619 research outputs found
The isolation of products from the bovine adrenal perfusions with progesterone and progesterone-4-C14
Thesis (Ph.D.)--Boston UniversityIntroduction: On the basis of various in vitro studies, progesterone appeared to be an intermediate in the biosynthesis of some of the adrenal cortical hormones. In particular, perfusion of the isolated cow adrenal with blood media containing added progesterone had led to the isolation of 11β-hydroxyprogesterone, 17α-hydroxyprogesterone, corticosterone, 17α-hydroxycorticosterone, allopregnane-3,20-dione, allopregnane-17α-ol-3,20-dione, and allopregnane-3β,17α-diol-20-one. Since these studies demonstrated that progesterone did in fact lead to adrenal cortical hormones, it appeared possible that other hormones of known or unknown constitution might be present in the above perfusates. Therefore, in the present research, adrenal perfusions with progesterone were performed and the resultant mixtures investigated.
Thus, the purpose of this research was to perfuse bovine adrenals with blood containing added progesterone in order to obtain substances of adrenocortical or other biological activity, metabolites of these hormones or their intermediates, and in fact, any and all substances derived from progesterone.
To achieve the aims of the research, four basic stages were involved. These were: 1. perfusion, 2. isolation of the steroids from the perfusates, 3. fractionation of the resultant mixtures into pure crystalline components, and 4. identification of these components.
Perfusion: The first series of perfusions was performed at G. D. Searle and Co., Chicago. In total 600 cow adrenals were perfused with 600 liters of bovine blood - Tyrode's solution (1:1) containing 90 g. of added progesterone. The second series was performed by C. A. Fish at the Worcester Foundation. In this, 73 cow adrenals were perfused with 73 liters of citrated whole blood containing 5.1 g. of progesterone-4-C14 (1.47 millicuries/mmole).
Isolation: The steroids were isolated from the first perfusate by adsorbing them onto charcoal and subsequently eluting them with acetone. Control studies performed before this research had indicated the method to be sufficiently efficient to be used. During this work however, some disadvantages of the charcoal procedure such as destructive nature toward certain steroids were reported by other investigators. Further, several other procedures for isolating corticosteroids from blood were described. One of these involved the shaking of the blood with solvents such as isopropyl acetate. Since this latter method appeared to have merit, the present research included a quantitative comparison of it with the charcoal procedure. This aspect of the work consisted of perfusing bovine adrenals with progesterone-4-C14 and subjecting aliquots of the perfusate to both procedures. The respective extracts were then compared (among other factors) for total recovery of radioactivity, amount of formaldehydogenic substance (on oxidation with periodic acid), and number of zones detected by color tests on paper chromatography of the residues. In these experiments the charcoal was pretreated in various ways such as digestion with potassium cyanide and with Versene (a chelating agent) in an attempt to reduce destructive surfaces. Furthermore, an attempt was made to remove the steroids from the charcoal via countercurrent elution at room temperature in a column in order to minimize chance for destruction due to heat. The room temperature elution proved to be successful in that the bulk of the radioactivity was removed in this step. The recovery of radioactivity was the same for both methods but the solvent procedure did however appear to have an advantage in that the formaldehydogenic values obtained were somewhat higher than those with the charcoal procedure.
Finally, an attempt was made to compare the crystalline recovery of cortisone from water, using the treated charcoal and the isopropyl acetate procedures. This experiment was performed since it had been reported that using untreated charcoal to adsorb cortisone and subsequent, continuous extraction by hot solvents in a soxhlet apparatus, to elute the cortisone, a crystalline recovery of 25-44% was obtained. The present comparative experiment resulted in crystalline recoveries of 33 and 92% respectively using the above modified charcoal and solvent procedures. This final experiment on the crystalline recovery of cortisone clearly demonstrated the superiority of the solvent extraction procedure to the charcoal procedure. The former was therefore used in the subsequent progesterone-4-C14 perfusions.
Fractionation of the extracts: The methods used to fractionate the mixtures extracted from the perfusates included the following: adsorption chromatography on silica gel, partition chromatography on paper and a diatomaceous earth (Celite), and fractional crystallization. Components were generally considered sufficiently pure for structure determination when crystallized to constant melting point.
Identification of components: Since components were frequently isolated in quantities of the order of 1 mg., the identifications had to be made on a micro scale. The classical methods of organic chemistry such as degradations and microanalyses for the elements had to be used very judiciously. In many cases there was insufficient material for a microanalysis.
To overcome this difficulty and learn the nature of functional groups present, spectrophotometry was used either directly or in conjunction with various color tests and microreactions. Another property found to be very useful was rates of movement of substances on paper or column chromatography. A study of relative running rates frequently suggested the number of oxygen atoms present on the molecule. Thus, spectrophotometry (infrared, ultraviolet, and visible), and chromatographic mobility data, combined with analogy, tacit assumptions that components were steroidal, and intuition were most valuable tools used throughout this research.
Although supporting data were used, the infrared spectrum of either the isolated sample or a degradation product, obtained through an unambiguous reaction sequence, was compared with that of an authentic sample in order to establish identity.
Steroids identified from these perfusates:
1. progesterone
2. Δ4-pregnene-2β-ol-3-one
3. allopregnane-3,20-dione*
4. allopregnane-3β-ol-20-one
5. allopregnane-17α-ol-3,20-dione*
6. allopregnane-3β,17α-diol-20-one
7. 17α-hydroxyprogesterone*
8. 11β-hydroxyprogesterone*
9. Δ4-androstene-11β-ol-3,17-dione**
10. 6β-hydroxyprogesterone
ll. 17α-hydroxy-11-desoxycorticosterone
12. corticosterone*
13. 19-hydroxy-11-desoxycorticosterone
14. 17α-hydroxycorticosterone*
15. allopregnane-3α,17α,11β,21-tetrol-20-one
16. Δ4-pregnene-6β,17α,21-triol-3,20-dione
17. allopregnane-3β,17α,11β,21-tetrol-20-one
18. Δ4-pregnene-17α,19,21-triol-3,20-dione
*From progesterone and progesterone-4-C14
**From progesterone-4-C14
Test of purity experiments: Experiments were also performed on the purity of some of the steroids isolated from the progesterone-4-C14 perfusates. In essence the methods involved chromatographing an aliquot of the sample on paper and determining the radioactivity in the region corresponding to the desired component relative to the total radioactivity present. These experiments indicated that samples otherwise thought to be pure could contain considerable amounts of impurity which were not detected by other methods used. Furthermore, it was found that some destruction of steroid appeared to be occuring during paper chromatography; probably during the air drying in daylight. Evidence for this is that in several rechromatographies of the zone corresponding to 17α-hydroxycorticosterone, the purity was found to be considerably lower than in the first.
Discussion: The isolation of substances 10 and 16 represents the first demonstration of hydroxylation occuring at carbon 6 by adrenal perfusion. 6β-Hydroxylation has, however, been reported earlier following incubation of 11-desoxycorticosterone with hog adrenal brei. The isolation of substances 13 and 18 represents the first demonstration of hydroxylation at carbon 19 by adrenal perfusion and is the first demonstration of the formation of 21 carbon steroids hydroxylated at carbon l9 by any in vivo or in vitro system. Simultaneous with the identification of substance 13 in these perfusates, 19-hydroxy-Δ4-androstene-3,17-dione was identified as a component formed, following incubation of Δ4-androstene-3,17-dione with adrenal tissue. Oxidation of substance 18 with sodium bismuthate resulted in a mixture from which was crystallized and identified, 19-hydroxy-Δ4-androstene-3,17-dione. The structure of substance 18 (isolated in quantity of about 10 mg.) appears therefore to be established as Δ4-pregnene-17α,19,2l-triol-3,20-dione, a hitherto unknown substance. Although the latter compound originally appeared to be biologically active in sodium ion retention assays, subsequent assays have failed to reproduce the activity. It now appears that a trace impurity of extremely high activity was present in the sample originally tested. Although the two samples tested were purified differently, the melting point ranges were identical. The possibility of an impurity's causing the initial activity is now being investigated by assaying appropriate mother liquors.
The isolation of substance 9 is among the first direct indications of a C-21 steroid transformed into a C-19 steroid. It was reported earlier that trace amounts of Δ4-androstene-3,11,17-trione were isolated from adrenal perfusions of cortisone.
The isolation of substance 11 has added substantiation to the postulated scheme of corticosteroid biosynthesis in which it had been proposed as an intermediate but never isolated.
The isolation of substances 1,3,5,6,7,8,12 and 14 had been reported before this research and at present represents only confirmatory findings. The remaining substances identified are all reduction products in ring A or at C-20 of progesterone or progesterone derivatives
A Study of Recent Advances in Drug Therapy for Use in Health Instruction
In recent years there has been a growing emphasis on the development of health education in the public schools. This emphasis has been due largely to the realization of the importance and need for training in healthful living. As the educational system in the United States has assumed more and more responsibility for the total development of the child, physically, mentally, specially, and emotionally, educators and parents have felt the need for a more functional health program in the school
Isolation and characterization of cyclo-(tryptophanyl-prolyl) and chloramphenicol from Streptomyces sp. SUK 25 with antimethicillin-resistant Staphylococcus aureus activity
Background: Zingiber spectabile, commonly known as Beehive Ginger, is used as an ethnobotanical plant in many countries as an appetizer or to treat stomachache, toothache, muscle sprain, and as a cure for swelling, sores and cuts. This is the first report of isolation of Streptomyces strain from the root of this plant. Strain Universiti Kebangsaan 25 (SUK 25) has a very high activity to produce secondary metabolites against methicillin-resistant Staphylococcus aureus (MRSA), which is associated with high morbidity and mortality rates due to acquired multidrug resistance genes and causes medication failure in some clinical cases worldwide. Phylogenetic analysis based on the 16S ribosomal RNA gene sequence exhibited that the most closely related strain was Streptomyces omiyaensis NBRC 13449T (99.0% similarity). Aim: This study was conducted to carry out the extraction, identification, and biological evaluation of active metabolites isolated from SUK 25 against three MRSA strains, namely, MRSA ATCC 43300, MRSA ATCC 33591, and MRSA ATCC 49476. Materials and methods: The production of secondary metabolites by this strain was optimized through Thronton’s media. Isolation, purification, and identification of the bioactive compounds were carried out using reversed-phase high-performance liquid chromatography, high-resolution mass spectrometry, Fourier transform infrared, and one-dimensional and twodimensional nuclear magnetic resonance. Results: During screening procedure, SUK 25 exhibited good antimicrobial potential against several strains of MRSA. The best biological activity was shown from fraction number VII and its subfractions F2 and F3 with minimum inhibitory concentration values at 16 µg/mL and 8 µg/mL, respectively. These two subfractions were identified as diketopiperazine cyclo(tryptophanyl-prolyl) and chloramphenicol. Conclusion: On the basis of obtained results, SUK 25 isolated from Z. spectabile can be regarded as a new valuable source to produce secondary metabolites against bacteria, especially MRSA
Chromatographic Fingerprinting Coupled with Chemometrics for Quality Control of Traditional Chinese Medicines
The holistic system of traditional Chinese medicine (TCM) is reflected by the integrity of the ingredients contained in herbal medicines, which creates a challenge in establishing quality control standards for raw materials and the standardization of finished herbal drugs because no
single component contributes to the total efficacy. Thus, the chromatographic fingerprinting technique of TCM has proved to be a comprehensive strategy for assessing the intact quality of herbal medicine, since the origin of the herbal medicines could be identified and classified based on
so-called phytoequivalence. On the other hand, chromatographic fingerprinting is essentially a high-throughput technique and an integral tool to explore the complexity of herbal medicines. In order to further control the comprehensive quality of TCMs, some strategies are proposed to trace
the chemical changes of chromatographic fingerprints both in product processing and/or after their administration by modern chromatographic techniques and chemometrics. Combined with the techniques developed in systems biology, it seems also possible to reveal the working mechanism of TCMs
and to further control their intrinsic quality
Rotas da ciência e da saúde: inovação em antibióticos entre a Europa e os Estados Unidos da América (1940-1960)
Neste estudo os autores apresentam um breve historial dos principais antibióticos entre os anos 40 e o início dos anos 60 do século XX remontando à penicilina dada a sua posição inaugural no processo de investigação dos antibióticos. Assim, torna-se claro como a pesquisa neste domínio iniciada na Grã-Bretanha, em plena Segunda Guerra Mundial, se transferiu para os Estados Unidos da América envolvendo a mobilidade de cientistas e em muitos casos a originalidade dos recursos naturais para a obtenção dos antibióticos. Os autores mostram, também, como a descoberta de uma vasta galeria de antibióticos depois da entrada da penicilina na terapêutica veio aumentar o arsenal medicamentoso e preencher lacunas existentes no tratamento das doenças infeciosas. Os efeitos nas dinâmicas e nas mobilidades demográficas, sociais e culturais desta complexa inovação científica, médica e farmacêutica continuaram a registar-se até hoj
Main antimicrobial components of Tinospora capillipes, and their mode of action against Staphylococcus aureus
AbstractIn this investigation, the antibacterial modes of action of Radix Tinosporae, its major single components, and nine antibiotics with different targets or modes-of-action on Staphylococcus aureus were studied. Metabolic profiles of cultures treated with different medicines were acquired by HPLC/ESI-MS. After HPLC-MS data pretreatment, those profiles acquired were reduced into several MS vectors. Then statistical processing by principal components analysis was carried out upon those vectors, two conclusions could be drawn: (1) the antibacterial mode of action of Radix Tinosporae is similar to that of rifampicin and norfloxacin, which act on nucleic acid; (2) its active components playing main antimicrobial roles on Staphylococcus aureus might be alkaloids, such as palmatine and jatrorrhizine
- …