Biomedical subjects
Publications and source records attributed to Tetsuo Iwagawa.
Four novel biscembranes have been isolated from the soft coral Sarcophyton glaucum, collected at Amami Oshima, two of which showed weak activity against proliferation of human promyelocytic leukemia cells (HL-60). Their absolute structures were determined on the basis of the CD spectra.
Further investigations of the secondary metabolites of a gorgonian Briareum sp., collected at Amami Oshima, Kagoshima Prefecture, have yielded 10 new briarane diterpenes, briarlides I-R (1-10). The structures were elucidated on the basis of spectral analysis.
Investigation of the fruits of Khaya senegalensis resulted in the isolation of three new mexicanolide limonoids containing a rare conjugated diene lactone system named seneganolide A (1), 2-hydroxyseneganolide A (2) and 2-acetoxyseneganolide A (3). Two known limonoids, 3-deacetyl-7-deacetoxy-7-oxokhivorin (4) and methyl 6-hydroxyangolensate (5), were also found. The structures of the new compounds were elucidated on the basis of spectral methods. The antifungal activity of compounds 1, 3 and 5 was tested against the fungus Botrytis cinerea.
Six phragmalin limonoids, named tabulalin and tabulalides A-E, were isolated from the root bark of Chukrasia tabularis (Meliaceae). Their structures were determined by spectroscopic methods, and their antifeedant properties evaluated.
New briarane diterpenes, briarlides A-H (1-8), have been isolated from a gorgonian Briareum sp., collected at Amami Oshima, Kagoshima Prefecture. Their structures and cytotoxity toward Vero and MDCK cells are described.
Three new rings B/D opened limonoids, two rearranged phragmalin limonoids named khayanolides D and E (1 and 2), and one limonoid glucoside named khayanoside (3) were isolated as insect antifeedants from the stem bark of Egyptian Khaya senegalensis. The structures of these compounds were established by spectroscopic methods, including 2D NMR and CD.
Two new degraded limonoids, azedararide and 12alpha-acetoxy fraxinellone, were isolated together with two known degraded limonoids, fraxinellone and fraxinellonone, as ichthyotoxic substances from the root bark of Melia azedarach. Their structures were elucidated by spectroscopic and chemical means.