Nitric oxide inhibitory activity of Strychnos spinosa (loganiaceae) leaf extracts and fractions

Background: The study was aimed at determining the anti-inflammatory activity of fractions and extracts obtained from Strychnos spinosa leaves on a mediator of inflammation nitric oxide (NO).Materials and Methods: Leaves were extracted with acetone and separated into fractions with different polarities by solventsolvent fractionation. The Griess assay was used to determine the nitric oxide (NO) inhibitory activity. Cellular toxicity was determined by "using the MTT reduction assay".Results: With the exception of the ethyl acetate fraction which had an IC50 >750 μg/mL, all extracts and fractions had significant nitric oxide-inhibitory activity. The most active being the water fraction, chloroform fraction and the dichloromethane/methanol extracts with IC50 values of 88.43 μg/mL, 96.72 μg/mL and 115.62 μg/mL, respectively. The extracts and fractions had low cytotoxicity on macrophage U937 cell lines.Conclusion: Extracts and fractions of Strychnos spinosa leaves may be promising sources of natural anti-inflammatory agents. Findings obtained from this study showed that Strychnos spinosa leaves possess promising anti-inflammatory action and could be used in the treatment of inflammation-related conditions.Keywords: Strychnos spinosa, inflammation, nitric oxide, cytotoxicit

Ethnopharmacological survey, antioxidant and antifungal activity of medicinal plants traditionally used in Baham locality (Cameroon) to treat fungal infections

Invasive fungal infections are important causes of mortality despite advances in antifungal therapy. The aim of this study was collect information on plants used by traditional healers for the treatment of fungal infections in the Baham subdivision (Western region of Cameroon) and to assess the in vitro antifungal and antioxidant potentials of the extracts from the medicinal plants surveyed. The antifungal activity was assessed by the broth micro-dilution method and the antioxidant activity was determined using the free-radical scavenging assays. The extracts for the plants Kotschya strigosa and Eryngium foetidum had potent antifungal activity with minimum inhibitory concentration value of 32 μg/mL against Cryptococcus neoformans. Eugenia gilgii extract had the highest free radical scavenging capacity in 2,2-Diphenyl-1-picrylhydrazyl assay (IC50 of 4.54μg/mL). There is a rich wealth of knowledge and usage of plants by traditional healers for the treatment of fungal infections and further studies should consider isolation of active compounds from the extracts in order to assess the potential for developing new, effective, safe and affordable phytomedicine for the treatment of fungal infections and other pharmacological applications.Keywords: Ethnomedicine; Fungal infections; Antifungal; Antioxidant; Extrac

Anti-inflammatory, anticholinesterase and antioxidant activity of leaf extracts of twelve plants used traditionally to alleviate pain and inflammation in South Africa

ETHNOPHARMAOLOGICAL RELEVANCE :Oxidative stress and inflammatory conditions are among the pathological features associated with the central nervous system in Alzheimer’s disease. Traditionally, medicinal plants have been used to alleviate inflammation, pains and also other symptoms possibly associated with Alzheimer’s disease. Therefore, the present study was designed to determine the in vitro antiinflammatory, antioxidant and anticholinesterase activity of twelve South African medicinal plants traditionally used to alleviate pain and inflammation. MATERIALS AND METHODS : Nitric oxide (NO) production in LPS-activated RAW 264.7 macrophages and 15-lipoxygenase (LOX) inhibitory assay were used to evaluate the anti-inflammatory activity. Acetylcholinesterase inhibition was assessed by using a modification of the Ellman’s method. Antioxidant activity, total phenolic and total flavonoids contents were determined using standard in vitro methods. RESULTS : The extract of Burkea africana had the highest anti-15-lipoxygenase activity with 85.92% inhibition at 100 μg/mL. All the extracts tested inhibited nitric oxide (NO) production in a dose dependant manner in LPS-stimulated RAW 264.7 macrophages. However, extracts from Leucaena leucocephala, Lippia javanica inhibited the production of NO by 97% at a concentration of 25 μg/mL. In addition, both Leucaena leucocephala and Englerophytum magaliesmontanum had strong activity against acetylcholinesterase with IC50 values of 118 μg/mL and 160 μg/mL respectively. Hight levels of phenolics and flavonoids were found in Leucaena leucocephala, Lippia javanica and Burkea africana. The correlation with antioxidant activities was not strong indicating that other metabolites may also be involved in antioxidant activity. CONCLUSIONS : The results obtained in this study validate the use of leaf extracts of these plants in South African traditional medicine against inflammation. Extracts of these plants species might be of value in the management of various diseases emerging from oxidative stress and related degenerative disorders.National Research Foundation (NRF) and Medical Research Council (MRC).http://www.elsevier.com/locate/jethpharm2016-02-28hb201

In vitro antifungal activity of Dorstenia mannii leaf extracts (Moraceae)

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.Keywords: Antifungal activity, Dorstenia mannii, yeasts, opportunistic candidiasi

In Vitro Antifungal Susceptibility of Environmental Isolates of Cryptococcus spp. from the West Region of Cameroon

BACKGROUND: Cryptococcus neoformans is responsible of cryptococcosis, a life-threatening infection that affects healthy and immunocompromised individuals. It is the first cause of adult acute meningitis in some sub-Saharan African countries with a mortality rate of about 100% in cases of inappropriate therapy. This study aimed at examining the occurrence and the antifungal patterns of Cryptococcus isolates from pigeon droppings and bat guanos in the west region of Cameroon.METHODS: A total of 350 samples were randomly collected from three selected localities of west region of Cameroon. The identification was performed based on capsule production assessed by Indian ink preparation. Additional tests performed were urea broth, glycine and tryptophan assimilation tests. The antifungal susceptibility test was performed by the broth microdilution method.RESULTS: Mycological analysis led to the identification of 98 isolates, of which 57 isolates of C. neoformans var. gattii and 41 isolates of C. neoformans var. neoformans. All the isolates showed resistance to antifungals tested except nystatin which showed MIC mean values ranging between 0.5 μg/mL and 0.65 μg/mL.CONCLUSION: The prevalence of C. neoformans in pigeons and bats excreta in the west region of Cameroon is 28.57 %. C. neoformans var. gattii and C. neoformans var. neoformans are the main serotypes. Isolates found to be resistant to fluconazole and ketoconazole. Our results emphasize the need for further study on the molecular epidemiology in comparison with clinical isolates.KEYWORDS: Cryptococcus neoformans, bird excreta, antifungal susceptibilit

Suppression of female flowers and pollen fertility of male flowers of banana plants

O objetivo deste trabalho foi avaliar o efeito da supressão das flores femininas sobre a fertilidade do pólen das flores masculinas de bananeira. Dois modos de supressão das flores femininas, parcial e completo, foram aplicados logo após o florescimento em genótipos diploides, triploides e tetraploides de bananeira. Avaliou-se o efeito da supressão do florescimento sobre o número de flores masculinas e o comprimento das suas anteras, assim como a viabilidade do pólen e o tamanho e o número de grãos de pólen por antera. Testes de polinização foram realizados para avaliar o número de sementes obtidas da descendência de alguns dos genótipos. A supressão total de flores femininas aumenta significativamente a fertilidade polínica, estimada por meio do aumento do número de grãos de pólen por antera (até 80% por antera). A supressão total das flores femininas também melhora significativamente a produção de sementes nos cruzamentos (de 35 a 160% por cacho polinizado), o que sugere influência positiva da seiva que flui através do cacho na eficiência do pólen da bananeira.The objective of this work was to evaluate the effect of the suppression of female flowers on the pollen fertility of male flowers of banana plants. Two modes of female flower suppression, one partial and one complete, were applied shortly after flowering to diploid, triploid, and tetraploid banana genotypes. The effect of flower suppression on the number of male flowers and the length of their anthers was evaluated, as well as pollen viability and the size and number of pollen grains per anther. Pollination tests were performed to evaluate the number of seed obtained from the progeny of some genotypes. The total suppression of female flowers significantly increases pollen fertility, estimated by an increase in the number of pollen grains per anther (up to 80% per anther). Total female flower suppression also improves significantly seed production in the crosses (from 35 to 160% per pollinated bunch), which suggests a positive influence of the sap flowing through the bunch on the efficiency of banana pollen

Development and functioning of the embryo sac in four triploid banana cultivars

O objetivo deste estudo foi investigar as causas da esterilidade em um novo conjunto de cultivares triploides de banana (Musa spp.) e avaliar as possibilidades de obter progênies por meio de polinização manual. Os estados de desenvolvimento do gametófito feminino foram histologicamente observados em óvulos de quatro cultivares de banana triploide. As amostras foram colhidas no dia da abertura das flores e da polinização e três dias depois. Os sacos embrionários morfologicamente maduros mostraram-se raros em dois clones do subgrupo 'Cavendish' e em 'Prata Anã'. Em 'Mysore', ocorreu a uma frequência variável e baixa. Em 'Terrinha', foi extremamente comum. Nos dois últimos casos, o processo de maturação dos sacos embrionários claramente continuava entre o dia da amostragem na floração e os três dias depois. Nenhum tubo polínico foi identificado em flores polinizadas nos integumentos de qualquer óvulo nos explantes mais velhos. Diferentes proporções de sacos embrionários são observadas entre os genótipos de bananas triploides. A presença de sacos embrionários não indica capacidade funcional. Outras causas de infertilidade em bananas cultivadas podem ser em razão de algum evento imediatamente antes ou depois da fertilização, como ausência de cariogamia ou aborto das sementes.The objective of this work was to investigate the causes of sterility in a new set of triploid banana (Musa spp.) cultivars and to assess the chances of obtaining some progenies by manual cross-pollination. The developmental stages of female gametophyte were histologically recorded in ovules of four distinct triploid banana cultivars. Samples were taken on the day of flower opening and pollination and three days later. Morphologically mature embryo sacs were very rare in the two clones of the 'Cavendish' subgroup and in 'Prata Anã'. In 'Mysore', it occurred at a variable and low frequency. In 'Terrinha', it was extremely common. In the last two cases, the embryo sac maturation process was clearly continuing between the sampling days of flower opening and three days later. No pollen tube was positively identified in pollinated flowers within the integuments of any ovule of the older explants. Different proportions of mature embryo sacs are observed among the studied triploid genotypes of banana. The presence of mature embryo sacs is not an indication of functional capacity. Other causes of infertility in cultivated bananas can be due to some event immediately before or after fertilization, for instance, pollination tube growth failure or seed abortion

Some Strychnos spinosa (Loganiaceae) leaf extracts and fractions have good antimicrobial activities and low cytotoxicities

BACKGROUND : Strychnos spinosa Lam. is a deciduous tree used in traditional medicine to treat infectious diseases. This study is designed to determine the antimicrobial, antioxidant and cytotoxic activities of extracts and fractions from leaves of S. spinosa. METHODS : Extracts were obtained by maceration with acetone, methanol and dichloromethane/methanol (1/1) while fractions were prepared by liquid-liquid fractionation of the acetone extract. A broth serial microdilution method with tetrazolium violet as growth indicator was used to determine the minimum inhibitory concentration (MIC) against fungi, Gram-positive and Gram-negative bacteria. The antioxidant activity was determined using free-radical-scavenging assays, and the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide reduction assay was used to determine cytotoxicity. RESULTS : Four extracts and five fractions had good to weak antimicrobial activity with MICs ranging from 0.04 to >1.25 mg/ml against both fungi and bacteria. The chloroform and ethyl acetate fractions had an MIC of 0.08 mg/ml against Aspergillus fumigatus. The n-butanol fraction had an MIC of 0.04 mg/ml against Cryptococcus neoformans. The hexane and chloroform fractions had an MIC of 0.08 mg/ml against Staphylococcus aureus. The antioxidant activities were much lower than that of the positive controls. Except for the alkaloid extract, all the extracts and fractions had free-radical-scavenging activity (IC50 ranging from 33.66 to 314.30 μg/ml). The cytotoxicity on Vero cells was reasonable to low with LC50 values ranging between 30.56 and 689.39 μg/ml. CONCLUSION : The acetone extract and the chloroform fraction had the highest antibacterial activity. By solvent-solvent fractionation it was possible to increase the activity against A. fumigatus and to decrease the cytotoxicity leading to a potentially useful product to protect animals against aspergillosis. Our results therefore support the use of S. spinosa leaves in traditional medicine to treat infectious diseases.A.I.I is grateful to the Nigerian Tertiary Education Training Fund (TETFund) through Ahmadu Bello University Academic Unit for supporting the work in this paper. M.D.A and J.P.D received Postdoctoral Fellowships from the University of Pretoria to work in the Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science.http://www.biomedcentral.com/bmccom/plementalternmedam201

Effet antifongique de deux extraits de plantes sur les agents pathogènes identifiés sur des fruits de l’anacardier (Anacardium occidentale L.) au Nord Cameroun

L’anacardier (Anacardium occidentale L.), importante culture de rente, est confrontée à la menace de nombreux pathogènes qui entravent sa productivité au Cameroun. Dès lors, cette étude se propose de déterminer le potentiel d’une lutte biologique à base d’extraits végétaux sur les champignons pathogènes identifiés sur des fruits prélevés dans le bassin de la Benoué. Pour atteindre ces objectifs, l’identification des agents pathogènes des fruits, des tests de pathogénicité et l’évaluation de l’effet antifongique in vitro et in vivo des extraits de piments et de neem ont été effectués. Les résultats ont montré que ces fruits abritent une diversité d’espèces fongiques dont les principales sont Colletotrichum gloeosporioides, Oïdium anacardii, Fusarium solani, Aspergillus niger et Phytophthora sp. Les tests de pathogénicité ont produit les symptômes des maladies observées sur le terrain. L’huile de neem et les extrait de piment ont inhibé totalement la croissance de C. gloeosporioides, O. anacardii et A. niger aux doses respectives de 7,5% v/v et 75 mg/ml. Cependant, l'huile de neem s'est avérée plus efficace. Ces résultats représentent des sources d'information précieuses pour l’implémentation d'une stratégie de lutte intégrée contre les agents pathogènes de l’anacardier à l’origine de la baisse de sa productivité, affectant ainsi son potentiel économique. English Title: Antifungal effect of two plant extracts on pathogens identified on fruits of Cashew tree (Anacardium occidentale L.) in North Cameroon The Cashew tree (Anacardium occidentale L.), an important cash crop, is challenged by the proliferation of pathogens that affect its productivity in Cameroon. Therefore, this study aims to determine the potential of a biological control based on plant extracts on pathogenic fungi identified on fruits collected in the Benoué basin. To achieve these objectives, identification of fruit pathogens, pathogenicity tests and evaluation of the in vitro and in vivo antifungal effect of chilli and neem extracts were carried out. The results showed that these fruits harbour a diversity of fungal species, of which the main ones are Colletotrichum gloeosporioides, Oïdium anacardii, Fusarium solani, Aspergillus niger and Phytophthora sp. The pathogenicity tests have generated the symptoms of the diseases observed in the field. Neem oil and chilli extracts completely inhibited the growth of C. gloeosporioides, O. anacardii and A. niger at doses of 7.5% v/v and 75 mg/ml respectively. However, neem oil proved to be more effective. These results represent valuable sources of information for the implementation of an integrated pest management strategy against cashew pathogens that impede the productivity of the tree, thereby affecting its economic potential

In vitro Antimycobacterial, Apoptosis-Inducing Potential, and Immunomodulatory Activity of Some Rubiaceae Species

Tuberculosis (TB), a disease caused by microorganisms of the Mycobacterium tuberculosis complex, infects almost one-third of the world’s population. The TB epidemic has been further exacerbated by the emergence of multi, extensively, and totally-drug-resistant (MDR, XDR, and TDRTB) strains. An effective immune response plays a crucial role in determining the establishment of TB infection. Therefore, the modulation of the immune system has been considered as a vital approach for the treatment or control of various immune-related diseases such as TB. In this study, the antimycobacterial, immunomodulatory, and apoptosis-inducing effects of six Rubiaceae species were evaluated. A twofold serial dilution method was used to determine the minimum inhibitory concentration values of the plant extracts. The effect of the extracts on the activity of 15-lipoxygenase was investigated. The levels of six different cytokines, IL-2, IL-4, IL-5, IL-10, IFN-γ, and TNF-α, were measured in LPS-activated U937 cell line while the apoptosis-inducing effect of the extracts was evaluated using an annexin V/PI assay using a flow cytometer. The results obtained revealed that all the six extracts tested had antimycobacterial activity against M. tuberculosis H37Rv, M. tuberculosis ATCC 25177, and Mycobacterium bovis ATCC 27299 strains, with MIC values ranging from 39 to 312 μg/mL. The extracts of Cremaspora triflora and Cephalanthus natalensis were the most active against M. tuberculosis (MIC = 39 μg/mL), followed by Pavetta lanceolata and Psychotria zombamontana against M. bovis (MIC = 78 μg/mL). The extracts of P. zombamontana and Psychotria capensis had remarkable IC50 values of 4.32 and 5.8 μg/mL, respectively, better than that of quercetin. The selected extracts promoted Th1/Th2 balances in an in vitro model at the tested concentration which may suggest the therapeutic value of the plant in diseases where inflammation is a significant factor such as TB. The addition of the crude extracts of C. triflora, P. capensis, and P. zombamontana at the tested concentrations to the cell culture medium induced apoptosis in a time- and dose-dependent manner. This interesting preliminary result generated from this study encourages further investigations of these extracts owing to the LOX-inhibitory effect, immunomodulatory, and apoptotic-inducing properties in addition to their antimycobacterial properties