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At least 163 records · Page 9Linked to original sources
PubMed1996

Molecular cloning and bacterial expression of a cDNA encoding furostanol glycoside 26-O-beta-glucosidase of Costus speciosus.

Furostanol glycoside 26-O-beta-glucosidase (F26G) purified from Costus speciosus rhizomes was digested with endoproteinase, and several internal peptide fragments were obtained. Degenerate oligonucleotide primers based on amino acid sequences of the peptides were used for amplification of F26G cDNA fragments by applying nested polymerase chain reactions to cDNAs from in vitro cultured plantlets of C. speciosus. Using primers based on sequences of the cDNA fragments, the 5'- and 3'-end clones were isolated by rapid amplification of cDNA ends (RACE) methods. Finally, the entire coding portion of F26G cDNA was cloned by using primers designed from sequences of the RACE products. The deduced amino acid sequence of CSF26G1, the protein encoded by the cloned cDNA, consists of 562 amino acids and shows high homology to a widely distributed family of beta-glucosidases (BGA family). Cell-free homogenate of Escherichia coli expressing CSF26G1 cDNA showed beta-glucosidase activity specific for cleavage of the C-26 glucosidic bond of furostanol glycosides.

Amino Acid Sequence↗
PubMed1978

Combined effects of clofibrate and diosgenin on cholesterol metabolism in rats.

Groups of male rats were fed various doses of clofibrate and diosgenin, both alone and in combination for 1 week. Clofibrate suppressed the diosgenin-induced increase in hepatic cholesterol synthesis but did not alter the effectiveness of diosgenin in reducing cholesterol absorption. Diosgenin did not affect the bioavailability of CPIB. Clofibrate reduced the diosgenin induced increase in biliary levels of cholesterol; none of the regimens altered biliary bile acids. The combination produced greater decreases in LDL cholesterol than did either compound alone; the diosgenin-induced elevation in HDL cholesterol was partially reversed by clofibrate. The data provide a basis for the combined use of clofibrate and diosgenin in the control of hyperlipoproteinemia.

Absorption↗
PubMed1993

Structure-activity relationships of synthetic tigogenyl glycosides.

Haemolytic activities of the five tigogenyl diglycosides and a maltotrioside were much stronger than those of nine monoglycosides. Among these glycosides, the glucoside, galactoside, maltoside, lactoside, gentiobioside, melibioside and maltotrioside had strong antifungal activity. By contrast, none of these glycosides showed any antibacterial activity.

Anti-Infective Agents↗
PubMed1991

Steroidal and phenolic constituents of Lilium speciosum.

Phytochemical examination of the fresh bulbs of Lilium speciosum forma vestale has led to the isolation of a new phenolic glycoside and a new steroidal saponin. The respective structures of the new compounds have been shown by spectral analysis to be 6'-O-feruloylsucrose and (25R,26R)-26-methoxyspirost-5-en-3 beta-o1 3-O-alpha-L-rhamnopyranosyl-(1----2)-beta-D-glucopyranoside. Several known phenolic glycosides and saponins have also been isolated and identified.

Acetylation↗
PubMed1996

Aferoside A, a steroidal saponin from Costus afer.

A new steroidal saponin, aferoside A, has been isolated from the roots of Costus afer. Its structure was established as 3-O-([beta-D-apiofuranosyl-(1-->2)]-[alpha-L-rhamnopyranosyl-(1--> 4)]-beta-D-glucopyranosyl)-25(R)-spirost-5-en-3 beta-ol by chemical transformations and various spectroscopic methods, mainly 2D NMR techniques (COSY, HMQC and HMBC).

Carbohydrate Conformation↗
PubMedDate not supplied

Effects of alpha- and beta-tigogenin cellobiosides on cholesterol absorption.

We have synthesized alpha- and beta-anomers of tigogenin cellobioside and have determined their effects on intestinal absorption of [1,2-3H]cholesterol in rats. We demonstrated that the loss of tritium label likely to occur in the conversion of cholesterol to coprostanone was minimal. Dose response studies showed that both anomers depressed intestinal absorption of cholesterol but the depression was greater with the beta-anomer.

Animals↗
PubMed1993

Conformational analysis of A and B rings in 2-, 4-, and 6-bromosubstituted steroidal 4-en-3-ones by nuclear magnetic resonance.

The conformational preference of A and B rings in four differently functionalized bromosubstituted 4-en-3-one steroids is studied by concerted application of high-resolution one- and two-dimensional nuclear magnetic resonance (NMR) techniques, such as homonuclear and heteronuclear correlated spectroscopy, transient and steady-state nOe spectroscopy, temperature-dependent chemical chemical shift variation, and application of a modified Karplus equation. The steroids studied include 6 beta-bromocholest-4-en-3-one (3), 4,6 beta-dibromocholest-1,4-dien-3-one (2), 2 alpha,4,6 beta-tribromocholest-4-en-3-one (1), and (25R)-2 alpha,6 beta-dibromospirost-4-en-3-one (4). Steroids 1-4 were prepared by either acid-catalyzed or free-radical bromination from appropriate 4-en-3-one steroid. The study has yielded an insight into the factors responsible for conformational preferences of the A and B rings of these bromosubstituted steroids. Bromosubstitution at the 2 alpha position is responsible for the inversion of the A ring to inverted 1 beta,2 alpha-halfchair conformation. The electronic interaction between 4-bromine and carbonyl oxygen distorts the A-ring conformation further. Inversion of the A ring has a concomitant effect of distortion in the chair form of the B ring. Conformational preferences of A and B rings are not found to be influenced by transmission effect of a side chain or oxygenated ring system. Temperature-dependent NMR studies indicate the reduced conformational flexibility of the A ring for 2 alpha-bromosubstituted steroids. Complete assignment of the 13C and 1H resonances of two of the steroids studied (3 and 4) is presented.

Bromides↗
PubMed2005

A new approach to the pharmacological regulation of memory: Sarsasapogenin improves memory by elevating the low muscarinic acetylcholine receptor density in brains of memory-deficit rat models.

The purpose of this paper is to study the basic pharmacological action of sarsasapogenin, a sapogenin from the Chinese medicinal herb Rhizoma Anemarrhenae, (abbreviated as ZMS in this paper), on learning ability and memory of three animal models: aged rats and two neurodegeneration models produced either by single unilateral injection of beta-amyloid 1-40 (Abeta1-40) plus ibotenic acid (Ibot A) or by bilateral injection of Ibot A alone into nucleus basalis magnocellularis. Y-maze test and step-through test revealed that learning ability and memory were impaired in the three models and were improved by oral administration of ZMS. ZMS did not inhibit acetylcholinesterase nor did it occupy the binding sites of muscarinic acetylcholine receptor (M receptor), hence it is neither an cholinesterase inhibitor nor an agonist or antagonist of M receptors. On the other hand, the densities of total M receptor and its M1 subtype in the brain of the three models were significantly lower than control rats, and ZMS significantly raised the densities of total M receptors and its M1 subtype. Linear regression revealed significant correlation between the learning ability/memory and the density of either total M receptor or its M1 subtype. Autoradiographic study with 3H-pirenzipine showed that the M1 subtype density was significantly lowered in cortex, hippocampus and striatum of aged rats, and ZMS could reverse these changes towards normal control level. Interestingly, the M1 receptor density after ZMS administration only approached but did not exceed that of normal young control rats. Therefore, ZMS seems to represent a new approach to the pharmacological regulation of learning and memory and appears to be not simply palliative but may modify the progression of the disease.

Acetylcholinesterase↗
PubMed2005

Preparations of vitamin D analogs, spirostanols and furostanols from diosgenin and their cytotoxic activities.

Vitamin D analogs 12 and 13 having a spiro ring in the side chain, various spirostanols 18-21, 26, 27, 29 and 37, and furostanols 34-36 having SCN and SeCN groups at the 26 position were prepared from diosgenin 1 via (20S,22R,25R)-spirost-1alpha,2alpha-epoxy-4,6-dien-3-one 19 as a key intermediate. The cytotoxic activities of these derivatives as well as 1 on scarcely P-gp-expressed HCT 116 cells and P-gp-overexpressed Hep G2 cells were examined by MTT assay. Furostanols 34 (IC(50) value: 4.9+/-0.3 microM) and 36 (IC(50) value: 1.3+/-0.2 microM) exhibited marked cytotoxic effects on HCT 116 cells, and spirostanol 29 (IC(50) value: 2.4+/-0.8 microM) and furostanol 36 (IC(50) value: 2.8+/-0.4 microM) on Hep G2 cells. Furthermore, the effects of vitamin D analog 12, spirostanol 26 and furostanol 36 on apoptosis-signaling pathways were investigated. Compounds 12 and 26 overexpressed p53 and Bax mRNAs, while compound 36 overexpressed only Bax mRNA.

Antineoplastic Agents↗
PubMed2004

Tissue and subcellular localization of oligofurostanosides and their specific degrading beta-glucosidase in Dioscorea caucasica Lipsky.

The application of the histochemical technique using the Ehrlich reagent showed that the oligofurostanosides--the steroid glycosides of the furostan series--are localized in idioblasts (special cells--receptacles) of the epidermal layer of Dioscorea caucasica leaves. The activity of oligofurostanoside-specific beta-glucosidase was localized mainly in the membrane fraction of the thylakoides and was also found in the Dioscorea caucasica leaves. We have suggested, that the differential tissue, the subcellular localization of the oligofurostanosides and their degrading enzymes provide the maintenance of the furostanol structure of steroid glycosides which is necessary for their transport within the leaf and from the leaf to the rhizome.

Centrifugation, Density Gradient↗