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 2025-12-25 and is reviewed periodically as new material appears.
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.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
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.
Epitalon appears in the literature primarily through a small number of research groups, most of them associated with the St. Petersburg Institute of Bioregulation and Gerontology. Publications describe cell culture experiments, animal studies, and a limited number of small human studies. Independent replication outside this network is sparse. As a result, reviews of the topic usually separate descriptive reports of observed effects from the question of whether those effects generalize, and they note the difficulty of comparing studies that use different preparations and endpoints.
Analytical characterization of epitalon relies on standard peptide methods. Reverse-phase high-performance liquid chromatography is used to assess purity, and mass spectrometry confirms identity by checking the observed mass against the expected value near 390 daltons. Amino acid analysis can verify composition. Because the peptide is short and hydrophilic, it elutes early on many reverse-phase columns, so method development often requires ion-pairing reagents to achieve adequate retention and resolution from related impurities.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
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.
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.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
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.
=== Other properties === Another important property for potential applications is the extent of phase separation, represented by the difference in polymer content in the two phases after phase separation. For most applications, phase separation in pure polymer and pure solvent would be desirable although it is practically impossible. The extent of phase separation in a given temperature interval depends on the particular polymer-solvent phase diagram. Example: From the phase diagram of polystyrene (molar mass 43,600 g/mol) in the solvent cyclohexane it follows that at a total polymer concentration of 10%, cooling from 25 to 20 °C causes phase separation into a polymer-poor phase with 1% polymer and a polymer-rich phase with 30% polymer content. Also desirable for many applications is a sharp phase transition, which is reflected by a sudden drop in transmittance. The sharpness of the phase transition is related to the extent of phase separation but additionally relies on whether all present polymer chains exhibit the same cloud point. This depends on the polymer endgroups, dispersity, or—in the case of copolymers—varying copolymer compositions. As a result of phase separation, thermoresponsive polymer systems can form well-defined self-assembled nanostructures with a number of different practical application such as in drug and gene delivery, tissue engineering, etc.
Hadacidin, and hadacidin analogues, have anticancer activity and activity against adenylosuccinate synthetase. Hadacidin is the simplest known naturally occurring hydroxamic acid. The hydroxylamino group is frequently donated by a hydroxylamino acid such as 8-N-hydroxyornithine of the siderochromes. This compound, first isolated and characterized by Kaczka et al. in 1962, seemed well suited for a study of the route of hydroxamic acid biosynthesis. The hydroxamate bond may be considered to be a peptide bond with an oxygen atom on the amide nitrogen, but there is no a priori reason to decide whether the oxygen atom is introduced before or after the formation of the amide bond. In the latter case, formylglycine would be an intermediate in hadacidin biosynthesis. N-Hydroxylation of an amide bond was reported by Cramer et al. (1960), who found that N-hydroxy-2-acetylaminofluorene was formed in the intact rat upon administration of 2-acetylaminofluorene. Nevertheless, this finding cannot be considered direct proof of N-hydroxylation of an amide bond because, as the authors point out, the acetyl group is labile in their experiments, and hydroxylation of the amino group might have occurred. Glycine, formate, and the 2-carbon of serine were all found to be very quickly incorporated into hadacidin during its synthesis by Penicillium aurantioviolaceum.
== Signals and noise == One of the most important components of analytical chemistry is maximizing the desired signal while minimizing the associated noise. The analytical figure of merit is known as the signal-to-noise ratio (S/N or SNR). Noise can arise from environmental factors as well as from fundamental physical processes.
Sources: en.wikipedia.org
=== Extraction === Lactobacillic acid can be isolated from the lipids of bacteria, as used by the working group during the discovery. First, hydrolysis (saponification) of the phospholipids or triglycerides is carried out, releasing the fatty acid bound as an ester. Since other fatty acids are present in addition to lactobacillic acid, separation is then carried out using urea extraction crystallization or column chromatography. The fractional crystallization process can also be used.
== Awards == Outback Steakhouse was ranked No. 1 in the 2023 American Customer Satisfaction Index (ACSI) restaurant study for overall satisfaction, menu variety, food quality and beverage quality. The Takeout published a related article, "America is falling in Love with Steakhouses all over again" which discusses the broader steakhouse category and Outback's standing in customer satisfaction coverage.
=== 2010 === On February 3, 2010, David A. Larson, an elected official in California who has a relationship with government contract personnel, made disclosures to the U.S. Department of Defense (DOD), Office of the Inspector General (OIG) alleging that under the Bush Administration, prisoners detained at Abu Ghraib, Guantanamo Bay, and undisclosed "black sites" were being used as involuntary research subjects for human biomedical experimentation, behavior modification research, and drug-testosterone delivery in a manner similar to past CIA Project MKULTRA activities investigated in 1977 by Senators Kennedy and Inuoye. The allegation supports information contained in an International Red Cross report relative to the expanded role of CIA medical personnel in torture and interrogation.
Sources: en.wikipedia.org
in Senegal, under the leadership of Léopold Sédar Senghor, in Ghana under the leadership of Kwame Nkrumah, in Guinea under Ahmed Sékou Touré and in Tanzania, under the leadership of Julius Nyerere, who developed the concept of Ujamaa, co-operative economoics) were heavily influenced by democratic socialism, although often drifting away from democracy after taking power. Embracing a new ideology called Third World socialism, countries in Africa, Asia and Latin America often nationalised industries held by foreign owners. In addition, the New Left, a movement composed of activists, educators, agitators and others who sought to implement a broad range of social reforms on issues such as gay rights, abortion, gender roles and drugs, in contrast to earlier leftist or Marxist movements that had taken a more vanguardist approach to social justice and focused mostly on labour unionisation and issues related to class, became prominent in the 1960s and 1970s. The New Left rejected involvement with the labour movement and Marxism's historical theory of class struggle.
In China, archaeological evidence of medicine in Chinese dates back to the Bronze Age Shang dynasty, based on seeds for herbalism and tools presumed to have been used for surgery. The Huangdi Neijing, the progenitor of Chinese medicine, is a medical text written beginning in the 2nd century BCE and compiled in the 3rd century. In India, the oldest known surgical text, the Sushruta Samhita written by the surgeon Sushruta, described numerous surgical operations, including the earliest forms of plastic surgery as well as methods of sterilization for surgical instruments. The earliest records of dedicated hospitals come from Mihintale in Sri Lanka where evidence of dedicated medicinal treatment facilities for patients are found.
== Honours and awards == In 1970 Iphigenia Vourvidou-Photaki was awarded the one-off Georgios Panopoulos Prize of the Academy of Athens, presented to her for "...her research on the chemical synthesis of polypeptide hormones and investigation of enzyme active sites, which constitute an internationally notable contribution of Greek science to the modern discipline of Chemistry". During her lifetime, she was invited many times as a distinguished researcher in academic conferences related to her subject; some examples were the personal invitations she received to the 3rd European Peptide Symposium (EPS) (Basel, 1960), the 5th EPS (Oxford, 1962), 6th EPS (Athens, 1963 as organiser), 6th International Biochemistry Conference (New York, 1964), 7th EPS (Budapest, 1964), Symposium on Natural Sulfur Compounds (Copenhagen, 1966), NATO Seminar of Molecular Biology (Spetses, 1966), 8th EPS (Noordwijk, 1966), 9th EPS (Paris, 1968), 10th EPS (Abano, 1970), 11th EPS (Vienna, 1971), 3rd American Peptide Symposium (APS) (Boston, 1972), 13th EPS (Kiryat, 1974), 4th APS (New York, 1975), and the 14th EPS (Wépion, 1976) over which she presided.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
Identity is normally confirmed by mass spectrometry, which checks the measured mass against the expected value near 390 daltons. Reverse-phase high-performance liquid chromatography is used alongside it to assess purity. Amino acid analysis can provide additional composition data.