Lyophilized powder raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-06-15 and is reviewed periodically as new material appears.
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.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Free acid form of the tetrapeptide |
| Molecular mass | About 390.35 Da | Calculated monoisotopic value |
| Appearance | White to off-white powder | Typical lyophilized presentation |
| Solubility | Soluble in water | Also dissolves in buffered saline |
| Storage temperature | Minus 20 degrees Celsius | Dry, dark conditions; avoid repeated thawing |
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
== Synthesis == Carbonyl sulfide was first described in 1841, but was apparently mischaracterized as a mixture of carbon dioxide and hydrogen sulfide. Carl von Than first characterized the substance in 1867. It forms when carbon monoxide reacts with molten sulfur:
In addition, we in Serbia and Montenegro must take into account that whatever form we take within the European Union, we have only but one choice and that is to work for the common good of all member nations. It is also central to take into account that stability in our region will be enhanced when Serbia is fully at peace with itself. Following Montenegro's successful independence referendum on 21 May 2006, the re-creation of the Serbian monarchy found its way into daily political debate. A monarchist proposal for the new Serbian constitution has been published alongside other proposals. The document approved in October is a republican one. The Serbian people have not had a chance to vote on the system of government. The Crown Prince raised the issue of a royal restoration in the immediate aftermath of the vote. In a press release issued on 24 May, he stated:
== Chemically driven rotary molecular motors == Source: An example of a prototype for a synthetic chemically driven rotary molecular motor was reported by Kelly and co-workers in 1999. Their system is made up from a three-bladed triptycene rotor and a helicene, and is capable of performing a unidirectional 120° rotation. This rotation takes place in five steps. The amine group present on the triptycene moiety is converted to an isocyanate group by condensation with phosgene (a). Thermal or spontaneous rotation around the central bond then brings the isocyanate group in proximity of the hydroxyl group located on the helicene moiety (b), thereby allowing these two groups to react with each other (c). This reaction irreversibly traps the system as a strained cyclic urethane that is higher in energy and thus energetically closer to the rotational energy barrier than the original state. Further rotation of the triptycene moiety therefore requires only a relatively small amount of thermal activation in order to overcome this barrier, thereby releasing the strain (d). Finally, cleavage of the urethane group restores the amine and alcohol functionalities of the molecule (e). The result of this sequence of events is a unidirectional 120° rotation of the triptycene moiety with respect to the helicene moiety. Additional forward or backward rotation of the triptycene rotor is inhibited by the helicene moiety, which serves a function similar to that of the pawl of a ratchet.
Sources: en.wikipedia.org
== Animal studies and PhIP == Rats were fed PhIP at concentrations of 25, 100, and 200 ppm. The rats gained weight throughout the experiment, but feeding concentration of PhIP remained constant. Rats were fed PhIP ad libitum at concentrations of 12.5 and 50ppm. Rats developed mammary tumors at each concentration of PhIP administered. An in vivo study found mice injected with 5, 10, 12, 18, 20, 24, 28, 32, or 36 mg/kg bw showed a strong correlation between consumption of PhIP and genetic damage.
The constitution grants freedom of religion, while establishing Islam as the "religion of the Federation". The freedom to change or leave a religion is limited for Muslims. According to the Population and Housing Census 2020 figures, ethnicity and religious beliefs correlate highly. Approximately 63.5% of the population practise Islam, 18.7% practise Buddhism, 9.1% Christianity, 6.1% Hinduism and 1.3% practise Confucianism, Taoism and other traditional Chinese religions. 2.7% declared no religion or practised other religions or did not provide any information. The states of Sarawak and Penang, as well as the federal territory of Kuala Lumpur have non-Muslim majorities. Sunni Islam of the Shafi'i school of jurisprudence is the dominant branch of Islam in Malaysia, while 18% are nondenominational Muslims. The Malaysian constitution strictly defines what makes a "Malay", defining Malays as those who are Muslim, speak Malay regularly, practise Malay customs, and lived in or have ancestors from Brunei, Malaysia and Singapore. Statistics from the 2010 Census indicate that 83.6% of the Chinese population identify as Buddhist, with significant numbers of adherents following Taoism (3.4%) and Christianity (11.1%), along with small Muslim populations in areas like Penang. The majority of the Indian population follows Hinduism (86.2%), with a significant minority identifying as Christians (6.0%) or Muslims (4.1%). Christianity is the predominant religion of the non-Malay bumiputera community (46.5%), while 40.4% identify as Muslims.
It can be argued that in the play Euripides portrays Medea as an enraged woman who kills her children to get revenge on her husband Jason because of his betrayal of their marriage. Medea is often cited as an example of the "madwoman in the attic" trope, in which women who defy societal norms are portrayed as mentally unstable. A competing interpretation is that Medea kills her children because she cares for them and worries about their well-being; once she commits to her plan to kill Creon and Jason's new bride, she knows her children are in danger of being murdered. This is not a paranoid fantasy; at this time in myth and history, helping one's friends and hurting one's enemies was considered a virtue. Thus, by their code of ethics, the Corinthians would do right to avenge their king and princess. (In another version of the myth, the people of Corinth kill her children to avenge the deaths of Creon and his daughter Glauce.) Conversely, a focus on Medea's rage leads to the interpretation that "Medea becomes the personification of vengeance, with her humanity 'mortified' and 'sloughed off'" (Cowherd, 129). Medea's heritage places her in a position more typically reserved for males. Hers is the power of the sun, appropriately symbolized by her great radiance, tremendous heat and boundless passion. In this view Medea is inhuman and her suffering is self-inflicted, just as Jason argues in his debate with her. And yet, if we see events through Medea's eyes, we view a wife intent on vengeance, and a mother concerned about her children's safety and quality of life.
Sources: en.wikipedia.org
Stability of isotopes is affected by the ratio of protons to neutrons, and also by presence of certain magic numbers of neutrons or protons which represent closed and filled quantum shells. These quantum shells correspond to a set of energy levels within the shell model of the nucleus; filled shells, such as the filled shell of 50 protons for tin, confers unusual stability on the nuclide. As in the case of tin, a magic number for Z, the atomic number, tends to increase the number of stable isotopes for the element. Just as electrons have the lowest energy state when they occur in pairs in a given orbital, nucleons (both protons and neutrons) exhibit a lower energy state when their number is even, rather than odd. This stability tends to prevent beta decay (in two steps) of many even–even nuclides into another even–even nuclide of the same mass number but lower energy (and of course with two more protons and two fewer neutrons), because decay proceeding one step at a time would have to pass through an odd–odd nuclide of higher energy. Such nuclei thus instead undergo double beta decay (or are theorized to do so) with half-lives several orders of magnitude larger than the age of the universe. This makes for a larger number of stable even–even nuclides, which account for 150 of the 251 total. Stable even–even nuclides number as many as three isobars for some mass numbers, and up to seven isotopes for some atomic numbers.
=== Other procedures === More recent approaches to the synthesis of N-substituted isatins involves the direct oxidation of commercially available, substituted indoles or oxindoles with different oxidizing agents such as TBHP, IBX-SO3K, tBuONO etc.
1RAR trained in Kenya from December 1943 to September 1944, when it transferred to Ceylon and became part of the 22nd (East Africa) Infantry Brigade alongside the 1st KAR and the 3rd Northern Rhodesia Regiment. In December 1944, after three months' training for jungle warfare, 1RAR and the other two components of the brigade joined the Burma Campaign at Chittagong under the command of the 15th Indian Corps. The brigade spent about three months supporting the 25th Indian Division in north-western Burma, advancing through the Mayu peninsula during January 1945 and taking part in the latter stages of the Battle of Ramree Island, landing on the island on 14 February. 1RAR fortified positions at Myinbin, Kyaukkale and Mayin but did not contact Japanese forces. A widespread belief developed among Japanese troops in Burma that the British Army's African soldiers were cannibals, partly because of deliberate disinformation spread by the black troops themselves as they travelled around the country. While entirely unfounded, the notion "that we Africans eat people", as one RAR soldier put it, had a fearsome psychological effect; men of 1RAR reported Japanese soldiers picking up their comrades' bodies in the midst of battle and running away. In March 1945 the 22nd Brigade was ordered south to Dalaba where it became part of the 82nd (West Africa) Division, which had been tasked with clearing the Taungup area of Japanese troops.
=== Metabolic and proteomic evidence === Pro-oxidative processes correlate with pain in fibromyalgia patients. Decreased mitochondrial membrane potential, increased superoxide activity, and increased lipid peroxidation production are observed. The high proportion of lipids in the central nervous system (CNS) makes the CNS especially vulnerable to free radical damage. Levels of lipid peroxidation products correlate with fibromyalgia symptoms. Fibromyalgia is associated with the deregulation of proteins related to complement and coagulation cascades, as well as to iron metabolism. An excessive oxidative stress response may cause dysregulation of many proteins.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.
No naturally occurring free form of the peptide has been described. The four-amino-acid sequence can appear as a fragment within larger proteins, but that is not the same as the intact compound being present as a circulating molecule. Materials used in research are synthetic.
Purity is usually checked by reverse-phase high-performance liquid chromatography, which separates the target peptide from related impurities. Mass spectrometry is commonly used alongside it to confirm molecular mass. Some suppliers also provide amino acid analysis for additional sequence confirmation.
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.