| 1. |
- Maeda, Gasper, et al.
(author)
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A Meroisoprenoid, Heptenolides, and C-Benzylated Flavonoids from Sphaerocoryne gracilis ssp. gracilis
- 2020
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In: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 83:2, s. 316-322
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Journal article (peer-reviewed)abstract
- A new meroisoprenoid (1), two heptenolides (2 and 3), two C-benzylated flavonoids (4 and 5), and 11 known compounds (6-16) were isolated from leaf, stem bark, and root bark extracts of Sphaerocoryne gracilis ssp. gracilis by chromatographic separation. The structures of the new metabolites 1-5 were established by NMR, IR, and UV spectroscopic and mass spectrometric data analysis. (Z)-Sphaerodiol (7), (Z)-acetylmelodorinol (8), 7-hydroxy-6-hydromelodienone (10), and dichamanetin (15) inhibited the proliferation of Plasmodium falciparum (3D7, Dd2) with IC50 values of 1.4-10.5 mu M, although these compounds also showed cytotoxicity against human embryonic kidney HEK-293 cells. None of the compounds exhibited significant disruption in protein translation when assayed in vitro.
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| 2. |
- Begum, Sartaz, et al.
(author)
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Antiplasmodial, Antimicrobial and Cytotoxic Activities of Extracts from Selected Medicinal Plants Growing in Tanzania
- 2020
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In: Journal of Biologically Active Products from Nature. - : Taylor & Francis Group. - 2231-1866 .- 2231-1874. ; 10:2, s. 165-176
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Journal article (peer-reviewed)abstract
- This paper reports on the evaluation of antiplasmodial, antimicrobial and cytotoxic activities of extracts from eleven plant species traditionally used by some Tanzanian coastal communities for treatment of malaria, microbial infections and related ailments. Crude extracts from selected plant species namely Acacia zanzibarica, Danais xanthorrhoea, Diospyros loureiriana ssp. rufescens, Erythrina sacleuxii, Newtonia paucijuga, Pentas lanceolata, Scorodophloeus fischeri, Stuhlmannia moavi, Tarenna pavettoides, Tessmannia burttii and Toussaintia orientalis growing in Tanzania were investigated using an imaging-based assay (antiplasmodial), well diffusion and microplate dilution methods (antimicrobial) and human embryonic kidney cells (HEK 293) and brine shrimp larvae assays (toxicity). The extracts exhibited activities of varying potencies and cytotoxicity with IC 50 values ranging from 0.45±0.09 to 75.70±24.19 μg/mL against Plasmodium falciparum (3D7 strain), MIC ranging from 0.25 to 2.0 mg/mL (against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans and Cryptococcus neoformans), LC 50 ranging from 0.75 to 1000 μg/mL against brine shrimp larvae (Artemia salina) and IC 50 ranging from 4.02±1.05 to more than 289 μg/mL against HEK 293 cells. The observed bioactivities of some of the investigated plant extracts validate their ethnomedicinal use and are indicative of the presence of bioactive ingredients for further phytochemical investigations.
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| 3. |
- Maeda, Gasper, et al.
(author)
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Oxygenated Cyclohexene Derivatives and Other Constituents from the Roots of Monanthotaxis trichocarpa.
- 2020
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In: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 83:2, s. 210-215
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Journal article (peer-reviewed)abstract
- Three new oxygenated cyclohexene derivatives, trichocarpeols A (1), B (2), and C (3), along with nine known secondary metabolites, were isolated from the methanolic root extract of Monanthotaxis trichocarpa. They were identified by NMR spectroscopic and mass spectrometric analyses, and the structure of trichocarpeol A (1) was confirmed by single-crystal X-ray diffraction. Out of the 12 isolated natural products, uvaretin (4) showed activity against the Gram-positive bacterium Bacillus subtilis with a MIC value of 18 μM. None of the isolated metabolites was active against the Gram-negative Escherichia coli at a ∼5 mM (2000 μg/mL) concentration. Whereas 4 showed cytotoxicity at EC50 10.2 μM against the MCF-7 human breast cancer cell line, the other compounds were inactive or not tested.
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| 4. |
- Zandi, Linda, et al.
(author)
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Secoiridoids and Iridoids from Morinda asteroscepa
- 2020
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In: Journal of Natural Products. - : AMER CHEMICAL SOC. - 0163-3864 .- 1520-6025. ; 83:9, s. 2641-2646
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Journal article (peer-reviewed)abstract
- The new 2,3-secoiridoids morisecoiridoic acids A (1) and B (2), the new iridoid 8-acetoxyepishanzilactone (3), and four additional known iridoids (4-7) were isolated from the leaf and stem bark methanol extracts of Morinda asteroscepa using chromatographic methods. The structure of shanzilactone (4) was revised. The purified metabolites were identified using NMR spectroscopic and mass spectrometric techniques, with the absolute configuration of 1 having been established by single-crystal X-ray diffraction analysis. The crude leaf extract (10 mu g/mL) and compounds 1-3 and 5 (10 mu M) showed mild antiplasmodial activities against the chloroquine-sensitive malaria parasite Plasmodium falciparum (3D7).
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