Publications by authors named "Jacob Midiwo"

The phytochemical investigation of the leaves and the roots of Suregada procera afforded the new ent-abietane diterpenoid sureproceriolide A (1) along with the known secondary metabolites 8,14β:11,12α-diepoxy-13(15)-abietane-16,12-olid (2), jolkinolide A (3), jolkinolide E (4), ent-pimara-8(14),15-dien-19-oic acid (5), sitosterol (6), oleana-9(11):12-dien-3β-ol (7), and oleic acid (8). Their structures were elucidated by NMR spectroscopic and mass spectrometric analyses, and the structure of jolkinolide A (3) was confirmed by single-crystal X-ray diffraction analysis. Sureproceriolide A (1) showed modest activity against the Gram-positive bacterium Staphylococcus lugdunensis (MIC = 31.

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The root extract of Baill. afforded six previously described -abietane diterpenoids, namely 7-oxo--abieta-5(6),8(14),13(15)-trien-16,12-olide (), mangiolide (), 8,14:11,12-diepoxy-13(15)-abietane-16,12-olide (), 7,11,12-trihydroxy--abieta-8(14),13(15)-diene-16,12-olide (), 8α,14-dihydro-7-oxo-jolkinolide E (), jolkinolide A (), together with 3-sitosterol (), scopoletin () and vanillin (). Their structures were deduced through 1D and 2D NMR spectroscopic techniques, and HRESIMS, as well as by comparison of the NMR data with those reported in the literature.

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The current study investigated and optimized key process parameters affecting mushroom hydrolysis with crude enzymatic extract. The crude enzyme was prepared by solid-state fermentation of pineapple peels using . The reaction parameters viz.

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Article Synopsis
  • A new flavanone-flavonol dimer named gnidiflavanone-flavonol and 10 other known compounds were isolated from the roots of a plant in the Thymelaeceae family.
  • The structures of these compounds were determined using advanced methods like NMR and mass spectrometry, with some compounds being reported for the first time from this plant family.
  • In terms of biological activity, the crude extract and isolated compounds were tested for antimicrobial and antiplasmodial effects, with two compounds showing promising antiplasmodial activity against both chloroquine-sensitive and resistant strains.
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A set of structurally related -methylated flavonoid natural products isolated from (), ( and ), (), (), and () plant species were characterized for their interaction with human monoamine oxidases (MAO-A and -B) in vitro. Compounds , , and showed selective inhibition of MAO-A, while and showed selective inhibition of MAO-B. Compound showed ~2-fold selectivity towards inhibition of MAO-A.

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Monoterpene derivatives are of great biological relevance in the pharmaceutical industry. In the present study, pyrrolidine derivative of a carvotacetone, 3-benzylcarvotacetone (), and selected monoterpenes (3-hydroxy-2-isopropyl-5-methyl--benzoquinone () and piperitol ()) were prepared to provide ()-1-(4-(benzyloxy)-5-isopropyl-2-methylcyclohexa-1,3-dien-1-yl)-pyrrolidine (), 2-isopropyl-5-methyl-3,6-dioxocyclohexa-1,4-dien-1-yl acetate (), 3-hydroxypiperitone () and carvacrol (). Structure of was determined based on NMR and HRMS spectral data.

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In an attempt to synthesize carvotacetone analogues, new 3--benzyl-carvotacetone ( and previously reported 3-hydroxy-2-isopropyl-5-methyl--benzoquinone () were synthesized from piperitone (). In this work, we describe the synthesis of and other analogues from . Luche reduction of to -piperitol (, followed by benzylation yielded 3--benzyl-piperitol ().

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Article Synopsis
  • Researchers isolated one new and one known alkamide compound from a specific extract, as well as four known compounds from another extract using chromatographic techniques.
  • Characterization of these compounds was done with NMR and MS spectroscopic methods.
  • The new alkamide exhibited moderate cytotoxicity against leukemia cell lines, showing greater activity than the standard drug doxorubicin against drug-resistant cells, suggesting the potential for future testing on various drug-resistant human cells.
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Background: Cancer constitutes a major hurdle worldwide and its treatment mainly relies on chemotherapy.

Objectives: The present study was designed to evaluate the cytotoxicity of eleven naturally occurring compounds including six phenolics amongst them were 4 chalcones and 2 flavanones as well as 5 terpenoids (3 clerodane and 2 trachylobane diterpenoids) against 6 human carcinoma cell lines and normal CRL2120 fibroblasts.

Materials And Methods: The neutral red uptake (NR) assay was used to evaluate the cytotoxicity of the compounds, whilst caspase-Glo assay was used to detect caspase activation.

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Background: Practices of biopiracy to use genetic resources and indigenous knowledge by Western companies without benefit-sharing of those, who generated the traditional knowledge, can be understood as form of neocolonialism.

Hypothesis: The One-World Medicine concept attempts to merge the best of traditional medicine from developing countries and conventional Western medicine for the sake of patients around the globe.

Study Design: Based on literature searches in several databases, a concept paper has been written.

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Infections caused by species belonging to the cluster' negatively affect the agricultural sector through losses in livestock productivity. These strains are resistant to many conventional antibiotics due to the total lack of cell wall. Therefore, there is an urgent need to develop new antimicrobial agents from alternative sources such as medicinal plants to curb the resistance threat.

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Article Synopsis
  • Four new diterpenoids (including two crotofolanes and two halimanes) and one new sesquiterpenoid were discovered from the root of Croton dichogamus, alongside fifteen known compounds.
  • Crotodichogamoin B is noted as a key intermediate in producing crotofolanes and represents the first report of patchoulene sesquiterpenoids in this plant genus.
  • When tested against NCI59 cell lines and Caco-2 cell lines, most compounds showed no significant activity, but 10-epi-Maninsigin D did reduce Caco-2 cell viability by 28% to 48% at certain concentrations.
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  • Seven diterpenes, including three kauranes and four trachylobanes, were extracted from the African plant Psiadia punctulata and tested against Mycobacterium tuberculosis, showing activity similar to cycloserine, a secondary drug for treating TB.
  • The study also analyzed various structural properties of these diterpenes, such as lipophilicity, HOMO and LUMO energies, charge density, and intramolecular hydrogen bond formation using theoretical calculations.
  • Significant correlations were found between the diterpenes' activity and their structural properties, particularly highlighting the relationships between activity, lipophilicity, and intramolecular hydrogen bond formation.
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Kaurenoic acid derivatives were prepared and submitted to in vitro assays with the fungus Colletotrichum lindemuthianum, which causes anthracnose disease in the common bean. The most active substances were found to be methyl and p-bromobenzylesters, 7 and 9, respectively, of the hydrogenated kaurenoic acid, which presented a minimum inhibitory concentration (MIC) of 0.097 and 0.

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Background: Cancer is a major public health concern globally and chemotherapy remains the principal mode of the treatment of various malignant diseases.

Methods: This study was designed to investigate the cytotoxicity of 14 naturally occurring quinones including; 3 anthraquinones, 1 naphthoquinone and 10 benzoquinones against 6 human carcinoma cell lines and normal CRL2120 fibroblasts. The neutral red uptake (NR) assay was used to evaluate the cytotoxicity of the compounds, whilst caspase-Glo assay was used to detect caspases activation.

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The pond-raised channel catfish (Ictaluruspunctatus) industry in the United States of America can incur losses of over a $100 million annually due to bacterial diseases including columnaris disease caused by Flavobacterium columnare. One management approach available to catfish producers is the use of medicated- feed containing antibiotics. However, the negative attributes of antibiotic use in agriculture include public concerns and the potential development of antibiotic-resistant bacteria.

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Ethnopharmocological Relevance: Members of 'Mycoplasma mycoides cluster' are important ruminant pathogens in Africa. Diseases caused by these Mycoplasma negatively affect the agricultural sector especially in developing countries through losses in livestock productivity, mortality and international trade restrictions. There is therefore urgent need to develop antimicrobials from alternative sources such as medicinal plants to curb these diseases.

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In the current study forty eight compounds belonging to anthraquinones, naphthoquinones, benzoquinones, flavonoids (chalcones and polymethoxylated flavones) and diterpenoids (clerodanes and kauranes) were explored for their antimicrobial potential against a panel of sensitive and multi-drug resistant Gram-negative and Gram-positive bacteria. The minimal inhibitory concentration (MIC) determinations on the tested bacteria were conducted using modified rapid INT colorimetric assay. To evaluate the role of efflux pumps in the susceptibility of Gram-negative bacteria to the most active compounds, they were tested in the presence of phenylalanine arginine β-naphthylamide (PAβN) (at 30 µg/mL) against selected multidrug resistance (MDR) bacteria.

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A new β-carboline alkaloid named sacleuximine A (1) together with known compounds palmatine (2), isotetrandrine (3), trans-N-feruloyltyramine (4), trans-N-caffeoyltyramine (5), yangambin (6), syringaresinol (7), sesamin (8), (+) epi-quercitol (9), 4-hydroxybenzaldehyde (10), β-sitosterol (11), quercetin 3-O-rutinoside (12) and myricetin 3-O-β-glucose (1→6) α-rhamnoside (13) have been isolated from methanol extract of Triclisia sacleuxii aerial parts. Compounds 1-10 were evaluated for their cytotoxicity against human adenocarcinoma (HeLa), human hepatocarcinoma (Hep3B) and human breast carcinoma (MCF-7) cells lines and also for antibacterial activities against both Gram-positive and Gram-negative bacteria. The cytotoxicity (IC) values ranged between 0.

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The roots of the endangered medicinal plant Croton megalocarpoides collected in Kenya were investigated and twenty-two compounds isolated. Among them were twelve new ent-clerodane (1-12) and a new abietane (13) diterpenoids, alongside the known crotocorylifuran (4 a), two known abietane and four known ent-trachylobane diterpenoids, and the triterpenoids, lupeol and acetyl aleurotolic acid. The structures of the compounds were determined using NMR, HRMS and ECD.

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Background: Biopiracy mainly focuses on the use of biological resources and/or knowledge of indigenous tribes or communities without allowing them to share the revenues generated out of economic exploitation or other non-monetary incentives associated with the resource/knowledge.

Methods: Based on collaborations of scientists from five continents, we have created a communication platform to discuss not only scientific topics, but also more general issues with social relevance. This platform was termed 'PhytCancer -Phytotherapy to Fight Cancer' (www.

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Ethnopharmacological Relevance: Plants from Kenyan flora are traditionally used against many ailments, including cancer and related diseases. Cancer is characterized as a condition with complex signs and symptoms. Recently there are recommendations that ethnopharmacological usages such as immune and skin disorders, inflammatory, infectious, parasitic and viral diseases should be taken into account when selecting plants that treat cancer.

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Background: Combretum zeyheri, belongs to the family Combretaceae and is one of the most popular herbal plants in tropical and subtropical countries. The leaves of Combretum zeyheri have been used as herbal medicine and have been reported to have pharmacological activity which includes anti-bacterial, anti-fungal, anticancer and antioxidant properties. The goal of this study was to isolate, identify and characterize compounds from C.

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Ethnopharmacological Relevance: Turraea robusta and Turraea nilotica are African medicinal plants used for the treatment of a wide variety of diseases, including malaria. The genus Turraea is rich in limonoids and other triterpenoids known to possess various biological activities.

Materials And Methods: From the stem bark of T.

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The root extract of Thespesia garckeana yielded three known oxidatively coupled sesquiterpenoids, namely (-)-gossypol (1) and two of its derivatives (-)-6-methoxygossypol (2) and (+)-6,6'-dimethoxygossypol (3), and the stem bark afforded (E)-docosyl-3-(3,4-dihydroxyphenyl) acrylate (4), stigmasterol (5) and betulinic acid (6). The structures of the isolated compounds were determined on the basis of full spectral data (1D and 2D NMR and HRMS) and comparison with literature values. Compound 1 showed potent antibacterial activity against vancomycin-resistant Enterococcus faecium (VRE) with IC50/MIC/MBC values of 1.

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