Volatile oils extracted by hydrodistillation from six plant species growing in the Kenyan coast, Croton pseudopulchellus Pax, Mkilua fragrans Verdc. (Annonaceae), Endostemon tereticaulis (poir.) Ashby, Ocimum forskolei Benth., Ocimum fischeri Guerke and Plectranthus longipes Baker (Labiateae), were evaluated for repellency on forearms of human volunteers against Anopheles gambiae sensu stricto. All oils were found to be more repellent (RC50 range = 0.67-9.21 x 10(-5) mg cm(-2)) than DEET (RC50 = 33 x 10(-5) mg cm(-2)). The individual components of the oils were identified by GC-MS and GC co-injections with authentic standards.The repellency of 15 of the main constituents of the different oils (which had not been previously assayed) was evaluated. Although some of these showed relatively high individual repellencies, none was comparable to the parent essential oils. Partial synthetic blends of selected constituents with moderate or relatively high individual repellency against the vector were also assayed. Four of these exhibited activities comparable to or higher than those of the corresponding parent oils, indicating interesting blend effects in the repellent action of the oils against the mosquito. The implication of these results in the utilization of the plants is discussed.

Toussaintine A (N-cinnamoyl-5,6-dehydro-4-hydroxyindolidin-2,7-dione), toussaintine B (Ncinnamoyl-5,6-dehydro-4,7-dihydroxyindolidin-2-one), toussaintine C (N-cinnamoyl-5,6-dehydro-4-hydroxyindolidin-7-one), toussaintine D (N-cinnamoyl-2-amino-4-hydroxy-7-oxo-2,3,8,9-tetrahydrobenzofuran) and toussaintine E (N-cinnamoyl-1-acetoxymethyl-2-amino-1-hydroxycyclox-5-en-4-one) were isolated as antibacterial and antifungal constituents of the leaves of Toussaintia orientalis Verdc. (Annonaceae) and their structures established from analysis of spectroscopic data. The compounds belong to a series of variously cyclized aminocinnamoyl tetraketide derivatives, showing the importance of rarely occurring Annonaceae species as sources of structurally diverse natural products.

The new aristolactam alkaloid toussalactam {2-hydroxy-1,6-dimethoxy-5H-dibenzo[cdf]indol-4-one} and the known ones, namely aristolactam AII, aristolactam BII, piperolactam C and aristolactam FII; 1-(2-C-methyl-β-D-ribofuranosyl)-uracil, 3,4,5-trimethoxyphenyl-β-D-glucopyranoside, and three catechinoids were isolated from the cytotoxic Toussaintia orientalis Verdc stem and root bark extracts, and their structures established based on analysis of spectroscopic data. The aristolactams exhibited antimicrobial and antiinflammatory activity, aristolactam FII showing almost the same level of activity as the standard anti-inflammatory agent Indomethacin. The compounds also exhibited either mild or no antiproliferative and cytotoxic activities, except aristolactam FII that showed the same level of cytotoxicity as the standard drug Camptothecin. 1-(2-C-Methyl-β-D-ribofuranosyl)-uracil, which is being reported for the first time as a natural product, was inactive in the antibacterial, antifungal, antiinflammatory, antiproliferative and cytotoxicity assays.

Parts of the plant Thalictrum rhyncocarpum are used in herbal medicine in Kenya to treat various infections. The aim of this study was to evaluate in-vitro anti-bacteria activities and phytochemical profiles of solvent extracts of the leaves, stem bark and root of Thalictrum rhyncocarpum against Bacillus subtilis-6633, Staphylococcus aures-SG 511, Escherichia coli SG 458, Pseudomonus aeruginosa-K799/61 and Mycobacterium vaccae-10670. Anti-bacterial activity tests were carried out using disc diffusion assay and tube dilution technique, and phytochemical screening was carried out through Thin Layer Chromatography. The crude extracts showed antibacterial effects on M. vaccae, P. aeruginosa and B. subtilis. M. vaccae was most sensitive, particularly to the methanol root extract. Phytochemical screening of the extracts suggested the presence of glycosides and alkaloids in the stem bark and root extracts, and flavonoids and triterpenes in the leaf extracts. The study showed interesting levels of activities of solvent extracts of different parts of T. rhyncocarpum against some of the bacteria tested (M. vaccae, P. aeruginosa and B. subtilis). The results provide some scientific rationale for the traditional use of the plant in Kenya to treat different microbial infections.

Objective: To evaluate the effect of binder concentration, granule size and distance between punches on mechanical strength and drug release properties of tablets containing Malva verticillata mucilage (MVM) as a binder.Methods: Paracetamol and lactose were converted into wet coherent masses by a liquid solution containing 1-3% w/w MVM as a binder. Granules containing 2% w/w binder was used to investigate the effect of granule size and distance between punches. Compressed tablets were evaluated for crushing strength, disintegration time and in vitro drug release using pharmacopeial methods.Results: Granules containing MVM were found to be free-flowing and compatible with paracetamol. Mechanical strength and drug release properties of mucilage tablets significantly correlated with the amount of MVM binder. Tablet crushing strength was 3.54-7.12 kg/cm 2 while disintegration time 7.13-16.67 min. Compression pressure and granule size had no significant effects on drug release properties of mucilage tablets. Crushing strength of mucilage tablets were higher and significantly different (t(26) = 7.9631, p Conclusion: Properties of tablets containing 2.5% w/w MVM matched the prescribed pharmaceutical limits and hence M. verticillata root mucilage has a great potential to become a new source of tablet binder. <0.05) from acacia tablets in the tested variables. The cumulative drug release rate of mucilage tablets was also lower than that of acacia tablets in tested concentrations.