, , OHa bFrom Sargassum ilicifolium dH Assignment depending on comparison with our
, , OHa bFrom Sargassum ilicifolium dH Assignment depending on comparison with our data from Sargassum ilicifolium. Original assignment in parentheses Chemical shift determined in the HSQC spectrumalcohol . Djerassi and coworkers synthesized both C epimers of stigmasta,dienbol and proved that the sample of Ikekawa was a mixture of both isomers . Isolations from living organisms have been reported from the marine sponge Haliclona spfrom the perennial herbaceous plant Saxifraga montana H. and other individuals. In , stigmasta,dienbol was isolated in the PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/22922283 Chinese brown alga Sargassum thunbergii by the group of Guo . The present report describes t
he very first isolation of stigmasta,dienbol in the brown alga S. ilicifolium. In an antimicrobial agar diffusion test, the crude extract of S. ilicifolium was located to be really active against the Gramnegative bacteria Shigella boydii and Klebsiella oxytoca, the Grampositive bacteria Streptococcus pneumoniae and Staphylococcus aureus, along with the yeasts Candida membranaefaciens, Trichosporon mucoides, and Cryptococcus neoformans (Table). Substantial activity was also observed against the Gramnegative bacterium Enterobacter cloacae and the Grampositive bacterium Bacillus cereus. No activity was identified against the Gramnegative bacteria Pseudomonas aeruginosa, Escherichia coli, Salmonella enteridis, and the yeast Candida albicans Sargassum incisifolium The brown alga Sargassum incisifolium was extracted with ethyl acetate. The ethyl acetate extract was adsorbed onsilica gel and subjected to flash chromatography with diethyl ether and then methanol. Purification on the diethyl ether fraction by column chromatography afforded fucosterol . The methanol fraction was subjected to normalphase column chromatography to give two fractions. Fraction afforded a mixture of inseparable monogalactosyldiacylglycerols bearing fatty acid side chains with only couple of olefinic groups based on the intensity of vinylic signals Rebaudioside A within the H NMR spectrum. Fraction was additional purified by reversedphase HPLC making use of THF O (::) as mobile phase to afford OpalmitoylOstearidonoylObDgalactopyranosylglycerol (Fig.) as an amorphous gum. The M NH peak at mz . along with the M NH Na H peak at m z . within the ESImass spectrum of in mixture together with the number and intensity of H and C NMR signals led for the molecular formula CHO. According to ESI mass spectrometry minor amounts of quite a few other monogalactosyldiacylglycerols bearing fatty acids using a lower degree of unsaturation are present within the mixture. This corresponds to findings of Marcolongo et al. who investigated the monogalactosyldiacylglycerol fraction isolated in the thermophilic bluegreen alga Phormidium sp. ETS and identified palmitic acid and stearidonic acid as primary acyl elements during their fatty acid evaluation by GC . The IR spectrum of exhibited absorption bands corresponding to hydroxyl (cm) and carboxylic ester Table Position , , aM. P. Rahelivao et al. C NMR spectroscopic data of From Sargassum ilicifolium dC (MHz, CDCl) (C)Assignment based on comparison with our data from Sargassum ilicifolium. Original assignment in parentheses(cm) groups. The D and D NMR spectra of displayed signals for any carbon chain bearing four methyleneinterrupted double bonds, a saturated carbon chain, a sugar moiety, a glycerol unit, and two carbonyl groups. The sugar residue could be identified as bDgalactose by comparison in the C NMR shifts with those of several sugars listed in Ref. plus the standard prot.
