Bioactive friedolanostanes and 11(10-->8)-abeolanostanes from the bark of Garcinia speciosa

A new friedolanostane, 7, and three triterpenes, 8, 9a, and 10, possessing the new 11(10-->8)-abeolanostane carbon skeleton were isolated from the bark of Garcinia speciosa. Structures were elucidated by spectroscopic and spectrometric studies and the structure of 8 by X-ray crystallographic analysis, thus forcing structure revision of a triterpene from the same source previously assumed to be a friedolanostane. These and several friedo- and lanostanes earlier isolated from the same source were evaluated for cytotoxicity against three human cell lines. Most were moderately active, with three friedolanostanes effective in inducing apoptosis in the MCF-7 cell line.

27-norlanostane glycosides from the bulbs of Muscari paradoxum

Eight 27-norlanostane glycosides (1-8), including five new compounds (3 and 5-8), were isolated from the MeOH extract of the bulbs of Muscari paradoxum. The structures of the new compounds were determined on the basis of extensive spectroscopic analysis, including 2D NMR data, and the results of hydrolytic cleavage. The cytotoxic activity of 1-8 against HSC-2 human oral squamous cell carcinoma cells is also reported.

Geranylgeraniol regulates negatively caspase-1 autoprocessing: implication in the Th1 response against Mycobacterium tuberculosis

Caspase-1 is a cysteine protease composed by two 20-kDa and two 10-kDa subunits that processes pro-IL-1beta and pro-IL-18 to their mature forms. This enzyme is present in cells as a latent zymogen that becomes active through a tightly regulated proteolytic cascade. Activation is initiated by the oligomerization of an adaptor molecule, or by the formation of a multiprotein complex named inflammasome. Negative regulation of caspase-1 activation is exerted by proteins that compete with the adaptor molecule or with the inflammasome formation. We previously reported that fluvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, increases caspase-1 activity in PBMC. This effect was strengthened by Mycobacterium tuberculosis, rending an exacerbated IL-1beta, IL-18, and IFN-gamma production. Mevalonate, the product of 3-hydroxy-3-methylglutaryl coenzyme A reductase, is a precursor for both nonsterol isoprenoid and sterol formation. In this study, we studied the involvement of mevalonate derivatives in the regulation of caspase-1 activation. Inhibition of sterol formation by SKF-104976 or haloperidol had no effect on IL-1beta release. However, the isoprenoid geranylgeraniol prevented both caspase-1 activation and the exacerbated IL production induced by fluvastatin. This isoprenoid significantly reduced the release of IL-18 and IFN-gamma by PBMC treated with mycobacteria, even in the absence of fluvastatin. In correlation with the increased caspase-1 activity, fluvastatin stimulated the proforms cleavage, enhancing the formation of active subunit p10. Geranylgeraniol not only prevented this effect, but induced proforms accumulation. Present results suggest that, once the proteolytic cascade is initiated, geranylgeraniol may exert an additional negative regulation on caspase-1 cleavage process.

A low-toxicity method for the separation of lanosterol and dihydrolanosterol from commercial mixtures

We describe an inexpensive, low-toxicity and high-yielding method for the production of pure lanosterol and dihydrolanosterol from the commercially available mixture. Optimum conditions are presented for the one-pot production of the intermediate 24,25 vicinal diol of lanosterol acetate (via either epoxidation or hydroxyhalogenation) which is readily separated from the unreacted dihydrolanosterol acetate. The lanosterol diol can then be converted to pure (>97%) lanosterol. Hypophosphorous acid was used for both the conversion of the epoxide to the diol, and as a catalyst for the hydroxyhalogenation by N-halosuccinimides of the olefinic bond.

Quantitation of lanosterol and its major metabolite FF-MAS in an inhibition assay of CYP51 by azoles with atmospheric pressure photoionization based LC-MS/MS

Azoles affect the steroid balance in all biological systems and may therefore be called endocrine disrupters. Lanosterol 14alpha-demethylase (CYP51) is an enzyme inhibited by azoles. Only few data have been reported showing their inhibitory potency since an assay in an in vitro system is not available so far. In the present work an inhibition assay using human recombinant CYP51, coexpressed with human P450 oxido-reductase by the baculovirus/insect cell expression system, and LC-MS/MS as analytical method is described. Atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI) sources were used with a triple quadrupole mass spectrometer to compare quantitation of lanosterol (substrate) and 4,4-dimethyl-5alpha-cholesta-8,14,24-triene-3beta-ol (FF-MAS) (product of CYP51) with d(6)-2,2,3,4,4,6-cholesterol (d(6)-cholesterol) as internal standard. Optimization of analytical parameters resulted in a LC-APPI-MS/MS method with a LOQ of 10 pg on column for FF-MAS. The sensitivity of the method (LOD 0.5 ng/ml) makes it possible to analyze supernatants of inhibition experiments after precipitation of proteins by isopropanol without any sample enrichment. The coefficient of variation of the analytical method was <20% (n = 5) for FF-MAS, lanosterol and d(6)-cholesterol. The external calibration curve was linear from 1 to 10,000 ng/ml with R(2) >/= 0.999 and an accuracy of 94-115%. Compared with APCI, APPI provides a ten- to 500-fold increase in sensitivity for the analytes in this study. IC(50) values of epoxiconazole and miconazole-two widely used azole fungicides used in agriculture and in human medicine, respectively-were 1.95 microM and 0.057 microM.

Selective anti-Toxoplasma gondii activities of azasterols

We report potent and selective inhibitory effects of 22,26-azasterol and 24,25-(R,S)-epiminolanosterol, known inhibitors of Delta24(25)-sterol methyltranferase (SMT) in fungi and protozoa, on the proliferation of Toxoplasma gondii in LLCMK2 cells. These compounds produced a dose-dependent reduction in parasite proliferation. 22,26-azasterol had an IC50 of 5.3 microM after 24 h and 4.5 microM after 48 h, while for 24,25-(R,S)-epiminolanosterol the IC50 values were 1 microM after 24 h and 0.12 microM after 48 h. The rapid reduction of parasite load suggested these compounds have selective cytotoxic effects against T. gondii. However, we were unable to detect 24-alkyl sterols in purified T. gondii tachyzoites using highly sensitive gas-liquid chromatography/mass spectrometry methods, a fact which indicated that the anti-proliferative effects of these azasterols were not mediated by inhibition of SMT. Transmission electron microscopy showed that the mitochondrion was the major target of drugs. Ultrastructural effects on plasma membrane, apicoplast and the formation of autophagosomal structures were also observed.

Ananosic acids B and C, two new 18(13-->12)-abeo-lanostane triterpenoids from Kadsura ananosma

Two new 18(13-->12)-abeo-lanostane triterpenoid acids, ananosic acids B (1) and C (2), were isolated from the stems of Kadsura anaosma. Their structures were elucidated by spectral studies and chemical transformation. Compounds 1 and 2 were evaluated for cytotoxicity using CCRF-CEM leukemia cells and HeLa cells.

Eucosterol-type nortriterpenoids from Merwilla natalensis

The bulbs of Merwilla natalensis have yielded two known homoisoflavanones, the known spirocyclic homoisoflavanone, scillascillin, four known nortriterpenoids, and the new nortriterpenoid, (22R,23S)-17alpha,23-epoxy-22,29-dihydroxy-27-nor-lanost-8-en-3,24-dione (1), bisnortriterpenoid, (22R,23S)-17alpha,23-epoxy-3beta,22,24xi-trihydroxy-27,28-bisnor-lanost-8-ene (2), and trisnortriterpenoid, (23S)-17alpha,23-epoxy-3beta,24xi-dihydroxy-27,28,29-trisnor-lanost-8-ene (3). The structures of 1-3 were determined by spectroscopic methods.

Efficient routes to epimerically-pure side-chain derivatives of lanosterol

A technically simple route is described to individual epimers of side-chain derivatives of lanosterol (3beta-hydroxy-5alpha-lanosta-8,24-diene). Epimerically pure 24,25-epoxy-, 24,25-dihydroxy- and 24-bromo-25-hydroxy-lanosterol have been prepared in good yield from commercial (50-60%) lanosterol. Hypophosphorous acid was used as a catalyst for the cohalogenation of the Delta24(25) bond and also for the efficient conversion of 24,25-epoxy- and 24-bromo-25-hydroxylanosterol to epimerically pure 24(R) or 24(S)-24,25-dihydroxylanosterols.

Enzymatic cyclization of 22,23-dihydro-2,3-oxidosqualene into euph-7-en-3beta-ol and bacchar-12-en-3beta-ol by recombinant beta-amyrin synthase

Recombinant beta-amyrin synthase from Pisum sativum converted 22,23-dihydro-2,3-oxidosqualene, a substrate analogue lacking the terminal double bond of 2,3-oxidosqualene, into a 4:1 mixture of euph-7-en-3beta-ol and bacchar-12-en-3beta-ol. This is the first demonstration of the enzymatic formation of the baccharene skeleton with a six-membered D-ring. In the absence of the terminal double bond, the proton-initiated cyclization first generated the tetracyclic dammarenyl cation, followed by a backbone rearrangement with loss of H-7alpha leading to the formation of euph-7-en-3beta-ol, while D-ring expansion to the baccharenyl cation and subsequent 1,2-hydride shifts with H-12alpha elimination yielded bacchar-12-en-3beta-ol. It is remarkable that the formation of the anti-Markovnikov six-membered D-ring did not depend on the participation of the terminal pi-electrons.

Two new cyclolanostanol glycosides from the aerial parts of Cimicifuga foetida

Two new cyclolanostanol glycosides, cimifoetiside IV (1) and cimifoetiside V (2) and two known compounds have been isolated from the aerial part of Cimicifuga foetida L. On the basis of spectral and chemical evidences, the structures of 1 and 2 were elucidated to be 25-O-acetylcimigenol-3-O-beta-D-glucopyranosyl-(1" --> 2')-beta-D-xylopyranoside (1) and cimigenol-3-O-beta-D-glucopyranosyl-(1"' --> 2")-beta-D-glucopyranosyl-(1" --> 2')-beta-D-xylopyranoside (2). The known compounds were identified as 25-O-acetylcimigenol-3-O-beta-D-glucopyranosyl-(1 --> 3)-beta-D-xylopyranoside (3) and 23-O-acetylshengmanol-3-O-beta-D-glucopyranosyl-(1 --> 3)-beta-D-xylopyranoside (4).

Phytoestrogen Cimicifugoside-Mediated Inhibition of Catecholamine Secretion by Blocking Nicotinic Acetylcholine Receptor in Bovine Adrenal Chromaffin Cells

We investigated the effect of the phytoestrogen cimicifugoside, one of the pharmacologically active ingredients of the medicinal plant Cimicifuga racemosa (black cohosh) that has been used to treat many kinds of neuronal and menopausal symptoms, such as arthritis, menopausal depression, and nerve pain. Cimicifugoside inhibited calcium increase induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), a nicotinic acetylcholine receptor (nAChR) agonist in bovine adrenal chromaffin cells with a half-maximal inhibitory concentration (IC(50)) of 18 +/- 2 microM. In contrast, cimicifugoside did not affect the calcium increases evoked by high K(+), veratridine, and bradykinin. The DMPP-induced sodium increase was also inhibited by cimicifugoside with an IC(50) of 2 +/- 0.3 microM, suggesting that the activity of nAChRs is inhibited by cimicifugoside. Cimicifugoside did not affect the KCl-induced secretion but markedly inhibited the DMPP-induced catecholamine secretion that was monitored by carbon-fiber amperometry in real time and high-performance liquid chromatography through electrochemical detection. The results suggest that cimicifugoside selectively inhibits nAChR-mediated response in bovine chromaffin cells.

Scale-Up of a Liquid Static Culture Process for Hyperproduction of Ganoderic Acid by the Medicinal Mushroom Ganoderma lucidum

Scale-up of a liquid static culture process was studied for hyperproduction of ganoderic acid (GA) by a famous Chinese traditional medicinal mushroom, Ganoderma lucidum. Initial volumetric oxygen transfer coefficient (K(L)a) and area of liquid surface per liquid volume (A(s)) were identified as key factors affecting cell growth and GA accumulation in liquid static cultures of G. lucidum, on the basis of which a multilayer static bioreactor was designed. At a low initial K(L)a level of 2.1 h(-1), a thick layer of white mycelia was formed on the liquid surface, and an optimal production of total GA (i.e., GA production in the liquid and on the liquid surface) was obtained. Both the formation of white mycelia and production of GA on the liquid surface were enhanced with an increase of A(s) within the range as investigated (0.24-1.53 cm(2)/mL). At an A(s) value of 0.90 cm(2)/mL, the total GA production reached maximum. A successful scale-up from a 20-mL static T-flask to a 7.5-L three-layer static bioreactor was achieved based on initial K(L)a. The maximum biomass (20.8 +/- 0.1 g DW/L), GA content (4.96 +/- 0.13 mg/100 mg DW), and total GA production (976 +/- 35 mg/L) were attained in static bioreactors. Not only GA content but also its production obtained in this work were the highest ever reported.

Anti-inflammatory lanostane-type triterpene acids from Piptoporus betulinus

Six lanostane-type triterpene acids were isolated from the fruiting bodies of Piptoporus betulinus. They were identified as polyporenic acids A (1) and C (2), three derivatives of polyporenic acid A (3-5), and a novel compound, (+)-12 alpha,28-dihydroxy-3 alpha-(3'-hydroxy-3'-methylglutaryloxy)-24-methyllanosta-8,24(31)-dien-26-oic acid (6). All these compounds suppressed the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema on mouse ears by 49-86% with a 400 nmol/ear application.

Antitumor agents 220. Antitumor-promoting effects of cimigenol and related compounds on Epstein-Barr virus activation and two-stage mouse skin carcinogenesis

Cimigenol (1) and 39 related compounds were screened as potential antitumor promoters by examining the ability of the compounds to inhibit Epstein-Barr virus early antigen (EBV-EA) activation (induced by 12-O-tetradecanoylphorbol-13-acetate) in Raji cells. Structure-activity relationship analysis indicated that compound 1 showed the highest activity and also exhibited significant inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These data suggest that 1 and the related compounds might be valuable anti-tumor promoters.

[Studies on the new triterpenoid saponin of the aerial part of Cimicifuga foetida]

OBJECTIVE

To find new active constituents from the aerial part of Cimicifuga foetida.

METHOD

Various column chromatographic techniques were used for the isolation and purification of the principles. The structures were elucidated on the basis of spectral data and chemical evidences.

RESULT

Four 9,19-cycloartane triterpenoid saponins were obtained and identified as Cimifoetiside III (25-anhydrocimigenol-3-O-beta-D-galactopyranoside, 1), 25-O-acetyl-cimigenol xylopyranoside (2), 25-O-acetyl-cimigenol galactopyranoside (3), 7 beta-hydrocimigenol xylopyranoside (4).

CONCLUSION

Compound 1 is new and compound 4 was isolated from this plant for the first time.

[Studies on new trierpenoid constituents from the Rhizoma of Cimicifuga foetida]

OBJECTIVE

To find new active constituents from Rhizome of Cimicifuga foetida.

METHOD

Various column chromatographic techniques were employed for isolation and purification. The structures were elucidated on the basis of spectral and chemical evidences.

RESULT

Four triterpenoid compounds were isolated and identified as 7,8-didehydro-27-deoxyactein(1), 24-O-acetylshengmanol-3-O-beta-D-xyl (23R, 24R)[2], cimigenol(3), cimigenol-3-O-beta-D-xyl(4).

CONCLUSION

Compound 1 is a new compound, 2-4 were obtained from this medicinal material for the first time. The antiosteoporosis activity screening in vitro(by the method of SRB) indicates that Compounds 1, 2 and 4 can promote the proliferation for rat Osteoblastoma cell line (UMR106) at the concentration of 10(-9) kg.L-1.

Triterpenoids from the orchids Agrostophyllum brevipes and Agrostophyllum callosum

Agrostophyllinol and agrostophyllinone, two new triterpenoids, were isolated from the orchid Agrostophyllum brevipes. Agrostophyllinone was also isolated from another orchid Agrostophyllum callosum. The structures of agrostophyllinol and agrostophyllinone were established as 24-methylene-lanosta-9(11)-en-3beta-ol (5a) and 24-methylene-lanosta-9(11)-en-3-one (5c), respectively, from spectral and chemical evidence. The above triterpenoids are of considerable biogenetic importance.

Creating new supramolecular materials by architecture of three-dimensional nanocrystal fiber networks

The architecture of three-dimensional interconnecting self-organized nanofiber networks from separate needlelike crystals of L-DHL (lanosta-8,24-dien-3beta-ol:24,25-dihydrolanosterol = 56:44) in di-isooctylphthalate has been achieved for the first time, on the basis of the completely new concept of branching creation by additives (branching promoters). [In this work, an additive, ethylene/vinyl acetate copolymer (EVACP), is used at a concentration of several 10 ppm.] We demonstrate that this novel technique enables us to produce previously unknown self-supporting supramolecular functional materials with tailormade micro- or nanostructures, possessing significantly modified macroscopic properties, by utilizing materials thus far considered to be "useless". In addition, both the self-organized structure and the properties of the new materials can be fine-tuned by altering the processing conditions. Our results show that the formation of the interconnecting 3D self-organized network structure is controlled by a new mechanism, so-called crystallographic mismatch branching mechanism, as opposed to the conventionally adopted molecular self-assembly mechanism. The principles and criteria for the selection of branching promoters are also discussed from the point of view of molecular structures.

Directed evolution experiments reveal mutations at cycloartenol synthase residue His477 that dramatically alter catalysis

[reaction: see text] Cycloartenol synthase cyclizes and rearranges oxidosqualene to the protosteryl cation and then specifically deprotonates from C-19. To identify mutants that deprotonate differently, randomly generated mutant cycloartenol synthases were selected in a yeast lanosterol synthase mutant. A novel His477Asn mutant was uncovered that produces 88% lanosterol and 12% parkeol. The His477Gln mutant produces 73% parkeol, 22% lanosterol, and 5% Delta(7)-lanosterol. These are the most accurate lanosterol synthase and parkeol synthase that have been generated by mutagenesis.

Novel hydroquinone as a matrix metallo-proteinase inhibitor from the mushroom, Piptoporus betulinus

The novel hydroquinone, (E)-2-(4-hydroxy-3-methyl-2-butenyl)-hydroquinone, and known compound, polyporenic acid C, were isolated as matrix metallo-proteinase inhibitors from the mushroom, Piptoporus betulinus.

Triterpenoid constituents isolated from the bark of Abies sachalinensis

Three new lanostane-type triterpenoids (1-3) were isolated from the bark of Abies sachalinensis along with a known compound (4). The structures of 1-4 were characterized by spectroscopic methods including NMR and MS. Compound 4 and some derivatives were tested for inhibitory effects on in vitro DNA topoisomerases I and II and found to be selective catalytic inhibitors of topoisomerase II activity with IC(50) values in the range 43-76 microM.

Is Pneumocystis a plant?

Pneumocystis, an AIDS-associated opportunistic pathogen of the lung has some unusual features. This article focuses on work done by my group to understand the organism's distinct sterols. Although Pneumocystis is closely related to fungi, it lacks the major fungal sterol, ergosterol. Several delta(7) 24-alkysterols synthesized by P. carinii are the same as those reported in some basidiomycete rust fungi. The 24-alkylsterols are synthesized by the action of S-adenosyl-L-methionine:C-24 sterol methyl transferase (SAM:SMT). Fungal SAM:SMT enzymes normally transfer only one methyl group to the C-24 position of the sterol side chain and the cells accumulate C28 24-alkylsterols. In contrast, the P. carinii SAM:SMT and those of some plants catalyze one or two methyl transfer reactions producing both C28 and C29 24-alkylsterols. However, unlike most fungi, plants, and the kinetoplastid flagellates Leishmania and Trypanosoma cruzi, P. carinii does not appear to form double bonds at C-5 of the sterol nucleus and C-22 of the sterol side chain. Furthermore, the P. carinii SAM:SMT substrate preference for C30 lanosterol differs from that of homologous enzymes in any other organisms studied. C31 24-Methylenelanosterol and C32 pneumocysterol, products of SAM:SMT activity on lanosterol, can accumulate in high amounts in some, but not all, human-derived Pneumocystis jiroveci populations.

The Pneumocystis carinii drug target S-adenosyl-L-methionine:sterol C-24 methyl transferase has a unique substrate preference

Pneumocystis is an opportunistic pathogen that can cause pneumonitis in immunodeficient people such as AIDS patients. Pneumocystis remains difficult to study in the absence of culture methods for luxuriant growth. Recombinant protein technology now makes it possible to avoid some major obstacles. The P. carinii expressed sequence tag (EST) database contains 11 entries of a sequence encoding a protein homologous to S-adenosyl-L-methionine (SAM):C-24 sterol methyl transferase (SMT), suggesting high activity of this enzyme in the organism. We sequenced the erg6 cDNA, identified the putative peptide motifs for the sterol and SAM binding sites in the deduced amino acid sequence and expressed the protein in Escherichia coli. Unlike SAM:SMT from other organisms, the P. carinii enzyme had higher affinities for lanosterol and 24-methylenelanosterol than for zymosterol, the preferred substrate in other fungi. Cycloartenol was not a productive substrate. With lanosterol and 24-methylenelanosterol as substrates, the major reaction products were 24-methylenelanosterol and pneumocysterol respectively. Thus, the P. carinii SAM:SMT catalysed the transfer of both the first and the second methyl groups to the sterol C-24 position, and the substrate preference was found to be a unique property of the P. carinii SAM:SMT. These observations, together with the absence of SAM:SMT among mammals, further support the identification of sterol C-24 alkylation reactions as excellent targets for the development of drugs specifically directed against this pathogen.