Biologically active glycosides from asteroidea, XXIV. Stereochemistry of the four diastereomers of phytosphingosine

New Ceramides and Cerebrosides from the Deep-Sea Far Eastern Starfish Ceramaster patagonicus

Three new ceramides (1−3) and three new cerebrosides (4, 8, and 9), along with three previously known cerebrosides (ophidiocerebrosides C (5), D (6), and CE-3-2 (7)), were isolated from a deep-sea starfish species, the orange cookie starfish Ceramaster patagonicus. The structures of 1−4, 8, and 9 were determined by the NMR and ESIMS techniques and also through chemical transformations. Ceramides 1−3 contain iso-C21 or C23 Δ9-phytosphingosine as a long-chain base and have C16 or C17 (2R)-2-hydroxy-fatty acids of the normal type. Cerebroside 4 contains C22 Δ9-sphingosine anteiso-type as a long-chain base and (2R)-2-hydroxyheptadecanoic acid of the normal type, while compounds 8 and 9 contain saturated C-17 phytosphingosine anteiso-type as a long-chain base and differ from each other in the length of the polymethylene chain of (2R)-2-hydroxy-fatty acids of the normal type: C23 in 8 and C24 in 9. All the new cerebrosides (4, 8, and 9) have β-D-glucopyranose as a monosaccharide residue. The composition of neutral sphingolipids from C. patagonicus was described for the first time. The investigated compounds 1−3, 5−7, and 9 exhibit slight to moderate cytotoxic activity against human cancer cells (HT-29, SK-MEL-28, and MDA-MB-231) and normal embryonic kidney cells HEK293. Compounds 2, 5, and 6 at a concentration of 20 µM inhibit colony formation of MDA-MB-231 cells by 68%, 54%, and 68%, respectively. The colony-inhibiting activity of compounds 2, 5, and 6 is comparable to the effect of doxorubicin, which reduces the number of colonies by 70% at the same concentration.

Terminaliamide, a new ceramide and other phytoconstituents from the roots of Terminalia mantaly H. Perrier and their biological activities

Terminaliamide (1), a new ceramide was isolated from the roots of Terminalia mantaly H. Perrier (Combretaceae) along with 4 known compounds (2-5). The structures of the compounds were elucidated using 1D and 2D NMR spectroscopy analysis and mass spectrometry. Compound 1 exhibited moderated antibacterial activity towards Staphylococcus aureus with MIC value of 62.5 μg/mL. The crude MeOH extract (TMr) highly reduced Plasmodium falciparum growth with an IC₅₀ value of 10.11 μg/mL, while hexane fraction (F1) highly reduced Trypanosoma brucei brucei growth with an IC₅₀ value of 5.60 µg/mL. All tested samples presented little or no in vitro cytotoxicity on HeLa cell line. The present work confirms that T. mantaly is medicinally important and may be used effectively as an antimicrobial, an antiplasmodial and an antitrypanosomial with promising therapeutic index.

Synthetic analogues of marine cytotoxic jaspine B and its stereoisomers

Synthetic analogues of the cytotoxic jaspine B and its stereochemical congeners have become an attractive target in the synthetic organic community owing to the search for novel therapeutic candidates with more potent anticancer activity, as cancer is the second leading cause of death worldwide. This review article provides insights into the different approaches and strategies available in the literature for the construction of jaspine B-related compounds.

A Novel Ceramide from the Indian Marine Sponge Fasciospongia Cavernosa

A new ceramide 1, has been isolated along with a known compound 3,6-diacetoxy-cholest-7-en-3β,5α,6β-triol (2) from a marine sponge Fasciospongia cavernosa collected off the Mandapam coast in the Gulf of Manner, India. The structures of 1 and 2 were determined by spectroscopic analysis.

Phytoceramides and acylated phytosterol glucosides from Pterospermum acerifolium Willd. seed coat and their osteogenic activity

Phytochemical investigation of seed coats of Pterospermum acerifolium afforded two phytoceramides (1, 2) and two acylated phytosterol glucosides (3, 4) together with five known compounds (5-9). Their structures were elucidated on the basis of extensive spectroscopic analysis using 1D, 2D NMR and Mass spectrometry. Compounds 1, 2, 3, and 4 were assessed for their osteogenic activity using primary cultures of osteoblasts harvested from neonatal rat calvaria. Among these compounds, 1 and 2 markedly stimulated osteoblast differentiation assessed by alkaline phosphatase production and osteoblast mineralization by alizarin red-S staining.

Four new long-chain aliphatics from the feces of Trogopterus xanthipes

Chemical investigation of Trogopterus feces has led to the isolation of four new long-chain aliphatics, including two new fatty alcohols, 8,15-nonacosanediol (1) and 6,13-nonacosanediol (2), one new fatty acid ester, dihexyl 7,7'-oxydiheptanoate (3), and one new ceramide, (2R)-2-hydroxy-N-[(2S,3S,4R,11E)-1,3,4-trihydroxydocos-11-en-2-yl]heneicosanamide (4). Their structures were elucidated by means of chemical and extensive spectroscopic analysis. Compound 3 exhibited moderate activity of antithrombin in vitro.

Two new compounds from transgenic Panax quinquefolium

A new ceramide and a new poly-hydroxyl octadecenoic acid were isolated from transgenic crown galls of Panax quinquefolium. Their structures were elucidated as (2S, 3S, 4R, 20E)-2-[(2'R)-2'-hydroxyl-palmitoyl-amino]-20-hexacosene-1, 3, 4-triol (1) and 12, 13, 15-trihydroxy-9-octadecenoic acid (2) respectively on the basis of spectroscopic and chemical methods.

Three new lipids from the seeds of Trogopterus xanthipes

Chemical investigation of Feces Trogopterus ( Trogopterus xanthipes) has led to the isolation of three new lipids, including two new cerebrosides, 1- O-β-D-glucopyranosyloxy)-(2 S,3 S,4 R,6 E)-2-[(2′ R)-2′-hydroxyheptadecanoylamino]-8-heptadecene-3,4-diol (1) and 1- O-β-D- glucopyranosyloxy)-(2 S,3 S,4 R,6 E)-2-[(2′ R)-2′-hydroxy-heptadecanoylamino]-8-nonadecene-3,4-diol (2), and one new fatty acid ester, bis(2,3-dihydoxypropyl)-tetracosanedioate (3). Their structures were elucidated by chemical and spectral means. This is the first report on the occurrence of cerebroside and fatty diacid diester in Feces Trogopterus.

Synthesis and biological properties of Pachastrissamine (jaspine B) and diastereoisomeric jaspines

The synthesis of isomeric jaspines (anhydro phytosphingosines), arising from intramolecular cyclization of the corresponding phytosphingosines with different configurations at C3 and C4 positions of the sphingoid backbone, is reported. Natural jaspine B is the most cytotoxic isomer on A549 cells and it induces cell death in a dose-dependent manner. The cytotoxicity of jaspine B has been correlated with a significant increase of intracellular dihydroceramides, which seem to play an active role in autophagy.

Two New Protease-Inhibiting Glycosphingolipids fromBuddleja crispa

Crispins A (1) and B (2), two new glycosphingolipids, were isolated from the whole plant Buddleja crispa, along with three known compounds: alpha-amyrin, linoleic acid, and stigmasterol. Their structures were elucidated by chemical and spectroscopic techniques. Both 1 and 2 showed significant inhibitory activity against alpha-chymotrypsin in a concentration-dependent manner.

A general, efficient and stereospecific route to sphingosine, sphinganines, phytosphingosines and their analogs

Sphingosine, sphinganines and phytosphingosines and their analogs were synthesized by an aldol condensation between an iminoglycinate bearing a (+)-(1R,2R,5R)-2-hydroxy-3-pinanone group as chiral auxiliary and an appropriate aldehyde. All condensations proceeded with excellent enantioselectivity to generate the (2S,3R)-D-erythro structures in good yields.

Isolation and structure determination of six glucocerebrosides from the starfish Luidia maculata

Two new glucocerebrosides, luidiacerebroside A (2) and B (6), were isolated from the cerebroside molecular species obtained from the less polar fraction of the CHCl3/MeOH extract of the starfish Luidia maculata using HPLC. Four known cerebrosides, CE-2b (1), astrocerebroside B (3), acanthacerebroside B (4), and CE-3-2 (5) have also been isolated and characterized. The structures of these cerebrosides were determined on the basis of chemical and spectroscopic evidence. Mass spectrometry of dimethyl disulfide derivatives was useful for the determination of the double-bond position in the long-chain base.

Synthesis of (+/-)-leucomalure [(3Z,6R*,7S*,9R*,10S*)-cis-6,7-cis-9,10-diepoxy-3-henicosene], the major components of the female sex pheromone of the satin moth

The racemate of leucomalure [(3Z,6R*,7S*,9R*,10S*)-cis-6,7-cis-9,10-diepoxy-3-henicosene (1)] and its (3Z,6R*,7S*,9S*,10R*)-isomer were synthesized via acetylenic intermediates in an unambiguous manner.

Cyclooxygenase-2 inhibitory cerebrosides from phytolaccae radix

A mixture of cerebrosides, called poke-weed cerebrosides, was purified from Phytolaccae Radix (Phytolaccaceae) and characterized as 1-O-beta-D-glucopyranosides of phytosphingosine type ceramides comprised of a common long chain base (2S,3S,4R,8Z)-2-amino-8-octadecene-1,3,4-triol and fatty acids. The fatty acyl chain of ceramide moieties was determined as (2R)-2-hydroxypentacosanoic acid, (2R)-2-hydroxylignoceric acid, (2R)-2-hydroxytricosanoic acid, (2R)-2-hydroxybehenic acid, (2R)-2-hydroxypalmitic acid, and palmitic acid. The pokeweed cerebroside inhibited the cyclooxygenase-2 dependent phase of prostaglandin D2 generation in bone marrow-derived mast cells in a concentration dependent manner with an IC50 of 6.2 microg/ml.

Chemical constituents of Typhonium giganteum Engl

A new cerebroside, named typhonoside (1), was isolated from the root tuber of Typhonium giganteum Engl. along with three known compounds dipalmitin (2), alpha-monopalmitin (3) and 2,6-diamino-9-beta-D-ribofuranosylpurine (4). The structure of 1 was determined to be 1-O-beta-D-glucopyranosyl-(2S,3S,4R,8Z)-2-[(2'-hydroxyl-docosanoyl)amino]-8-otadecene-1,3,4-triol on the basis of spectral data.

Selective Inversion of the Proximal or Distal Hydroxyl Groups in syn,syn-3-[N-(Alkoxycarbonyl)amino] 1,2-Diols via Cyclic Sulfates

The formation of cyclic sulfates (4) from syn,syn-3-[N-(benzyloxycarbonyl)amino] 1,2-diols provides a common intermediate to access other diastereomers via two inversion procedures. Thermolysis of the cyclic sulfates in acetonitrile normally leads to inversion of the distal hydroxyl group to form a 1,3-oxazin-2-one (6). Catalytic hydrogenation of the cyclic sulfates under basic conditions (NEt(3)) results in inversion at the proximal hydroxyl group to form a 1,3-oxazolidin-2-one (5).