A practical reference on epithalamin: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-17. Anything still debated is marked as such rather than presented as settled.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Linear tetrapeptide, also written AEDG |
| Molecular mass | About 390.35 g/mol | Value calculated from the sequence |
| Appearance | White to off-white powder | Lyophilised material forms a loose cake |
| Solubility | Freely soluble in water | Also dissolves in isotonic saline |
| Storage | -20 °C, desiccated | Aliquot solutions to avoid freeze–thaw cycling |
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
== History == Barbituric acid was first synthesized 27 November 1864, by German chemist Adolf von Baeyer, and later perfected in 1879 by the French chemist Edouard Grimaux, who developed and improved the synthesis. This was done by condensing urea with diethyl malonate. There are several stories about how the substance got its name. The most likely story is that Baeyer and his colleagues went to celebrate their discovery in a tavern where the town's artillery garrison were also celebrating the feast of Saint Barbara – the patron saint of artillerymen. An artillery officer is said to have christened the new substance by amalgamating Barbara with urea. Another story holds that Baeyer synthesized the substance from the collected urine of a Munich waitress named Barbara. No substance of medical value was discovered, however, until 1902 when two German scientists working at Bayer, Emil Fischer and Joseph von Mering, discovered that barbital was very effective in putting dogs to sleep. Barbital was then marketed by Bayer under the trade name Veronal. It is said that Mering proposed this name because the most peaceful place he knew was the Italian city of Verona. In 1912, Bayer introduced another barbituric acid derivative, phenobarbital, under the trade name Luminal, as a sedative–hypnotic. It was not until the 1950s that the behavioral disturbances and physical dependence potential of barbiturates became recognized. Since the 1970s, most barbiturates were replaced by benzodiazepines.
== Medical use == Inotuzumab ozogamicin is used to treat relapsed or refractory B-cell precursor acute lymphoblastic leukemia. In March 2024, the US Food and Drug Administration approved inotuzumab ozogamicin for the treatment of children aged one year and older with relapsed or refractory CD22-positive B-cell precursor acute lymphoblastic leukemia.
Serotonergic psychedelics, including drugs like psilocybin (found in psilocybin mushrooms), dimethyltryptamine (DMT) (found in ayahuasca), lysergic acid diethylamide (LSD), mescaline (found in peyote cactus), and 5-MeO-DMT (found in Anadenanthera trees and the Bufo alvarius toad), are non-selective agonists of the serotonin receptors and mediate their hallucinogenic effects specifically by activation of the serotonin 5-HT2A receptor. This is evidenced by the fact that serotonin 5-HT2A receptor antagonists and so-called "trip killers" like ketanserin block the hallucinogenic effects of serotonergic psychedelics in humans, among many other findings. Some serotonergic psychedelics, like psilocin, DMT, and 5-MeO-DMT, are substituted tryptamines and are very similar in chemical structure to serotonin. Serotonin itself, despite acting as a serotonin 5-HT2A receptor agonist, is thought to be non-hallucinogenic. The hallucinogenic effects of serotonergic psychedelics are believed to be related to activation of serotonin 5-HT2A receptors expressed in a population of cortical neurons in the medial prefrontal cortex (mPFC). These serotonin 5-HT2A receptors, unlike most serotonin and related receptors, are expressed intracellularly. In addition, the neurons containing them lack expression of the serotonin transporter (SERT), which normally transports serotonin from the extracellular space to the intracellular space within neurons.
=== Causes === The most common cause of periwound issues is excessive moisture present in the area surrounding the wound. Exudate from heavily draining wounds causes irritation of the periwound that may lead to maceration, excoriation, and otherwise compromise skin integrity. This type of damage is more common in chronic wounds due to exudate composition which differs from fluids produced in acute wounds or burns. Chronic wound exudate contains proteolytic enzymes and other components that degrade skin integrity and predispose it to inflammation. Moisture-associated skin damage can also be caused by bodily fluids or other contaminants that enter the periwound areas, for example, in patients with urinary or fecal incontinence, or colostomy patients. Other causes include dryness of the skin due to ageing and skin or systemic disorders, allergic reactions to wound care products, damage that may result from poor application and removal technique of adhesive products used in wound treatment, as well as exposure to infection or extrinsic contaminants at the time of wound dressing changes.
=== Pests === Common herbarium pests include: silverfish, book lice (psocids), cigarette or tobacco beetles (Lasioderma), dermestids, drugstore beetles (Stegobium paniceum) A reoccurring threat to the longevity of herbarium specimens is insects, a number of which find dried plants palatable. Historically, various methods have been used to kill insects, which either come in with the plants when they are collected or are in the building where the plants are stored. Pests are commonly treated with two different methods:
Sources: en.wikipedia.org
=== Build === Though Neanderthals are often imagined as short and stocky, they were on average the same height as pre-industrial Europeans, or even slightly taller. The body mass index of the average European Neanderthal was comparable to 20th century Canadians and Americans. Neanderthal body size varied by location; West Asian Neanderthals were taller and more slightly built than European Neanderthals. In a sample of 45 Neanderthal long bones from 14 men and 7 women, the average height was 164 to 168 cm (5 ft 5 in to 5 ft 6 in) for males and 152 to 156 cm (5 ft 0 in to 5 ft 1 in) for females. The fossil record shows that adult Neanderthals varied from about 147.5 to 177 cm (4 ft 10 in to 5 ft 10 in) in height. The average male body mass index was 26.9–28.3. Neanderthal pelvic bones were extremely wide; with Neanderthal male hips being approximately 31% wider than those of modern humans males. As in all archaic species, there is no evidence of sexual dimorphism in the Neanderthal pelvis; both males and females had large pelvic bones relative to their body size, with larger males having the largest pelvises. The Neanderthal chest was deep and wide, with a proportionally expansive thoracic cavity, and possibly stronger lung performance. and much higher caloric demands. The limbs are proportionally short. The body plan has traditionally been explained as a "hyper-arctic" adaptation (Allen's rule). Neanderthals would also have been effective sprinters: stronger lungs, and shorter limbs would have boosted efficiency.
==== Fruiting and dispersal ==== After fertilization, one or both ovules develop into fruit-like structures containing seeds. The fruits are 1.5–2 cm (5⁄8–3⁄4 in) long, with a soft, fleshy, yellow-brown outer layer (the sarcotesta) that is attractive in appearance, but contains butyric acid (also known as butanoic acid) and smells foul like rancid butter or vomit when fallen. Ginkgo seed stalks are as long as its leaf stalks, with 1–2 seeds at their tips. Ripe seeds shed with autumn leaves, or may persist a little longer. Beneath the sarcotesta is the hard sclerotesta (the "shell" of the seed) and a papery endotesta, with the nucellus surrounding the female gametophyte at the center. Despite its perception by humans as foul, the fruit odor is attractive to certain small mammals that eat the fruit and disperse the seeds: these include the gray squirrel and, in East Asia, the palm civet and raccoon dog. The sclerotesta resists digestion, and so the seeds are passed intact into feces, which thus provide a dispersal mechanism.
Explorations of artificial materials for manipulating electromagnetic waves began at the end of the 19th century. Some of the earliest structures that may be considered metamaterials were studied by Jagadish Chandra Bose, who in 1898 researched substances with chiral properties. Karl Ferdinand Lindman studied wave interaction with metallic helices as artificial chiral media in the early twentieth century. In the late 1940s, Winston E. Kock from AT&T Bell Laboratories developed materials that had similar characteristics to metamaterials. In the 1950s and 1960s, artificial dielectrics were studied for lightweight microwave antennas. Microwave radar absorbers were researched in the 1980s and 1990s as applications for artificial chiral media. Negative-index materials were first described theoretically by Victor Veselago in 1967. He proved that such materials could transmit light. He showed that the phase velocity could be made anti-parallel to the direction of Poynting vector. This is contrary to wave propagation in naturally occurring materials. In 1995, John M. Guerra fabricated a sub-wavelength transparent grating (later called a photonic metamaterial) having 50 nm lines and spaces, and then coupled it with a standard oil immersion microscope objective (the combination later called a super-lens ) to resolve a grating in a silicon wafer also having 50 nm lines and spaces. This super-resolved image was achieved with illumination having a wavelength of 650 nm in air.
=== Four base (quadruplet) codons === While triplet codons are the basis of the genetic code in nature, programmed +1 frameshift is a natural process that allows the use of a four-nucleotide sequence (quadruplet codon) to encode an amino acid. Recent developments in genetic code engineering also showed that quadruplet codon could be used to encode non-standard amino acids under experimental conditions. This allowed the simultaneous usage of two unnatural amino acids, p-azidophenylalanine (pAzF) and N6-[(2-propynyloxy)carbonyl]lysine (CAK), which cross-link with each other by Huisgen cycloaddition. Quadrupled decoding in wild-type, non-recoded strains is very inefficient. This stems from the fact that the interaction between engineered tRNAs with ternary complexes or other translation components is not as favorable and strong as with cell endogenous translation elements. This problem can be overcome by specifically engineering and evolving tRNA that can decode quadruplet codons in non-recoded strains. Up to 4 different quadruplet orthogonal tRNA/tRNA synthethase pairs can be generated in this manner. Quadruplet codon decoding approach has also been applied to the construction of an HIV-1 vaccine.
Sources: en.wikipedia.org
== Clinical significance == Tβ4 has been studied in a number of clinical trials. In phase 2 trials with patients having pressure ulcers, venous pressure ulcers, and epidermolysis bullosa, Tβ4 accelerated the rate of repair. It was also found to be safe and well tolerated. In human clinical trials, Tβ4 improves the conditions of dry eye and neurotrophic keratopathy with effects lasting long after the end of treatment.
In Indonesia, especially among the Javanese, the jamu traditional herbal medicine may have originated in the Mataram kingdom era, some 1300 years ago. The bas-reliefs on Borobudur depict the image of people grinding herbs with stone mortar and pestle, a drink seller, a herbalist, and masseuse treating people. The Madhawapura inscription from Majapahit period mentioned a specific profession of herb mixer and combiner (herbalist), called Acaraki. The book from Mataram dated from circa 1700 contains 3,000 entries of jamu herbal recipes, while Javanese classical literature Serat Centhini (1814) describes some jamu herbal concoction recipes. Though possibly influenced by Indian Ayurveda systems, the Indonesia archipelago holds numerous indigenous plants not found in India, including plants similar to those in Australia beyond the Wallace Line. Jamu practices may vary from region to region, and are often not recorded, especially in remote areas of the country. Although primarily herbal, some Jamu materials are acquired from animals, such as honey, royal jelly, milk, and Ayam Kampung eggs.
Austin was involved in the concluding segment at ECW One Night Stand on June 12 in which he had a beer bash with the ECW locker room. He also appeared on the internet themed event Cyber Sunday in 2007 and 2008. Austin also made appearenced to promote WWE material, like the WWE Films' production The Condemned, the revival of Tough Enough in 2011.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.
AEDG is the one-letter code for the four amino acids alanine, glutamate, aspartate and glycine in that order. The same molecule is written in three-letter form as Ala-Glu-Asp-Gly.
Identity is normally confirmed by mass spectrometry against the calculated mass of roughly 390.35 g/mol. Purity is then estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection.
Mass spectrometry provides the identity check, because the observed mass is compared with the theoretical mass of the AEDG sequence. Chromatography separates and quantifies impurities but does not by itself prove which peptide is present. The two techniques are normally used together.