Steryl esters and phenylethanol esters from Syringa komarowii

Three new steryl esters and a new phenylethanol ester, together with 22 known compounds were isolated from the aqueous ethanolic extract of the whole plants of Syringa komarowii. The new compounds were elucidated as stigmastane-3beta,6alpha-diol 3-O-tetradecanoate (1), stigmastane-3beta,6alpha-diol 3-O-palmitate (2), stigmastane-3beta,6alpha-diol 3-O-stearate (3), and 2-(4-hydroxyphenyl)-ethyl dotriacontanoate (4) on the basis of extensive spectral data and chemical evidences.     

Ethanol directly increases dihydrotestosterone conversion to 5 alpha-androstan-3 beta,17 beta-diol and 5 alpha-androstan-3 alpha,17 beta-diol in rat Leydig cells

The direct effect of ethanol on dihydrotestosterone (DHT) conversion to 5 alpha-androstan-3 beta,17 beta-diol (3 beta-diol) and 5 alpha-androstan-3 alpha,17 beta-diol (3 alpha-diol) by adult rat Leydig cells was examined. Concentrations of ethanol comparable to blood levels of alcoholic men (2.2 - 65 mM) increased DHT conversion to 3 beta - and 3 alpha-diol, in direct relation to the dose of ethanol added; a 2-fold or greater stimulation was observed. Because this effect was blocked by 4-methylpyrazole or a saturating NADH concentration, these results suggest that this action is mediated by Leydig cell alcohol dehydrogenase activity. These results may have significant impact in the testis and/or other DHT sensitive tissues because ethanol may decrease the availability of the proposed active androgen.     

Potential cancer chemopreventive constituents of the leaves of Macaranga triloba

Activity-guided fractionation of the leaves of Macaranga triloba, using an in vitro bioassay based on the inhibition of cyclooxygenase-2, resulted in the isolation of a rotenoid, 4,5-dihydro-5'alpha-hydroxy-4'alpha-methoxy-6a,12a-dehydro-alpha-toxicarol (1), as well as 12 known compounds, (+)-clovan-2beta,9alpha-diol, ferulic acid, 3,7,3',4'-tetramethylquercetin, 3,7,3'-trimethylquercetin, 3,7-dimethylquercetin, abscisic acid, 1beta,6alpha-dihydroxy-4(15)-eudesmene, 3beta-hydroxy-24-ethylcholest-5-en-7-one, loliolide, scopoletin, taraxerol, and 3-epi-taraxerol. The structure of compound 1 was determined using spectroscopic methods. All isolates were evaluated for their potential to inhibit cyclooxygenases-1 and -2 by measuring PGE(2) production, and to induce quinone reductase in cultured Hepa 1c1c7 mouse hepatoma cells.     

Synthesis and antitumor activity of cholest-4 alpha-methyl-7-en-3beta-ol derivatives

Cholest-4 alpha-methyl-7-en-3beta-ol (1) has potent inhibitory activity against pc 12 tumor with 0.5043 ratio (10 microg/mL). This paper describes a series of structural modification of this compound, which focus on 3beta-hydroxyl group and 7(8)-double bond. The synthesized derivatives of 1 were tested for human cancer cell lines including colon cancer (HCT-8), liver cancer (BEL-7402) and nasopharyngeal cancer (KB) cells. The results showed that cholest-4 alpha-methyl-8-en-3beta,7 alpha-diol 6a inhibits KB cell significantly with IC(50) 1.32 x 10(-9)microg/mL. In addition, the cytotoxic properties of this compound against HCT-8 and BEL-7402 are excellent with IC(50) 1.2 microg/mL.     

Diterpenes and sesquiterpenes from the bark of Taxus yunnanensis

Two taxane-type diterpenes, 10beta-acetoxy-2alpha,5alpha,7beta,9alpha-tetrahydroxytaxa-4(20),11-dien-13-one and 2alpha-acetoxy-9alpha-benzoyloxy-5alpha,7beta,10beta,15-tetrahydroxy-11(15-->1)- abeotaxa-4(20),11-dien-13-one, and two new drimane-type sesquiterpenes, 1beta-acetoxy-7-drimen-11alpha-ol-12,11-lactone and 1beta-acetoxy-11,12-epoxy-6-drimen-8alpha,11alpha-diol, were isolated from the bark of Taxus yunnanensis together with 35 known taxane-type diterpenes, a known drimane-type sesquiterpene and a known flavanone.     

A new sesquiterpene alcohol from Pterocarpus marsupium

The petrol extract of Pterocarpus marsupium afforded a new sesquiterpene alcohol of the eudesmane type, selin-4(15)-en-1β,11-diol, besides β-eudesmol, erythrodiol-3-monoacetate and pterostilbene.     

Role of a single amino acid in the evolution of glycans of invertebrates and vertebrates

Structures of glycoconjugate N-glycans and glycolipids of invertebrates show significant differences from those of vertebrates. These differences are due largely to the vertebrate beta1,4-galactosyltransferase-1 (beta4Gal-T1), which is found as a beta1,4-N-acetylgalactosaminyltransferase (beta4GalNAc-T1) in invertebrates. Mutation of Tyr285 to Ile or Leu in human beta4Gal-T1 converts the enzyme into an equally efficient beta4GalNAc-T1. A comparison of all the human beta4Gal-T1 ortholog enzymes shows that this Tyr285 residue in human beta4Gal-T1 is conserved either as Tyr or Phe in all vertebrate enzymes, while in all invertebrate enzymes it is conserved as an Ile or Leu. We find that mutation of the corresponding Ile residue to Tyr in Drosophila beta4GalNAc-T1 converts the enzyme to a beta4Gal-T1 by reducing its N-acetylgalactosaminyltransferase activity by nearly 1000-fold, while enhancing its galactosyltransferase activity by 80-fold. Furthermore, we find that, similar to the vertebrate/mammalian beta4Gal-T1 enzymes, the wild-type Drosophila beta4GalNAc-T1 enzyme binds to a mammary gland-specific protein, alpha-lactalbumin (alpha-LA). Thus, it would seem that, during the evolution of vertebrates from invertebrates over 500 million years ago, beta4Gal-T1 appeared as a result of the single amino acid substitution of Tyr or Phe for Leu or Ile in the invertebrate beta4GalNAc-T1. Subsequently, the pre-existing alpha-LA-binding site was utilized during mammalian evolution to synthesize lactose in the mammary gland during lactation.     

The in vivo metabolism of 7 beta, 17-dimethyltestosterone-6,7-3H.

7 beta, 17-Dimethyltestosterone (17 beta-hydroxy-7 beta, 17-dimethyl-4-androsten-3-one) (I) was given to three subjects in oral doses of 400 mg per day for ten days. The initial dose contained the steroid tritiated in the 6 and 7 positions. Plasma levels and urinary excretion patterns were followed in all three subjects. Isolations were done on the urine, plasma, and stools of one patient. From the urine 7 beta, 17-dimethyl- 5 alpha-androstane-3 beta,17 beta-diol (VI) was isolated from the nonhydrolyzed fractions. Unchanged (I), 7 beta,17-dimethyl-5 beta-androstane-3 alpha,17 beta-diol (III) and 7 beta, 17-dimethyl-5 beta-androstane-3 beta,17 beta-diol (IV) were isolated from the nonhydrolyzed and enzyme-hydrolyzed fractions. 7 beta,17-dimethyl-5 alpha-androstane-3 alpha,17 beta-diol (V) was isolated from the enzymatic fractions. From the stools were isolated unchanged (I), (III), (IV), (V), and (VI). Unchanged (I) and its 5 alpha-dihydro derivative (17 beta-hydroxy-7 beta,17-dimethyl-5 alpha-androstan-3-one) (II) were identified in the plasma. The total recovery of radioactivity in the one patient on whom the isolations were done was 57%; 40% from the urine and 17% from the stools.     

Three new D-ring unsaturated sterols from the Mediterranean sponge Topsentia aurantiaca: structure determination and complete nuclear magnetic resonance assignment.

Three novel sterols with a rare D-ring unsaturation were isolated from the marine sponge Topsentia aurantiaca and identified as 5 alpha-cholest-14-ene-3 beta,16 alpha-diol (2), 24R-ethyl-5 alpha-cholest-14-ene-3 beta,16 alpha-diol (3), and 24S-ethyl-5 alpha-cholest-14-ene-3 beta,16 alpha-diol (4). The sponge also elaborates a further D-ring unsaturated sterol, 5 alpha-cholest-15-en-3 beta-ol (1), which has been previously described only as a synthetic product. All the 1H and 13C nuclear magnetic resonances of compounds 1 and 2 were assigned to the relevant protons and carbons by bidimensional COSY, HETCOR, and HMQC nuclear magnetic resonance experiments.     

Triterpenoidal glycosides from Justicia betonica

dFrom the aerial portion of Justicia betonica L., four triterpenoidal glycosides (justiciosides A-D) were isolated. Their structures were established through chemical and NMR spectroscopic analyses as olean-12-ene-1beta,3beta,11alpha,28-tetraol 28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside, olean-12-ene-1beta,3beta,11alpha,28-tetraol 28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside, 11alpha-methoxy-olean-12-ene-1beta,3beta,28-triol 28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside, 11alpha-methoxy-olean-12-ene-1beta,3beta,28-triol 28-O-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranoside, respectively.     

Structure of inflexinol,a new cytotoxic diterpene from Rabdosia inflexa

From the leaves of Rabdosia inflexa a new cytotoxic diterpenoid, inflexinol was isolated, together with the known inflexin, and the structure was established as ent-kaur-16-en-15-one-1α,3α,6β,11β-tetraol 1,3-diacetate.     

Guaiane sesquiterpenes from Amoora rohituka

The petroleum ether extract of the stem bark of Amoora rohituka afforded two novel guaiane-derived sesquiterpenoids, 6beta,7beta-epoxyguai-4-en-3-one (1) and 6beta,7beta-epoxy-4beta,5-dihydroxyguaiane (2). The structures of 1 and 2 were determined by extensive NMR and MS analyses and by comparison of their spectral data with related compounds. The relative stereochemistry of the asymmetric centers in 1 and 2, except at C-5 of 2, were determined by selective 1D-NOESY experiments.     

Sesquiterpenoids from Homalomena occulta affect osteoblast proliferation, differentiation and mineralization in vitro

Chemical investigation of rhizomes of Homalomena occulta (Lours) resulted in isolation and identification of two sesquiterpenoids (6,7), and one daucane ester 8, together with five known sesquiterpenoids, oplodiol, oplopanone, homalomenol C, bullatantriol, and 1beta,4beta,7alpha-trihydroxyeudesmane. Their structures were elucidated using 1D and 2D NMR spectroscopic and X-ray analyses. The chloroform extract of this plant and compounds 1-7 were tested in vitro for their activities in stimulating osteoblast (OB) proliferation, differentiation and mineralization. Compounds 1-4 had a stimulative effect on significantly proliferation and differentiation of culture osteoblasts, while the chloroform extract and 1 significantly stimulated mineralization of cultured osteoblasts in vitro.     

Inhibitors of sterol synthesis. Chemical syntheses, properties and effects of 4,4-dimethyl-15-oxygenated sterols on sterol synthesis and on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity in cultured mammalian cells

The chemical syntheses of a number of 4,4-dimethyl substituted 15-oxygenated sterols have been pursued to permit evaluation of their activity in the inhibition of the biosynthesis of cholesterol and other biological effects. Described herein are the first chemical syntheses of 4,4-dimethyl-14 alpha-ethyl-5 alpha-cholest-7-en-3 beta-ol-15-one, 3 beta,15 alpha-diacetoxy-4,4-dimethyl-14 alpha-ethyl-5 alpha-cholest-7-ene, 3 beta-acetoxy-4,4-dimethyl-14 alpha-ethyl-5 alpha-cholest-7-en-15 beta-ol, 4,4-dimethyl-14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol, 4,4-dimethyl-14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta,15 beta-diol, 4,4-dimethyl-14 alpha-ethyl-5 alpha-cholest-7-en-15 alpha-ol-3-one, 3 beta-benzoyloxy-4,4-dimethyl-5 alpha-cholest-8(14)-ene-7 alpha,15 alpha-diol, 7 alpha,15 alpha-diacetoxy-3 beta-benzoyloxy-4,4-dimethyl-5 alpha-cholest-8(14)-ene, 4,4-dimethyl-5 alpha-cholest-8(14)-en-3 beta-ol-15-one and 3 beta,7 alpha,15 alpha-tri-o-bromobenzoyloxy-5 alpha-cholest-8(14)-ene. Also prepared for use in the biological experiments were 4,4-dimethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol, 4,4-dimethyl-5 alpha-cholest-8-ene-3 beta,15 alpha-diol and 4,4-dimethyl-5 alpha-cholest-8(14)-ene-3 beta,7 alpha,15 alpha-triol. The effects of twelve 4,4-dimethyl substituted 15-oxygenated sterols and of four 4,4-dimethyl substituted 32-oxygenated sterols on sterol synthesis and on the level of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity were evaluated in mouse L cells. With the exception of 4,4-dimethyl-5 alpha-cholest-8(14)-ene-3 beta,7 alpha,15 alpha-triol, all of the 4,4-dimethyl substituted 15-oxygenated sterols caused a 50% inhibition of sterol synthesis at less than 10(-6) M and six of the 4,4-dimethyl substituted 15-oxygenated sterols caused a 50% inhibition of sterol synthesis at less than 10(-7) M. 4,4-Dimethyl-14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol caused a 50% decrease in sterol synthesis at 10(-8) M. The potencies of the 4,4-dimethyl substituted 15-oxygenated and C-32-oxygenated sterols with respect to inhibition of sterol synthesis and suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity have been compared with those of the corresponding sterols lacking the 4,4-dimethyl substitution.     

Configurational analysis and relative binding affinities of 16-methyl-5alpha-androstane derivatives

The four possible isomers 16beta-hydroxymethyl-5alpha-androstane-3beta,17beta-diol 1, 16alpha-hydroxymethyl-5alpha-androstane-3beta,17beta-diol 2, 16beta-hydroxymethyl-5alpha-androstane-3beta,17alpha-diol 3 and 16alpha-hydroxymethyl-5alpha-androstane-3beta,17alpha-diol 4 with proven configuration were converted into the corresponding 16beta-methyl-5alpha-androstane-3beta,17beta-diol 5, 16alpha-methyl-5alpha-androstane-3beta,17beta-diol 6, 16beta-methyl-5alpha-androstane-3beta,17alpha-diol 7, 16alpha-methyl-5alpha-androstane-3beta,17alpha-diol 8, furthermore into the 16beta-methyl-17beta-hydroxy-5alpha-androstane-3-one 13, 16alpha-methyl-17beta-hydroxy-5alpha-androstan-3-one 14, 16beta-methyl-17alpha-hydroxy-5alpha-androstan-3-one 15 and 16alpha-methyl-17alpha-hydroxy-5alpha-androstan-3-one 16. The steric structures of the resulting epimers were determined by means of 1H-, and 13C-NMR spectroscopy. In this way, comparison was possible with the C-16 epimers 5, 6 and 13, 14 prepared earlier by a different route, and the series of isomers could be completed with the steric structures of 16beta-methyl-17alpha-hydroxy-5alpha-androstan-3beta-ol 7 and 16alpha-methyl-17alpha-hydroxy-5alpha 8 and with their 3-keto derivatives 15 and 16. The relative binding affinities of the 16-methyl-5alpha-androstane-3beta,17-diols 5, 6, 7, 8 and 17-hydroxy-16-methyl-5alpha-androstan-3-ones 13, 14, 15, 16 were studied. The introduction of a 16-methyl substituent into 5alpha-androstane molecules substantially decreases the binding affinity to the androgen receptor and 16alpha-methyl derivatives were always bound more weakly than the 16beta-methyl isomers.     

Eudesmane and megastigmane glucosides from Laggera alata

Four eudesmane glucosides, alatosides A-D (1-4), and one megastigmane glucoside, alatoside E (5), were isolated from the BuOH fraction of Laggera alata along with six known compounds. Structures of the new compounds were elucidated by a combination of chemical and spectroscopic methods. Alatosides A-E were characterized as: 1alpha-O-(beta-D-glucopyranosyloxyl)-7-epi-eudesma-11-en-2beta,4alpha-diol (1), 2beta-O-(beta-D-glucopyranosyloxyl)-eudesma-4alpha-hydroxyl-11(13)-en-12-oic-acid (2), 5beta-O-(beta-D-glucopyranosyloxyl)-eudesma-4(15),11(13)-dien-12-oic-acid (3), 5alpha-O-(beta-D-glucopyranosyloxyl)-eudesma-3,11(13)-dien-12-oic acid (4) and 3beta-O-(beta-D-glucopyranosyloxyl)-megastigma-9-one (5), respectively. Based on the chemical characteristics of eudesmane derivatives isolated from the Laggera genus, it was suggested that there are probably two different biogenetic pathways for these secondary metabolites in this genus.     

Irreversible protein binding of norethisterone (norethindrone) epoxide.

14,15-3H-Norethisterone-4 beta, 5 beta-epoxide, a metabolite of norethisterone, was incubated with several proteins and nucleic acids. After 30 min incubation 0.19 nmol of the epoxide were irreversibly bound per mg albumin which contains free sulfhydryl groups; proteins without SH-groups, such as concanavalin A, gamma-globulin, DNA and RNA, did not irreversibly bind norethisterone epoxide. A superoxide (O2) generating enzyme system comprised of xanthine oxidase and hypoxanthine was capable of catalyzing the irreversible binding of the parent compound, norethisterone, to albumin, indicating that an oxidation product was formed which reacted with the protein. When norethisterone epoxide was incubated for 60 min with hepatic microsomes of rats in absence of NADPH, about 2.0 nmol of the epoxide were irreversibly incorporated per mg microsomal protein. This binding was increased to 5.2 nmol by addition of a NADPH regenerating system. Addition of glutathione and cytosol decreased only the NADPH-dependent protein binding; phenobarbital pretreatment of rats induced this NADPH-dependent binding of norethisterone epoxide to microsomal protein by a factor of 2. In presence of NADPH, binding of the epoxide to microsomal protein depended on substrate concentration used. The results indicate that norethisterone epoxide is able to chemically react with proteins. In addition, hepatic microsomal enzymes convert the epoxide to another metabolite which also can react with proteins.     

Stereospecific 1,4-addition to an alpha,beta-unsaturated steroidal epoxide: syntheses of new 15-oxygenated sterols

3 beta-Benzoyloxy-14 alpha,15 alpha-epoxy-5 alpha-cholest-7-ene (1) is a key intermediate in the synthesis of C-7 and C-15 oxygenated sterols. Treatment of 1 with benzoyl chloride resulted in the formation of 3 beta,15 alpha-bis-benzoyloxy-7 alpha-chloro-5 alpha-cholest-8(14)-ene (2). Reaction of 2 with LiAlH4 or LiAlD4 resulted in the formation of 5 alpha-cholest-7-ene-3 beta,15 alpha-diol (3a) or [14 alpha-2H]5 alpha-cholest-7-ene-3 beta,15 alpha-diol (3b). Diol 3b was selectively oxidized by Ag2CO3/celite to [14 alpha-2H]5 alpha-cholest-7-en-15 alpha-ol-3-one (4). Treatment of 1 with MeMgI/CuI gave 7 alpha-methyl-5 alpha-cholest-8(14)-ene-3 beta,15 alpha-diol (5). Selective oxidation of 5 with pyridinium chlorochromate (PCC)/pyridine or oxidation with PCC resulted in the formation of 7 alpha-methyl-5 alpha-cholest-8(14)-en-3 beta-ol-15-one (6) and 7 alpha-methyl-5 alpha-cholest-8(14)-ene-3,15-dione, respectively. Reduction of 6 with LiAlH4 yielded 5 and 7 alpha-methyl-5 alpha-cholest-8(14)-ene-3 beta,15 beta-diol (6). Reaction of 1 with benzoic acid/pyridine gave 3 beta,7 alpha-bis-benzoyloxy-5 alpha-cholest-8(14)-en-15 alpha-ol (9). Treatment of 9 with LiAlH4 or ethanolic KOH resulted in the formation of 5 alpha-cholest-8(14)-ene-3 beta,7 alpha,15 alpha-triol (10). Dibenzoate 9, upon brief treatment with mineral acid, gave 3 beta-benzoyloxy-5 alpha-cholest-8(14)-ene-15-one (11). Oxidation of 9 with PCC yielded 3 beta,7 alpha-bis-benzoyloxy-5 alpha-cholest-8(14)-ene-15-one (12). Ketone 12 was also prepared by the selective hydride reduction of 5 alpha-cholest-8(14)-en-7 alpha-ol-3,15-dione (13) to give 5 alpha-cholest-8(14)-ene-3 beta,7 alpha-diol-15-one (14), which was then treated with benzoyl chloride to produce 12.     

Inhibitory effect of 15-oxygenated sterols on cholesterol synthesis from 24,25-dihydrolanosterol

Several 15-oxygenated sterols were examined as to their inhibitory activity toward cholesterol synthesis from [24,25-3H]-24,25-dihydrolanosterol in the 10,000 X g supernatant fraction of a rat liver homogenate. At 40 microM, three 15 alpha-hydroxylated compounds, 14 alpha-ethylcholest-7-ene-3 beta,15 alpha-diol, 14 alpha-methylcholest-7-ene-3 beta,15 alpha-diol, and lanost-7-ene-3 beta,15 alpha-diol, were found to be extremely potent inhibitors (more than 90% inhibition) of dihydrolanosterol metabolism. The inhibitory effect of the C-15 substituents appeared to be in the order of: 15 alpha-hydroxyl greater than 15-ketone greater than 15 beta-hydroxyl.     

Taraxastane-type triterpenoids from Saussurea petrovii.

Two taraxastane triterpenoids, i.e. taraxast-20-ene-3beta,30-diol (1) and 20alpha,21alpha-epoxy-taraxastane-3beta,22alpha-diol (2), as well as four known triterpenes taraxast-20(30)ene-3beta,21alpha-diol (3), taraxast-20(30)-ene-3beta-ol (4), taraxast-20-ene-3beta-ol (5) and taraxastane-3beta,20alpha-diol (6) were isolated from the Chinese medicinal plant Saussurea petrovii. Their structures were elucidated by spectroscopic methods. These compounds, especially 1 and 2, exhibit significant antitumor and antibacterial activity.