|
Michellamine
Michellamines are a group of atropisomeric alkaloid which have been found to be HIV viral replication inhibitors '' in vitro''. It was discovered in the leaves of ''Ancistrocladus korupensis''. There are three michellamines represented as A, B, and C; however, michellamine B is the most active against the NID-DZ strain of HIV-2. Occurrence Michellamine A and B occur naturally in ''Ancistrocladus korupensis'' leaves. Other chemical substances including alkaloids, tannins, and saponins are found in the roots, leaves, stems, flowers, or bark. Synthesis There are two methods explored to synthesize michellamines A and B. The first one, originally synthesized in 1994, is a retrosynthesis that leads to a biomimetic pathway that uses the construction of naphthalene/ isoquinoline bonds before the naphthalene/naphthalene axis. The second method, originally synthesized only a few montes after the first method, is a complementary pathway that would use the naphthalene/naphthalene axis aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancistrocladus Korupensis
''Ancistrocladus korupensis'' is a species of liana endemic to southwestern Cameroon and the neighbouring regions of Nigeria. The type locality is Korup National Park. The plant was identified as new to science in 1993 after pharmacologically intriguing alkaloids were found in its leaves. Description Like other members of its genus '' Ancistrocladus'', this plant starts life as a free-standing bushy plant, with rosettes of eight to ten long leaves at the tip of each branch. When the sapling is three or four metres tall, one shoot develops into an aerial, hooked stem with alternate long leaves, which quests upward in search of a host. When this stem is established in a tree, the rosettes at the base die off. The flowers have yellowish-green sepals, pinkish or yellowish petals, ten stamens in two whorls and three styles. The fruits have five wings. They do not disperse very far, and the function of the wings seems to be to position the fruits correctly for germination rather tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atropisomer
Atropisomers are stereoisomers arising because of hindered rotation about a single bond, where energy differences due to steric strain or other contributors create a barrier to rotation that is high enough to allow for isolation of individual conformers. They occur naturally and are important in pharmaceutical design. When the substituents are achiral, these conformers are enantiomers (''atropoenantiomers''), showing axial chirality; otherwise they are diastereomers (''atropodiastereomers''). Etymology and history The word ''atropisomer'' ( el, άτροπος, , meaning "without turn") was coined in application to a theoretical concept by German biochemist Richard Kuhn for Karl Freudenberg's seminal ''Stereochemie'' volume in 1933. Atropisomerism was first experimentally detected in a tetra substituted biphenyl, a diacid, by George Christie and James Kenner in 1922. Michinori Ōki further refined the definition of atropisomers taking into account the temperature-dependence asso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.Chemical Encyclopedia: alkaloids xumuk.ru Alkaloids are produced by a large variety of organisms including , , Medicinal plant, plants, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In Vitro
''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology and its subdisciplines are traditionally done in labware such as test tubes, flasks, Petri dishes, and microtiter plates. Studies conducted using components of an organism that have been isolated from their usual biological surroundings permit a more detailed or more convenient analysis than can be done with whole organisms; however, results obtained from ''in vitro'' experiments may not fully or accurately predict the effects on a whole organism. In contrast to ''in vitro'' experiments, ''in vivo'' studies are those conducted in living organisms, including humans, and whole plants. Definition ''In vitro'' ( la, in glass; often not italicized in English usage) studies are conducted using components of an organism that have been isolated fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HIV-2
The subtypes of HIV include two major types, HIV type 1 (HIV-1) and HIV type 2 (HIV-2). HIV-1 is related to viruses found in chimpanzees and gorillas living in western Africa, while HIV-2 viruses are related to viruses found in the sooty mangabey, a vulnerable West African primate. HIV-1 viruses can be further divided into groups M, N, O and P. The HIV-1 group M viruses predominate and are responsible for the AIDS pandemic. Group M can be further subdivided into subtypes based on genetic sequence data. Some of the subtypes are known to be more virulent or are resistant to different medications. Likewise, HIV-2 viruses are thought to be less virulent and transmissible than HIV-1 M group viruses, although HIV-2 is also known to cause AIDS. One of the obstacles to treatment of the human immunodeficiency virus (HIV) is its high genetic variability. Major types HIV-1 HIV-1 is the most common and pathogenic strain of the virus. Over 2 million such infections occur annually. Scientists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkaloids
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar structure may also be termed alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and, more rarely, other elements such as chlorine, bromine, and phosphorus.Chemical Encyclopedia: alkaloids xumuk.ru Alkaloids are produced by a large variety of organisms including , , |
Tannins
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'', from Medieval Latin ''tannāre'', from ''tannum'', oak bark) refers to the use of oak and other bark in tanning animal hides into leather. By extension, the term ''tannin'' is widely applied to any large polyphenolic compound containing sufficient hydroxyls and other suitable groups (such as carboxyls) to form strong complexes with various macromolecules. The tannin compounds are widely distributed in many species of plants, where they play a role in protection from predation (acting as pesticides) and might help in regulating plant growth. The astringency from the tannins is what causes the dry and puckery feeling in the mouth following the consumption of unripened fruit, red wine or tea. Likewise, the destruction or modification of tann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saponin
Saponins (Latin "sapon", soap + "-in", one of), also selectively referred to as triterpene glycosides, are bitter-tasting usually toxic plant-derived organic chemicals that have a foamy quality when agitated in water. They are widely distributed but found particularly in soapwort (genus Saponaria), a flowering plant, the soapbark tree (''Quillaja saponaria'') and soybeans (''Glycine max'' L.). They are used in soaps, medicinals, fire extinguishers, speciously as dietary supplements, for synthesis of steroids, and in carbonated beverages (the head on a mug of root beer). Structurally, they are glycosides, sugars bonded to another organic molecule, usually a steroid or triterpene, a steroid building block. Saponins are both water and fat soluble, which gives them their useful soap properties. Some examples of these chemicals are glycyrrhizin, licorice flavoring; and quillaia (alt. quillaja), a bark extract used in beverages. Uses The saponins are a subclass of terpenoids, the larges ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomimetic
Biomimetics or biomimicry is the emulation of the models, systems, and elements of nature for the purpose of solving complex human problems. The terms "biomimetics" and "biomimicry" are derived from grc, βίος (''bios''), life, and μίμησις ('' mīmēsis''), imitation, from μιμεῖσθαι (''mīmeisthai''), to imitate, from μῖμος (''mimos''), actor. A closely related field is bionics. Living organisms have evolved well-adapted structures and materials over geological time through natural selection. Biomimetics has given rise to new technologies inspired by biological solutions at macro and nanoscales. Humans have looked at nature for answers to problems throughout their existence. Nature has solved engineering problems such as self-healing abilities, environmental exposure tolerance and resistance, hydrophobicity, self-assembly, and harnessing solar energy. History One of the early examples of biomimicry was the study of birds to enable human flight. Alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naphthalene
Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs. History In the early 1820s, two separate reports described a white solid with a pungent odor derived from the distillation of coal tar. In 1821, John Kidd cited these two disclosures and then described many of this substance's properties and the means of its production. He proposed the name ''naphthaline'', as it had been derived from a kind of naphtha (a broad term encompassing any volatile, flammable liquid hydrocarbon mixture, including coal tar). Naphthalene's chemical formula was determined by Michael Faraday in 1826. The structure of two fused benzene rings was proposed by Emil Erlenmeye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoquinoline
Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline and quinoline are benzopyridines, which are composed of a benzene ring fused to a pyridine ring. In a broader sense, the term isoquinoline is used to make reference to isoquinoline derivatives. 1-Benzylisoquinoline is the structural backbone in naturally occurring alkaloids including papaverine. The isoquinoline ring in these natural compound derives from the aromatic amino acid tyrosine. Properties Isoquinoline is a colorless hygroscopic liquid at temperatures above its melting point with a penetrating, unpleasant odor. Impure samples can appear brownish, as is typical for nitrogen heterocycles. It crystallizes in platelets that have a low solubility in water but dissolve well in ethanol, acetone, diethyl ether, carbon disulfide, and other common organic solvents. It is also soluble in dilute acids as the protonated derivative. Being an analog of pyridine, isoquinolin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Kinase C
In cell biology, Protein kinase C, commonly abbreviated to PKC (EC 2.7.11.13), is a family of protein kinase enzymes that are involved in controlling the function of other proteins through the phosphorylation of hydroxyl groups of serine and threonine amino acid residues on these proteins, or a member of this family. PKC enzymes in turn are activated by signals such as increases in the concentration of diacylglycerol (DAG) or calcium ions (Ca2+). Hence PKC enzymes play important roles in several signal transduction cascades. In biochemistry, the PKC family consists of fifteen isozymes in humans. They are divided into three subfamilies, based on their second messenger requirements: conventional (or classical), novel, and atypical. Conventional (c)PKCs contain the isoforms α, βI, βII, and γ. These require Ca2+, DAG, and a phospholipid such as phosphatidylserine for activation. Novel (n)PKCs include the δ, ε, η, and θ isoforms, and require DAG, but do not require Ca2+ for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
