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Other names | Biacalein; Noroxylin |
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ECHA InfoCard | 100.164.911 |
Chemical and physical data | |
Formula | C15H10O5 |
Molar mass | 270.240 g·mol−1 |
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Baicalein (5,6,7-trihydroxyflavone) is a flavone, a type of flavonoid, originally isolated from the roots of Scutellaria baicalensis and Scutellaria lateriflora . It is also reported in Oroxylum indicum (Indian trumpetflower) and Thyme . [1] It is the aglycone of baicalin. Baicalein is one of the active ingredients of Sho-Saiko-To, which is a Chinese classic herbal formula, and listed in Japan as Kampo medicine.[ citation needed ]
Baicalein, along with its analogue baicalin, is a positive allosteric modulator of the benzodiazepine site and/or a non-benzodiazepine site of the GABAA receptor but with an affinity over 250× lower than diazepam. [2] [3] [4] [5] [6] [7] It displays subtype selectivity for α2 and α3 subunit-containing GABAA receptors. [8] In accordance, baicalein shows anxiolytic effects in mice without incidence of sedation or myorelaxation. [7] [8] [9] It is thought that baicalein, along with other flavonoids, may underlie the anxiolytic effects of S. baicalensis and S. lateriflora. [10] [11] Baicalein is also an antagonist of the estrogen receptor, or an antiestrogen. [11]
The flavonoid has been shown to inhibit certain types of lipoxygenases [12] and act as an anti-inflammatory agent. [13] It has antiproliferative effects on ET-1-induced proliferation of pulmonary artery smooth muscle cell proliferation via inhibition of TRPC1 channel expression. [14] Possible antidepressant effects have also been attributed to baicalein in animal research. [15]
Baicalein is an inhibitor of CYP2C9, [16] an enzyme of the cytochrome P450 system that metabolizes drugs in the body.
A derivative of baicalin is a known prolyl endopeptidase inhibitor. [17]
Baicalein has been shown to inhibit Staphylococcus aureus biofilm formation and the quorum sensing system in vitro. [18]
It has also been shown to be effective in vitro against all forms of Borrelia burgdorferi and Borrelia garinii . [19]
Kavalactones are a class of lactone compounds found in kava roots and Alpinia zerumbet. Kavalactones are under research for potential to have various psychotropic effects, including anxiolytic and sedative/hypnotic activities.
An imidazopyridine is a nitrogen containing heterocycle that is also a class of drugs that contain this same chemical substructure. In general, they are GABAA receptor agonists, however recently proton pump inhibitors, aromatase inhibitors, NSAIDs and other classes of drugs in this class have been developed as well. Despite usually being similar to them in effect, they are not chemically related to benzodiazepines. As such, GABAA-agonizing imidazopyridines, pyrazolopyrimidines, and cyclopyrrones are sometimes grouped together and referred to as "nonbenzodiazepines." Imidazopyridines include:
The GABAA receptor (GABAAR) is an ionotropic receptor and ligand-gated ion channel. Its endogenous ligand is γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Accurate regulation of GABAergic transmission through appropriate developmental processes, specificity to neural cell types, and responsiveness to activity is crucial for the proper functioning of nearly all aspects of the central nervous system (CNS). Upon opening, the GABAA receptor on the postsynaptic cell is selectively permeable to chloride ions (Cl−) and, to a lesser extent, bicarbonate ions (HCO3−).
Scutellaria is a genus of flowering plants in the mint family, Lamiaceae. They are known commonly as skullcaps. The generic name is derived from the Latin scutella, meaning "a small dish, tray or platter", or "little dish", referring to the shape of the calyx. The common name alludes to the resemblance of the same structure to "miniature medieval helmets". The genus has a subcosmopolitan distribution, with species occurring nearly worldwide, mainly in temperate regions.
Alpidem, sold under the brand name Ananxyl, is a nonbenzodiazepine anxiolytic medication which was briefly used to treat anxiety disorders but is no longer marketed. It was previously marketed in France, but was discontinued due to liver toxicity. Alpidem is taken by mouth.
Apigenin (4′,5,7-trihydroxyflavone), found in many plants, is a natural product belonging to the flavone class that is the aglycone of several naturally occurring glycosides. It is a yellow crystalline solid that has been used to dye wool.
Bretazenil (Ro16-6028) is an imidazopyrrolobenzodiazepine anxiolytic drug which is derived from the benzodiazepine family, and was invented in 1988. It is most closely related in structure to the GABA antagonist flumazenil, although its effects are somewhat different. It is classified as a high-potency benzodiazepine due to its high affinity binding to benzodiazepine binding sites where it acts as a partial agonist. Its profile as a partial agonist and preclinical trial data suggests that it may have a reduced adverse effect profile. In particular bretazenil has been proposed to cause a less strong development of tolerance and withdrawal syndrome. Bretazenil differs from traditional 1,4-benzodiazepines by being a partial agonist and because it binds to α1, α2, α3, α4, α5 and α6 subunit containing GABAA receptor benzodiazepine receptor complexes. 1,4-benzodiazepines bind only to α1, α2, α3 and α5GABAA benzodiazepine receptor complexes.
Scutellaria baicalensis, with the common name Baikal skullcap or Chinese skullcap, is a species of flowering plant in the family Lamiaceae.
DMCM is a drug from the β-carboline family that induces anxiety and convulsions by acting as a negative allosteric modulator of GABAA receptors — functionally opposite to benzodiazepines and related drugs which are positive allosteric modulators — and is used in scientific research for these properties to test new anxiolytic and anticonvulsant medications, respectively. It has also been shown to produce analgesic effects in animals, which is thought to be the drug's induced panic reducing the perception of pain.
Scutellaria lateriflora, is a hardy perennial herb of the mint family, Lamiaceae, native to North America.
CGS-20625 is an anxiolytic drug used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic. It produces anxiolytic and anticonvulsant effects, but with no sedative effects even at high doses, and no significant muscle relaxant effects. It is orally active in humans, but with relatively low bioavailability.
As baicalin is a flavone glycoside, it is a flavonoid. It is the glucuronide of baicalein.
ELB-139 (LS-191,811) is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic.
TPA-023 (MK-0777) is an anxiolytic drug with a novel chemical structure, which is used in scientific research. It has similar effects to benzodiazepine drugs, but is structurally distinct and so is classed as a nonbenzodiazepine anxiolytic. It is a mixed, subtype-selective ligand of the benzodiazepine site of α1, α2, α3, and α5-containing GABAA receptors, where it acts as a partial agonist at benzodiazepine sites of the α2 and α3-containing subtypes, but as a silent antagonist at α1 and α5-containing subtypes. It has primarily anxiolytic and anticonvulsant effects in animal tests, but with no sedative effects even at 50 times the effective anxiolytic dose.
Wogonin is an O-methylated flavone, a flavonoid-like chemical compound which is found in Scutellaria baicalensis.
Oroxylin A is an O-methylated flavone, a chemical compound that can be found in the medicinal plants Scutellaria baicalensis and Scutellaria lateriflora, and the Oroxylum indicum tree. It has demonstrated activity as a dopamine reuptake inhibitor, and is also a negative allosteric modulator of the benzodiazepine site of the GABAA receptor. Oroxylin A has been found to improve memory consolidation in mice by elevating brain-derived neurotrophic factor (BDNF) levels in the hippocampus.
Scutellarin is a flavone, a type of phenolic chemical compound. It can be found in the Asian "barbed skullcap" Scutellaria barbata and the north American plant S. lateriflora both of which have been used in traditional medicine. The compound is found only in trace amounts in the "Chinese skullcap" Scutellaria baicalensis, another plant used in traditional Chinese medicine.
6-Hydroxyflavone is a flavone, a type of chemical compound. It is one of the noncompetitive inhibitors of cytochrome P450 2C9. It is reported in Crocus and leaves of Barleria prionitis Linn. . 6-Hydroxyflavone may have a potential as a therapeutic drug capable for the treatment of anxiety-like disorders.
Cartazolate (SQ-65,396) is a drug of the pyrazolopyridine class. It acts as a GABAA receptor positive allosteric modulator at the barbiturate binding site of the complex and has anxiolytic effects in animals. It is also known to act as an adenosine antagonist at the A1 and A2 subtypes and as a phosphodiesterase inhibitor. Cartazolate was tested in human clinical trials and was found to be efficacious for anxiety but was never marketed. It was developed by a team at E.R. Squibb and Sons in the 1970s.
Baicalin-beta-D-glucuronidase (EC 3.2.1.167, baicalinase) is an enzyme with systematic name 5,6,7-trihydroxyflavone-7-O-beta-D-glucupyranosiduronate glucuronosylhydrolase. This enzyme catalyses the following chemical reaction