Compounds Of Natural Origin Research Articles

Occurrence of Geosmin and Other Odorous Compounds of Natural Origin in Surface and Drinking Waters. A Case Study

The concentrations of geosmin and other natural compounds in raw water from the Llobregat river and tap water from Barcelona (N.E. Spain) were measured by CLSA and GC-MS. From 1997 to mid 1999. average concentrations of 86 and 33 ng/l of geosmin were recorded in Llobregat river water at the entrance to the two main water treatment plants (WTP1, WTP2), whereas their treated waters contained 24 and <5 ng/l, respectively. Barcelona's tap water coming from the WTP3 supplied by Ter river had also an average value of <5 ng/l for geosmin. The presence of geosmin in Barcelona's tap water can be attributed to the blending of the two Llobregat WTPs and also to the blending of Llobregat and Ter river treated waters. Geosmin is one of the compounds responsible for complaints from consumers. Neither 2-methyl-isoborneol (MIB) nor 2-alkyl-3-methoxypirazines were detected among other compounds with low odor threshold concentrations (OTC).

Herbicidal potential of pyrenophorol isolated from aDrechslera avenae pathotype

A pathotype of Drechslera avenae (Eidam) Scharif exhibited host-specificity, being pathogenic to Avena sterilis L but not to a number of related or unrelated species tested. In culture, the fungus produces a metabolite which was identified as the macrodiolide pyrenophorol (5,13-dihydroxy-8,16-dimethyl-1,9-dioxa-cyclohexadeca-3,11-diene-2,10-dione). This compound at a concentration of 320 µM was phytotoxic to A sterilis and considerably less so to Avena fatua L. The phytotoxicity was expressed as leaf necrosis on seedling cuttings partially immersed in pyrenophorol solution and as ‘green islands’ on detached leaves on which droplets of the solution were placed. Seed germination and seedling growth of A sterilis were not affected. Pyrenophorol at concentrations up to 640 µM did not cause any symptoms of phytotoxicity to a number of other monocotyledons or dicotyledons tested, with the exception of Lycopersicon esculentum Miller on which leaf necrosis was observed after application of the substance through the vascular system to seedling cuttings. These findings are discussed in relation to the exploitation of such compounds of natural origin as wild oat herbicides. © 2000 Society of Chemical Industry

Halocarbons produced by natural oxidation processes during degradation of organic matter.

Volatile halogenated organic compounds (VHOC) play an important role in atmospheric chemical processes-contributing, for example, to stratospheric ozone depletion. For anthropogenic VHOC whose sources are well known, the global atmospheric input can be estimated from industrial production data. Halogenated compounds of natural origin can also contribute significantly to the levels of VHOC in the atmosphere. The oceans have been implicated as one of the main natural sources, where organisms such as macroalgae and microalgae can release large quantities of VHOC to the atmosphere. Some terrestrial sources have also been identified, such as wood-rotting fungi, biomass burning and volcanic emissions. Here we report the identification of a different terrestrial source of naturally occurring VHOC. We find that, in soils and sediments, halide ions can be alkylated during the oxidation of organic matter by an electron acceptor such as Fe(III): sunlight or microbial mediation are not required for these reactions. When the available halide ion is chloride, the reaction products are CH3Cl, C2H5Cl, C3H7Cl and C4H9Cl. (The corresponding alkyl bromides or alkyl iodides are produced when bromide or iodide are present.) Such abiotic processes could make a significant contribution to the budget of the important atmospheric compounds CH3Cl, CH3Br and CH3I.

In vitro assessment of paracetamol-induced toxicity in the rat Reuber hepatoma H4IIEC3/G − cell line competent of xenobiotics metabolism

H4IIEC3/G − cells, descendants of rat Reuber hepatoma, were characterized for their response to paracetamol (acetaminophen; AAP) toxicity during log-phase of growth. The cells in culture were found to contain high contents of constitutive and dexamethasone inducible rat cytochrome P4503A besides other CYP members reported earlier. AAP produced dose-dependent decrease in cellular growth (50% at 0.7 m m). The drug steadily reduced the activity of UDP-glucuronyltransferase (UGT) towards 3-hydroxybenzo[ a]pyrene, decreased the contents of UDP-glucuronic acid (UDPGA) and significantly lowered GSH contents with length of exposure. After 48 hr of treatment, the GSH levels registered a fall of 50% while UGT and UDPGA exhibited a moderate decline of less than 25%. Decrease in the conjugation capacity of cells correlated with LDH leakage in the medium. Three compounds of natural origin, silymarin, kutkin and andrographolide at 10–20 μ m, offered relatively modest protection ranging from 24 to 55% at best, against the growth inhibitory effect of paracetamol. The hepatoma cells investigated appeared metabolically competent to respond to AAP toxicity and might prove useful for screening of agents against AAP-induced hepatotoxicity.

50] Nitric oxide radical scavenging of flavonoids

Publisher Summary This chapter discusses the nitric oxide radical scavenging of flavonoids. Flavonoids are a group of naturally occurring benzo-γ-pyron derivatives that are ubiquitous in photosynthesizing cells. It is estimated that the flavonoids comprise approximately 5,000 different compounds of natural origin. The flavonoids comprise a huge number of compounds. Because of the chemical heterogeneity, the biological activity of the various flavonoids is very diverse, and no general molecular mechanism underlying all their activities can be expected. A major activity shared by most flavonoids is free radical scavenging. Strategies used for assessing nitric oxide (NO . ) scavenging of flavonoids include (1) bioassays, (2) competition assays, and (3) kinetic assays. The advantage of a bioassay is its relative ease and the direct measurement of a biologically relevant effect. Effects of flavonoids on the NO . system other than NO . scavenging should be taken into consideration when using a bioassay for measuring NO . scavenging. The chapter concludes with a discussion of the various procedures for in situ generation of NO .

Discovery of Highly Sweet Compounds from Natural Sources

Sucrose, the most widely used sweetener globally, is of plant origin. In addition, a number of other plant constituents are employed as dietary sucrose substitutes in one or more countries, including the diterpenoid, stevioside, the triterpenoid, glycyrrhizin, and the protein, thaumatin. Accordingly, there has been much interest in discovering further examples of potently sweet compounds of natural origin, for potential use in foods, beverages, and medicines. Approximately 75 plant-derived compounds are presently known, mainly representative of the flavonoid, proanthocyandin, protein, steroidal saponin, and terpenoid chemotypes.In our program directed towards the elucidation of further highly sweet molecules from plants, candidate sweet-tasting plants for laboratory investigation are obtained from ethnobotanical observations in the field or in the existing literature. Examples of novel sweet-tasting compounds obtained so far are the sesquiterpenoids, hernandulcin and 4beta-hydroxyhemandulcin; the triterpe...

Sesquiterpenes of Lactarius origin, antifeedant structure-activity relationships

Antifeedant activity of 53 sesquiterpenes of Lactarius origin was measured against the storage pests Tribolium confusum, Trogoderma granarium and Sitophilus granarius. The activities of the compounds are discussed in relation to their structures and oxidation state. Conclusions concerning structure-activity relationships have been drawn. It was found that compounds with lactarane and marasmane skeletons were more active than isolactaranes. Also an increasing number of hydroxyl groups present in a molecule decreased its activity. Generally compounds of natural origin, with the exception of keto derivatives, possessed stronger activity than their chemically modified analogues.

Novel nucleoside transport inhibitors of natural origin.

The salvage pathway of nucleotide biosynthesis is one of the attractive targets for cancer chemotherapy. Dipyridamole, a nucleoside transport inhibitor, may be used for blocking the salvage pathways. Studies have demonstrated that dipyridamole can reduce the rescue effect of exogenous nucleosides and potentiated the cytotoxicity of acivicin, an antimetabolite of de novo pathways of nucleotide biosynthesis, in hepatoma cells1, 2. The inhibitory effect of dipyridamole was cell growth phase -dependent. Cultured hepatoma cells in lag and log phase were highly sensitive to dipyridamole; by contrast, cells in stationary phase were insensitive3, 4. The combination of acivicn and dipyridamole administered in rats bearing s.c. transplanted hepatoma yielded a summation effect, decreasing NTP and dNTP pools5. The synergistic effect of dipyridamole and acivicin was also demonstrated in colon cancer cells6. There have been reports that dipyridamole potentiated the cytotoxicity of several antimetabolites including methotrexate, 5-fluorouracil and N-phosphonacetyl-L-aspartate (PALA)7, 8, 9. In addition to potentiating antimetabolites, dipyridamole was found to enhance the cytotoxicity of doxorubicin, etoposide, vincristine and mitoxantrone10, 11, 12. These synergistic effects of dipyridamole and drugs which are not antimetabolites were due to, at least in part, increased intracellular concentrations of anticancer drugs. Drug sensitivity of multidrug resistant cells may be modulated by dipyridamole13. The use of dipyridamole in cancer chemotherapy has drawn much attention and clinical trials have been underway14, 15. The study of dipyridamole indicates that blocking nucleoside salvage pathways by inhibition of nucleoside transport may be one of the effective ways in chemotherapy. By examination of a series of compounds of natural origin, we have found that green tea polyphenols (GP), antibiotics C3368-A (CA) and C3368-B (CB) are highly active in blocking nucleoside transport in cancer cells. Investigations have demonstrated that GP, CA or CB show synergistic effects with anticancer drugs.

Carcinogenicity and drinking water.

Water is a powerful solvent that readily dissolves many natural and synthetic substances from the environment (e.g. inorganic salts, humic acids and pesticide residues). The processes of purification, disinfection and preparation and storage necessary to provide and distribute drinking water may introduce further chemicals, including some used for these purposes and others derived by interaction between them and the compounds of natural origin. The composition of drinking water, therefore, is complex and varies between sites and with the seasons. Modern technology is employed to minimise the amounts of many of these substances, but some may persist, including derivatives generated by halogenation and ozonation for disinfection. Some of the substances are genotoxic in the laboratory and a few are proven experimental carcinogens--all at much higher concentrations than those normally found in a drinking water supply. Many ecological and epidemiological surveys have been done to compare the occurrence of various types of tumour in man with exposure to different types of drinking, but no consistent or reliable association has been found. There are serious and probably irremediable methodological weaknesses in these attempts, because of the difficulty of defining the nature of the waters consumed over a major part of life, and the variable composition of waters. The surveys do not permit even a realistic assessment of the upper confidence limit of the exclusion of the risk. Thus, although there is some experimental indication of the possible presence of carcinogenic substances in most or all drinking waters, and of how they are formed, the concentrations are very low and there is no realistic evidence that they have caused harm to man.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluxes and transport of anthropogenic and natural polycyclic aromatic hydrocarbons in the western Mediterranean Sea

Surface sediments were collected in the Gulf of Lions and in the Rhône delta and analyzed for composition of polycyclic aromatic hydrocarbons (PAH). After isolation of lipids, the hydrocarbons were separated into fractions by high-performance liquid chromatography (HPLC) and fractions were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Annual PAH fluxes were calculated for the northwestern Mediterranean basin. The fluxes of open-sea sediments varied from 164 μg m −2 year −1, for a station located far from the coast and influenced by atmospheric deposition, up to 1420 μg m −2 year −1 for stations directly influenced by the Rhône river inputs, whereas stations located in the Rhône delta were characterized by higher fluxes, up to 12 250 μg m −2 year −1. PAH concentrations decreased significantly with distance from the river mouth. Detailed analysis of PAH revealed the presence of anthropogenic compounds, pyrolytic and petrogenic, and naturally derived compounds. The distribution and ratios of specific compounds of PAH are discussed as a function of morphological and sedimentological features to evaluate and characterize the respective importance of atmospheric and Rhône-derived river inputs. Pyrolytic inputs from anthropogenic combustion processes were predominant at all studied stations. Compounds of natural origin were quantified, such as retene and related abietic acid precursors, and pentacyclic triterpenes derived from α- and β-amyrins. Anthropogenic PAH fluxes, determined for an open-sea sediment corresponding to the end of the nineteenth century (∼ 100 years ago), were three to four times less than the current flux; however, the retene flux was equal to or higher than that of today.

Establishing a data-base for toxic compounds of natural origin: D. Mebs and Ina Claus (Zentrum der Rechtsmedizin, University of Frankfurt, Kennedyallee 104, Frankfurt-70, F.R.G.)

Establishing a data-base for toxic compounds of natural origin: D. Mebs and Ina Claus (Zentrum der Rechtsmedizin, University of Frankfurt, Kennedyallee 104, Frankfurt-70, F.R.G.)

Antiatherosclerotic properties of certain components of tea

In the prophylaxis and therapy of cardiovascular diseases, in addition to the traditional pharmacotherapy, biologically active compounds of natural origin are finding increasingly wide use; the list of these sources is extremely substantial and includes products of the sea and many species of plants and fungi [1-3, 13, 14]. Of interest from this standpoint are sources of biologically active compounds widely used by various population groups in their daily life. They include certain types of tea, the components of which -tannins (catechins) and saponins -possess the ability to normalize impaired microcirculation, to lower the intensity of processes of lipid peroxidation, and to exert a hypocholesterolemic effect [6, 8, 9], which permits us to consider tea as a source of substances possessing antiatherosclerotic activity. In view of this, in the present work an attempt was undertaken to assess experimentally the possible antiatherosclerotic and antiatherogenic properties of tea and certain biologically active substances contained in it in substantial amounts.

ChemInform Abstract: Intensely Sweet Compounds of Natural Origin

ChemInformVolume 20, Issue 17 Reviews ChemInform Abstract: Intensely Sweet Compounds of Natural Origin A. D. KINGHORN, A. D. KINGHORN Dep. Med. Chem. Pharm. Prog. Coll. Res. Pharm. Sci., Coll. Pharm., Univ., Chicago, IL 60612, USASearch for more papers by this authorD. D. SOEJARTO, D. D. SOEJARTO Dep. Med. Chem. Pharm. Prog. Coll. Res. Pharm. Sci., Coll. Pharm., Univ., Chicago, IL 60612, USASearch for more papers by this author A. D. KINGHORN, A. D. KINGHORN Dep. Med. Chem. Pharm. Prog. Coll. Res. Pharm. Sci., Coll. Pharm., Univ., Chicago, IL 60612, USASearch for more papers by this authorD. D. SOEJARTO, D. D. SOEJARTO Dep. Med. Chem. Pharm. Prog. Coll. Res. Pharm. Sci., Coll. Pharm., Univ., Chicago, IL 60612, USASearch for more papers by this author First published: April 25, 1989 https://doi.org/10.1002/chin.198917377Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume20, Issue17April 25, 1989 RelatedInformation

Intensely sweet compounds of natural origin.

Intensely sweet compounds of natural origin.

Fast-atom ionization mass spectra of some lichen metabolites

A mass-spectrometric study of lichen metabolites (depsides, depsidones, etc.) with the aim of determining their molecular weights and obtaining structurally informative fragmentary ions has been carried out previously with the aid of electron-impact mass spectrometry [i, 2]. However, in the electron-impact spectra of depsides and of depsidones having an oxoalkyl chain in the ortho position to the carbonyl group the peak of the molecular ions was not observed. Therefore the mass spectra could be regarded only as an indirect confirmation of the structures of the compounds as a whole, since the fragmentary ions unambiguously determine the nature of the substituents only in monomeric rings [3]. In rare cases, when it was observed in the spectrum, its intensity did not exceed 0.1%. In view of the successful use of the method of mass spectrometry with ionization by fastatom bombardment -- the atom--ion emission (ALE) method -- for the analysis of thermally unstable organic compounds of natural origin [4, 5], we decided to evaluate the possibility of this method for analyzing lichen metabolites. With this aim we have investigated depsides of the orcinol series: gyrophoric (i), 4-O-methylgyropheric (2), umbilicaric (3), lecanoric (4), evermic (5), and diffractaic (6) acids, and the depsidone alectoronic acid (7).

Etudes de lignanes : 7 - syntheses totales des (±)-α et -β-conidendrines et des methyl (±)-α et -β-conidendrals

Michael addition of the carbanion of the dithian 8 on butenolide, followed by alkylation with the benzylic bromide 11 and regeneration of the ketonic carbonyl group, gave the α,β-disubstitued lactone 13 . Reduction of the ketonic carbonyl of the latter using NaBH 4, followed by treatment with CF 3CO 2H and catalytic hydrogenolysis afforded (±)-α-conidendrin 1 . DIBAL reduction of O -dibenzyl (±)-α-conidendrin 15 and subsequent methylation of the intermediate lactol and catalytic hydrogenolysis, gave methyl 1-epi-(±)-α-conidendral 3a . This compound is an epimer of methyl α-conidendral described by Cambie as having also the structure 3a . Sodium methoxide treatment of 15 followed by catalytic hydrogenolysis yielded (±)-β-conidendrin 2 . Sodium methoxide treatment of 15 followed by DIBAL reduction, subsequent methylation of the intermediate lactol and catalytic hydrogenolysis afforded methyl (±)-β-conidendral 4 , whose diacetate was identical with the compound of natural origin.

Specific sequestering agents for the actinides. 7. Synthesis and structural chemistry of tetrakis(thiohydroxamato)hafnium(IV) in Hf(CH3C6H4(S)N(O)CH3)4.C2H5OH

A continuing project in this laboratory has been the design and synthesis of specific sequestering agents for the actinide IV ions. The degree of success so far achieved in this goal has been reviewed recently. The approach used relies on the similar coordination chemistry of high-spin Fe/sup 3 +/ and Pu and the molecular architecture of the siderophores (ferric ion specific chelating agents of microbial origin). While hydroxamate and catecholate chealating groups are the primary functional groups in siderophores, the thiohydroxamate chelating unit also occurs in at least one compound of natural origin. The tetrakis(catecholato)metalate(IV) complexes of Th(IV), U(IV), and Hf(IV) have all been prepared and structurally characterized. They are isostructural, with the D/sub 2d/ coordination symmetry of the trigonal-faced dodecahedron. Both the hydroxamate complexes tetrakis(N-isoproply-3,3-dimethylbutanehydroxamato)hafnium(IV)/sup 2/ and tetrakis(N-phenylbenzohydroxamato)hafnium(IV)/sup 9/ have this same D/sub 2d/ geometry. In contrast, the more sterically hindered complex, tetrakis(N-isopropyl-2,3-dimethylpropanehydroxamato)thorium(IV), is distorted substantially toward a cubic coordination polyhedron. No tetrakis(thiohydroxamate) complexes have been structurally characterized to date. Determination of the coordination geometry of the unconstrained tetrakis(bidentate)metalate(IV) complexes are a fundamental component in the design of an octadentate chelating agent that incorporates four such functionalities to form an optimum metal coordination environment. While we have prepared thiohydroxamatemore » complexes of Th(IV), no crystals suitable for structural analysis have been obtained. Instead, we report the synthesis and structural characterization of the hafnium complex, the title compound.« less

Bioactivity — A function of structure. VII. Modeling bioactivity of batrachotoxin analogs

The method of mathematical description of the interrelationship between the structure of compounds and their bioactivity has been developed in recent years as an instrument for learning the intimate mechanisms of physiological activity. In general, compounds of different, relatively simple structural types, containing a limited number of functional groups, are advantageously considered as objects for modeling [i, 2]. The mathematical modeling of the bioactivity of compounds with a more complex structure, in particular, structural analogs of compounds of natural origin, was studied in isolated cases only. In this connection, it was important to evaluate the possibility of modeling the bioactivity of homologs and analogs of batrachotoxin (BCT), a derivative of pregnene, and this paper presents this subject. This compound was chosen for modeling because of the special place occupied in the pharmacology by BCT itself, as an extraordinarily effective neurotropic compound: