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Hypericin
Hypericin is a naphthodianthrone, an anthraquinone derivative which, together with hyperforin, is one of the principal active constituents of '' Hypericum'' ( Saint John's wort). Hypericin is believed to act as an antibiotic, antiviral and non-specific kinase inhibitor. Hypericin may inhibit the action of the enzyme dopamine β-hydroxylase, leading to increased dopamine levels, although thus possibly decreasing norepinephrine and epinephrine. It was initially believed that the anti-depressant pharmacological activity of hypericin was due to inhibition of monoamine oxidase enzyme. The crude extract of ''Hypericum'' is a weak inhibitor of MAO-A and MAO-B. Isolated hypericin does not display this activity, but does have some affinity for NMDA receptors. This points in the direction that other constituents are responsible for the MAOI effect. The current belief is that the mechanism of antidepressant activity is due to the inhibition of re-uptake of certain neurotransmitters. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saint John's Wort
''Hypericum perforatum'', known as St. John's wort, is a flowering plant in the family Hypericaceae and the type species of the genus ''Hypericum''. Possibly a hybrid between '' H. maculatum'' and '' H. attenuatum'', the species can be found across temperate areas of Eurasia and has been introduced as an invasive weed to much of North and South America, as well as South Africa and Australia. While the species is harmful to livestock and can interfere with prescription drugs, it has been used in folk medicine over centuries, and remains commercially cultivated in the 21st century. Hyperforin, a phytochemical constituent of the species, is under basic research for possible therapeutic properties. Description ''Hypericum perforatum'' is an herbaceous perennial plant with extensive, creeping rhizomes. Its reddish stems are erect and branched in the upper section, and can grow up to high. The stems are woody near their base and may appear jointed from leaf scars. The branches a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypericum
''Hypericum'' is a genus of flowering plants in the family Hypericaceae (formerly considered a subfamily of Clusiaceae). The genus has a nearly worldwide distribution, missing only from tropical lowlands, deserts and polar regions. Many ''Hypericum'' species are regarded as invasive species and noxious weeds. All members of the genus may be referred to as St. John's wort, and some are known as goatweed. The white or pink flowered marsh St. John's worts of North America and eastern Asia are generally accepted as belonging to the separate genus '' Triadenum'' Raf. ''Hypericum'' is unusual for a genus of its size because a worldwide taxonomic monograph was produced for it by Norman Robson (working at the Natural History Museum, London). Robson recognizes 36 sections within ''Hypericum''. Description ''Hypericum'' species are quite variable in habit, occurring as trees, shrubs, annuals, and perennials. Trees in the sense of single stemmed woody plants are rare, as most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperforin
Hyperforin is a phytochemical produced by some of the members of the plant genus ''Hypericum'', notably ''Hypericum perforatum'' (St John's wort). Hyperforin may be involved in the pharmacological effects of St. John's wort, specifically in its antidepressant effects. Occurrence Hyperforin has only been found in significant amounts in ''Hypericum perforatum'' with other related species such as '' Hypericum calycinum'' containing lower levels of the phytochemical. It accumulates in oil glands, pistils, and fruits, probably as a plant defensive compound. The first natural extractions were done with ethanol and afforded a 7:1 yield of crude extract to phytochemical however, this technique produced a mixture of hyperforin and adhyperforin. The extraction technique has since been modernized using lipophilic liquid CO2 extraction to afford a 3:1 crude to phytochemical extraction which is then further purified away from adhyperforin. This CO2 extraction is rather tricky still because t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthodianthrone
''For the parent molecule 9,10-anthraquinone, see anthraquinone'' Anthraquinones (also known as anthraquinonoids) are a class of naturally occurring phenolic compounds based on the 9,10-anthraquinone skeleton. They are widely used industrially and occur naturally. Occurrence in plants : Natural pigments that are derivatives of anthraquinone are found, inter alia, in aloe latex, senna (plant), senna, rhubarb, and rhamnus purshiana, cascara buckthorn, fungi, lichens, and some insects. A type II polyketide synthase is responsible for anthraquinone biosynthesis in the bacterium ''Photorhabdus luminescens''. Chorismate, formed by isochorismate synthase in the shikimate pathway, is a precursor of anthraquinones in ''Morinda citrifolia''. Tests for anthraquinones in natural extracts have been established. *Senna glycosides from the Senna (plant), senna. *Frangulin in Frangula alnus. *Aloe-emodin in aloe resin. *Carmine, a bright-red pigment derived from insects. *Hypericin and fagopyrin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merck Index
''The Merck Index'' is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monograph on single substances or groups of related compounds published online by the Royal Society of Chemistry. History The first edition of the Merck's Index was published in 1889 by the German chemical company Emanuel Merck and was primarily used as a sales catalog for Merck's growing list of chemicals it sold. The American subsidiary was established two years later and continued to publish it. During World War I the US government seized Merck's US operations and made it a separate American "Merck" company that continued to publish the Merck Index. In 2012 the Merck Index was licensed to the Royal Society of Chemistry. An online version of The Merck Index, including historic records and new updates not in the print edition, is commonly available through research libraries. It also includes an appendix with monographs on organic named reactions. The 15th edition was published in A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromophore
A chromophore is the part of a molecule responsible for its color. The color that is seen by our eyes is the one not absorbed by the reflecting object within a certain wavelength spectrum of visible light. The chromophore is a region in the molecule where the energy difference between two separate molecular orbitals falls within the range of the visible spectrum. Visible light that hits the chromophore can thus be absorbed by exciting an electron from its ground state into an excited state. In biological molecules that serve to capture or detect light energy, the chromophore is the moiety that causes a conformational change in the molecule when hit by light. Conjugated pi-bond system chromophores Just like how two adjacent p-orbitals in a molecule will form a pi-bond, three or more adjacent p-orbitals in a molecule can form a conjugated pi-system. In a conjugated pi-system, electrons are able to capture certain photons as the electrons resonate along a certain distanc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemicals In Hypericum
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be simple substances (substances consisting of a single chemical element), chemical compounds, or alloys. Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical. Chemical substances exist as solid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyols
In organic chemistry, a polyol is an organic compound containing multiple hydroxyl groups (). The term "polyol" can have slightly different meanings depending on whether it is used in food science or polymer chemistry. Polyols containing two, three and four hydroxyl groups are diols, triols, and tetrols, respectively. Classification Polyols may be classified according to their chemistry. Some of these chemistries are polyether, polyester, polycarbonate and also acrylic polyols. Polyether polyols may be further subdivided and classified as polyethylene oxide or polyethylene glycol (PEG), polypropylene glycol (PPG) and Polytetrahydrofuran or PTMEG. These have 2, 3 and 4 carbons respectively per oxygen atom in the repeat unit. Polycaprolactone polyols are also commercially available. There is also an increasing trend to use biobased (and hence renewable) polyols. Uses Polyether polyols have numerous uses. As an example, polyurethane foam is a big user of polyether polyols. Polyes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyketides
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity. History Naturally produced polyketides by various plants and organisms have been used by humans since before studies on them began in the 19th and 20th century. In 1893, J. Norman Collie synthesized detectable amounts of orcinol by heating deh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virucides
A virucide (alternatively spelled viricide or named biocidal agent or known as microbicides or biocides) is any physical or chemical agent that deactivates or destroys viruses. The substances are not only virucidal but can be also bactericidal, fungicidal, sporicidal or tuberculocidal. Virucides are to be used outside the human body, and as such fall into the category of disinfectants (applied not to the human body) and antiseptics (applied to the surface of skin) for those safe enough. Overall, the notion of virucide differs from an antiviral drug such as Aciclovir, which inhibits the proliferation of the virus inside the body. CDC's Disinfection and Sterilization list of ''Chemical Disinfectants'' mentions and discusses substances such as: Alcohol, Chlorine and chlorine compounds, Formaldehyde, Glutaraldehyde, Hydrogen peroxide, Iodophors, Ortho-phthalaldehyde (OPA), Peracetic acid, Peracetic acid and hydrogen peroxide, Phenolics, Quaternary ammonium compounds, with different, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyketide
Polyketides are a class of natural products derived from a precursor molecule consisting of a chain of alternating ketone (or reduced forms of a ketone) and methylene groups: (-CO-CH2-). First studied in the early 20th century, discovery, biosynthesis, and application of polyketides has evolved. It is a large and diverse group of secondary metabolites caused by its complex biosynthesis which resembles that of fatty acid synthesis. Because of this diversity, polyketides can have various medicinal, agricultural, and industrial applications. Many polyketides are medicinal or exhibit acute toxicity. Biotechnology has enabled discovery of more naturally-occurring polyketides and evolution of new polyketides with novel or improved bioactivity. History Naturally produced polyketides by various plants and organisms have been used by humans since before studies on them began in the 19th and 20th century. In 1893, J. Norman Collie synthesized detectable amounts of orcinol by heating de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is coherence (physics), ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and Photolithography#Light sources, lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimated light, collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow frequency spectrum, spectru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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