title: Didemnacerides A and B: two new glycerides from Red Sea ascidian Didemnum species.
abstract: Two new glycerides, didemnacerides A (1) and B (2), together with three known sterols, 24-ethyl-25-hydroxycholesterol (3), cholest-6-en-3,5,8-triol (4) and cholestane-3β,5α,6β-26-tetrol (5), were isolated from the Red Sea ascidian Didemnum sp. Their structures were elucidated by using extensive 1D ((1)H, (13)C) and 2D ((1)H-(1)H COSY, HSQC and HMBC) NMR studies and mass spectroscopic data (GC-MS and HR-MS) as well as alkaline hydrolysis followed by GC-MS and NMR spectral analyses of the fatty acid methyl esters. This is the first report of compounds 3-5 from the Red Sea ascidian Didemnum species.
authors.affiliation: a Department of Pharmacognosy and Medicinal Chemistry , Faculty of Pharmacy, Taibah University , Al Madinah Al Munawwarah 41477 , Saudi Arabia.
authors.forename: Sabrin R M
authors.initials: SR
authors.lastname: Ibrahim
authors.forename: Gamal A
authors.initials: GA
authors.lastname: Mohamed
authors.forename: Lamiaa A
authors.initials: LA
authors.lastname: Shaala
authors.forename: Diaa T A
authors.initials: DT
authors.lastname: Youssef
authors.forename: Ali A
authors.initials: AA
authors.lastname: Gab-Alla
mesh_terms: D000818:Animals; D005989:Glycerides / Q000737:chemistry / Q000302:isolation & purification*; D006888:Hydroxycholesterols; D019156:Indian Ocean; D008386:Marine Biology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D013261:Sterols / Q000737:chemistry / Q000302:isolation & purification; D014561:Urochordata / Q000737:chemistry*
chemical_list: D005989:Glycerides; D006888:Hydroxycholesterols; D013261:Sterols; C000594073:didemnaceride A; C000594074:didemnaceride B; C007997:25-hydroxycholesterol
keywords: glycerides; marine ascidian; Didemnum species; sterols