Analysis of additivity and synergism in the anti-plasmodial effect of purified compounds from plant extracts

In the search for antimalarials from ethnobotanical origin, plant extracts are chemically fractionated and biological tests guide the isolation of pure active compounds. To establish the responsibility of isolated active compound(s) to the whole antiplasmodial activity of a crude extract, the literature in this field was scanned and results were analysed quantitatively to find the contribution of the pure compound to the activity of the whole extract. It was found that, generally, the activity of isolated molecules could not account on their own for the activity of the crude extract. It is suggested that future research should take into account the “drugs beside the drug”, looking for those products (otherwise discarded along the fractionation process) able to boost the activity of isolated active compounds

Activit&#233 antifongique des extraits de quelques plantes m&#233dicinales Camerounaises

No Abstract.Nigerian Journal of Natural Products and Medicine Vol. 10 () 2006: pp.94-9

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

Screening of traditionally used Tanzanian medicinal plants for antifungal activity

Kisangau DP, Hosea KM, Lyaruu HVM, et al. Screening of traditionally used Tanzanian medicinal plants for antifungal activity. PHARMACEUTICAL BIOLOGY. 2009;47(8):708-716.Fungal infections represent a significant cause of morbidity and mortality especially in immunocompromised patients in the world today. Dichloromethane (DM) and aqueous (W) extracts of nine plants used traditionally for the treatment of fungal infections in Bukoba rural district in Tanzania were screened for antifungal activity against Candida albicans, Cryptococcus neoformans, and Aspergillus niger using agar well and disk diffusion methods. Dichloromethane extracts of Capparis erythrocorpos [CE] Isert (Capparaceae), Cussonia arborea [CA] Hochst. Ex A. Rich (Araliaceae), Drocaena steudneri [DS] Engl. (Dracaenaceae), Lannea schimperi [LS] (A. Rich) Engl. (Anacardiaceae), Rouvolfia vomitoria [RV] Afz (Apocynaceae), and Sapium ellipticum [SE] (Krauss) Pax (Euphorbiaceae) showed activity against all three fungi. Extracts of Rumex usambarensis [RU] (Dammer) Dammer (Polygonaceae) and Zehneria scabro [ZS] (L.f.) Sond. (Cucurbitaceae) had an activity limited to only one or two of the test organisms. Rhoicissus tridentata [RT] (L.Q Wild & Drum (Vitaceae) was the only plant without activity. Fractions of the active extracts CE, CA, DS, LS, and SE exhibited higher antifungal activity against one or more of the three fungi. Four compounds isolated from S. ellipticum also exhibited antifungal activity against one or more of the three fungi. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs), determined using the microplate assay method, ranged between 0.4 and 50.0 mu g/mL for crude extracts, 1.6 and 50.0 mu g/mL for semi-purified fractions, and 0.12 and 1.0 mu g/mL for pure compounds, as compared to 0.016-1.5 mu g/mL for fluconazole. We confirm the potential of traditionally used plants as a source of new drugs for treatment of fungal infections