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- Acetylcholinesterase Inhibitory Activity of Extracts from Angolan Medicinal PlantsPublication . Fernandes, Nelson; Canelo, Laura; Mendonca, Dina; Mendonça, AntónioPlants are considered important sources of new chemical entities that can be used in the development of novel therapeutic drugs for the symptomatic treatment of Alzheimer’s disease. The inhibition of acetylcholinesterase by 38 extracts from 13 medicinal plants used in Angola folk medicine are presented: Adenodolichos huillensis (roots and leaves); Boscia microphylla (leaves); Croton gratissimus (aerial part); Gymnosporia senegalensis (branches); Hymenodictyon floribundum (barks); Parinari capensis (leaves); Peucedano angolense (aerial part); Phragmanthera glaucocarpa (roots); Rhus kirkii (leaves); Solanecio mannii (branches); Solanum incanum (fruit); Tinnea antiscorbutica (aerial part) and Xylopia odoratissima (leaves). TLC bioautographic assay and Ellman’s method were used. The best results for IC50 were obtained with the toluene extract of B. microphylla leaves (0.55 ± 0.01 mg/mL) and the methanol extract of G. senegalensis branches (0.30 ± 0.00 mg/mL). The aqueous extract of the leaves of P. capensis also demonstrated acetylcholinesterase inhibitory activity in the two methods used. In conclusion, the medicinal plants P. capensis, B. microphylla and G. senegalensis represent promising sources of natural compounds with acetylcholinesterase inhibitory properties.
- Three New Labdanes Isolated from Eragrostis viscosaPublication . Sebastião, N'Soki; Fernandes, Nelson; Vieira, Liliana; Mendonça, António; Gaspar, Jorge; Martins, Célia; Rueff, José; Diakanamwa, Carlos; Mendonça, DinaThree new labdanes with 8α,15-epoxy ring [methyl 8α,15-epoxylabdan-16β-oate, 8α,15-epoxylabdan-16β-ol and 8α,15-epoxy-16-norlabdan-13β-ol] and five known compounds [8α,15-epoxy-16-norlabdan-13-one, 8α,15-epoxylabdan-16β-oic acid, 3β-(3'',4''-dihydroxy)(E)-cinnamoyloxylup-20(29)-ene, 3-(2',3',4',6'-tetra-O-acetyl-β-D-glucopyranosyloxy)β-sitosterol and 16-acetoxy-8α,15-epoxylabdane] were isolated from toluene and dichloromethane extracts of aerial parts of Eragrostis viscosa. The structures of all the compounds were established based on their spectroscopic data and X-ray diffraction analysis of 8α,15-epoxylabdan-16β-ol. It was also studied the genotoxicity of E. viscosa, particularly compounds 16-acetoxy-8α, 15-epoxylabdane, 8α,15-epoxy-16-norlabdan-13-one and 8α, 15-epoxilabdan-16β-ol, using a cytokinesis-block micronucleus assay and the Ames test to assess mutagenicity. Both assays were negative. Cytotoxicity was also analyzed using an MTT assay, and 8α,15-epoxy-16β-ol was shown to be the most cytotoxic of the compounds tested. E. viscosa extracts were also tested to determine their antioxidant capacities, peroxide values and total phenolic contents.