were sensitive to the crude methanol extract (7/10), n-hexane ethyl-acetate (Hex-EA) (75%) (8/10) and ethyl-acetate (100%) (8/10). The minimum inhibitory concentrations (MICs) for the test samples varied from 80 to 1280 µg/ml. The crude extract and ethyl-acetate (100%) were the most active plant samples with both fungistatic and fungicidal effects (MIC/MFC values from 80 to 640 µg/ml) though not as the reference drug. Candida tropicalis was the least sensitive to the test samples. Some fractions exerted no fungicidal actions on Cryptococcus neoformans, Candida lusitaniae and Candida tropicalis. The present work shows that the crude methanol extract and fractions (n-hexane, ethyl acetate and residue) from the leaves of D. mannii possess growth inhibitory effect on pathogenic yeast. The active ingredients of this plant could be an addition to the antifungal arsenal to opportunistic fungal yeast pathogens. Key words: Antifungal activity, Dorstenia mannii, yeasts, opportunistic candidiasis.

Identification of the Bioactive Compounds Hypotensive Effect in the Ethyl Acetate Extract of &amp;lt;i&amp;gt;Eribroma oblongum &amp;lt;/i&amp;gt; (Malvaceae) Stem Bark

The stem bark of Eribroma oblongum (malvaceae) is used in traditional Cameroonian medicine to treat various metabolic illnesses including the management of hypertension but there is no scientific evidence to how relief is brought about. The present study was to evaluate the effect of the ethyl acetate extract of the dried stem bark of E. oblongum on arterial blood pressure and heart rate in normotensive rat (NTR) and their mechanisms of EAEO. The effects of ethyl acetate extract of Eribroma oblongum (EAEO; 10, 20, 30 mg/kg; i.v) was tested on systolic blood pressure (SBP) and heart rate (HR) of normotensive rat. The mechanism of EAEO (20mg/kg) was studied in the presence of atropine, yohimbine, propranolol, L-NAME or reserpine. At the end of the experiment, SBP and HR were recorded. EAEO (10-20 mg/kg) induced a significant hypotensive effect of SBP. The hypotensive effects of EAEO (20 mg/kg) were inhibited by pre-treatment of rats with atropine, reserpine, yohimbine and L-NAME. At the end of this study the result demonstrates that the hypotensive as well as the antihypertensive effects of the ethyl acetate extract of the stem bark of Eribroma oblongum. Our data validate the use of the extract in traditional medicine against hypertension. The effect on blood pressure is, at least in part, due to a modulation of the orthosympathetic nervous system and to the improvement of the antioxidant status. Further studies are from now needed to study the toxicity of Eribroma oblongum.

Antityphoid properties and toxicity evaluation of Harungana madagascariensis Lam (Hypericaceae) aqueous leaf extract

ContextHarungana madagascariensis Lam is commonly used in Cameroonian folk medicine for the treatment of malaria and typhoid fever. ObjectiveTo investigate the therapeutic potentials of H. madagascariensis aqueous leaf extract for the treatment of salmonellosis (e.g. typhoid fever, gastroenteritis). Materials and methodsA Salmonella Typhimurium-infected rat model was used. The faeces of these rats were analysed for viable Salmonella Typhimurium before and after infection, and during the treatment period. The physiological, biochemical and histopathological markers of possible side effects of the extract were also studied using standard methods and kits. Results and discussionThe in vivo antisalmonellal study revealed that this extract significantly (P<0.05) reduced the number of viable Salmonella Typhimurium recovered from faeces, and could stop salmonellosis after 10 days of treatment for male and female rats, with non-toxic doses. However, the biochemical and histological analyses revealed that at relatively high-doses (≥100mg/kg for females and 200mg/kg for males) the extract could induce liver damage, as illustrated by a rise of serum transaminases (ALT and AST), significant inflammation of the parenchyma and portal vein, as well as cell necrosis. There were also increases in cholesterol levels in both sexes. No significant unwanted side effect of the extract was observed on the kidney, as shown by both serum and urinary creatinine, and urinary protein levels. ConclusionThe results obtained showed that H. madagascariensis has a promising antisalmonellal effect and, therefore, the potential to provide an effective treatment against salmonellosis, including typhoid fever.

Acute and sub-chronic toxicity studies of three plants used in Cameroonian ethnoveterinary medicine: Aloe vera (L.) Burm. f. (Xanthorrhoeaceae) leaves, Carica papaya L. (Caricaceae) seeds or leaves, and Mimosa pudica L. (Fabaceae) leaves in Kabir chicks

Ethnopharmacological relevanceAloe vera (L.) Burm. f. (Xanthorrhoeaceae), Carica papaya L. (Caricaceae) and Mimosa pudica L. (Fabaceae) are widely used in the Cameroonian ethnoveterinary medicine as a panacea, and specifically for gastrointestinal disorders as well as an anthelmintic and antibacterial. Aim of the studyThe present study evaluated the potential toxicity of the hydroalcoholic extracts of Aloe vera leaves, Carica papaya leaves or seeds, and Mimosa pudica leaves after acute and sub-chronic administration in chicks. Materials and methodsFor the acute toxicity test a single administration of each of the four hydroalcoholic extracts was given orally at doses ranging from 40 to 5120mg/kg (n=5/group/sex). In the sub-chronic study, these extracts were given orally as a single administration to chicks at doses of 80, 160, 320 and 640mg/kg/day for 42 days. The anti-angiogenic properties of these extracts (5–320µg/mg) were investigated in the chick chorioallantoic membrane in vivo. ResultsIn the acute toxicity test, none of the four studied hydroalcoholic extracts induced mortality or significant behavioural changes. The sub-acute treatment with the four plant extracts did not alter either the body weight gain or the food and water consumption. However, the results indicated that Aloe vera leaf extract acute treatment by oral route at doses up to 2560mg/kg did not produce death in 50% (5/10) of chicks during 24h or 14 days of observation, but 20% (2/10) chicks died. The haematological and biochemical analyses did not show significant differences in any of the parameters examined in female or male groups, with the exception of a transient rise in white blood cell counts at high doses (640mg/kg). Additionally, these extracts did not have the potential for anti-angiogenic effects through the inhibition of neo-angiogenesis in the chick chorioallantoic membrane in vivo. ConclusionThe results showed that the therapeutic use of the hydroalcoholic extracts of Aloe vera leaves, Carica papaya leaves or seeds and Mimosa pudica leaves had very low toxicity in oral acute high dose administration and no toxicity in oral sub-chronic low dose administration and indicate that the plants could be considered safe for oral medication in chicks.

Effects of the Methanolic Extract of Vitellaria paradoxa Stem Bark Against Scopolamine-Induced Cognitive Dysfunction and Oxidative Stress in the Rat Hippocampus.

Vitellaria paradoxa C.F. Gaertn (Sapotaceae) is a perennial three which naturally grows in the northern part of Cameroon. It has been traditionally used in the Cameroonian folk medicine for treating inflammation and pain. In the present study, we evaluate the possible anti-amnesic and antioxidative effects of the methanolic extract of V. paradoxa stem bark in an Alzheimer's disease (AD) rat model of scopolamine. Rats received a single injection of scopolamine (1.5mg/kg) before behavioral testing and were treated with the methanolic extract (25 and 50mg/kg), daily, for eight continuous days. Also, the antioxidant activity in the hippocampus was assessed using the total content of reduced glutathione and malondialdehyde levels. The scopolamine-treated rats exhibited the following: decrease of exploratory time and discrimination index within the novel object recognition test, decrease of spontaneous alternations percentage within Y-maze task, and increase of working memory errors, reference memory errors, and time taken to consume all five baits within radial arm-maze task. Administration of the methanolic extract significantly improved these parameters, suggesting positive effects on memory formation processes and antioxidant potential. Our results suggest that the methanolic extract ameliorates scopolamine-induced memory impairment by attenuation of the oxidative stress in the rat hippocampus.

Anti-Staphylococcus aureus activity of methanol extracts of 12 plants used in Cameroonian folk medicine.

BackgroundThe emergence of bacterial infections including those associated with Staphylococcus aureus causes a benefit of interest to medicinal plants as an effective means of control. The present study was designed to investigate the activities of 12 selected Cameroonian medicinal plants against S. aureus isolates.MethodsThe plant extracts were prepared by maceration in methanol at laboratory temperature. Qualitative phytochemical analysis was performed by chemical reaction methods. The broth microdilution method was used to evaluate the activities of plant extracts against 11 S. aureus clinical isolates.ResultsDacryodes edulis was found to have significant antibacterial activity on all the S. aureus isolates (MIC = 64–256 µg/ml). Occimum gratissimum revealed significant inhibitory activity on 9 of the 11 isolates while Commelina erecta and Spilanthes filicaulis revealed similar results on 6 of the 11 clinical isolates.ConclusionThe present findings showed that D. eduli, O. gratissimum,C. erecta and S. filicaulis possess interesting inhibitory properties against S. aureus species. These plants could therefore be good candidates to overcome infectious diseases associated with these microorganisms.