New Polyhydroxy Sterols, Dysidamides, and a Dideoxyhexose from the Sponge Dysidea herbacea

Abstract

Six novel marine natural products, dysidamides B [3] and C [5], three highly oxygenated sterols 9, 11, and 13, and a 1,4-dideoxyhexose 15 were isolated from the Red Sea sponge Dysidea herbácea, along with the previously known 24-methylene-5ot-cholest-7--3ß,5,6ß-« 1 [7], furodysinin lactone, and -D-xy lopy ranose. Structures of all new compounds were determined from spectroscopic data, especially extensive ID and 2D nmr experiments.Many interesting metabolites have been isolated from Dysidea species (1-7). Recently we have reported the isolation of a chlorinated nitrogenous metabolite, dysidamide [1], from a Dysidea sp. collected near Massawa, Ethiopia (8), a sponge which has now been fully identified as Dysidea herbácea Keller (family Dysideidae, order Dictyoceratida). An unusually diverse array of metabolites has been isolated from various specimens of D. herbácea (1,4). Herewith we wish to report several minor metabolites from the same sponge: two new dysidamides, B [31 and C {5}, four polyoxygenated sterols 7, 9, 11, and 13, and a dideoxyhexose 15, which were isolated with Dxylose and furodysinin lactone (7).The EtOH extract of the sponge was separated into four fractions by chromotography on a Sephadex LH-20 column prepared and eluted with petroleum ether-CH2Cl2-MeOH (2:1:1); the fractions contained (a) glycerides and non-polar sterols, (b) dysidamides, (c) polar sterols, and (d) monosaccharides. The three latter fractions were further purified by repeated chromatography on Sephadex LH-20 and RP-18 columns and also, in some cases, on Si gel after acetylation with Ac2OZpyridine (it was verified that there are no natural acetates of the new compounds). Together with compound 1, which was the major metabolite (2% dry wt of the sponge), we have now isolated small

Antitumor sterols from the mycelia of Cordyceps sinensis

“…The observation of cross-peaks in the HMBC between the signal at 5.20 ppm with the 13 C signals corresponding to C5, C9 and C14 and the cross peaks for the signal at 3.50 ppm with the 13 C signals corresponding to C5, C7, C8 and C10 indicate the epoxide is in the 5,6 position. The down®eld chemical shift of the 3b-hydroxy methine at 3.90 ppm is consistent with the a stereochemistry for the 5, 6-epoxy group (Aiello, Fattorusso, Magno, Mayol & Menna, 1990;Isaacs, Berman & Kashman, 1991;Venkateswarlu, Reddy & Rao, 1996). 5a, 6a-Epoxy sterols similar to compound 2 are unknown.…”

“…5a, 6a-Epoxy sterols similar to compound 2 are unknown. A small number of 5a, 6a-epoxy sterols have been isolated from marine sponges and corals (Aiello et al, 1990;Isaacs, Berman & Kashman, 1991;Venkateswarlu, Reddy & Rao, 1996;Kobayashi & Kanda, 1991) and have been shown to have cytotoxic activities.…”

Two isomeric epoxysitosterols from Rhododendron formosanum: 1H and 13C NMR chemical shift assignments

“…The high-frequency chemical shift of the 3˛-hydroxy methine at υ 3.90 is consistent with its deshielding by˛-stereochemistry of the 5,6-epoxy group. 5,6 Thě -orientation of H-6 was deduced from the its NOESY correlation with H-7ˇat υ 1.88, which in turn showed a NOESY correlation with H-8ˇat υ 1.34. These data showed that the protons mentioned above were on the sameˇface of the ring.…”

Untitled

“…77 Three highly oxygenated sterols (230-232) were isolated from the Red Sea sponge Dysidea herbacea, along with the previously known compound 24-methylene-5α-cholest-7-ene-3β,5,6β-triol (233). 78 In 2001, as part of a search for novel inhibitors of human deficiency virus type 1 (HIV-1) reverse transcriptase (RT), the methanol ethyl acetate extract of a Red Sea sponge, Clathria sp., was shown to be active. Bioassay-guided fractionation of the extract yielded a sterol sulfate, clathsterol (234), which was responsible for the activity and was found to be active at a concentration of 10 mM.…”

“…97 Dysidamides B (288), dysidamide C (289), and a 1,4-dideoxyhexose (290) were isolated from the Red Sea sponge Dysidea herbacea, along with the previously known furodysinin lactone (291), and α-D-xylopyranose (292). 78 Two hexapreynylhydroquinone-derived disulfates, shaagrockol B (293) and C (294) were obtained from the Red Sea sponge Toxiclona toxius. 98 Four hexaprenoid hydroquinone sulfates, toxicols A-C (295-297) and toxiusol A (298) were isolated from the Red Sea sponge Toxiclona toxius.…”