tetrapeptide 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.
Last reviewed on 2025-10-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by HPLC area | Higher grades are also offered |
| Primary analytical method | Reversed-phase HPLC, UV detection | Frequently paired with mass spectrometry |
| Confirmatory technique | Electrospray mass spectrometry | Observed mass compared with theory |
| Storage temperature | Minus 20 degrees Celsius, dry powder | Sealed, desiccated, protected from light |
| Solution handling | Prepare fresh before use | Hydrolysis proceeds in aqueous media |
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.
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.
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.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
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 epic Mahabharata details the use of multi-tiered military formation that resembles a blooming lotus called Padmavyuha and its disc-shaped variant Chakravyuha in the 18-day long Kurukshethra war.Padmasana, or the lotus pose, in yoga and Sahasrara, the thousand petalled lotus chakra, in tantra are some examples of the use of lotus imagery. Lotus motifs are found in Indian architecture, for example: domes resembling lotus buds, pillars resembling lotus stalk, arches resembling inverted lotus, and other lotus engravings in Hindu and Buddhist temples.In Asian art, a lotus throne is a stylized lotus flower used as the seat or base for a figure in Buddhist art and Hindu art and is often seen in Jain art. Originating in Indian art, it followed Indian religions to East Asia in particular. Lotus flowers are also often held by figures.The Nelumbo nucifera, which is also called Nilufar Abi in Persian, can be seen in many reliefs of the Achaemenid period (552 BC) such as the statue of Anahita in the Persepolis. The lotus flower was included in Kaveh the blacksmith's Derafsh and later as the flag of the Sasanian Empire Derafsh Kaviani. Today, it is the symbol of the Iranian Solar Hijri calendar. The lotus flower is also mentioned in the Bible. The lotus flower also holds cultural and religious significance in Ismaili Muslim and related South Asian traditions. For example, in South Asian Ismaili literature, the lotus is compared to the pure soul. A poem describes the lotus' beauty, describing how its delicate white petals remain pure and beautiful, despite its murky environment.
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Surrounding skin: Appearance of the surrounding skin can provide clues to underlying disease processes, such as redness/erythema due to cellulitis, maceration due to uncontrolled wound exudate, or eczematous changes due to a chronic irritation (e.g. allergic reaction to wound dressing). Infection: Classic signs of infection are redness, warmth, swelling, odor, and pain out of proportion to wound appearance. Pain: Pain can be nociceptive, neuropathic, or inflammatory, each of which can provide clues to the cause of a wound. Proper pain control is an important consideration in wound management, particularly in burn care where analgesia is often necessary prior to dressing changes. A thorough wound evaluation, particularly evaluation of wound depth and removal of necrotic tissue, should be performed only by a licensed healthcare professional in order to avoid damage to nearby structures, infection, or worsening pain.
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"Any Song" by R&B and rap artist Zico became number one on the Korean music charts due to the popularity of the #anysongchallenge, where users dance to the choreography of the song. The platform has also launched many songs that failed to garner initial commercial success into sleeper hits, particularly since the outbreak of the COVID-19 pandemic. However, it has received criticism for not paying royalties to artists whose music is used on the platform. Classic stars are able to connect with younger audiences born decades after a musician's first debut and across traditional genres. In 2020, Fleetwood Mac's "Dreams" was used in a skating video and a recreation by Mick Fleetwood. The song re-entered Billboard Hot 100 after 43 years and topped Apple Music. In 2022, Kate Bush's "Running Up That Hill" went viral among fans of Stranger Things, topping the UK singles chart 37 years after its original release. In 2023, Kylie Minogue's "Padam Padam" entered the Radio 1 playlist after being shared by Gen Z, although many youth radio stations refused to play the song. Other older artists with strong engagement on TikTok include Elton John and Rod Stewart. In Japan, artists from the 1970s to 1990s, such as Kohmi Hirose, Yōko Oginome, Akina Nakamori, Seiko Matsuda, Momoe Yamaguchi and Saki Kubota, have become popular on TikTok during the Showa (and early Heisei) retro boom.
The method, known as the Kolbe-Schmitt reaction, entails nucleophilic attack of the phenoxide on carbon dioxide. In some cases, alkenes undergo hydrocarboxylation using a mixture of carbon dioxide and H2:
In 2025, CBSE decided to conduct two board examinations from the academic year 2025–26 to ease the pressure on students. CBSE has also rationalised much of the content in its syllabus after the COVID period to ease the children
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The usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.
The dry powder is commonly kept at minus twenty degrees Celsius, desiccated and away from light. Solutions are generally prepared fresh because they break down faster than the solid form.
Tandem mass spectrometry or enzymatic peptide mapping can establish residue order. A single intact mass value indicates composition and molecular weight but not always the precise arrangement of residues.
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.