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Mycotoxin contamination of wheat kernels and diversity of fungal pathogens were monitored in a survey of 26 fields in Nakuru district, Kenya, in 2006. Sampling was performed twice; at mid-anthesis in July for leaves, stems and spikelets and at harvest in September for spikelets and kernels. Kernels were analysed for the occurrence of 32 mycotoxins using a high performance liquid chromatography – electrospray tandem mass spectrometry (LC-ESI-MS/MS) method. Fungi were isolated from surface-sterilized tissues and differentiated morphologically to the genus level. Fusarium isolates were identified based on the sequence of translation elongation factor 1-alpha gene. Eleven Fusarium-related mycotoxins were quantified with deoxynivalenol being detected at highest frequency (69%) and highest concentrations. Occurrence of enniatins in wheat (50%) is reported for the first time in Kenya. Non- Fusarium mycotoxins detected included aflatoxin G2, ochratoxin A, alternariol and alternariol monomethyl ether. Prevalence of Fusarium species on different wheat parts was 100% at both growth stages. Nineteen Fusarium species were identified with seven species – Fusarium chlamydosporum, Fusarium boothi, Fusarium poae, Fusarium scirpi, Fusarium arthrosporioides, Fusarium oxysporum and Fusarium graminearum– accounting for 80% of infections. At anthesis, spikelets and leaves were the most and least susceptible tissue, respectively. At harvest, infection of spikelets was 59% higher than that of kernels. [ABSTRACT FROM AUTHOR]

Two new norhopane derivatives namely 3β,6β,22-trihydroxy-7β,11α-di[(4-hydroxybenzoyl)oxy]-21αH-24-norhopa-4(23)-ene (1) and 3β,6β,22-trihydroxy-7β-[(4-hydroxybenzoyl)oxy]-21αH-24-norhopa-4(23)-ene (2) together with two previously reported compounds, including a norhopane, 3β,6β,11α-trihydroxy-7β-[(4-hydroxybenzoyl)oxy]-24-norhopa-4(23),17(21)-diene (3) and a norneohopane, (21αH)-24-norneohopa-4(23), 22(29)-diene-3β,6β,7β-triol 7-caffeate (4) were isolated from the root bark of Fagaropsis angolensis. Elucidation of their structures was achieved by spectroscopic (NMR, IR and UV) and spectrometric (HRESIMS) data and by comparison of these data with those of related compounds in the literature. Compounds 1–4 were evaluated for their anti-inflammatory activity by measuring the levels of cytokines, IL-1β, IL-2, GM-CSF and TNF-α in lipopolysaccharide (LPS) stimulated peripheral blood mononuclear cells (PBMC). All tested compounds decreased secretion of IL-1β and TNF-α. Compounds 2 and 4 caused significant decrease of the production of IL-2, GM-CSF and TNF-α compared to the reference drug, ibuprofen. These findings showed that the root barks of F. angolensis are rich source of norhopane derivatives and further provide a scientific rationale of using this plant in Kenyan folk medicine to relieve pain. Unlabelled Image [ABSTRACT FROM AUTHOR]

From the leaves of Kenyan medicinal plant Bersama abyssinica Subspecies abyssinica, four previously undescribed compounds namely, three bufadienolides, 10β-formylpaulliniogenin B, 10β-formylpaulliniogenin A and 1β-acetoxy-3β,5β-dihydroxy-15-methoxy-16,19-dioxobufa-14(15),20,22-trienolide, and a phenolic compound 2,6,4'-trihydroxybenzophenone-4-O-(6‴-cinnamoyl)-β-D-glucoside were isolated together with four known compounds. The structural elucidation of the compounds was based on 1D and 2D NMR spectroscopy and HRMS data analyses. The relative configurations were defined by NOESY correlations. Cytotoxic activities on L929 and KB3.1 cell lines of the isolated compounds were investigated using MTT assay. The 1β-acetoxy-3β,5β-dihydroxy-15-methoxy-16,19-dioxobufa-14(15),20,22-trienolide showed significant cytotoxic activity against KB3.1 cell lines with IC 50 of 3.9 ± 0.99 μM., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Three new bufadienolides, namely, paulliniogenin A ( 1 ), paulliniogenin B ( 2 ), and 16β-formyloxybersamagenin 1,3,5-orthoacetate ( 3 ), together with two known bufadienolides and six known phenolic substances, were isolated from the stem bark of Bersama abyssinica subsp. abyssinica and B. abyssinica subsp. paullinioides . The structures of the compounds were elucidated based on their NMR and HRMS data analyses. The relative configurations were defined by single-crystal X-ray crystallography and NOESY correlations. Cytotoxicity against the L929 and KB3.1 cancer cell lines of the isolated compounds was investigated using an MTT assay. Paulliniogenin A ( 1 ) and 16β-hydroxybersamagenin-1,3,5-orthoacetate ( 4 ) showed cytotoxicity against the KB3.1 cell line with IC 50 values of 1.4 ± 0.77 and 1.6 ± 0.81 μM, respectively. Moreover, paulliniogenin A ( 1 ) and paulliniogenin B ( 2 ) demonstrated weak activity against Staphylococcus aureus .

Four new steroidal sapogenins, dracaenogenins CF (1-4), a new conjugated chalcone-stilbene, 3''-methoxycochinchinenene H (5) together with eight known compounds namely, (25S)-spirosta-1,4-dien-3-one (6), trans-resveratrol (7), 4,4'-dihydroxy-3'-methoxychalcone (8), N-trans-coumaroyltyramine (9), N-trans-p-coumaroyloctopamine (10), N-trans-feruloyloctopamine (11), 7-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-N 2 ,N 3 -bis(4-hydroxyphenethyl)-6-methoxy-1,2-dihydronaphthalene-2,3-dicarboxamide (12) and grossamide (13) were isolated from the stems of Dracaena usambarensis Engl. from Kenya. It is important to note that compounds 12 and 13 are being reported from this genus for the first time. Structural elucidation of the isolated compounds was done using spectroscopic (NMR, UV, IR, optical rotation) and spectrometric (HRESIMS) techniques. The absolute and relative configurations of the isolated compounds were determined by employing single crystal X-ray crystallography analysis, NOESY correlations and coupling constants. The anti-inflammatory potencies of the isolated compounds were evaluated by measuring the levels of four cytokines (IL-1β, IL-2, GM-CSF and TNF-α) in the supernatant media of human peripheral blood mononuclear cells (PBMCs) stimulated by lipopolysaccharide (LPS). At the tested concentration of 100 μM, the new conjugated chalcone-stilbene 5, the dihydrochalcone, 8 and the lignanamide, 13 were substantially more potent than the standard drug, ibuprofen, inhibiting the release of all the cytokines, IL-1β, IL-2, GM-CSF and TNF-α from 0.06-58.04% compared to LPS control. These compounds should therefore be considered for development into anti-inflammatory drug candidates. Compound 7 significantly decreased the release of GM-CSF (6.11% of LPS control) and TNF-α (18.35% of LPS control). The cytokine TNF-α was sensitive to all the tested compounds 1-13., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Phytochemical investigation of Tephrosia vogelii seedpods led to the isolation of twelve compounds: vogelisoflavone A (1), vogelisoflavone B (2), isopongaflavone (3), onogenin, luteolin, 4',7-dihydroxy-3'-methoxyflavanone, trans-p-hydroxycinnamic acid, tephrosin, 2-methoxygliricidol, dehydrorotenone, 6a,12a-dehydro-α-toxicarol and pinoresinol. Compounds 1 and 2 are reported as new natural products. Isopongaflavone (3) was structurally modified using hydrazine to pyrazoisopongaflavone (4). These compounds were characterized based on their NMR and HRESIMS data. Further, four compounds (1-4) were evaluated for their anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells (PBMCs). Treatment of the LPS-stimulated PBMCs with the compounds at a concentration of 100 μM suppressed the secretion of interleukin IL-1β interferon-gamma (IFN-γ), granulocyte macrophage-colony stimulating factor (GM-CSF) and tumour necrosis factor-alpha (TNF-α)., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article., (Copyright © 2020 Elsevier B.V. All rights reserved.)