Epithalamin comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2025-08-24. Numbers and descriptions here follow the published literature rather than marketing material.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic tetrapeptide | Four residues, linear chain |
| Residue sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Calculated mass | 390.3 daltons | Value for the free, uncharged form |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility | Freely soluble in water | Often handled as a salt form |
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
Peptides of this size are generally stable as dry solids but degrade in solution over time. The principal routes are hydrolysis of the peptide backbone and oxidation, with hydrolysis favoured by elevated temperature and extreme pH. Aqueous solutions held at room temperature can show measurable loss of purity within days, while frozen aliquots are considerably more durable. Because the sequence contains neither cysteine nor methionine, oxidation is less of a concern than for many other peptides, but pH control during handling still matters.
Typical storage for the lyophilized powder is −20 °C or lower, in a sealed container protected from light and moisture. Hygroscopic material should be allowed to equilibrate to room temperature before the vial is opened, which limits condensation on the contents. Working solutions are commonly divided into single-use aliquots and frozen to avoid repeated freeze-thaw cycles. Dilute solutions are more prone to adsorption onto plastic surfaces and to loss during filtration, so procedures that minimize transfers and use low-binding labware are preferable.
Notably, targeted proteomics shows increased reproducibility and repeatability compared with shotgun methods, although at the expense of data density and effectiveness. Data quality. Proteomic analysis is highly amenable to automation and large data sets are created, which are processed by software algorithms. Filter parameters are used to reduce the number of false hits, but they cannot be eliminated. Scientists have expressed the need for awareness that proteomics experiments should adhere to the criteria of analytical chemistry (sufficient data quality, sanity check, validation).
Lithium fluoride had already been proposed in the USA in 1950 by Farrington Daniels (1889-1972), Charles A. Boyd and Donald F. Saunders (1924-2013) for solid-state dosimetry using thermoluminescent dosimeters. The intensity of the thermoluminescent light is proportional to the amount of radiation previously absorbed. This type of dosimetry has been used since 1953 in the treatment of cancer patients and wherever people are occupationally exposed to radiation. The thermoluminescence dosimeter was followed by OSL dosimetry, which is not based on heat but on optically stimulated luminescence and was developed by Zenobia Jacobs and Richard Roberts at the University of Wollongong (Australia). The detector emits the stored energy as light. The light output, measured with photomultipliers, is then a measure of the dose.
The closest relatives within the genus are Ambrosiella xylebori, the symbiont of Xylosandrus compactus (the black twig borer), and Ambrosiella grosmanniae, the symbiont of Xylosandrus germanus (the black stem borer). The genera of Ceratocystidaceae have been revised multiple times based on molecular data, incorporating sequences derived from other Ambrosiella species but not necessarily A. roeperi (and sometimes only including Ambrosiella that have now been moved elsewhere). These analyses imply the genus is most closely related to Huntiella. Within this taxon, studies incorporating the LSU rDNA of A. roeperi suggest that it, A. xylebori, A. hartigii, and A. beaveri comprise a monophyletic lineage excluding A. ferruginea (now Phialoporopsis ferruginea) and most closely aligned to Ceratocystis adiposa, subsequent analysis using 18S rDNA and translation elongation factor alpha confirms this and suggests a monophyletic clade of Ambrosiella associated with the scolytine tribe Xyleborini.
=== Mood and stress === The involvement of KOR in stress, as well as in consequences of chronic stress such as depression, anxiety, anhedonia, and modulating drug-seeking behavior, has been widely investigated. KOR is postulated to play an important and varied role in regulating various affective state and stress responses in humans through multiple complex processes. There have been numerous studies implicating KOR in pathology of various psychiatric disorders. One of the main premises for this investigation comes from the receptor activation causing cellular hyperpolarization and, in neurons, decreased neurotransmitter release through a reduction in calcium and increase in potassium conductance. Through these mechanisms, KORs are thought to regulate the release of many signaling molecules including: γ-aminobutyric acid (GABA), glutamate, serotonin, dopamine, norepinephrine. Results on exact influence on neuronal activity and neurotransmitter release vary in vivo. KOR activation elicits immediate hyperpolarization of dopamine neurons (in 1–2 min), followed by decreased dopamine release (5–10 min) and secondary effects on serotonin and glutamate (10–30 min).
== Metabolism and excretion == Pholcodine is slowly biotransformed in the body via oxidation and conjugation to a series of metabolites that are eliminated primarily in the urine. With an average half-life of approximately 2.3 days, steady-state in someone taking the drug chronically would not be reached for nearly 2 weeks. Nearly one-half of a single dose is eventually excreted as free or conjugated parent drug. The most important urinary metabolite is conjugated morphine, which may be detectable for days or weeks after the last dose. This could trigger a positive result for opiates in a urine drug testing program.
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A multiaxial joint (polyaxial joint or triaxial joint) is a synovial joint that allows for several directions of movement. In the human body, the shoulder and hip joints are multiaxial joints. They allow the upper or lower limb to move in an anterior-posterior direction and a medial-lateral direction. In addition, the limb can also be rotated around its long axis. This third movement results in rotation of the limb so that its anterior surface is moved either toward or away from the midline of the body.
This phase is also known as the pacemaker potential. Immediately following repolarization, when the membrane potential is very negative (it is hyperpolarised), the voltage slowly begins to increase. This is initially due to the closing of potassium channels, which reduces the flow of potassium ions (Ik) out of the cell (see phase 2, below). Hyperpolarization also causes activation of hyperpolarisation-activated cyclic nucleotide–gated (HCN) channels. The activation of ion channels at very negative membrane potentials is unusual, therefore the flow of sodium (Na+) and some potassium (K+) through the activated HCN channel is referred to as a funny current (If). With the funny current, the channel opens when the cell is relaxed (negative charge), lets both sodium and potassium through the channel and "leaks" positive charge into the cell. This current drives the membrane potential oscillations in sinoatrial node myocytes as it provides substantial driving forces in both inward and outward directions. The funny current is the primary driver of the membrane clock or voltage-dependant ion channels in the sarcolemma. This funny current causes the membrane potential of the cell to gradually increase, as the positive charge (Na+ and K+) is flowing into the cell. Another mechanism involved in pacemaker potential is known as the calcium clock. This refers to the spontaneous release of calcium from the sarcoplasmic reticulum (a calcium store) into the sarcoplasm (muscle cell cytoplasm), also known as calcium sparks.
In addition, composite materials incorporating MOFs with polymers, carbon materials, or magnetic nanoparticles have been developed to improve mechanical stability, facilitate recovery, and enhance overall treatment efficiency. Despite these promising applications, several challenges remain for the large-scale implementation of MOFs in water treatment systems. These include limited stability in aqueous environments for certain frameworks, the cost and scalability of synthesis, and the need for improved durability under realistic operating conditions . Ongoing research efforts are therefore focused on developing more robust MOF structures and scalable production methods to enable their practical deployment in water purification technologies.
On July 5, 1932, to honor the memory of the recently deceased Dr. Llansó, the name was changed again to the Hogar Nacional Masónico Llansó (English: Llansó National Masonic Retirement Home), and its mission was changed from being a homeless shelter to that of a retirement home and hospice for the elderly.
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Baran began his independent career at the Scripps Research Institute in the summer of 2003, and received tenure just three years later. In the 20 years since then, he has supervised over 300 graduate students, post-doctoral scholars, visiting scholars and interns. He is currently the Dr. Richard A. Lerner Endowed Chair at Scripps Research
Recently, Ke et al. developed a NanoVelcro chip that captures the CTCs from the blood samples. When blood is passed through the chip, the nanofibers coated with protein antibodies bind to the proteins expressed on the surface of cancer cells and act like Velcro to trap CTCs for analysis. The NanoVelcro CTC assays underwent three generations of development. The first generation NanoVelcro Chip was created for CTC enumeration for cancer prognosis, staging, and dynamic monitoring. The second generation NanoVelcro-LCM was developed for single-cell CTC isolation. The individually isolated CTCs can be subjected to single-CTC genotyping. The third generation Thermoresponsive Chip allowed for CTC purification. The nanofiber polymer brushes undergo temperature-dependent conformational changes to capture and release CTCs.
=== Persian period === In 537–520 BCE, Zerubbabel became Yehud's governor and started work on the Second Temple, which was stopped. In 520–516 BCE, Haggai and Zechariah goaded the Judahites to resume work on the Temple. Upon completion, Joshua became its high priest. In 458–433 BCE, Ezra and Nehemiah led another group of Judahites to Yehud, with Artaxerxes's permission. Nehemiah rebuilt the temple after some unspecified disaster and removed foreign influence from the Judahite community. That said, some Judahites elected to stay in Persia, where they almost faced annihilation. This period is covered by the entirety of the Book of Ezra, Book of Nehemiah, the Book of Esther, the Book of Haggai, the Book of Zechariah, and the Book of Malachi.
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In December 2022, NBC News reported in a television segment that some TikTok and YouTube influencers were being given free and discounted cosmetic surgeries in order for them to advertise the surgeries to users of the platforms. In 2022, it was reported that a trend called "de-influencing" had become popular on the platform as a backlash to influencer marketing. TikTok creators participating in this trend made videos criticizing products promoted by influencers and asked their audiences not to buy products they did not need. However, some creators participating in the trend started promoting alternative products to their audiences and earning commission from sales made through their affiliate links in the same manner as the influencers they were originally criticizing. In June 2022, NBC News reported that some of the influencers paid by FeetFinder, a website that sells foot fetish content, did not disclose their videos were ads. FeetFinder said that it has suggested to influencers to be upfront about who was funding them. Existing sellers on FeetFinder said that the videos often misrepresented how "easy" it is to make money from posting feet pictures. Other TikTok creators have spoken out against accepting sponsorship deals indiscriminately and criticized those who posted undisclosed FeetFinder ads.
Sources: en.wikipedia.org
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.
Epithalamin refers to a crude preparation derived from bovine pineal tissue, which contains many components. Epitalon is a single synthetic tetrapeptide identified from that material and produced by chemical synthesis. The two names are sometimes confused because early reports treated the synthetic peptide as an active fragment of the extract.
It has been registered for clinical use in Russia, where it is associated with a small family of short peptides. In most other jurisdictions it is not an approved medicine and is traded as a research chemical. Regulatory status varies by country and changes over time.
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.