Antiplasmodial activity of some phenolic compounds from Cameroonians Allanblackia

Background: Plasmodium falciparum, one of the causative agents of malaria, has high adaptability through mutation and is resistant to many types of anti-malarial drugs. This study presents an in vitro  assessment of the antiplasmodial activity of some phenolic compounds isolated from plants of the genus Allanblackia.Methods: Tests were performed on well plates filled with a fixed parasitized erythrocytes volume. Compounds to be tested were then added in wells. After incubation, tritiated hypoxanthine is added and the plates were returned to the incubator. After thawing, the nucleic acids are collected. Inhibitory Concentration 50 (IC50) was determined by linear interpolation.Results: From Allanblackia floribunda, have been isolated and characterized 1,7-dihydroxyxanthone 1, macluraxanthone 4, morelloflavone 9, Volkensiflavone 10 and morelloflavone 7-O-glucoside 11; from Allanblackia monticola, α-mangosine 2, rubraxanthone 3, allaxanthone C 5, norcowanine 6 , tovophiline A 7, allaxanthone B 8 and from Allanblackia gabonensis, 1,7-dihydroxyxanthone 1. Six of them were  evaluated for their antimalarial properties. The most active compound, macluraxanthone, presented a  very interesting activity, with an IC50 of 0.36 and 0.27 μg/mL with the F32 and FcM29 strains  respectively.Conclusion: This work confirms that species of Allanblackia genus are medicinally important plants containing many biologically active compounds that can be used effectively as antiplasmodial.Key words: Guttiferaceae, Allanblackia, Phenolic compounds, Antiplasmodial activit

Activités antibactérienne et cytotoxique In vitro de différents extraits des écorces du tronc de Diospyros canaliculata (Ebenaceae)

In this study, we have evaluated the antimicrobial and cytotoxic activities of the aqueous, Hexane, ethyl acetate and methanolic extracts of Diospyros canaliculata. The study of the antimicrobial activity has been achieved by the Agar well diffusion method for the determination of the the inhibition zones and the liquide dilution method for the determination of the minimal inhibition concentraion of the different extracts on ten bacterial strains implicated in several human infections. Brine Shrimp lethality bioassay was used in the cytotoxicity investigations. The results showed a weak inhibitory activity of the aqueous extract, on 9 of the 10 microbial strains. Ethyl acetate and methanolic extracts also presented a weak inhibitory effects though active on all the tested bacterial strains. On the other hand a strong antibacterial activity of the hexane extrat was observed on all the tested pathogenic agents. Cytotoxic assay showed that the different extracts were non toxic. The LD50 has been determined only for the ethyl acetate extract. It was of 495.156 μg/ml. The results of this study indicated that this plants could be used in the control of the pathology implicated bacteria.Keywords: Diospyros canaliculata, antibacterial activity, cytotoxicityR ésum é Dans cette tude, nous avons valu les activits antimicrobienne et cytotoxique des extraits l\'eau, l\'hexane, l\'actate d\'thyle et au mthanol de Diospyros canaliculata. L\'tude de l\'activit antimicrobienne a t ralise par les techniques de diffusion par puits sur glose pour la dtermination des diamtres des zones d\'inhibition et de dilution en milieu liquide pour la dtermination des concentrations minimales inhibitrices (CMI) des diffrents extraits sur dix souches bactriennes impliques dans plusieurs infections humaines. La cytotoxicit de ces extraits a quant elle t dtermine sur les crevettes par la technique de dilution l\'eau sale. Les rsultats ont montr une faible activit inhibitrice de l\'extrait aqueux, actif sur 9 des 10 souches microbiennes. Les extraits l\'actate d\'thyle et au mthano ont galement prsent un faible effet inhibiteur bien qu\'actif sur toutes les souches bactriennes testes. Par contre une forte activit de l\'extrait l\'hexane a t observe sur les agents pathognes. Les tudes cytotoxiques ont montres que les diffrents extraits taient non toxiques. La DL 50 n\'a pu tre dtermine que pour l\'extrait l\'acate d\'ethyle. Elle tait de 495,156 μg/ml. Les rsultats obtenus dans cette tude ont montr que cette plante pouvait tre utilise dans le contrle des pathologie lies aux bactries.Mots cls: Diospyros canaliculata, activit antibactrienne, cytotoxicitWest African Journal of Pharmacology and Drug Research Vol. 20(1&2) 2005: 22-2

Eco-friendly synthesis, characterization, in vitro and in vivo anti-inflammatory activity of silver nanoparticle-mediated Selaginella myosurus aqueous extract

Philippe Belle Ebanda Kedi,1,2 Francois Eya’ane Meva,3 Lebogang Kotsedi,2,4,5 Edwige Laure Nguemfo,6 Calvin Bogning Zangueu,1 Agnes Antoinette Ntoumba,1 Hamza Elsayed Ahmed Mohamed,2,4 Alain Bertrand Dongmo,1 Malik Maaza2,4 1Department of Animal Biology and Physiology, Faculty of Science, University of Douala, Douala, Cameroon; 2Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, Somerset, South Africa; 3Department of Pharmaceutical Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon; 4UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Pretoria, South Africa; 5Department of Physics, University of the Western Cape, Bellville, Cape Town, South Africa; 6Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon Introduction: There is emerging interest in medicinal plants in the biomedical field, due to their multitude of chemicals which show anti-inflammatory, antimicrobial, antiviral, or antitumoral potential. Research on medicinal plants has shown that nanotechnology could offer new solutions in the quality control, delivery aspects, or in sustaining herbal biological activities. This work reports on the preparation and characterization of silver nanoparticle-mediated Selaginella myosurus plant extract. Methods: Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and selected area electron diffraction have been used to characterize the prepared silver nanoparticles. The synthetic stability was studied by varying concentrations and pH of reactants. Egg albumin denaturation and carrageenan-induced rat paw edema model were used to ascertain the anti-inflammation. Results: Ultraviolet-visible spectroscopy gave plasmon resonance ranging between 420 and 480 nm while Fourier transform infrared spectroscopy proved nano interface functionalized with organics. The powder X-ray diffraction pattern is in agreement with silver and silver chloride nanoparticles of crystallite size 33.7 nm and 44.2 nm for silver and silver chloride, respectively. Energy dispersive X-ray spectroscopy enables elemental characterization of the particles consisting of silver and silver chloride among main elements. Spherical silver grain of 58.81 nm average size has been depicted with high-resolution scanning electron microscopy and high-resolution transmission electron microscopy. Inhibitions of 99% and 60% were obtained in vitro and in vivo, respectively. Conclusion: The albumin denaturation and carrageenan-induced rat hind paw edema model to assess the anti-inflammatory potential of generated nanoparticles suggests that the silver nanoparticles may act as reducing/inhibiting agents on the release of acute inflammatory mediators. Hence, this work clearly demonstrated that silver nanoparticles mediated-Selaginella myosurus could be considered as a potential source for anti-inflammatory drugs. Keywords: eco-friendly synthesis, silver nanoparticles, Selaginella myosurus, anti-inflammator