Chinoketides A and B, Two New Antimicrobial Polyketides from the Endophytes of Distylium chinense with the “Black-Box” Co-culture Method

Two new polyketides, chinoketides A and B (1 – 2) with a known compound xylarphthalide A (3), were isolated from the solid medium of the endophytes from the leaves of the relic plant Distylium chinense with the “black-box” co-culture method, and the structures of two new compounds were elucidated by NMR, MS and CD spectra. And the absolute configurations of chinoketides A (1) and B (2) were determined as 2R,3R,8S and 5R,6S by calculating their ECD spectra to compare with the experimental CD spectra. Finally, the antimicrobial activities were evaluated to Erwinia carotovora sub sp. Carotovora (Jones) Bersey et al, and the results showed that compounds 1 – 3 displayed the antimicrobial activities with MIC value at 20.5, 30.4 and 10.2 µg/mL.

Immunomodulatory activity of a lupane triterpenoid ester isolated from the eastern Nigeria mistletoe, Loranthus micranthus (Linn)

OBJECTIVE@#To provide further evidence for the ethnomedicinal use of the Eastern Nigeria mistletoe, Loranthus micranthus (L. micranthus), as an immunostimulant.@*METHODS@#Solvent fractions from the crude extract of the mistletoe plant was obtained and screened by the cell mediated delayed type hypersensitivity reaction (DTHR) model in mice. Then the immunomodulatory potentials of a major lupane triterpenoid ester isolated from an active hexane fraction of the Eastern Nigeria mistletoe was investigated. Three lupeol-based triterpenoid esters: 7β 15α-dihydroxyl-lup-20(29)-ene-3β-palmitate (I), 7β, 15α-dihydroxyl-lup-20(29)-ene-3β-stearate (II) and 7β, 15α-dihydroxyl-lup-20(29)-ene-3β-decadecanoate (III) were isolated from the plant leaves epiphyting on a local kola nut tree and were characterized. Compound 1 was subjected to cell proliferation studies using C57Bl/6 splenocytes at three dose levels (5, 25 and 100 μg/mL) in presence of controls. Furthermore, the effect of this compound on IL-8 receptor expression was evaluated at three doses (1, 5 and 10 μg/mL) using the real time polymerase chain reaction assay.@*RESULTS@#This triterpenoid ester produced some enhancement of the splenocytes at the tested doses but at doses higher than 5 μg/mL caused inhibition of the IL-8 receptor expression.@*CONCLUSIONS@#The present findings support the ethnomedicinal use of the Eastern Nigeria Mistletoe in the management of diseases affecting the immune system. The triterpenoid(s) have some immunomodulatory abilities on splenocytes and IL-8 receptors and may partly account for the overall immunomodulatory activity of this plant.

Two new imidazole alkaloids from leucetta chagosensis sponge

Chemical investigation of the sponge Leucetta chagosensis, has led to the isolation of two new imidazole alkaloids, methyldorimidazole [1], preclathridine B [2] along with the know compounds naamine E [3] and leucettamine C [4]. The structures of the newly compounds [1 and 2] were elucidated by employing spectroscopic techniques [[1] HNMR, MS and UV]. The structures of the known compounds 3 and 4 were determined by comparison of their [1] HNMR and Mass spectroscopic data with published values

Bromopyrrole alkaloids from marine sponge Agelas oroides

Following a bioassay-guided approach four bromopyrrole alkaloids, oroidin [1], 4,5-dibromopyrrole-2-carboxanijde [2], 4,5-dibromopyrrole-2-carboxylic acid [3] and 4,5-dibromopyrrole-2-[N methoxymethyl] carboxamide [4], were isolated from the bioactive ethyl acetate extract of the tropical marine sponge Agelas oroides. The structures of the isolated compounds were elucidated using their UV, NMR [I D and II D] and mass spectra. Fish feeding, brine shrimp, cytotoxic activity against L5178Y and Hela cell lines, protein kinase inhibition test and the antimicrobial activities for the isolated compounds were investigated. The fish-feeding assay showed that the total alcoholic extract was highly active and the major compound, oroidin, is responsible for this activity [in concentration of 80 mg/10 ml]

Imidazole alkaloids from the indopacific sponge Pericharax heteroraphis

Chemical investigation of the sponge Pericharax heteroraphis [Polejeff] collected in Indonesia, has led to the isolation of three imidazole alkaloids, preclathridine-A [1], leucettamine-B [2] and leucettamine-A [3]. The structures of the isolated compounds were unambiguously established by [1]D and [2]D NMR and mass data. This is the first report of this class of compounds from the P. heteroraphis sponge. Investigation of the antimicrobial activities of the isolated compounds showed that leucettamin-A [3] was active against the gram-positive bacteria Staphylococcus aureus and the fungus Cladosporium herbarum, while other compounds were inactive