The short version of Epitalon fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-10-07 and is reviewed periodically as new material appears.
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.
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.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Electrospray or MALDI mass spectrometry | Observed mass compared with theoretical 390.35 Da |
| Purity specification | 95 percent or greater by RP-HPLC | Common convention for research-grade peptide |
| Counter-ion | Acetate or trifluoroacetate | Affects net peptide content of a weighed sample |
| Solution storage | −80 °C as single-use aliquots | Repeated freeze–thaw cycles accelerate loss |
| Main degradation route | Aspartimide formation at Asp-Gly | Produces isoaspartate and related species |
Animal and clinical reports appear mainly in Russian-language journals from the 1990s and 2000s, covering endpoints such as melatonin rhythm, lifespan in aged rodents, and retinal function. Many of these papers involve small groups, lack blinding or placebo comparison, and are difficult to retrieve through indexed databases. Review articles published in English generally summarise the claims without reanalysing the underlying data. Because no large randomised trial exists, the clinical importance of these reported effects stays unresolved and is properly described as an open question.
No national medicines regulator has approved epitalon as a therapeutic product. It is generally distributed as a research chemical, and in some jurisdictions selling peptides for human consumption without approval is restricted or prohibited. Certificates of analysis accompanying commercial material vary in which tests are performed, and independent verification of identity and purity is uncommon. Statements about anti-ageing or disease-prevention benefits on vendor pages are marketing claims rather than regulatory findings, a distinction that shapes how the compound is discussed in scientific and popular sources alike.
The most frequently cited laboratory finding is that AEDG increased telomerase activity and extended telomere length in cultured human somatic cells. That work used fetal fibroblast strains and reported changes in enzyme activity alongside altered division counts. Replication by unrelated groups has been limited, and the published record is largely a single-laboratory series rather than a multi-centre programme. The result supports a hypothesis about peptide influence on gene expression in cell culture; it does not by itself establish an effect on telomere length in living animals or in people.
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
=== Loose connective tissue === Loose connective tissue contains fibers, extracellular matrix, cells, nerves and blood vessels. The extracellular compartment consists of Type 1, 3, and 5 collagen fibers bundles embedded in intercellular substance. The PDL collagen fibers are categorized according to their orientation and location along the tooth. The cells include fibroblast, defence cells and undifferentiated mesenchymal cells.
=== Storage and commercial use === Currently, most rhizomes are consumed fresh, and it is not common to store them due to their poor shelf life performance. This limits export possibilities for producing countries in Asia. Rhizomes lose water quickly, oxidation occurs, and nutrient composition changes within a short time after harvest. Optimal storage temperatures range between 5 and 8 °C (41 and 46 °F). There are three different approaches to storing rhizomes. By stacking the rhizomes, they can be stored, remaining fresh for about three weeks. Special stacking with silver sand and soil results in five to six layers that prevent water loss, thus, the rhizome stays fresh for up to two months. However, this method is not suitable for commercial sale but rather for home use. Hydrogen sulfide fumigation reduces enzymatic browning and therefore ensures rhizome quality. Dipping the rhizomes in a salt solution prevents oxidation and bacterial reproduction, which allows storage for up to five months and greater export ability. This treatment is related to the high cost and inefficient cleaning process before eating the rhizomes.
Recent size estimates in 2023 have this sauropod reaching lengths of up to 44 m (144 ft) long and placed in a colossal weight range of around 110000–170000 kg (240000–370000 lb). If these upper estimates are true, Bruhathkayosaurus would have rivaled the blue whale and Perucetus colossus as one of the largest animals to have ever existed. The largest carnivorous dinosaur was Spinosaurus, reaching a length of 12.6 to 18 meters (41 to 59 ft) and weighing 7 to 20.9 metric tons (7.7 to 23.0 short tons). Other large carnivorous theropods included Giganotosaurus, Carcharodontosaurus, and Tyrannosaurus. Therizinosaurus and Deinocheirus were among the tallest of the theropods. The largest ornithischian dinosaur was probably the hadrosaurid Shantungosaurus giganteus, which measured 16.6 meters (54 ft). The largest individuals may have weighed as much as 16 metric tons (18 short tons).
Sources: en.wikipedia.org
== Other animals == Animal models of androgenic alopecia occur naturally and have been developed in transgenic mice; chimpanzees (Pan troglodytes); bald uakaris (Cacajao rubicundus); and stump-tailed macaques (Macaca speciosa and M. arctoides). Of these, macaques have demonstrated the greatest incidence and most prominent degrees of hair loss. Baldness is not a trait unique to human beings. One possible case study is about a maneless male lion in the Tsavo area. The Tsavo lion prides are unique in that they frequently have only a single male lion with usually seven or eight adult females, as opposed to four females in other lion prides. Male lions may have heightened levels of testosterone, which could explain their reputation for aggression and dominance, indicating that lack of mane may at one time have had an alpha correlation. Although nonhuman primates do not go bald, their hairlines do undergo recession. In infancy, the hairline starts at the top of the supraorbital ridge, but slowly recedes after puberty to create the appearance of a small forehead.
The People's Liberation Army (PLA) is the military wing of the Chinese Communist Party (CCP) and the primary armed forces of the People's Republic of China (PRC). It consists of four services—Ground Force, Navy, Air Force, and Rocket Force—and four arms—Aerospace Force, Cyberspace Force, Information Support Force, and Joint Logistics Support Force. It operates under the CCP's absolute control and is led by the Central Military Commission (CMC) with its chairman as commander-in-chief. Alongside the paramilitary People's Armed Police (PAP) and the Militia, the PLA forms the bulk of the country's armed forces. The PLA can trace its origins during the Republican era to the left-wing units of the National Revolutionary Army (NRA) of the Kuomintang (KMT), when they broke away in 1927 in an uprising against the nationalist government as the Chinese Red Army before being reintegrated into the NRA as units of New Fourth Army and Eighth Route Army during the Second Sino-Japanese War. The two NRA communist units were reconstituted as the PLA in 1947. Since 1949, the PLA has used nine different military strategies, which it calls "strategic guidelines". The most important came in 1956, 1980, and 1993. Politically, the PLA and the PAP have the largest delegation in the National People's Congress (NPC); the joint delegation currently has 281 deputies—over 9% of the total—all of whom are CCP members. The PLA is the armed wing of the CCP and controlled by the party, not by the state. The PLA's primary mission is the defense of the party and its interests.
== Unbinding == Substrate unbinding is influenced by various factors. Larger ligands generally stay in the active site longer, as do those with more rotatable bonds (although this may be a side effect of size). When the solvent is excluded from the active site, less flexible proteins result in longer residence times. More hydrogen bonds shielded from the solvent also decrease unbinding.
Cyclophosphamide is a common cytotoxic drug used in this manner and is often used in conjunction with total body irradiation. Chemotherapeutic drugs may be used at high doses to permanently remove the recipient's bone marrow cells (myeloablative conditioning) or at lower doses that will prevent permanent bone marrow loss (non-myeloablative and reduced intensity conditioning). When used in non-cancer setting, the treatment is still called "chemotherapy", and is often done in the same treatment centers used for people with cancer.
Sources: en.wikipedia.org
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.
Yes. Trifluoroacetate and acetate ions remain associated with the peptide after purification, so a weighed quantity of powder contains less peptide than the nominal mass suggests. Certificates that report net peptide content rather than raw weight are more directly comparable between suppliers.
Dilute aqueous solutions are less stable than the dry powder and are usually aliquoted and frozen to avoid repeated freeze–thaw cycles. Lyophilised material is best stored desiccated at −20 °C, protected from light. Working solutions are typically prepared fresh from a frozen aliquot.
It is a synthetic tetrapeptide built from alanine, glutamate, aspartate and glycine. The four residues are joined by standard peptide bonds, giving a linear chain rather than a branched structure.