Mestranol: the assignment of its 1H and 13C NMR spectra by means of two-dimensional NMR spectroscopy, and its photochemical decomposition

The 1H- and 13C-nmr spectra of mestranol were assigned with the help of a 2 D-J-resolved, a 2D spin echo J-correlated (SECSY) and a 2D 1H-13C hetero-shift correlation experiment. The analysis of the spectra facilitated the identification of some of the photodecomposition products of mestranol. It was shown that, upon irradiation with UV-B light in water-ethanol (1:1, v/v), products are formed by oxidation of rings B and C of the steroid.     

Norethindrone acetate (NA) and ethinyl estradiol (EE) related oxidative transformation products in stability samples of formulated drug product: synthesis of authentic references

Preparative chemical methods for the synthesis of eight oxidative transformation products of ethinyl estradiol (EE) and norethindrone acetate (NA) are described. The prepared materials are useful as reference materials and standards for pharmaceutical analysis of EE and NA as bulk chemical or in formulated product. All eight products result from oxidation of the A and/or B rings of the parent compounds. Oxidation of the heteroannular 3,5 dienyl acetate derivative of NA resulted in the 6 alpha-hydroxy, 6 beta-hydroxy and 6-keto NA. Oxidation of 6-keto NA led to the preparation of 6 alpha-hydroxy, 6 beta-hydroxy, 6-keto- and Delta(6) EE. Delta(11) EE was prepared from estrone.     

Aspects for the future of biotransformations

Biotransformations have gained extensive importance in practical use as a support for chemical synthesis or in the conversion of natural products. Biotransformations may present an enlargement, a sequential degradation or a specific modification of synthetic or natural compounds. The tools for biotransformations are principally mammalian, plant or microbial cells and their cell-free enzymes. In technical practice the biocatalysts are so far limited to the use of microorganisms and some cell-free enzymes of low cost. Although numerous microbial or enzymatical reactions were already developed for industrial processes, the capacities of biotransformations offer a broad field of inexhaustible possibilities for the future.

     

Synthesis and Stereochemical Characterization of Hydroxy- and Epoxy-derivatives of Rotenone

One to four routes of synthesis are described for 8′-hydroxyrotenone, 5′-hydroxyrotenone, two epimers of 6′,7′-dihydro-6′,7′-dihydroxyrotenone, two epimers of 6′,7′-epoxyrotenone and the four rotenolones derived from each of these compounds. The stereochemical relationships are determined, in each case, by chemical interconversion, ORD and monochromatic rotation to assess the absolute configuration of the B/C ring juncture and by IR, MS and NMR for the cis- or trans-nature of this juncture. The new compounds described are useful standards for studies on the metabolites and photodecomposition products of rotenone insecticide chemical.     

食物链中氰甙的降解研究进展

本文主要概括了糖甙的种类和植物性氰甙的降解方法,氰甙是一种植物内源性有毒糖甙,被人或动物取食后,会引起食物性中毒,氰甙类化合物的降解方法主要有化学方法和生物技术方法两种,化学方法常用的有加热,水或溶剂浸提法等,而生物技术法包括发酵法,植物酶法,微生物酶法,其中微生物酶法可能是最简单,最有效,最经济的方法。     

Chromatographic patterns of urinary ethynyl estrogen metabolites in various populations

Radioactive mestranol (ME) and/or ethynylestradiol (EE) were administered to women in Nigeria, Sri Lanka, and the USA, and the types and patterns of radioactive urinary conjugates examined by Sephadex LH-20 chromatography. There are no differences in the total excretion of urinary radioactivity over 3 days. Consistent geographic differences appear to be present in the proportion of 3-, 17-, and 3,17-glucuronides. If confirmed on larger population samples, these observations may indicate significant geographic differences in the hepatic metabolism of ethynyl estrogens.High performance liquid chromatographic patterns of the urinary aglycone metabolites of ME and EE were examined in a number of women. The separation was accomplished on a Chromegaprep Diol column with a gradient of isopropanol in heptane. Ethynyl estrogen metabolism shows considerable individual variation. EE is usually the principal compound excreted following ME or EE administration. Unmetabolized ME is present in the ME profiles. The profiles of EE and ME are similar, with EE demonstrating a more complex pattern. Oxidative metabolism occurs chiefly at positions 2, 6, and 16 and is fairly extensive in the USA subjects. The Sri Lankan women generally show less of the oxidative products and the Nigerian group display a notable lack of oxidative metabolism. There is no difference in the metabolic patterns of long-term oral contraceptive users vs. non-users. Using silver sulfoethylcellulose column chromatography, from 14.1 to 34.7% of the excreted radiolabeled aglycones are non-ethynyl (i.e., either D-homo or de-ethynylated estrogens).     

Synthetic cannabinoids: Analysis and metabolites

Cannabimimetics (commonly referred to as synthetic cannabinoids), a group of compounds encompassing a wide range of chemical structures, have been developed by scientists with the hope of achieving selectivity toward one or the other of the cannabinoid receptors CB1 and CB2. The goal was to have compounds that could possess high therapeutic activity without many side effects. However, underground laboratories have used the information generated by the scientific community to develop these compounds for illicit use as marijuana substitutes. This chapter reviews the different classes of these “synthetic cannabinoids” with particular emphasis on the methods used for their identification in the herbal products with which they are mixed and identification of their metabolites in biological specimens.     

Biodegradation of halogenated organic compounds.

In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant compounds. Recent developments in designing recombinant microorganisms and hybrid metabolic pathways are discussed.     

Radioimmunoassay of contraceptive steroids. II. Synthesis of 6,7-3H-mestranol and ethinylestradiol of high specific activity

This paper describes a simple and convenient method for the preparation of tritiated mestranol and ethinylestradiol of high specific activity as a prerequisite in the development of the radioimmunoassay of the unlabelled compounds. Radioactive mestranol was prepared from estrone-6,7-³H (40 Ci/mmole) by methylation followed by ethinylation and purification by TLC. Radioactive ethinylestradiol could not be made from this mestranol by demethylation with boron tribromide, but it could be made directly from estrone-6,7-³H by ethinylation, removing the unreacted estrone by Girard's reagent T and purifying the product by TLC. Purities of these compounds were checked by TLC in two solvent systems and finally by the isotopic dilution technique. The specific activity of the final products was calculated by determining the loss of tritium during each step of reaction with a double isotopic method.     

Thermophilic anaerobic biodegradation of [C]lignin, [C]cellulose, and [C]lignocellulose preparations

Thermophilic (55 degrees C) anaerobic enrichment cultures were incubated with [C-lignin]lignocellulose, [C-polysaccharide]lignocellulose, and kraft [C]lignin prepared from slash pine, Pinus elliottii, and C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were recovered as gaseous end products. Percentages of label recovered from lignin-labeled substrates as dissolved degradation products were approximately equal to percentages recovered as gaseous end products. High-pressure liquid chromatographic analyses of CuO oxidation products of sound and degraded pine lignin indicated that no substantial chemical modifications of the remaining lignin polymer, such as demethoxylation and dearomatization, occurred during biodegradation. The polysaccharide components of pine lignocellulose and purified cellulose were relatively rapidly mineralized to methane and carbon dioxide; 31 to 37% of the pine polysaccharides and 56 to 63% of the purified cellulose were recovered as labeled gaseous end products. An additional 10 to 20% of the polysaccharide substrates was recovered as dissolved degradation products. Overall, these results indicate that elevated temperatures can greatly enhance rates of anaerobic degradation of lignin and lignified substrates to methane and low-molecular-weight aromatic compounds.     

Manganese‐oxidizing bacteria mediate the degradation of 17α‐ethinylestradiol

Manganese (II) and manganese‐oxidizing bacteria were used as an efficient biological system for the degradation of the xenoestrogen 17α‐ethinylestradiol (EE2) at trace concentrations. Mn²⁺‐derived higher oxidation states of Mn (Mn³⁺, Mn⁴⁺) by Mn²⁺‐oxidizing bacteria mediate the oxidative cleavage of the polycyclic target compound EE2. The presence of manganese (II) was found to be essential for the degradation of EE2 by Leptothrix discophora, Pseudomonas putida MB1, P. putida MB6 and P. putida MB29. Mn²⁺‐dependent degradation of EE2 was found to be a slow process, which requires multi‐fold excess of Mn²⁺ and occurs in the late stationary phase of growth, implying a chemical process taking place. EE2‐derived degradation products were shown to no longer exhibit undesirable estrogenic activity.     

Reactions of oxyl radicals with DNA

The importance of radical-induced damage to DNA is apparent from the ever-increasing number of publications in this area. This review focuses on the damage caused to DNA by reactive oxygen-centred radicals, however formed. These may be hydroxyl radicals, which arise either from the radiolysis of water by ionizing radiation (γ-rays or X-rays), or from a purely chemical source. Alternatively, metal-bound oxyl radicals (M–O·) are also active intermediates in DNA-cleaving reactions and may be formed from synthetic compounds or from natural products such as bleomycin (BLM). Chemical mechanisms leading to the observed degradation products are covered in detail. The biological effects of some of the DNA base lesions formed are touched upon, concentrating on the molecular mechanisms behind the initial events that lead to mutagenesis.     

植物来源药用天然产物的合成生物学研究进展

大多数药用天然产物在植物中含量低微,提取分离困难;而且这些化合物一般结构复杂,化学合成难度大,还容易造成环境污染.基于合成生物学技术获得药用天然产物具有绿色环保和可持续发展等优点.文中以药用萜类化合物人参皂苷、紫杉醇、青蒿素、丹参酮,生物碱类化合物长春新碱、吗啡以及黄酮类化合物灯盏花素为例,总结了植物来源药用萜类、生物...     

Natural products as a screening resource

Natural products have been the most productive source of leads for new drugs, but they are currently out of fashion with the pharmaceutical industry. New approaches to sourcing novel compounds from untapped areas of biodiversity coupled with the technical advances in analytical techniques (such as microcoil NMR and linked LC-MS-NMR) have removed many of the difficulties in using natural products in screening campaigns. As the 'chemical space' occupied by natural products is both more varied and more drug-like than that of combinatorial chemical collections, synthetic and biosynthetic methods are being developed to produce screening libraries of natural product-like compounds. A renaissance of drug discovery inspired by natural products can be predicted.     

海洋真菌抗污损活性天然产物研究

黏附于海洋船舶或人工设施表面的污损生物给人类海洋生产活动与生态环境带来诸多不利影响.将具有抗污损活性的化合物开发成防污涂料是目前防治海洋生物污损的最常用手段之一.而大量传统有机金属防污剂因其严重毒副作用被禁用,亟须开发高效、环境友好型抗污损涂料.海洋真菌能够产生大量结构新颖、作用机制独特的高效、低毒/无毒抗污损活性次级...     

Thermophilic Anaerobic Biodegradation of [14C]Lignin, [14C]Cellulose, and [14C]Lignocellulose Preparations

Thermophilic (55°C) anaerobic enrichment cultures were incubated with [¹⁴C-lignin]lignocellulose, [¹⁴C-polysaccharide]lignocellulose, and kraft [¹⁴C]lignin prepared from slash pine, Pinus elliottii, and ¹⁴C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were recovered as gaseous end products. Percentages of label recovered from lignin-labeled substrates as dissolved degradation products were approximately equal to percentages recovered as gaseous end products. High-pressure liquid chromatographic analyses of CuO oxidation products of sound and degraded pine lignin indicated that no substantial chemical modifications of the remaining lignin polymer, such as demethoxylation and dearomatization, occurred during biodegradation. The polysaccharide components of pine lignocellulose and purified cellulose were relatively rapidly mineralized to methane and carbon dioxide; 31 to 37% of the pine polysaccharides and 56 to 63% of the purified cellulose were recovered as labeled gaseous end products. An additional 10 to 20% of the polysaccharide substrates was recovered as dissolved degradation products. Overall, these results indicate that elevated temperatures can greatly enhance rates of anaerobic degradation of lignin and lignified substrates to methane and low-molecular-weight aromatic compounds.     

Occurrence and Fate of Estrone, 17β-estradiol and 17α-ethynylestradiol in STPs for Domestic Wastewater

Estrone (E1), 17β-estradiol (E2) and 17α-ethynylestradiol (EE2) discharged from sewage treatment plants (STPs) into surface waters, are seen as a threat effecting aquatic life by its estrogenic character. Therefore, much research is conducted on the fate and removal of these compounds. Since these compounds are present in influents and effluents in the ng/l range, methods for detection deserve special attention. Most important processes that play a role in the removal of estrogens are: adsorption, aerobic degradation, anaerobic degradation, anoxic biodegradation and photolytic degradation. Halflifes tend to vary and are remarkably shorter when low initial concentrations are applied. In general anaerobic conditions result in longer halflifes then aerobic conditions. EE2 shows far most persistence of the compounds, thereby also the estrogenic effect in vitro is about 2–3-fold higher compared to E2. The three compounds show a higher affinity to sorb to sludge compared to other tested adsorption materials like sediment. Aerobic degradation is far the most efficient in removing these compounds, but adsorption seems to play a significant role in retaining the estrogens inside full-scale STPs. Removal rates in full scale plants depend on the HRT, SRT and loading rates, but lack of information on the exact dependency so far prevents an optimal design able to fully eliminate estrogens from wastewater.     

Tailoring of microbes for the production of high value plant-derived compounds: From pathway engineering to fermentative production

Plant natural products have been an attracting platform for the isolation of various active drugs and other bioactives. However large-scale extraction of these compounds is affected by the difficulty in mass cultivation of these plants and absence of strategies for successful extraction. Even though, synthesis by chemical method is an alternative method; it is less efficient as their chemical structure is highly complex which involve enantio-selectivity. Thus an alternate bio-system for heterologous production of plant natural products using microbes has emerged. Advent of various omics, synthetic and metabolic engineering strategies revolutionised the field of heterologous plant metabolite production. In this context, various engineering methods taken to synthesise plant natural products are described with an additional focus to fermentation strategies.     

Microbial degradation of recalcitrant compounds and synthetic aromatic polymers

The evolution of microbial catabolic enzymes cannot keep pace with the rapid introduction of novel compounds into the environment. These new synthetic compounds that are slowly biodegradable or non-biodegradable are known as recalcitrant compounds, and range from simple halogenated hydrocarbons to complex polymers. Recalcitrant compounds can be made biodegradable by developing microorganisms capable of degrading the compound and by treating the compound to make it more conducive to mirobial attack. Many factors contribute to recalcitrance. The organism may lack the necessary genetic information. The organism can acquire this information by plasmid transfer or de novo enzyme synthesis. Plasmids have been characterized that degrade or transform antibiotics, pesticides, and hydrocarbons. By the use of chemostat techniques or chemical mutagens, organisms have been shown to synthesize de novo enzymes. The compound may be too large to enter the cell, or a transport system may not exist to transport it across the membrane. The compound may be insoluble, either as a solid or a liquid, and the microorganism may lack the proper nutrients. Recalcitrant compounds can be oxygenated prior to degradation, in the presence of a readily assimilable carbon source. In the absence of the assimilable carbon source, the recalcitrant compound is not degraded, or only very slowly. Examples of such co-oxidative metabolism are alkane and lignin degradation. Polymers, particularly synthetic ones, are prime examples of difficult-to-degrade compounds. The initial rate of polymer degradation follows a Freundlich or modified Langmuir isotherm rather than Michaelis-Menten kinetics. Microorganisms can irreversibly bind to solid surfaces by various methods. Soil microorganisms have been found to degrade styrene monomers and dimers. Polystyrene has been shown to be biodegradable by ¹⁴CO₂ evolution but at a very slow rate. In car tyres, styrene as a copolymer of butadiene is co-metabolized in the presence of other assimilable carbon sources.     

Use of a Battery of Chemical and Ecotoxicological Methods for the Assessment of the Efficacy of Wastewater Treatment Processes to Remove Estrogenic Potency

Endocrine Disrupting Compounds pose a substantial risk to the aquatic environment. Ethinylestradiol (EE2) and estrone (E1) have recently been included in a watch list of environmental pollutants under the European Water Framework Directive. Municipal wastewater treatment plants are major contributors to the estrogenic potency of surface waters. Much of the estrogenic potency of wastewater treatment plant (WWTP) effluents can be attributed to the discharge of steroid estrogens including estradiol (E2), EE2 and E1 due to incomplete removal of these substances at the treatment plant. An evaluation of the efficacy of wastewater treatment processes requires the quantitative determination of individual substances most often undertaken using chemical analysis methods. Most frequently used methods include Gas Chromatography-Mass Spectrometry (GCMS/MS) or Liquid Chromatography-Mass Spectrometry (LCMS/MS) using multiple reaction monitoring (MRM). Although very useful for regulatory purposes, targeted chemical analysis can only provide data on the compounds (and specific metabolites) monitored. Ecotoxicology methods additionally ensure that any by-products produced or unknown estrogenic compounds present are also assessed via measurement of their biological activity. A number of in vitro bioassays including the Yeast Estrogen Screen (YES) are available to measure the estrogenic activity of wastewater samples. Chemical analysis in conjunction with in vivo and in vitro bioassays provides a useful toolbox for assessment of the efficacy and suitability of wastewater treatment processes with respect to estrogenic endocrine disrupting compounds. This paper utilizes a battery of chemical and ecotoxicology tests to assess conventional, advanced and emerging wastewater treatment processes in laboratory and field studies.