Novel synthesis of cholesterol analogs: condensation of pregnenolone with dihydropyran or dihydrofuran.

Pregnenolone 3-(2'-tetrahydropyranyl) ether (1) was condensed with 3,4-[2H]dihydropyran to mainly give (20R)-[6'-(3',4'-[2'H]dihydropyranyl)]-pregn-5-ene-3 beta,20-diol 3-(2'-tetrahydropyranyl) ether (20R-3), according to nuclear magnetic resonance (NMR). Cold, dilute HCl in ethanol removed the tetrahydropyranyl group at C-3 and also opened the dihydropyranyl ring at the C-20 position of 20R-3 to give (20R)-27-norcholest-5-en-22-one-3 beta,20,26-triol (20R-5). Analogous results were obtained by condensing pregnenolone 3-acetate with 3,4-[2H]dihydropyran to provide (20R)-[6'-(3',4'-[2'H]dihydropyranyl)]-pregn-5-ene-3 beta,20-diol 3-acetate (20R-4). Acid-catalyzed opening of the dihydropyranyl ring at C-20 in 20R-4 yielded 20R-7, which, on acetylation followed by crystallization, provided (20R)-27-norcholest-5-en-22-one-3 beta,20,26-triol 3,26-diacetate (20R-8), identical to the diacetate made from 20R-5. Varying the reaction sequence beginning with 20(R,S)-4 gave an 84:16 ratio of 20R to 20S in a mixture of 20(R,S)-8, according to NMR analysis. Crystallization of the mixture from methanol provided pure 20R-8. Condensing 2,3-dihydrofuran and 1 for producing (20R)-[5'-(2',3'-dihydrofuranyl)]-pregn-5-ene-3 beta,20-diol 3-(2'-tetrahydropyranyl) ether (6) gave instead (20R)-26,27-bisnorcholest-5-en-22-one-3 beta,20,25-triol 3-(2'-tetrahydropyranyl) ether (20R-9) by partial hydrolysis during workup. Treating 20R-9 briefly with dilute HCl produced (20R)-26,27-bisnorcholest-5-en-22-one-3 beta,20,25-triol (20R-10).(ABSTRACT TRUNCATED AT 250 WORDS)     

New polyoxygenated steroids from the Antarctic octocoral Dasystenella acanthina

The chemical study of the Antarctic octocoral Dasystenella acanthina has led to the isolation of the new polyoxygenated steroids (24R,22E)-24-hydroxycholest-4,22-dien-3-one (1), 23-acetoxy-24,25-epoxycholest-4-en-3-one (2), 12beta-acetoxycholest-4-en-3,24-dione (3), 12beta-acetoxy-24,25-epoxycholest-4-en-3-one (4), (22E)-25-hydroxy-24-norcholest-4,22-dien-3-one (5), 3alpha-acetoxy-25-hydroxycholest-4-en-6-one (6), and 3alpha,11alpha-diacetoxy-25-hydroxycholest-4-en-6-one (7), whose structures have been established by spectroscopic analysis. The absolute stereochemistry at C-24 in compound 1 has been determined through the 1H NMR study of the corresponding (R)- and (S)-MPA esters. All the new compounds showed significant activities as growth inhibitors of several human tumor cell lines. In addition, cytostatic and cytotoxic effects were also observed on selected tumor cell lines.     

1,5-Hydride shift in Wolff-Kishner reduction of (20R)-3beta,20, 26-trihydroxy-27-norcholest-5-en-22-one: synthetic, quantum chemical, and NMR studies.

Heating (20R)-3beta,20,26-trihydroxy-27-norcholest-5-en-22-one (1) with hydrazine and KOH at 160 degrees C completely converted the steroid to a diastereoisomeric mixture of the new (20R,22RS)-27-norcholest-5-ene-3beta,20,22-triols (2). Exclusive formation of 2 suggests that the expected Wolff-Kishner reduction to a methylene group at the C-22 ketone in 1 was diverted to the C-26 position by a 1,5-hydride shift. All attempts under acid conditions failed to produce a C-22 phenyl hydrazone from 1. However, reaction of 1 was reacted with phenylhydrazine in hot KOH, gave the C-26 phenylhydrazone 4 as the sole product. Evidently, under alkaline conditions, first a hydride ion undergoes an intramolecular transfer from the C-26 CH(2)OH group to the C-22 ketone in 1, and then the phenylhydrazine traps the newly formed aldehyde. To examine this hypothesis, we constructed computer-simulated transition state models from quantum chemical calculations and then compared data from these models with NMR measurements of the reaction mixtures containing 2. The NMR data showed that the C-22 diastereoisomers of 2 are formed in a nearly 1:1 ratio exactly as predicted from the energy-optimized transition states, which were calculated for intramolecular 1,5-hydride shifts that produced each of the two C-22 diastereoisomers. Accordingly, these results support the hypothesis that an intramolecular 1,5-hydride shift mechanism promotes complete conversion of 1 to 2 under classical Wolff-Kishner reduction conditions.     

Chemical constituents of leaves and stem bark of Plumeria obtusa

The continued studies on the constituents of the fresh leaves and stem bark of Plumeria obtusa Linn. have led to the isolation and characterization of four new triterpenoids, dammara-12,20(22)Z-dien-3-one (1), dammara-12,20(22)Z-dien-3beta-ol (2), olean-12-en-3beta,27-diol (3), and 27-hydroxyolean-12-en-3-one (4) and 12 known compounds, which included eight triterpenoids; dammara-3beta,20(S),25-triol (5), urs-12-en-3beta-hydroxy-27-Z-feruloyloxy-28-oic acid (6), 3beta-hydroxyolean-12-en-28-oic acid (7), 3beta,27-dihydroxylupan-29-ene (8), 3beta-hydroxylupan-29-en-28-oic acid (9), 3beta-hydroxyursan-12-en-28-oic acid (11), 3beta-hydroxy-27-p-coumaroyloxy-olea-12-en-28-oic acid (12) and urs-12-en-3-one (15); an iridoid 1alpha-plumieride (10); a cardenolide 3alpha,14beta-dihydroxy-17beta-card-20(22)-enolide (13); a fatty acid ester methyl n-octadecanoate (14) and a steroid 3beta-hydroxy-delta5-stigmastane (16). The new constituents were characterized through spectroscopic studies including 1D (1H and 31C NMR) and 2D (COSY-45, NOESY, J-resolved, HMQC and HMBC) NMR and chemical transformations. This is the first report on the isolation of dammarane triterpenoids from P. obtusa. Compounds 5 and 6 are hitherto unreported from P. obtusa. The known compounds were identified by comparison of their spectral data with those reported in the literature.     

Steroidal glycosides from the rhizomes of Ruscus hypophyllum

Seven steroidal glycosides, along with one known glycoside, were isolated from the rhizomes of Ruscus hypophyllum (Liliaceae). Comprehensive spectroscopic analysis, including 2D NMR spectroscopy, and the results of acid hydrolysis allowed the chemical structures of the compounds to be assigned as (23S,25R)-23-hydroxyspirost-5-en-3beta-yl O-alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranoside (1), 1beta-hydroxyspirosta-5,25(27)-dien-3beta-yl O-alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranoside (2), (22S)-16beta,22-dihydroxycholest-5-en-3beta-yl O-alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranoside (3), (22S)-16beta-[(beta-d-glucopyranosyl)oxy]-22-hydroxycholest-5-en-3beta-yl O-alpha-l-rhamnopyranosyl-(1-->4)-beta-d-glucopyranoside (4), (22S)-16beta-[(beta-d-glucopyranosyl)oxy]-22-hydroxycholest-5-en-3beta-yl beta-d-glucopyranoside (5), (22S)-16beta-[(beta-d-glucopyranosyl)oxy]-3beta,22-dihydroxycholest-5-en-1beta-yl O-alpha-l-rhamnopyranosyl-(1-->2)-(3,4-di-O-acetyl-beta-d-xylopyranoside) (6), and (22S)-16beta-[(beta-d-glucopyranosyl)oxy]-3beta,22-dihydroxycholest-5-en-1beta-yl O-alpha-l-rhamnopyranosyl-(1-->2)-O-[beta-d-xylopyranosyl-(1-->3)]-beta-d-xylopyranoside (7), respectively. This is the first isolation of a series of cholestane glycosides from a Ruscus species.     

Fluoro norcholesterol analogues. Synthesis of 6β-(2'-fluoro)ethyl-19-norcholest-5(10)-EN-3β-OL

A synthetic route for labelling 6β-(2'-fluoro)ethyl-19-norcholest-5(10)-en-3β-ol (VII) with fluorine-18 was developed to evaluate the potential utility of VII as an adrenal imaging agent. 6β-p-Toluenesulphpnyloxymethyl-19-norcholest-5(10)-en-3β-ol acetate (I) was converted to the 6β-(2'-hydroxy)ethyl (VI) in a five-step process. The treatment of VI with N,N-diethyl(2-chloro-1,1,2-trifluoroethyl)amine in methylene chloride and subsequent hydrolysis with base gave the required VII. Iodination of VI with triphenoxymethylphosphonium iodide followed by alkaline hydrolysis gave the 6β-(2'-iodo)ethyl (IX) which, on treatment with silver fluoride in acetonitrile, furnished the 6β-(2'-fluoro)ethyl (VII). Excellent conversion of the 6β-(2'-p-toluenesulphonyloxy)ethyl (X) into VII was also achieved by heating with potassium fluoride for 2 hr in diethylene glycol in 76% yield, which is a readily applicable method for labelling with fluorine-18.     

Two new steryl esters from the basidiomycete Tricholomopsis rutilans

Two new steryl esters with a polyhydroxylated ergostane-type nucleus, 3beta,5alpha-dihydroxy-(22E,24R)-ergosta-7,22-dien-6beta-yl oleate (1) and 3beta,5alpha-dihydroxy-(22E,24R)-ergosta-22-en-7-one-6beta-yl oleate (2), were isolated from the fruiting bodies of the basidiomycete Tricholomopsis rutilans along with three known sterols (3, 4, and 5). The structures of compounds 1 and 2 were established on the basis of spectroscopic means and chemical methods.     

Synthesis of (+)-(2R,3S,4R)-2,3,4-trihydroxycyclohexanone from D-glucose

We have described the synthesis of (+)-(2R,3S,4R)-2,3,4-trihydroxycyclohexanone by the reduction of a keto-conduritol derivative, the latter being prepared in five steps from (-)-(2S,3R,4S,5S)-2,3,4-tribenzyloxy-5-hydroxycyclohexanone, which is in turn readily synthesized from D-glucose.     

Synthesis of deuterated isotopomers of 7alpha- and (25R,S)-26-hydroxycholesterol, internal standards for in vivo determination of the two biosynthetic pathways of bile acids

Deuterated isotopomers of 7alpha- and (25R,S)-26-hydroxycholesterol, internal standards for in vivo determination of the two biosynthetic pathways of bile acids formation from cholesterol, were prepared from [2,2,3,4,4,6-2H(6)]-cholesterol and (20S)-[7,7,21,21-2H(4)]-3beta-(tert-butyldimethylsilyl)oxy-20-methylpregna-5-en-21-ol, respectively.     

C-25 hydroxylation of 1alpha,24(R)-dihydroxyvitamin D3 is catalyzed by 25-hydroxyvitamin D3-24-hydroxylase (CYP24A1): metabolism studies with human keratinocytes and rat recombinant CYP24A1

Recently, 25-hydroxyvitamin D3-24-hydroxylase (CYP24A1) has been shown to catalyze not only hydroxylation at C-24 but also hydroxylations at C-23 and C-26 of the secosteroid hormone 1alpha, 25-dihydroxyvitamin D3 (1alpha,25(OH)2D3). It remains to be determined whether CYP24A1 has the ability to hydroxylate vitamin D3 compounds at C-25. 1alpha,24(R)-dihydroxyvitamin D3 (1alpha,24(R)(OH)2D3) is a non-25-hydroxylated synthetic vitamin D3 analog that is presently being used as an antipsoriatic drug. In the present study, we investigated the metabolism of 1alpha,24(R)(OH)2D3 in human keratinocytes in order to examine the ability of CYP24A1 to hydroxylate 1alpha,24(R)(OH)2D3 at C-25. The results indicated that keratinocytes metabolize 1alpha,24(R)(OH)2D3 into several previously known both 25-hydroxylated and non-25-hydroxylated metabolites along with two new metabolites, namely 1alpha,23,24(OH)3D3 and 1alpha,24(OH)2-23-oxo-D3. Production of the metabolites including the 25-hydroxylated ones was detectable only when CYP24A1 activity was induced in keratinocytes 1alpha,25(OH)2D3. This finding provided indirect evidence to indicate that CYP24A1 catalyzes C-25 hydroxylation of 1alpha,24(R)(OH)2D3. The final proof for this finding was obtained through our metabolism studies using highly purified recombinant rat CYP24A1 in a reconstituted system. Incubation of this system with 1alpha,24(R)(OH)2D3 resulted in the production of both 25-hydroxylated and non-25-hydroxylated metabolites. Thus, in our present study, we identified CYP24A1 as the main enzyme responsible for the metabolism of 1alpha,24(R)(OH)2D3 in human keratinocytes, and provided unequivocal evidence to indicate that the multicatalytic enzyme CYP24A1 has the ability to hydroxylate 1alpha,24(R)(OH)2D3 at C-25.     

Syntheses of 19-[O-(carboxymethyl)oxime] haptens of epipregnanolone and pregnanolone

O-(Carboxymethyl)oximes 1 and 2 derived from two epimeric 5beta-pregnanolones (3beta-hydroxy-5beta-pregnan-20-one and 3alpha-hydroxy-5beta-pregnan-20-one) in position 19 were prepared. Two synthetic routes were employed, both using protection of the 20-keto group after reduction into the (20R)-alcohol in the form of acetate. In the first route, (20R)-19-hydroxy-5beta-pregnan-3beta,20-diyl diacetate (3) was transformed into the corresponding 19-[O-(carboxymethyl)oxime] methyl ester 6, then deacetylated by acid and partially silylated with tert-butyldimethylsilyl chloride. The desired 3-O-silylated derivative 8 was separated, oxidized to the 20-ketone and protecting groups were sequentially removed to give the first title hapten 1. The second route started from (20R)-19-hydroxy-3-oxopregn-4-en-20-yl acetate (11), which was hydrogenated in the presence of base to the 5beta-pregnan-3-one derivative 12, protected in position 19 with tert-butyldimethylsilyl group and reduced with borohydride. The prevailing 3alpha-alcohol 15 was separated, protected in position 3 with a methoxymethyl group, deprotected in position 19 and transformed into the 19-[O-(carboxymethyl)oxime] 19. After deacetylation, esterification with diazomethane and oxidation in position 20, the pregnanolone skeleton was regenerated. Final deprotection steps gave the second title hapten 2. Both haptens, i.e., (19E)-3beta- and -3alpha-hydroxy-20-oxo-5beta-pregnan-19-al 19-[O-(carboxymethyl)oxime], were designed for the development of immunoassays of the corresponding parent neuroactive steroids.     

Cytotoxic lupane-type triterpenoids from Acacia mellifera

One new and eight previously described lupane-type metabolites were isolated for the first time from Acacia mellifera (Leguminosae). Based on spectral analyses, the structure of the new compound was elucidated as 28-hydroxy-3-oxo-lup-20-(29)-en-30-al (1), while the known compounds were identified as 3-oxo-lup-20-(29)-en-30-al (2), 3-hydroxy-lup-20-(29)-en-30-al (3), 28-hydroxy-lup-20-(29)-en-3-one (4), lupenone (5), lupeol (6), betulin (7), betulinic acid (8), and betulonic acid (9). Metabolites 2, 3, and 4 are reported for the first time in the Leguminosae family. The cytotoxicity of the isolated metabolites was evaluated on the NSCLC-N6 cell line, derived from a human non-small-cell bronchopulmonary carcinoma. Compounds 1 and 3 exhibited significant levels of activity.     

Characterization and detection of lysine-arginine cross-links derived from dehydroascorbic acid

Covalently cross-linked proteins are among the major modifications caused by the advanced Maillard reaction. So far, the chemical nature of these aggregates is largely unknown. L-dehydroascorbic acid (DHA, 5), the oxidation product of L-ascorbic acid (vitamin C), is known as a potent glycation agent. Identification is reported for the lysine-arginine cross-links N6-[2-[(4-amino-4-carboxybutyl)amino]-5-(2-hydroxyethyl)-3,5-dihydro-4H-imidazol-4-ylidene]-L-lysine (9), N6-[2-[(4-amino-4-carboxybutyl)amino]-5-(1,2-dihydroxyethyl)-3,5-dihydro-4H-imidazol-4-ylidene]-L-lysine (11), and N6-[2-[(4-amino-4-carboxybutyl)amino]-5-[(1S,2S)-1,2,3-trihydroxypropyl]-3,5-dihydro-4H-imidazol-4-ylidene]-L-lysine (13). The formation pathways could be established starting from dehydroascorbic acid (5), the degradation products 1,3,4-trihydroxybutan-2-one (7, L-erythrulose), 3,4-dihydroxy-2-oxobutanal (10, L-threosone), and L-threo-pentos-2-ulose (12, L-xylosone) were proven as precursors of the lysine-arginine cross-links 9, 11, and 13. Products 9 and 11 were synthesized starting from DHA 5, compound N6-[2-[(4-amino-4-carboxybutyl)amino]-5-[(1S,2R)-1,2,3-trihydroxypropyl]-3,5-dihydro-4H-imidazol-4-ylidene]-L-lysine (16) via the precursor D-erythro-pentos-2-ulose (15). The present study revealed that the modification of lysine and arginine side chains by DHA 5 is a complex process and could involve a number of reactive carbonyl species.     

Synthesis of (−)-Methyl Shikimate via Enzymatic Resolution of (1S*, 4R*, 5R*)-4-Hydroxy-6-oxabicyclo[3.2.1]oct-2-en-7-one

The synthesis of methyl (?)-shikimate [(?)-2] was achieved via lipase-catalyzed optical resolution of (1S^*,4R^*,5R^*)-4-hydroxy-6-oxabicyclo[3.2.1]oct-2-en-7-one (3). Transesterification of (±)-3 and vinyl acetate with lipase MY and subsequent hydrolysis gave optically pure (?)-3. This compound was converted to (?)-2 in two steps.     

Constituents of the stems of Macrococculus pomiferus and their inhibitory activities against cyclooxygenases-1 and -2

As part of our program directed towards the discovery of new cancer chemopreventive agents from plants, the EtOAc-soluble extract of the stems of M. pomiferus was found to inhibit the enzyme cyclooxygenase-2 (COX-2). Bioassay-directed fractionation of this extract led to the isolation of two dibenzylbutyrolactone lignans, (8R,8'R)-3'-O-demethyl-5-hydroxymatairesinol (1) and (8R,8'R)-3'-O-demethyl-5-methoxymatairesinol (2), as well as seven known compounds, (-)-5'-methoxyyatein (3), blumenol A, (-)-deoxypodophyllotoxin (anthricin), (-)-deoxypodorhizone, 2,6-dimethoxyhydroquinone, 4-hydroxybenzaldehyde, and beta-sitosterol glucoside. The structures of compounds 1 and 2 were determined using spectroscopic data (1D and 2D NMR, and HREIMS), and the 8R and 8'R absolute stereochemistry was established for both 1 and 2 on the basis of their CD spectra. All isolates obtained in the present study were evaluated for their inhibitory effects with both COX-1 and -2. Of these, only 5'-methoxyyatein (3) showed weak activity against COX-2, while all other compounds isolated were inactive. The COX-2 inhibitory activity of the EtOAc extract was also traced to the presence of several common fatty acids by LC-MS.     

Microbial transformation of cadina-4,10(15)-dien-3-one, aromadendr-1(10)-en-9-one and methyl ursolate by Mucor plumbeus ATCC 4740

The sesquiterpenes cadina-4,10(15)-dien-3-one (1) and aromadendr-1(10)-en-9-one (squamulosone) (14) along with the triterpenoid methyl ursolate (21) were incubated with the fungus Mucor plumbeus ATCC 4740. Substrates 1, 14 and ursolic acid (20) were isolated from the plant Hyptis verticillata in large quantities. M. plumbeus hydroxylated 1 at C-12 and C-14. When the iron content of the medium was reduced, however, hydroxylation at these positions was also accompanied by epoxidation of the exocyclic double bond. In total nine new oxygenated cadinanes have been obtained. Sesquiterpene 14 was converted to the novel 2alpha,13-dihydroxy derivative along with four other metabolites. Methyl ursolate (21) was transformed to a new compound, methyl 3beta,7beta,21beta-trihydroxyursa-9(11),12-dien-28-oate (22). Two other triterpenoids, 3beta,28-dihydroxyurs-12-ene (uvaol) (23) and 3beta,28-bis(dimethylcarbamoxy)urs-12-ene (24) were not transformed by the micro-organism, however.     

The spirostenol (22R, 25R)-20alpha-spirost-5-en-3beta-yl hexanoate blocks mitochondrial uptake of Abeta in neuronal cells and prevents Abeta-induced impairment of mitochondrial function

Abeta(1-42) has been shown to uncouple the mitochondrial respiratory chain and promote the opening of the membrane permeability transition (MPT) pore, leading to cell death. We have previously reported that the spirostenol derivative (22R, 25R)-20alpha-spirost-5-en-3beta-yl hexanoate (SP-233) protects neuronal cells against Abeta(1-42) toxicity by binding to and inactivating the peptide. Picomolar concentrations of Abeta(1-42) decreased the mitochondrial respiratory coefficient in mitochondria isolated from the rat forebrain, and this decrease was partially reversed by SP-233. SP-233 abolished the uncoupling of oxidative phosphorylation induced by carbonyl cyanide 3-chlorophenylhydrazone on isolated mitochondria. These results are consistent with a direct effect of SP-233 on the MPT. Moreover, SP-233 displayed a neuroprotective effect on SK-N-AS human neuroblastoma cells treated with the MPT promoter, phenylarsine oxide. Treatment of SK-N-AS cells with Abeta(1-42) resulted in an accumulation of the peptide in the mitochondrial matrix; SP-233 completely scavenged Abeta(1-42) from the matrix. In addition, SP-233 protected the cells against mitochondrial toxins targeting complexes IV and V of the respiratory chain. These results indicate that Abeta(1-42) and SP-233 exert direct effects on mitochondrial function and SP-233 protects neuronal cells against Abeta-induced toxicity by targeting Abeta directly.     

Neuroprotective function of R-(-)-1-(benzofuran-2-yl)-2-propylaminopentane, [R-(-)-BPAP], against apoptosis induced by N-methyl(R)salsolinol, an endogenous dopaminergic neurotoxin, in human dopaminergic neuroblastoma SH-SY5Y cells

R-(-)-1-(Benzofuran-2-yl)-2-propylaminopentane HCl [R-(-)-BPAP] is one of "catecholaminergic and serotonergic enhancers", which were proposed to improve symptoms through increase in impulse-evoked release of monoamine neurotransmitters for Parkinson's disease. It was reported that (-)-BPAP up-regulated the synthesis of neurotrophic factors in mouse astrocytes, suggesting the neuroprotective potency of (-)-BPAP. In this paper, the neuroprotective function of (-)-BPAP and the related compounds was examined against apoptosis induced by an endogenous neurotoxin, N-methyl(R)salsolinol [NM(R)Sal], a possible pathogenic toxin in Parkinson's disease, in human dopaminergic neuroblastoma SH-SY5Y cells. The anti-apoptotic activity was confirmed with some of (-)-BPAP analogues, and the mechanism was found to be due to the direct stabilization of mitochondrial membrane potential and the induction of anti-apoptotic Bcl-2. The studies on structure-activity relationship demonstrated that the potency to stabilize the mitochondrial membrane potential depended on the absolute stereo-chemical structure of BPAP derivatives. The compounds with dextrorotation prevented the mitochondrial permeability transition, whereas those with levorotation did not. The presence of a propargyl or propyl group at the amino residue of R-(-)-1-(benzofuran-2-yl)-2-propylamine increased potency to stabilize the membrane potential and prevent apoptosis. R-FPFS-1169 and R-FPFS-1180 had more potent to induce Bcl-2 and prevent apoptosis than the corresponding S-enantiomers. These results are discussed with the possible application of BPAP derivatives as neuroprotective agents in Parkinson's disease and other neurodegenerative disorders.     

Dihydroisocoumarin from Xyris pterygoblephara active against dermatophyte fungi

The ethanol extract from Xyris pteygoblephara aerial parts was evaluated against five microorganism strains, by the microdilution and agar diffusion methods. Extract fractionation led to the isolation of three compounds, whose structures were assigned by spectrometric data (1D and 2D NMR, IR, MS and UV) as (3R,4R)-(-)-6-methoxy-3,4-dihydro-3-n-pentil-4-acethoxy-1H-2-benzopyran-1-one (1), moronic acid and quercetin. The absolute configuration of 1 was defined by circular dichroism spectroscopy and comparison with data reported for other dihydroisocoumarins. Assay of 1 (100 microg/disc) by the agar diffusion method against clinical isolates of the dermatophytes Epidermophyton floccosum (inhibition zone, mm+/-s.d.: 4.5+/-0.8), Trichophyton mentagrophytes (4.8+/-0.4) and Trichophyton rubrum (10.2+/-0.8) revealed similar inhibition zones to the positive control amphotericin B (32 microg/disc; 5.0+/-0.2; 5.0+/-0.6 and 8.8+/-1.2, respectively). The result corroborates the ethnomedical use of Xyris species to treat dermatitis.     

Isolation and absolute configuration of new bioactive marine steroids from Euryspongia n. sp

The apolar fraction of the crude alcoholic extract of the sponge Euryspongia n. sp. was shown to display anti-inflammatory activity. Bioassay guided chromatographic purification led to the isolation of a known compound petrosterol (1) of 3beta-hydroxy-24-norchol-5-en-23-oic acid (2), which has never yet been found as a natural substance, and of a new steroid, 3beta-hydroxy-26-norcampest-5-en-25-oic acid (3). The absolute configurations of 2 and 3 were deduced from comparative 1H NMR data of the (S)- and (R)-phenylglycine methyl ester derivatives. These compounds were evaluated for their anti-inflammatory activity against 6-keto-prostaglandinF1alpha release in a human keratinocyte cell line HaCaT.