If you have been reading about lyophilised powder and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-09-19. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
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 parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
| 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 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.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
On the other hand, zolpidem, eszopiclone, baclofen, and gabapentin all did not substitute for tiagabine. The GABAA receptor antagonist (+)-bicuculline at non-convulsant doses partially antagonized tiagabine's interoceptive effects, whereas higher doses that might more fully antagonize its cue were not assessed due to risk of convulsions. These findings suggest involvement of the GABAA receptor in the subjective effects of tiagabine, at least in rodents. Conversely, the GABAB receptor does not appear to be involved. Tiagabine increases benzodiazepines' affinity to cortical and limbic GABAA receptors and influences electroencephalography (EEG) measurements by increasing frontal activity and reducing posterior activity in the brain. With regard to pharmacophore, the most stable binding mode of tiagabine in the GAT-1 is that where the nipecotic acid fragment is located in the main ligand binding site, and aromatic thiophene rings are arranged within the allosteric site, which yields GAT-1 in an outward-open state. This interaction is mediated through GAT-1's sodium ion mimicry, hydrogen bonding and hydrophobic interactions.
Regulatory guidance from the FDA recommends that sponsors of oligonucleotide drug applications assess DDI potential through in vitro transporter studies and, where indirect CYP modulation is plausible, through induction assays, even when direct CYP inhibition is absent.
== Treatment == By definition, TIAs are transient, self-resolving, and do not cause permanent impairment. However, they are associated with an increased risk of subsequent ischemic strokes, which can be permanently disabling. Therefore, management centers on the prevention of future ischemic strokes and addressing any modifiable risk factors. The optimal regimen depends on the underlying cause of the TIA.
Studies in biochemistry show that endogenous, bacterial chaperones of curli are capable of briefly interacting with Syn and controlling its aggregation. The clinical and pathological findings support the hypothesis that aSyn disease in PD occurs via a gut-brain pathway. For early diagnosis and early management in the phase of creation and propagation of aSyn, it is therefore of utmost importance to identify pathogenic aSyn in the digestive system, for example, by gastrointestinal tract (GIT) biopsies. According to a growing body of research, intestinal dysbiosis may be a major factor in the development of Parkinson's disease by encouraging intestinal permeability, gastrointestinal inflammation, and the aggregation and spread of asyn. Not just the CNS but other peripheral tissues, such as the GIT, have physiological aSyn expression as well as its phosphorylated variants. As suggested by Borghammer and Van Den Berge (2019), one approach is to recognise the possibility of PD subtypes with various aSyn propagation methods, including either a peripheral nervous system (PNS)-first or a CNS-first route. While the GI tract has been linked to other neurological disorders such autism spectrum disorder, depression, anxiety, and Alzheimer's disease, protein aggregation and/or inflammation in the gut represent a new topic of investigation in synucleinopathies.
== External links == Prof. Matthias Tschöp (16 May 2012). Medicine: Prof. Matthias Tschöp. Alexander von Humboldt Foundation. Prof. Matthias Tschöp, Chair of Metabolic Diseases, TUM School of Medicine
Sources: en.wikipedia.org
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The atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons (together called nucleons), while the electron cloud consists of negatively charged electrons which orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons. The nucleus is dense; the mass of a nucleon is approximately 1,836 times that of an electron, yet the radius of an atom is about 10,000 times that of its nucleus. The atom is also the smallest entity that can be envisaged to retain the chemical properties of the element, such as electronegativity, ionization potential, preferred oxidation state(s), coordination number, and preferred types of bonds to form (e.g., metallic, ionic, covalent).
Immediately after the 17th Party Congress, Xi was elected by the first plenary session of the 17th Central Committee to be the 6th-ranking member of the Politburo Standing Committee on 22 October 2007. In addition, Xi became a member of the 17th Secretariat. He also led the Central Leading Group for Party Building and the Central Hong Kong and Macau Affairs Leading Group, as well as being the deputy leader of the Central Foreign Affairs Leading Group. He was ranked above Li Keqiang in the PSC, an indication that he was going to succeed Hu Jintao as China's next leader. This assessment was further supported at the first session of the 11th National People's Congress in March 2008, when Xi was elected as vice president of China. Following his elevation, Xi held a broad range of portfolios. He was put in charge of the comprehensive preparations for the 2008 Summer Olympics in Beijing, as well as being the central government's leading figure in Hong Kong and Macau affairs. In addition, he also became the president of the Central Party School, the CCP's cadre-training and ideological education school. In the wake of the 2008 Sichuan earthquake, Xi visited Shaanxi, which was also hit by the earthquake. After the Olympics, Xi was assigned the post of committee chair for the preparations of celebrations for the 60th anniversary of the People's Republic of China. He was also reportedly at the helm of a top-level CCP committee dubbed the 6521 Project, which was charged with ensuring social stability during a series of politically sensitive anniversaries in 2009.
The system studied – the part of the patient that is the object of the examination (blood plasma, pituitary gland, skin, kidney, whole body) The component – the specific part or process that is of interest in the system studied (glucose, hormone secretion, bacteria, urine excretion) The kind-of-property - (amount-of-substance concentration, secretion rate, number, volume) An SI unit or WHO where relevant – (for measurable properties, i.e. differential or rational [not ordinal] quantities). These statements are ordered in a fixed syntax:
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.
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.