Metabolism of (24R and 24S)-27-nor-24-methyl-3α,7α-dihydroxy-5β-cholestan-26-oic acids and 27-nor-3α,7α-dihydroxy-5β-cholestan-26-oic acid in guinea pigs

[7β-³H]-(24R and 24S)-27-nor-24-methyl-3α,7α-dihydroxy-5β-cholestan-26-oic acids and [7β-³H]-27-nor-3α,7α-dihydroxy-5β-cholestan-26-oic acid (C₂₇ and C₂₆ bile acids having the same nuclear configuration as cheno-deoxycholic acid and its precursor, 3α,7α-dihydroxy-5β-cholestan-26-oic-acid) were synthesized and administered intraperitoneally to bile fistula guinea pigs. The biliary bile acids formed were hydrolyzed and analyzed by thin layer chromatography, and the metabolites were identified by the inverse isotope dilution method. The results showed that both (24R and 24S)-27-nor-24-methyl-3α,7α-dihydroxy-5β-cholestan-26-oic acids were not metabolized by the liver and were excreted unchanged as their taurine and glycine conjugates whereas 27-nor-3α,7α-dihydroxy-5β-cholestan-26-oic acid was converted to chenodeoxycholic acid.     

Triterpenes in Ganoderma lucidum

Four new oxygenated triterpenes, isolated from the mycelia of the fungus Ganoderma lucidum, were determined to be lanosta-7,9(11),24-trien-3α, 15α-dihydroxy-26-oic acid, lanosta-7,9(11),24-trien-3β, 15α-dihydroxy-26-oic-acid, lanosta-7,9(11),24-trien-3β,22β-diacetoxy-15α-hydroxy-26-oic acid and lanosta-7,9(11),24-trien-15α,22β-diacetoxy-3β-hydroxy-26-oic acid by spectroscopic methods.     

Bile acid biosynthesis: the metabolism of 7 alpha-hydroxy-4-cholesten-3-one in the bile fistula rat.

The two primary bile acids, cholic acid (3α,7α,12α-tri-hydroxy-5β-cholan-24-oic acid) and chenodeoxycholic acid (3α,7α-dihydroxy-5β-cholan-24-oic acid), are initially synthesized by way of identical precursors, and the point of divergence of this pathway is thought to occur at the intermediate 7α-hydroxy-4-cholesten-3-one. In order to test this hypothesis, bile fistula rats received simultaneous intra-venous infusions of ³H-7α-hydroxy-4-cholesten-3-one and ¹⁴C-cholesterol (5-cholesten-3β-ol). Assays of equal specific activities of the two bile acids from an infusion of ¹⁴C-cholesterol demonstrated the achievement of a steady state, and assays of equal specific activities from an infusion of ³H-7α-hydroxy-4-cholesten-3-one would-validate the above postulate. However, the infusion of ³H-7α-hydroxy-4-cholesten-3-one resulted in unequal specific activities in the bile acids of the rats investigated, with cholic acid always of a lower value. These results suggest that either 7α-hydroxy-4-cholesten-3-one is not the last common intermediate in the production of cholic acid and chenodeoxycholic acid, or that the infused bile acid intermediate was not metabolized in a fashion similar to that formed in the liver from cholesterol.     

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.     

Friedolanostane, friedocycloartane and benzophenone constituents of the bark and leaves of Garcinia benthami

Friedolanostanes, (22Z,24E)-3β-acetoxy-9α-hydroxy-17,14-friedolanosta-14,22,24-trien-26-oic acid, (22Z,24E)-3β,9α-dihydroxy-17,14-friedolanosta-14,22,24-trien-26-oic acid, (22Z,24E)-9α-hydroxy-3-oxo-17,14-friedolanosta-14,22,24-trien-26-oic acid, a friedocycloartane, (22Z,24E)-3α-hydroxy-17,13-friedocycloarta-12,22,24-trien-26-oic acid, and a benzophenone, benthaphenone, together with known compounds (22Z,24E)-3α,9α-dihydroxy-17,13-friedolanosta-12,22,24-trien-26-oic acid, methyl (24E)-3α,23-dihydroxy-17,14-friedolanosta-8,14,24-trien-26-oate, glutinol, lupeol, and stigmasterol, were isolated from leaves and bark of Garcinia benthami. Their structures were elucidated using spectroscopic techniques, mainly 1-D and 2-D NMR spectroscopy, and chemical correlations.     

Cerebrospinal Fluid Steroidomics: Are Bioactive Bile Acids Present in Brain?

In this study we have profiled the free sterol content of cerebrospinal fluid by a combination of charge tagging and liquid chromatography-tandem mass spectrometry. Surprisingly, the most abundant cholesterol metabolites were found to be C₂₇ and C₂₄ intermediates of the bile acid biosynthetic pathways with structures corresponding to 7α-hydroxy-3-oxocholest-4-en-26-oic acid (7.170 ± 2.826 ng/ml, mean ± S.D., six subjects), 3β-hydroxycholest-5-en-26-oic acid (0.416 ± 0.193 ng/ml), 7α,x-dihydroxy-3-oxocholest-4-en-26-oic acid (1.330 ± 0.543 ng/ml), and 7α-hydroxy-3-oxochol-4-en-24-oic acid (0.172 ± 0.085 ng/ml), and the C₂₆ sterol 7α-hydroxy-26-norcholest-4-ene-3,x-dione (0.204 ± 0.083 ng/ml), where x is an oxygen atom either on the CD rings or more likely on the C-17 side chain. The ability of intermediates of the bile acid biosynthetic pathways to activate the liver X receptors (LXRs) and the farnesoid X receptor was also evaluated. The acidic cholesterol metabolites 3β-hydroxycholest-5-en-26-oic acid and 3β,7α-dihydroxycholest-5-en-26-oic acid were found to activate LXR in a luciferase assay, but the major metabolite identified in this study, i.e. 7α-hydroxy-3-oxocholest-4-en-26-oic acid, was not an LXR ligand. 7α-Hydroxy-3-oxocholest-4-en-26-oic acid is formed from 3β,7α-dihydroxycholest-5-en-26-oic acid in a reaction catalyzed by 3β-hydroxy-Δ⁵-C₂₇-steroid dehydrogenase (HSD3B7), which may thus represent a deactivation pathway of LXR ligands in brain. Significantly, LXR activation has been found to reduce the symptoms of Alzheimer disease (Fan, J., Donkin, J., and Wellington C. (2009) Biofactors 35, 239–248); thus, cholesterol metabolites may play an important role in the etiology of Alzheimer disease.     

Biliary bile acids in birds of the Cotingidae family: taurine-conjugated (24R,25R)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid and two epimers (25R and 25S) of 3α,7α-dihydroxy-5β-cholestan-27-oic acid

Three C(27) bile acids were found to be major biliary bile acids in the capuchinbird (Perissocephalus tricolor) and bare-throated bellbird (Procnias nudicollis), both members of the Cotingidae family of the order Passeriformes. The individual bile acids were isolated by preparative RP-HPLC, and their structures were established by RP-HPLC, LC/ESI-MS/MS and NMR as well as by a comparison of their chromatographic properties with those of authentic reference standards of their 12α-hydroxy derivatives. The most abundant bile acid present in the capuchinbird bile was the taurine conjugate of C(27) (24R,25R)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid, a diastereomer not previously identified as a natural bile acid. The four diastereomers of taurine-conjugated (24ξ,25ξ)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid could be distinguished by NMR and were resolved by RP-HPLC. The RRT of the diastereomers (with taurocholic acid as 1.0) were found to be increased in the following order: (24R,25R)<(24S,25R)<(24S,25S)<(24R,25S). Two epimers (25R and 25S) of C(27) 3α,7α-dihydroxy-5β-cholestan-27-oic acid were also present (as the taurine conjugates) in both bird species. Epimers of the two compounds could be distinguished by their NMR spectra and resolved by RP-HPLC with the (25S)-epimer eluting before the (25R)-epimer. Characterization of the taurine-conjugated (24R,25R)-3α,7α,24-trihydroxy-5β-cholestan-27-oic acid and two epimers (25R and 25S) of 3α,7α-dihydroxy-5β-cholestan-27-oic acid should facilitate their detection in peroxisomal disease and inborn errors of bile acid biosynthesis.     

Synthesis of homoursodeoxycholic acid and [11,12-3H]homoursodeoxycholic acid

Homoursodeoxycholic acid and [11,12-³H]homoursodeoxycholic acid were synthesized from ursodeoxycholic acid and homocholic acid, respectively. Ursodeoxycholic acid (Ia) was converted to 3α,7β-diformoxy-5β-cholan-24-oic acid (Ib) using formic acid. Reaction of the diformoxy derivative (Ib) with thionyl chloride yielded the acid chloride (II) which was treated with diazomethane to produce 3α,7β-diformoxy-25-diazo-25-homo-5β-cholan-24-one (III). Homoursodeoxycholic acid (IV) was formed from the diazoketone (III) by means of the Wolff rearrangement of the Arndt-Eistert synthesis.N-Bromosuccinimide oxidation of homocholic acid (V), which was prepared from cholic acid by the same procedure described above, afforded 3α,12α-dihydroxy-7-oxo-25-homo-5β-cholan-25-oic acid (VI). Reduction of the 7-ketohomodeoxycholic acid (VI) with sodium in 1-propanol gave 3α,7β,12α-trihydroxy-25-homo-5β-cholan-25-oic acid (VII). The methyl ester of 7-epihomocholic acid (VII) was partially acetylated to give methyl 3α,7β-diacetoxy-12α-hydroxy-25-homo-5β-cholan-25-oate (VIII) using a mixture of acetic anhydride, pyridine and benzene. Dehydration of the diacetoxy derivative (VIII) with phosphorus oxychloride yielded methyl 3α,7β-diacetoxy-25-homo-5β-chol-11-en-25-oate (IX). Reduction of the unsaturated ester (IX) with tritium gas in the presence of platinum oxide catalyst followed by alkaline hydrolysis gave [11,12-³H]homoursodeoxycholic acid.     

Synthesis, aggregation behavior and cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid)

Synthesis, aggregation behavior and in vitro cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid, EPCA) are reported. The synthesis of this unnatural epimer of pythocholic acid (3α,12α,16α-trihydroxy-5β-cholan-24-oic acid, PCA) involves a series of simple and selective chemical transformations with an overall yield of 21% starting from readily available cholic acid (CA). The critical micellar concentration (CMC) of 16-epi-pythocholate in aqueous media was determined using pyrene as a fluorescent probe. In vitro cholesterol solubilization ability was evaluated using anhydrous cholesterol and results were compared with those of other natural di- and trihydroxy bile acids. These studies showed that 16-epi-pythocholic acid (16β-hydroxy-deoxycholic acid) behaves similar to cholic acid (CA) and avicholic acid (3α,7α,16α-trihydroxy-5β-cholan-24-oic acid, ACA) in its aggregation behavior and cholesterol dissolution properties.     

Effect of taurocholate on the conversion of 3α, 7α, 12α-Trihydroxy-5β-Cholestan-26-OIC acid into cholic acid

To determine if the conversion of the intermediate, 3α, 7α, 12α-trihydroxy-5β-cholestan-26-oic acid (THCA), into cholic acid is influenced by taurocholate, two rats were infused intravenously with [³H] THCA until they reached a steady state. Taurocholate was then added and infused at a rate of 1 μmole/min/rat for 48 hours. The percentage of [³H] THCA recovered in the bile did not increase indicating that taurocholate does not suppress the conversion of THCA into cholic acid.     

Chenodeoxycholic acid synthesis in the hamster: A metabolic pathway via 3β, 7α-dihydroxy-5-cholen-24-oic acid

The quantitative significance of the metabolism of 3β, 7α-dihydroxy-5-cholen-24-oic acid to chenodeoxycholic acid was evaluated in the hamster. A precursor-product relationship was established in this species by the finding that intravenous administration to an animal previously given cholesterol-4-¹⁴C caused a significant reduction in the specific activity of chenodeoxycholic acid. Administration of 12.9 μmole of the precursor was followed by a 10-fold increase in chenodeoxycholic acid excretion although the predominant excretory pathway was via biliary excretion as a monosulfate. The data indicate that synthesis of bile acid from cholesterol via the intermediate 3β, 7α-dihydroxy-5-cholen-24-oic acid can be a quantitatively important pathway.     

Antiplasmodial and other constituents from four Indonesian Garcinia spp.

Phytochemical investigations of four Garcinia spp. from Indonesia, i.e. Garcinia griffithii T. Anderson, Garcinia celebica L., Garcinia cornea L. and Garcinia cymosa K. Schum (Clusiaceae), have resulted in the isolation of a xanthone, 1,5-dihydroxy-3,6-dimethoxy-2,7-diprenylxanthone, 1,7-dihydroxyxanthone, isoxanthochymol, β-sitosterol-3-O-β-d-glucoside and stigmasterol-3-O-β-d-glucoside from the stem bark of G. griffithii; friedelin and 3β-hydroxy-23-oxo-9,16-lanostadien-26-oic acid or garcihombronane D from leaves of G. celebica; 23-hydroxy-3-oxo-cycloart-24-en-26-oic acid and epicatechin from stem bark of G. cornea; (±)-morelloflavone, morelloflavone-7-O-β-d-glucoside or fukugiside, the triterpene 3β-hydroxy-5-glutinen-28-oic acid and canophyllol from stem bark of G. cymosa. The xanthone and garcihombronane D displayed a selective activity against Plasmodium falciparum; isoxanthochymol and the triterpene β-hydroxy-5-glutinen-28-oic acid a broad but non-selective antiprotozoal activity.     

Seven new triterpenoids from the aerial parts of Ilex cornuta and protective effects against H2O2-induced myocardial cell injury

Seven new triterpenoids (1–7), together with two known ones (8–9), were isolated from the aerial parts ofIlex cornuta. The leaves of I. cornuta are the major source of “Kudingcha”, a popular herbal tea consumed in China and other countries. The structures of compounds 1–7 were determined as 20-epi-urs-12,18-dien-28-oic acid 3β-O-α-l-arabinopyranoside (1), 20-epi-urs-12,18-dien-28-oic acid 2′-O-acetyl-3β-O-α-l-arabinopyranoside (2), 20-epi-urs-12,18-dien-28-oic acid 3β-O-β-d-glucuronopyranoside-6-O-methyl ester (3), 3β,23-dihydroxy-20-epi-urs-12,18-dien-28-oic acid (4), 23-hydroxy-20-epi-urs-12,18-dien-28-oic acid 3β-O-α-l-arabinopyranoside (5), 23-hydroxy-20-epi-urs-12,18-dien-28-oic acid 3β-O-β-d-glucuronic acid (6), 23-hydroxy-20-epi-urs-12,18-dien-28-oic acid 3β-O-β-d-glucuronopyranoside-6-O-methyl ester (7), on the basis of spectroscopic analyses (IR, ESI–MS, HR-ESI–MS, 1D and 2D NMR) and chemical reactions. Protective effects against H₂O₂-induced H9c2 cardiomyocyte injury were tested in vitro for compounds 1–9, and the data showed that compound 4 had significant cell-protective effect. Compounds 1-9 did not show significant DPPH radical scavenging activity.     

7β,12β-dihydroxy-5β-cholan-24-oic acid as an internal standard for quantitative determination of bile acids by gas chromatography

In order to find an artificial internal standard compound for quantitative determination of bile acids by gas chromatography, 7α,12α-,7α, 12β-, 7β,12α- and 7β,12β-dihydroxy-5β-cholan-24-oic acids were chemically synthesized with cholic acid (1) as the first starting material. The gas chromatographie retention time of 7β,12β-dihydroxy-5β-cholan-24-oic acid (ββ-isomer) was more different from that of natural bile acids than the other isomers. Moreover, ββ-isomer was extracted in the same fraction as the bile acids from urine, and no urinary substance had the same retention time as ββ-isomer. No artifact was produced from ββ-isomer during the analysis procedure. It was concluded that the ββ-isomer is an internal standard compound with certain advantages for the quantitative determination of bile acids in urine by gas chromatography, irrespective of the recovery rate during the analysis procedure.     

Plectranthoic acid,acetylplectranthoic acid and plectranthadiol,three triterpenoids from Plectranthus rugosus

Sitosterol and three new pentacyclic triterpenoids, plectranthoic acid, acetylplectranthoic acid and plectranthadiol, have been isolated from leaves of P. rugosus. From spectroscopic evidence and chemical behaviour the structure of plectranthoic acid was established as (19S)-3α-hydroxy-18α-urs-12-en-29β-oic acid and acetylplectranthoic acid is the 3α-acetyl derivative of this compound. Plectranthadiol is (19S)- 3α-hydroxy-18α-urs-12-en-29β-ol.     

Metabolomics reveals an essential role for peroxisome proliferator-activated receptor α in bile acid homeostasis

Peroxisome proliferator-activated receptor α (PPARα) is a nuclear receptor that regulates fatty acid transport and metabolism. Previous studies revealed that PPARα can affect bile acid metabolism; however, the mechanism by which PPARα regulates bile acid homeostasis is not understood. In this study, an ultraperformance liquid chromatography coupled with electrospray ionization qua dru pole time-of-flight mass spectrometry (UPLC-ESI-QTOFMS)-based metabolomics approach was used to profile metabolites in urine, serum, and bile of wild-type and Ppara-null mice following cholic acid (CA) dietary challenge. Metabolomic analysis showed that the levels of several serum bile acids, such as CA (25-fold) and taurocholic acid (16-fold), were significantly increased in CA-treated Ppara-null mice compared with CA-treated wild-type mice. Phospholipid homeostasis, as revealed by decreased serum lysophos phati dylcholine (LPC) 16:0 (1.6-fold) and LPC 18:0 (1.6-fold), and corticosterone metabolism noted by increased urinary excretion of 11β-hydroxy-3,20-dioxopregn-4-en-21-oic acid (20-fold) and 11β,20α-dihydroxy-3-oxo-pregn-4-en-21-oic acid (3.6-fold), were disrupted in CA-treated Ppara-null mice. The hepatic levels of mRNA encoding transporters Abcb11, Abcb4, Abca1, Abcg5, and Abcg8 were diminished in Ppara-null mice, leading to the accumulation of bile acids in the liver during the CA challenge. These observations revealed that PPARα is an essential regulator of bile acid biosynthesis, transport, and secretion.     

肋果茶中的萜类化学成分研究

从肋果茶(Sladenia celastrifolia)95％乙醇提取物的乙酸乙酯部位中分离得到15个萜类化合物,经波谱学方法分别鉴定为sladeniafolin A(1),grasshopper ketone (2),(3S,5R,6S,7E,9R) -7-megastigmene-3,6,9-triol (3),hedytriol (4),(3S,5R,6R,7E,9R) -3,5,6,9-tetrahydroxy-7-megastigmene(5),1′S*,4′R*-8-(4′-hydroxy-2′,6′,6′-trimethylcyclohex-2-enyl)-6-methyloct-3E,5E,7E-trien -2-one (6),2α,3α,19α,23-tetrahydroxyurs-12-en-28-oic acid (7),2α,3β,19α,23-tetrahydroxyurs-12-en-28-oic acid(8),pomolic acid(9),3-O-acetyl pomolic acid(10),ursaldehyde (11),camarolide (12),3β-hydroxyurs-11-en-13β(28) -olide (13),3β-hydroxy -11α,12α-epoxy-urs-13β,28-olide (14)和28-0-β-D-glucopyranosyl euscaphic acid (15).以上化合物均首次从该植物中分离得到,其中1为新的C9裂环烯醚萜.     

Terpenes of Dipterocarpus and Doona species

From the resins of Dipterocarpus hispidus, Dipterocarpus zeylanicus and Doona macrophylla, asiatic (2α,3β,23α-trihydroxyurs-12-en-28-oic) and 2α,3β-dihydroxyurs-12-en-28-oic acids have been isolated. The resin of Doona macrophylla contains ursolic acid and that of Doona congestiflora asiatic acid, 20β-hydroxy-3-oxo dammar-23-ene (Dipterocarpol) and a dihydroxyolean-12-en-28-oic acid. The bark of Dipterocarpus hispidus contains betulinic acid, dipterocarpol, and 3β,20β-dihydroxydammar-23-ene (dammarenediol 20S) whilst the timber contained dipterocarpol and asiatic acid.     

New derivatives of ursolic acid through the biotransformation by Bacillus megaterium CGMCC 1.1741 as inhibitors on nitric oxide production

Microbial transformation of ursolic acid (1) by Bacillus megaterium CGMCC 1.1741 was investigated and yielded five metabolites identified as 3-oxo-urs-12-en-28-oic acid (2); 1β,11α-dihydroxy-3-oxo-urs-12-en-28-oic acid (3); 1β-hydroxy-3-oxo-urs-12-en-28, 13-lactoe (4); 1β,3β, 11α-trihydroxyurs-12-en-28-oic acid (5) and 1β,11α-dihydroxy-3-oxo-urs-12-en-28-O-β-d-glucopyranoside (6). Metabolites 3, 4, 5 and 6 were new natural products. Their nitric oxide (NO) production inhibitory activity was assessed in lipopolysaccharide (LPS) – stimulated RAW 264.7 cells. Compounds 3 and 4 exhibited significant activities with the IC₅₀ values of 1.243 and 1.711 μM, respectively. A primary structure-activity relationship was also discussed.     

A new triterpenic acid from the wood rotting fungi

A new triterpenic acid, assigned the trivial name polyporenic acid D, has been isolated from the wood rotting fungus Polyporus officinalis. It has been shown to have the structure 3α-hydroxy-4,4,14α-trimethyl-5α-ergosta-8, 24(28)-dien-26-oic acid.