Search

Extensive chemical investigation of the endophytic fungus, Fusarium solani JK10, harbored in the root of the Ghanaian medicinal plant Chlorophora regia, using the OSMAC (One Strain Many Compounds) approach resulted in the isolation of seven new 7-desmethyl fusarin C derivatives (1-7), together with five known compounds (8-12). The structures of the new compounds were elucidated by analysis of their spectroscopic data including 1D, 2D NMR, HRESI-MS n and IR data. The relative configuration of compounds 1/2 was deduced by comparison of their experimental electronic circular dichroism (ECD) and optical rotation data with those reported in literature. The absolute configuration of solaniol (10), a known compound with undefined absolute stereochemistry, was established for the first time by X-ray diffraction analysis of a single-crystal structure using Cu-Kα radiation. The antibacterial activities of the crude fungal extract and the compounds isolated from the fungus were evaluated against some clinically important bacterial strains such as Staphylococcus aureus and Bacillus subtilis, as well as an environmental strain of Escherichia coli and the soil bacterium Acinetobacter sp. BD4. Compounds 3/4 and 6 exhibited antibacterial efficacies against the soil bacterium Acinetobacter sp., comparable to the reference standard streptomycin. All the tested compounds (1-9) demonstrated antibacterial activity against the environmental strain of E. coli, whereas no antibacterial activity was observed against S. aureus and B. subtilis. The antibacterial activity of the isolated compounds typically against E. coli and Acinetobacter sp. provides further insight into the possible involvement of root-borne endophytes in chemical defense of their host plants in selected ecological niches., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Extracts of Chlorophora regia are frequently used in Ghana in traditional medicine. There is, however, no reported data on the chemical composition of the plant. Comprehensive phytochemical investigation of the stem bark of C. regia resulted in the isolation of three new prenylated 2-arylbenzofuran derivatives, regiafuran A-C (1-3), and one new prenylated flavonol (4), together with fifteen known compounds (5-19). Their structures were elucidated by combined spectroscopic analysis of their NMR and HRESI-MS(n) data. Compounds 1, 2, 5, 9 and 15 exhibited remarkable free radical scavenging properties with IC50 values of 1.9 μg/ml, 2.4 μg/ml, 2.2 μg/ml, 2.1 μg/ml and 1.8 μg/ml, respectively, compared to the standard trolox (IC50 1.1 μg/ml). The isolated compounds did not, however, show any anti-inflammatory potential when tested using a PGE2 (prostaglandin E2) competitive enzyme immunoassay., (Copyright © 2015 Elsevier B.V. All rights reserved.)