Biotransformation studies of prednisone using human intestinal bacteria Part II: Anaerobic incubation and docking studies

Anaerobic incubation of prednisone 1 with human intestinal bacteria (HIB) afforded nine metabolites: 5β-androst-1-ene-3,11,17-trione 3, 3α-hydroxy-5α-androstane-11,17-dione 4, 3β,17α,20-trihydroxy-5α-pregnan-11-one 5, 3α,17α-dihydroxy-5α-pregnane-11,20-dione 6, 3α,17α-dihydroxy-5β-pregnane-11,20-dione 7, 3β,17β-dihydroxy-5α-androstan-11-one 8β, 3β,17α-dihydroxy-5α-androstan-11-one 8α, 3α,17β-dihydroxy-5α-androstan-11-one 9β, and 3α,17α-dihydroxy-5α-androstan-11-one 9α. The structures of these metabolites (3–9) were elucidated using several spectroscopic techniques. Computer-aided prediction of potential biological activities of the isolated prednisone metabolites (3–9) revealed potential inhibition of prostaglandin E2 9-ketoreductase (PGE2 9-KR). Docking studies applied to PGE2 9-KR allowed recommendation of the metabolites 4, 8β, and 8α for further pharmacological study as PGE2 9-KR inhibitors.     

Biotransformation of dehydroepiandrosterone with Macrophomina phaseolina and β-glucuronidase inhibitory activity of transformed products

The biotransformation of dehydroepiandrosterone (1) with Macrophomina phaseolina was investigated. A total of eight metabolites were obtained which were characterized as androstane-3,17-dione (2), androst-4-ene-3,17-dione (3), androst-4-ene-17β-ol-3-one (4), androst-4,6-diene-17β-ol-3-one (5), androst-5-ene-3β,17β-diol (6), androst-4-ene-3β-ol-6,17-dione (7), androst-4-ene-3β,7β,17β?triol (8), and androst-5-ene-3β,7α,17β-triol (9). All the transformed products were screened for enzyme inhibition, among which four were found to inhibit the β-glucuronidase enzyme, while none inhibited the α-chymotrypsin enzyme.     

New triterpenoid saponins from Patrinia scabiosaefolia

Phytochemical investigation of the methanol extract from the whole plants of Patrinia scabiosaefolia Fisch. resulted in the isolation of four new triterpenoid saponins (1–4) along with six known compounds (5–10). On the basis of spectroscopic and chemical methods, the structures of the new compounds were established as 3-O-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl-12β,30-dihydroxy-olean-28,13β-olide (1), 3-O-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl-12β,30-dihydroxy-olean-28,13β-olide (2), 3-O-β-d-xylopyranosyl-(1→2)-β-d-glucopyranosyl-12β, 30-dihydroxy-olean-28,13β-olide (3), and 3-O-β-d-glucopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyl-oleanolic acid 28-O-β-d-glucopyranoside (4), respectively. Compounds 1–3 possess a novel 12β,30-dihydroxy-olean-28,13β-lactone aglycone and a 12β-hydroxy substituent that is rarely found in this kind of triterpenoid saponin.     

Microbiological hydroxylation of androst-1,4-dien-3,17-dione by Neurospora crassa

Nine hydroxy-derived androstadiene compounds were isolated from the fermentation broth of Neurospora crassa when incubated in the presence of androst-1,4-dien-3,17-dione (ADD; I) for 7 days. Hydroxylations at 6β, 7β, 11α, 14α- positions and 17-carbonyl reduction of the substrate were the characteristics observed in this biotransformation. Their structures were determined by spectroscopic methods as 17β-hydroxyandrost-1,4-dien-3-one (II), 14α-hydroxyandrost-1,4-dien-3,17-dione (III), 6β-hydroxyandrost-1,4-dien-3,17-dione (IV), 11α-hydroxyandrost-1,4-dien-3,17-dione (V), 6β,17β-dihydroxyandrost-1,4-dien-3-one (VI), 7β-hydroxyandrost-1,4-dien-3,17-dione (VII), 14α,17β-dihydroxyandrost-1,4-dien-3-one (VIII), 6β,14α-dihydroxyandrost-1,4-dien-3,17-dione (IX), and 11α,17β-dihydroxyandrost-1,4-dien-3-one (X). A new steroid substance, 6β,14α-dihydroxyandrost-1,4-dien-3,17-dione (IX), was also characterized during this study. The best fermentation condition was found to be 7-day incubation at 25°C and pH values of 5.0–6.0 in the presence of 0.05 g 100 mL^?1 of the substrate. At a concentration above 0.075 g 100 mL^?1, the biotransformation was completely inhibited.     

Synthesis of blockwise alkylated (1→4) linked trisaccharides as surfactants: influence of configuration of anomeric position on their surface activities

New carbohydrate-based surfactants consisting of hydrophilic cellobiosyl and hydrophobic glucosyl residues, methyl β-d-glucopyranosyl-(1→4)-α-d-glucopyranosyl-(1→4)-2,3,6-tri-O-methyl-α-d-glucopyranoside 1 (GβGαMα, G: glucopyranosyl residue, α and β: α-(1→4)- and β-(1→4) glycosidic bonds, M: methyl group), 2 (G_βG_βM_α), 3 (G_βG_αM_β), 4 (G_βG_βM_β), 5 (G_βG_αE_α, E: ethyl group), 6 (G_βG_βE_α), 7 (G_βG_αE_β), 8 (G_βG_βE_β) and eight α-and β-glycoside mixtures (a mixture of 1 and 2: 1/2 = 62/38 (9), 32/68 (10); a mixture of 3 and 4: 3/4 = 69/31 (11), 32/68 (12); a mixture of 5 and 6: 5/6 = 62/38 (13), 33/67 (14); a mixture of 7 and 8: 7/8 = 59/41 (15), 29/71 (16)) were synthesized via combined methods consisting of acid-catalyzed alcoholysis of cellulose ethers and glycosylation of phenyl thio-cellobioside derivatives. Their surface activities in aqueous solution depended on their chemical structures: α- or β-(1→4) linkage between hydrophilic cellobiosyl and hydrophobic glucosyl blocks, methyl or ethyl groups of hydrophobic glucosyl block, and α- or β-linked ether group at the C-1 of hydrophobic glucosyl block. The mixing effect of α- and β-glycosides on surface activities was also investigated. As a result, ethyl β-d-glucopyranosyl-(1→4)-α-d-glucopyranosyl-(1→4)-2,3,6-tri-O-ethyl-β-d-glucopyranoside 7 (G_βG_αE_β) had the highest surface activity, and its critical micellar concentration (CMC) and γ_CMC (surface tension at CMC) values of compound 7 were 0.5 mM (ca. 0.03 wt %) and 34.5 mN/m, respectively. The surface tensions of α- and β-glycoside mixtures except for compounds 9 and 10 were almost equal to those of pure compounds. The syntheses of the mixtures of α- and β-glycosides without purification process are easier than those of pure compounds. Thus, the mixtures should be more practical compounds for industrial use as a surfactant.     

Two new steroidal saponins from Dioscorea panthaica

Two new furostanol saponins, 3-O-[α-l-rhamnopyranosyl-(1→4)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,22(23)-dien-3β,20α,26-triol (1), 3-O-[β-d-glucopyranosyl-(1→3)-O-α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-20(R)-methoxyl-25(R)-furosta-5,22(23)-dien-3β,26-diol (2) were isolated from the Dioscorea panthaica along with five known steroidal saponins (3–7). The structures of the new saponins were determined by detailed analysis of spectral data (including 2D NMR spectroscopy). The inhibitory activities of the saponins against α-glucosidase were investigated, gracillin (4) and 3-O-[α-l-rhamnopyranosyl-(1→2)-β-d-glucopyranosyl]-26-O-β-d-glucopyranosyl-25(R)-furosta-5,20(22)-dien-3β,26-diol (5) were found to exhibit potent activities with IC₅₀ values of 0.11 ± 0.04 mM and 0.09 ± 0.01 mM.     

Three New Sesquiterpenoid Glycosides from Tobacco

Three sesquiterpenoid glycosides, 3β-hydroxysolanascone-β-sophoroside 1a, 3β-hydroxy-solavetivone-β-glucoside 2a and rishitin glycoside 3a, were isolated from tobacco.     

Synthesis and Biological Evaluation of Some 5-Nitro- and 5-Amino Derivatives of 2′-Deoxycytidine, 2′,3′-Dideoxyuridine,and 2′,3′-Dideoxycytidine

Abstract

In this article, we describe the synthesis of 5-nitro-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (4α), 5-nitro-1-(2-deoxy-β-D-erythro-pentofuranosyl)cytosine (4β), 5-amino-1-(2-deoxy-α-D-erythro-pentofuranosyl)cytosine (5α), 5-nitro-1- (2-deoxy-β-D-erythro-pentofuranosyl)cytosine (5β), 5-nitro-1-(2,3-dideoxy-β- D-ribofuranosyl)uracil (6β), 5-amino-1-(2,3-dideoxy-α,β-D-ribofuranosyl)uracil (7), 5-nitro-1-(2,3-dideoxy-α,β-D-ribofuranosyl)cytosine (8) and 5-amino-1-(2,3-dideoxy-β-D-ribofuranosyl)cytosine (9β). The prepared compounds were tested for their activity against HIV and HBV viruses, but they did not show significant activity.     

New Bitter C27 and C30 Terpenoids from the Fungus Ganoderma lucidum (Reishi)

Four new bitter terpenoids, lucidenic acids A (1), B (2), C (3) and ganoderic acid C (5), were isolated from the fruiting bodies of Ganoderma lucidum, together with the known bitter ganoderic acid B (4). On the basis of spectroscopic data and chemical conversion, their structures were determined to be 7β-hydroxy-4,4,14α-trimethyl-3,11,15-trioxo-5α-chol-8-en-24-oic acid, 7β,12β-dihydroxy-4,4,14α-trimethyl-3,11,15-trioxo-5α-chol-8-en-24-oic acid, 3β,7β,12β-trihydroxy-4,4,14α-trimethyl-11,15-dioxo-5α-chol-8-en-24-oic acid and 7β-hydroxy-3,11,15,23-tetraoxo-5α-lanost- 8-en-26-oic acid, respectively.     

9-(2-Deoxy-ß-D-xylofuranosyl)adenine and 1-(2-Deoxy-ß-D-xylofuranosyl)thymine: Phosphorylation and Stability

Abstract

Phosphorylation of 1-(2-deoxy-β-D-xylofuranosyl)thymine (1) or 9-(2-deoxy-β-D-xylofuranosyl)adenine (3) with phosphoryl chloride gives the cyclic 3′,5′-phosphates (2 and 4a) but not the 5′-monophosphates 8a or 8b. The latter are obtained by phosphorylation of the 3′-0-benzoylated 2′-deoxy-β-D-xylonucleosides (7a, b) and subsequent base-catalyzed removal of the benzoyl groups. Compound 3, as the parent dA, depurinates in acidic medium, a reaction which is facilitated in the case of the N⁶-benzoyl derivative 9b and reduced after the introduction of an amidine protecting group. N-Glycosylic bond hydrolysis of 2′-deoxy-β-D-xylofuranosyl nucleosides is enhanced by a factor of two compared to 2′-deoxy-β-D-ribofuranosyl nucleosides.     

Synthesis and stability assay of 4-methylumbelliferyl (1→3)-β-D-pentaglucoside

The synthesis and stability of 4-methylumbelliferyl (1 → 3)-β-D-pentaglucoside 3 are described. The (1 → 3)-β-D-glucan isolated from the cell walls of Saccharomyces cerevisiae was recovered from the aqueous medium as water-insoluble particles by the spray drying (GS) method. The acid-solubilized (1 → 3)-β-D-oligoglucosides were prepared by partial acid hydrolysis of glucan. The peracetylated (1 → 3)-β-D-pentaglucoside 1 was obtained by isolation of peracetylated (1 → 3)-β-D-oligoglucoside mixture. The peracetylated 4-methylumbelliferyl (1 → 3)-β-D-pentaglucoside 2 was synthesized by treating compound 1 with the 4-methylumbelliferone and a Lewis acid (SnCl₄) catalyst. NaOMe in dry methanol was used for the deacetylation of the blocked derivative, to give the target compound 3 in an overall yield of 35%. Activity assays with β-glucosidase indicated that compound 3 was much more stable than the corresponding pentasaccharide.     

Minor diterpenoid glycosides from the leaves of Stevia rebaudiana

From the commercial extract of the leaves of Stevia rebaudiana, three new diterpenoid glycosides were isolated besides eight known steviol glycosides including stevioside, rebaudiosides A–F and dulcoside A. The structures of the three compounds were identified as 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-kaur-16-en-18-oic acid-(6-O-β-d-xylopyranosyl-β-d-glucopyranosyl) ester (1), 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-17-hydroxy-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (2), and 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-17-oxo-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (3) on the basis of extensive NMR and MS spectral studies. Another known diterpenoid glycoside, 13-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl) oxy]-kaur-15-en-18-oic acid β-d-glucopyranosyl ester (4) was also isolated and its complete NMR spectral assignments were made on the basis of COSY, HSQC and HMBC spectral data.     

New ester derivatives of dehydroepiandrosterone as 5α-reductase inhibitors

The aim of this study was to synthesize different ester derivatives of dehydroepiandrosterone with therapeutic potential as antiandrogens.The biological effect of these steroids was demonstrated in in vivo as well as in vitro experiments. In the in vivo experiments, we measured the activity of seven steroids on the weight of the prostate and seminal vesicles of gonadectomized hamsters treated with testosterone. For the in vitro studies, we determined the IC₅₀ values by measuring the concentration of the steroidal derivatives that inhibits 50% of the activity of 5α-reductase present in human prostate and also its binding capacity to the androgen receptors (AR) obtained from rat’s prostate cytosol. The results from these experiments indicated that compounds 7 5α,6β-dibromo-3β-propanoyloxyandrostan-17-one, 8 5α,6β-dibromo-3β-butanoyloxyandrostan-17-one and 9 5α,6β-dibromo-3β-(3′-oxapentanoyloxy)-androstan-17-one, significantly decreased the weight of the prostate and seminal vesicles as compared to testosterone treated animals; this reduction of the weight of these glands was comparable to that produced by Finasteride 11. On the other hand, compounds 4 3β-acetoxyandrost-5-en-17-one, 5 3β-hexanoyloxyandrost-5-en-17-one 6 3β-(3′-oxapentanoyloxy)-androst-5-en-17-one, 7 and 12 dehydroepiandrosterone, (commercially available) inhibited the enzyme 5α-reductase. Compounds 4, 5, 6, 8 and 9 (IC₅₀ values of 5.2 ± 1.2, 0.049 ± 0.002, 6.4 ± 1.1, 0.10 ± 0.045, and 6.8 ± 0.9 nM, respectively) exhibited the highest inhibitory activity. However, none of these compounds binds to the AR.     

Syntheses of Several β-l-Rhamnopyranosides

To investigate the substrate specificity of β-l-rhamnosidase, the following β-l-rhamnopyranosides were synthesized: 1-(β-l-rhamnopyranosyl)-dl-glycerol (1), methyl β-l-rhamnopyranoside (2), methyl 2-O-(β-l-rhamnopyranosyl)-β-d-glucopyranoside (3) and methyl 2-O-β(β-l-rhamnopyranosyl)-α-l-arabinopyranoside (4). The synthesis of 3 was performed using l-quinovose with neighboring group participation, which lead stereoselectively to the β-l-quinovoside. The 2-OH of the l-quinovo-unit was selectively deblocked, oxidized to the keto group, and then stereoselectively reduced, whereby 3 was produced.     

Biotransformation of 5α-hydroxycaryophylla-4(12),8(13)-diene with Cunninghamella elegans and Rhizopus stolonifer

Abstract

Biotransformation of 5α-hydroxycaryophylla-4(12),8(13)-diene (1) was studied with Cunninghamella elegans and Rhizopus stolonifer. Incubation of 1 with C. elegans gave regioselective oxidative addition (hydration) and isomerization at the C-4(12) exocyclic double bond and hydroxylation at C-3 and C-15, and thus provided two polar metabolites, (3Z),8(14)-caryophylladiene-5α,(11R)-15-diol (2) and 3β,4β,5α-trihydroxycaryophylla-8(13)-ene (3). Incubation of 1 with R. stolonifer gave a transannular cyclization reaction and afforded 2β-methoxyclovan-9-one (4), clovan-2β-ol-9-one (5) and 8-methoxycaryolane-5α,13β-diol (6). Compounds 3 and 6 are new compounds described here for the first time; their structures were deduced with the help of different spectroscopic techniques.     

Biosynthesis of Coumarin Glycosides by Transgenic Hairy Roots of Polygonum multiflorum

To investigate the substrate specificity and regio-selectivity of coumarin glycosyltransferases in transgenic hairy roots of Polygonum multiflorum, esculetin (1) and eight hydroxycoumarins (2–9) were employed as substrates. Nine corresponding glycosides (10–18) involving four new compounds, 6-chloro-4-methylcoumarin 7-O-β-D-glucopyranoside (15), 6-chloro-4-phenylcoumarin 7-O-β-D-glucopyranoside (16), 8-hydroxy-4-methylcoumarin 7-O-β-D-glucopyranoside (17), and 8-allyl-4-methylcoumarin 7-O-β-D-glucopyranoside (18), were biosynthesized by the hairy roots.     

A Novel Method for the Synthesis of ddA and F-ddA Via Regioselective 2′-O-Deacetylation of 9-(2,5-DI-O-Acetyl-3-bromo-3-deoxy-β-D-xylofuranosyl)adenine

Abstract

Regioselective 2′-O-deacetylation of 9-(2,5-di-O-acetyl-3-bromo-3-deoxy-β-D-xylofuranosyl)adenine (1) is achieved by treatment of 1 with β-cyclodextrin (β-CyD) / aq. NaHCO₃ or N₂H₄·H₂O / EtOH. The 9-(5-O-Acetyl-3-bromo-3-deoxy-β-D-xylo-furanosyl)adenine (2) obtained is a common intermediate for the synthesis of 2′,3′-dideoxy-adenosine (ddA) (7) and 9-(2-fluoro-2,3-dideoxy-β-D-threo-pentofuranosyl)-adenine (F-ddA) (9).     

Design,Synthesis, and Antiviral Evaluation of Some Polyhalogenated Indole C-nucleosides

2,5,6-Trichloro-1-(β-D-ribofuranosyl)benzimidazole (TCRB), 2-bromo-5,6-dichloro-1-(β-D-ribofuranosyl)benzimidazole (BDCRB) and 2-benzylthio-5,6-dichloro-1-(β-D-ribofuranosyl)benzimidazole (BTDCRB) are benzimidazole nucleosides that exhibit strong and selective anti-HCMV activity. Polyhalogenated indole C-nucleosides were prepared as 1-deaza analogs of the benzimidazole nucleosides TCRB and BDCRB. A mild Knoevenagel coupling reaction between an indol-2-thione and a ribofuranose derivative was developed for the synthesis of 2-benzylthio-5,6-dichloro-3-(β-D-ribofuranosyl)indole (12). 3-(β-D-ribofuranosyl)-2,5,6-trichloroindole (16) was prepared from 12 in 4 steps. A Lewis acid-mediated glycosylation method was then developed to prepare the targeted 2-haloindole C-nucleoside 16 stereoselectively in four steps from the corresponding 2-haloindole aglycons. Only 12 was active against HCMV but it also was somewhat cytotoxic.     

Ring-Opening of 3-β-D-Ribofuranosyl-3,7,8,9-Tetrahydropyrimido [1,2-i]Purin-8-ol and Preparation of 2-Thio- and 2-aza-Adenosine Derivatives

The adduct 3-β-D-ribofuranosyl-3,7,8,9-tetrahydropyrimido[1,2-i]purin-8-ol (2), obtained from adenosine and epichlorohydrin, underwent ring fission at basic conditions. The initial ring-opening took place at C2 of the pyrimidine unit resulting in 2-(5-amino-1-β-D-ribofuranosyl-imidazol-4-yl)-1,4,5,6-tetrahydropyrimidin-5-ol (3). Also the tetrahydropyrimidine ring of 3 could be opened resulting in 5-amino-1-(β-D-ribofuranosyl)-imidazole-4-(N-3-amino-2-hydroxyl-propyl)-carboxamide (4). In hot acid conditions, 2 was both deglycosylated and ring-opened yielding 2-(5-amino-imidazol-4-yl)-1,4,5,6-tetrahydropyrimidin-5-ol (7) as the final product. When reacting 3 with CS₂ or HNO₂ ring-closure took place and 3-β-D-ribofuranosyl-3,4,7,8,9-pentahydropyrimido[1,2-i]purin-8-ol-5-thione (5), and 3-β-D-ribofuranosyl-imidazo[4,5-e]-3,7,8,9-tetrahydropyrimido[1,2-c][1,2,3]triazine-8-ol (6), respectively, were obtained. Also, the pyrimidine ring of the epichlorohydrin adduct with adenine, 10-imino-5,6-dihydro-4H,10H-pyrimido[1,2,3-cd]purin-5-ol (10), underwent ring fission and the product was identified as 3-hydroxy-1,2,3,4-tetrahydroimidazo[1,5-a]pyrimidine-8-carboximidamide (11).