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Seven naphthoquinones and nine anthraquinones were isolated from the roots of Aloe dawei by chromatographic separation. The purified metabolites were identified by NMR and MS analyses. Out of the sixteen quinones, 6-hydroxy-3,5-dimethoxy-2-methyl-1,4-naphthoquinone is a new compound. Two of the isolates, 5,8-dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione and 1-hydroxy-8-methoxy-3-methylanthraquinone showed high cytotoxic activity (IC 50 1.15 and 4.85 µM) on MCF-7 breast cancer cells, whereas the others showed moderate to low cytotoxic activity against MDA-MB-231 (ER Negative) and MCF-7 (ER Positive) cancer cells.

Extracts of the rhizomes of Kniphofia foliosa exhibited antiplasmodial activities against the chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum with IC 50 values of 3-5 g/mL. A phenyloxanthrone, named 10-acetonylknipholone cyclooxanthrone (1) and an anthraquinoneanthrone dimer, chryslandicin 10-methyl ether (2), were isolated from the rhizomes, along with known quinones, including the rare phenylanthraquinone dimers, joziknipholones A and B. The structures of these compounds were determined based on spectroscopic data. This is the second report on the occurrence of the dimeric phenylanthraquinones in nature. In an in vitro antiplasmodial assay of the isolated compounds, activity was observed for phenylanthraquinones, anthraquinone-anthrone dimers and dimeric phenylanthraquinones, with joziknipholone A being the most active. The new compound, 10-acetonylknipholone cyclooxanthrone, also showed anti-plasmodial activity. In an in vivo assay, knipholone anthrone displayed marginal antimalarial activity.

Introduction: Plants from Kenyan flora are traditionally used to manage a number of ailments including; chronic and infectious disease, to bolster the body immunity and for general health protections. The current investigation was designed to validate the quality with respect to the pharmacological significance of 156 fresh plant materials resulting from 27 ethno-medicinal plants, from Ngong forest, Kenya. Materials and Methods: Pharmacological screening was carried out using the field deployable GIBEX Screens-To-Nature (STN) validated assays. The plant extracts were screened for antifungal; general protozoal lethality; round worm lethality and antioxidant potential. Results: Different plant parts exhibited a range of activities; related to their traditional uses; with eleven out of twenty-seven extracts exhibiting highest activities in only one out of four categories of assays studied. All plant parts of only one plant C. axillaris exhibited high activities in all (4/4) the categories of assays evaluated. The other plants that exhibited high activities in three out of four (3/4) categories of assays studied included; A. oppositifolia, B. huillensis and T. trichocarpa. Conclusion: The current investigation provided additional data in relation to the usefulness of the studied ethno-medicinal plants, mostly of the following plants; C. axillaris, A. oppositifolia, B. huillensis and T. trichocarpa in the management of diseases that are infectious and to bolster the immunity. The reported data will contribute towards authenticating the claimed traditional use of these plants. The extracts that exhibited high activities should be investigated further to determine their effective concentrations.ance on the traditional use and cultural implication of use these plants as traditional medicine. For each plant two samples were collected, for extraction and positive taxonomic identification and retention as herbarium specimen. Plant ExtractionExtraction of all plant materials was achieved after mincing 2 g of the plant material and then pulverizing in 4 ml ethanol in a small vial using Dremel® rotary tool for 10 min. The vial and contents were allowed to sit for approximately 5 min and then filtered through filter paper and kept at 4 °C for different bioassays. Pharmacological ScreeningPharmacological screening of different plant parts was carried out by simple and rapid bioassays; GIBEX Screens-To-Nature (STN) system; deployable in field experiments to explore/investigate the pharmaceutical relevancy of natural plant extracts for human health protection. The STN system involved the following activities; plant identification and collection, study of traditional, historical plant use and ethnobotany, vouchering and archiving, extraction tactics and screening plant samples using biologically relevant validated bioassays. The resultant extracts were screened for the biological activities listed below: General Antifungal AssayThe local strain of Saccharomyces cerevisiae (Common baker's yeast), obtained from the drug analysis and ...