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PubMed2004

Cytotoxic epimeric withaphysalins from leaves of Acnistus arborescens.

Phytochemical analysis of the leaves of Acnistus arborescens (Solanaceae) resulted in the isolation of two new epimeric withaphysalins (17S,20R,22R)-5beta,6beta: 18,20-diepoxy-4beta,18-dihydroxy-1-oxowitha-24-enolide (2, 18R and 18S), together with the known withaphysalin F (1, 18R and 18S). Their structures were established by spectroscopic methods, including 2D NMR data and comparison with literature data. Compounds 1 and 2 dis-played potent cytotoxic activities against several cancer cell lines with IC50 values in the range of 0.20 to 1.46 microg/mL for 1 and 0.89 to 8.08 microg/mL for 2. The strong cytotoxicity presented by 1 suggests that in this series of compounds, the 2,3-unsaturated ketone moiety is an important pharmacophoric unit. The cytotoxic activity seemed to be related to DNA synthesis inhibition, as revealed by the reduction of 5-bromo-2'-deoxyuridine incorporation after 24 hours of incubation on leukemic cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

The structure of physalin T from Physalis alkekengi var. franchetti.

A new steroidal constituent named physalin T (3) was isolated from the aqueous extract of Physalis alkekengi var. francheti. Based on 1H and 13C NMR spectral studies the structure was assigned as 2,3-dihydrophysalin D, i.e., 5alpha,6beta-dihydroxy-2,3,5,6-tetrahydrophysalin B, which is the first example of a natural physalin possessing a saturated ring A moiety. The structure was confirmed by the chemical transformation from the known physalin D (2) to physalin T.

Antineoplastic Agents, Phytogenic↗
PubMed1989

Steroid catechol degradation: disecoandrostane intermediates accumulated by Pseudomonas transposon mutant strains.

Eleven transposon mutant strains affected in bile acid catabolism were each found to form yellow, muconic-like intermediates from bile acids. To characterize these unstable intermediates, media from the growth of one of these mutants with deoxycholic acid was treated with ammonia, then the crude product was methylated with diazomethane. Four compounds were subsequently isolated; spectral evidence suggested that they were methyl 12 alpha-hydroxy-3-oxo-23,24-dinorchola-1,4-dien-22-oate, methyl 4-aza-12 beta-hydroxy-9(10)-secoandrosta-1,3,5-triene-9,17-dione-3-carboxyl ate, 4-aza-9 alpha, 12 beta-dihydroxy-9(10)-secoandrosta-1,3,5-trien-17-one-3- methyl carboxylate and 4 alpha-[3'-propionic acid]-5-amino-7 beta-hydroxy-7 alpha beta-methyl- 3a alpha, 4,7,7a-tetrahydro-1-indanone-delta-lactam. It is proposed that the mutants are blocked in the utilization of such muconic-like compounds as the 3,12 beta-dihydroxy-5,9,17-trioxo-4(5),9(10)- disecoandrostal (10),2-dien-4-oic acid formed from deoxycholic acid. A further mutant was examined, which converted deoxycholic acid to 12 alpha-hydroxyandrosta-1,4-dien-3,17-dione, but accumulated yellow products from steroids which lacked a 12 alpha-hydroxy function, such as chenodeoxycholic acid. The products from the latter acid were treated as above; spectral evidence suggested that the two compounds isolated were methyl 4-aza-7-hydroxy-9(10)-secoandrosta-1,3,5- triene-9,17-dione-3-carboxylate and 4 alpha-[1'alpha-hydroxy-3'-propionic acid]-5-amino-7a beta-methyl-3a alpha,4,7,7a-tetrahydro-1-indanone-delta-lactam.

Androstanes↗
PubMed2002

D-Secoestrone derivatives. V1. 3-Methoxy-17-oxo-17-phenyl-16,17-secoestra-1,3,5(10)-triene-16-nitrile and 17-hydroxy-3-methoxy-17-phenyl-16,17-secoestra-1,3,5(10)-triene-16-nitrile.

The two title 16,17-secoestrone derivatives, 3-methoxy-17-oxo-17-phenyl-16,17-secoestra-1,3,5(10)-triene-16-nitrile, C(25)H(27)NO(2), (I) (17-oxo substituent), and 17-hydroxy-3-methoxy-17-phenyl-16,17-secoestra-1,3,5(10)-triene-16-nitrile, C(25)H(29)NO(2), (II) (17-hydroxy substituent), have quite different conformations in the solid state. These conformational differences can be minimized by molecular mechanics calculations. Thus, the remarkable difference in the biological activity of the two compounds, e.g. the strong oestrogenic characteristics of (I) and the moderate antioestrogenic action of (II), must be caused by the difference in substitution at C17. In (II), the molecules are linked by O-H...N hydrogen bonds, forming spirals along the b direction.

Crystallography, X-Ray↗
PubMed1980

On the number of steroid-binding sites of delta 5-3-oxosteroid isomerase.

The number of steroid-binding sites in delta 5-3-oxosteroid isomerase of Pseudomonas testosteroni (EC 5.3.3.1) has been determined from measurements of the red shift of the ultraviolet chromophore of 19-nortestosterone upon binding to the enzyme. The experiments include spectroscopic measurements when limiting concentrations of either 19-nortestosterone or isomerase are titrated with varying concentrations of the complementary ligand. Analysis of the results indicates one binding site per subunit (Mr 13 394). Scatchard plots indicate a single family of equivalent binding sites. 5, 10-Secoestr-5-yne-3, 10, 17-trione is a suicide substrate of isomerase [Batzold & Robinson (1975) J. Am. Chem. Soc. 97, 2576]. The time course for inactivation of isomerase with an excess of 5, 10-seco[7-3H]estr-5-yne-3, 10, 17-trione was parallel to the covalent incorporation of steroid and gave a final stoichiometry of nearly one steroid molecule per subunit of enzyme. Alkylation of [14C] isomerase with excess of this 3H-labeled steroid followed by gel-filtration and dialysis gave an inactivated enzyme with a 3H/14C ratio that corresponds to one molecule of steroid bound per subunit; this stoichiometry was constant over a wide range of protein concentrations (0.1--10 mg/ml). Diffusion of [3H]progesterone into hexagonal crystals of isomerase showed that at saturation one steroid molecule was bound per protomer. Taken together these findings strongly support the conclusion that one molecule of steroid is bound per subunit of isomerase both in solution and in the crystal state.

Binding Sites↗
PubMed1973

Isotachysterol-3 and 25-hydroxyisotachysterol-3: analogs of 1,25-dihydrox vitamin D3.

Isotachysterol(3), 25-hydroxyisotachysterol(3), and isovitamin D(3) have been synthesized and tested for biological activity. Like 1,25-dihydroxyvitamin D(3), isotachysterol(3) stimulates intestinal calcium transport and bone calcium mobilization in anephric rats, whereas 25-hydroxyvitamin D(3) does not. Although isovitamin D(3) is biologically active in normal rats it is inactive in anephric rats.

Animals↗
PubMed2003

A new bacterial steroid degradation gene cluster in Comamonas testosteroni TA441 which consists of aromatic-compound degradation genes for seco-steroids and 3-ketosteroid dehydrogenase genes.

In Comamonas testosteroni TA441, testosterone is degraded via aromatization of the A ring, which is cleaved by the meta-cleavage enzyme TesB, and further degraded by TesD, the hydrolase for the product of TesB. TesEFG, encoded downstream of TesD, are probably hydratase, aldolase, and dehydrogenase for degradation of 2-oxohex-4-enoicacid, one of the products of TesD. Here we present a new and unique steroid degradation gene cluster in TA441, which consists of ORF18, ORF17, tesI, tesH, ORF11, ORF12, and tesDEFG. TesH and TesI are 3-ketosteroid-Delta(1)-dehydrogenase and 3-ketosteroid-Delta(4)(5alpha)-dehydrogenase, respectively, which work in the early steps of steroid degradation. ORF17 probably encodes the reductase component of 9alpha-hydroxylase for 1,4-androstadiene-3,17-dione, which is the product of TesH in testosterone degradation. Gene disruption experiments showed that these genes are necessary for steroid degradation and do not have any isozymes in TA441. By Northern blot analysis, these genes were shown to be induced when TA441 was incubated with steroids (testosterone and cholic acid) but not with aromatic compounds [phenol, biphenyl, and 3-(3-hydroxyphenyl)propionic acid], indicating that these genes function exclusively in steroid degradation.

Amino Acid Sequence↗
PubMed1992

Immunomodulatory activity of various fractions derived from Physalis angulata L extract.

The immunomodulatory effects of Physalis angulata L. extract fraction VII (PA-VII), PA-VII-A, PA-VII-B and PA-VII-C were investigated in this study. The results showed that PA-VII and PA-VII-C strongly enhanced blastogenesis response, PA-VII-B had moderate activity, and PA-VII-A exerted only slight effect on cell proliferation. A synergistic effect was observed when the suboptimal dosage of phytohemagglutinin (PHA) or lipopolysaccharide (LPS) was added to the culture. Furthermore, PA-VII and PA-VII-C possessed stimulatory activity on B cells and less effect on T cells. The antibody responses were also augmented by PA-VII, PA-VII-B and PA-VII-C, but not by PA-VII-A. The enhancement of antibody response could be observed both in BALB/c and C3H/HeJ mice.

Animals↗
PubMed2006

In-vitro and in-vivo antitumour activity of physalins B and D from Physalis angulata.

We have evaluated the in-vitro and in-vivo antitumour activity of physalin B and physalin D isolated from the aerial parts of Physalis angulata. In-vitro, both compounds displayed considerable cytotoxicity against several cancer cell lines, showing IC50 values in the range of 0.58 to 15.18 microg mL(-1) for physalin B, and 0.28 to 2.43 microg mL(-1) for physalin D. The antitumour activity of both compounds was confirmed in-vivo using mice bearing sarcoma 180 tumour cells. The in-vivo antitumour activity was related to the inhibition of tumour proliferation, as observed by the reduction of Ki67 staining in tumours of treated animals. Histopathological examination of the kidney and liver showed that both organs were affected by physalin treatment, but in a reversible manner. These compounds were probably responsible for the previously described antitumour activity of ethanol extracts of P. angulata, and their identification and characterization presented here could explain the ethnopharmacological use of this species in the treatment of cancer.

Animals↗
PubMed2006

Biotransformation of physalin H and leishmanicidal activity of its transformed products.

The transformation of physalin H (1) with Rhizopus stolonifer and Cunninghamella elegans has afforded two new physalins, 6,7-dehydrophysalin H (2) and 6-deoxyphysalin H (3), along with a known isophysalin B (4). Their structures were elucidated by spectroscopic analysis. All of these compounds have shown potent leishmanicidal activity with IC50 values in the range of 6.03-13.80 microM.

Animals↗
PubMedDate not supplied

Feeding stimulative activity of steroidal and secoiridoid glucosides and their hydrolysed derivatives toward the olive weevil (Dyscerus perforatus).

Beta-sitosteryl-D-glucoside and oleuropein isolated from the olive tree (Olea europaea) and their hydrolysed derivatives were tested by a feeding stimulative activity bioassay using the olive weevil (Dyscerus perforatus). Although the steroidal glucoside showed potent feeding stimulative activity, the activity of the aglycone (beta-sitosterol) was significantly lower than that of the glucoside. On the other hand, the difference in the activity between oleuropein, a secoiridoid glucoside, and the hydrolysed derivatives was not significant.

Animals↗
PubMed2006

Studies on antimicrobial activity, in vitro, of Physalis angulata L. (Solanaceae) fraction and physalin B bringing out the importance of assay determination.

Complex physalin metabolites present in the capsules of the fruit of Physalis angulata L. have been isolated and submitted to a series of assays of antimicrobial activity against Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, S. aureus ATCC 6538P, Neisseria gonorrhoeae ATCC 49226, Escherichia coli ATCC 8739; E. coli ATCC 25922, Candida albicans ATCC 10231 applying different methodologies such as: bioautography, dilution broth, dilution agar, and agar diffusion techniques. A mixture of physalins (pool) containing physalins B, D, F, G inhibit S. aureus ATCC 29213, S. aureus ATCC 25923, S. aureus ATCC 6538P, and N. gonorrhoeae ATCC 49226 at a concentration of 200 mg/microl, using agar dilution assays. The mixture was inactive against P. aeruginosa ATCC27853, E. coli ATCC 8739; E. coli ATCC 25922, C. albicans ATCC 10231 when applying bioautography assays. Physalin B (200 microg/ml) by the agar diffusion assay inhibited S. aureus ATCC 6538P by +/- 85%; and may be considered responsible for the antimicrobial activity.

Agar↗
PubMedDate not supplied

[Production of the methyl ether of 8,14-seco-delta,3,5,(10),9(11)-estratetraendiol-3,17beta-one-14 using a culture of Saccharomyces cerevisiae BKMU-488].

The culture Saccharomyces cerevisiae BKMU-499 was selected from 100 strains of different Saccharomyces species to obtain an optically active methyl ester 8,14-seco-delta1,3,5(10),9(11)-estratetraendiol-3-17beta-on-14. Various conditions of the transformation were examined. The yield of this keto-alcohol depended on the following factors: level of aeration, method of steroid administration, physiological state of the culture, and composition of the cultivation medium. The optimal yeild of the optically active product was 84%.

Aerobiosis↗