Everything below concerns Epithalamin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-10-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
| 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 |
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.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
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==== In alchemy ==== Sulfur has also been a major ingredient in alchemy since its early days, different branches of Indian, Muslim and European alchemists ascribing it esoteric symbolism based on its strong bond with mercury and the interactions between the two elements. Greco-Alexandrian practitioners of Hellenistic alchemy like Mary the Jewess and Zosimos of Panopolis were interested in sulfur and sulfur compounds, and mentioned them in their writings. Indian alchemists, practitioners of the "science of chemicals" (Sanskrit: रसशास्त्र, romanized: rasaśāstra), wrote extensively about the use of sulfur in alchemical operations with mercury, from the eighth century AD onwards. In the rasaśāstra tradition, sulfur is called "the smelly" (गन्धक, gandhaka), and is thought to represent the feminine principle, the menstrual blood of the goddess Gauri (Shakti), while mercury is its male counterpart, the semen of Shiva. Alchemists in Europe and the Islamic world (basing themselves off the "sulfur-mercury theory of metals" from Arabic alchemical texts of the ninth century) had the opposite imagery in their traditions, with sulfur representing the masculine principle and mercury the feminine one, mixing together to form various metals. This theory of metals was very influential during the Middle Ages, and persisted until the eighteenth century, when Lavoisier proved that metals were distinct elements. In the sixteenth century, Paracelsus added Salt as a third element to the Sulfur-Mercury dyad, making them the three basic pillars of alchemy according to his theory: the Tria Prima.
In late 1999, al-Qaeda associate Walid bin Attash ("Khallad") contacted al-Mihdhar and told him to meet in Kuala Lumpur, Malaysia; al-Hazmi and Abu Bara al Yemeni would also be in attendance. The NSA intercepted a telephone call mentioning the meeting, al-Mihdhar, and the name "Nawaf" (al-Hazmi); while the agency feared "Something nefarious might be afoot", it took no further action. The CIA had already been alerted by Saudi intelligence about al-Mihdhar and al-Hazmi being al-Qaeda members. A CIA team broke into al-Mihdhar's Dubai hotel room and discovered that Mihdhar had a U.S. visa. While Alec Station alerted intelligence agencies worldwide, it did not share this information with the FBI. The Malaysian Special Branch observed the January 5, 2000, meeting of the two al-Qaeda members and informed the CIA that al-Mihdhar, al-Hazmi, and Khallad were flying to Bangkok, but the CIA never notified other agencies of this, nor did it ask the State Department to put al-Mihdhar on its watchlist. An FBI liaison asked permission to inform the FBI of the meeting but was told: "This is not a matter for the FBI."
The peptide sequence tag approach developed at the EMBL was one of the first methods for the identification of peptides based on mass spectra and genome data. Nano-electrospray (an electrospray technique with very low flow rates) was the first method that allowed femtomole sequencing of proteins from polyacrylamide gels. A recently developed metabolic labeling technique called SILAC (stable isotope labeling with amino acids in cell culture) is widely used in quantitative proteomics.
== Contraindications == Loratadine is usually compatible with breastfeeding (classified category L-2 - probably compatible, by the American Academy of Pediatrics). In the U.S., it is classified as category B in pregnancy, meaning animal reproduction studies have failed to demonstrate a risk to the fetus, but no adequate and well-controlled studies in pregnant women have been conducted.
Sources: en.wikipedia.org
Cancer research progress:The largest study of whole cancer genomes reports 58 new mutational signatures and shows that for each organ "cancers have a limited number of common signatures and a long tail of rare signatures". A study reports presence of certain bacteria in the prostate and urine for aggressive forms of prostate cancer, with biomarker- and therapeutic potentials being unclear (18 Apr). 25 April Novel foods such as under-development cultured meat, existing microbial foods and ground-up insects are shown to have the potential to reduce environmental impacts by over 80% in a study. A review about meat and sustainability of food systems, animal welfare, and healthy nutrition concludes that its consumption has to be reduced substantially for sustainable consumption and names broad potential measures such as "restrictions or fiscal mechanisms". A new type of cell death 'erebosis' is reported after copper-dependent cell death was first reported the previous month. 26 April Scientists report the detection of purine and pyrimidine nucleobases in several meteorites, including guanine, adenine, cytosine, uracil and thymine, and claim that such meteoritic nucleobases could serve as "building blocks of DNA and RNA on the early Earth".
The oxidative coupling polymerization of many 2,6-disubstituted phenols using a catalytic complex of a cuprous salt and amine form aromatic polyethers, commercially referred to as poly(p-phenylene oxide) or PPO. Neat PPO has little commercial uses due to its high melt viscosity. Its available products are blends of PPO with high-impact polystyrene (HIPS).
==== Neurocognitive and behavioral consequences ==== Nocturnal sleep fragmentation has been linked to neurocognitive impairments, therefore, the identification of SDB such as OSA is crucial in children, those impairments having the possibility to be reversible with the appropriate treatment for the sleep disorder. The neurocognitive and behavioral dysfunctions commonly present in children with OSA include the following: hyperactivity, impulsivity, aggressive behaviors, low social and communication abilities and reduced adaptive skills. Children with OSA commonly show cognitive deficits, resulting in attention and concentration difficulties, as well as lower academic performance and IQ. Poor academic performances have been linked to OSA and suggested to result from cortical and sympathetic arousals and hypoxemia which affects memory consolidation. A study with Indian children affected by OSA has shown poor school grades, including mathematics, science, language, and physical education. This study allowed us to see the overall impact of OSA on learning abilities associated with language or numeracy skills and physical development. It has been suggested that the deficits in academic performance related to OSA could be mediated through reduced executive functions or language skills, those domains contributing highly to learning abilities and behavior. The deficits in school performance can nevertheless be improved if adenotonsillectomy is performed on children to treat the OSA.
== Side effects == Rarely, heart failure and stroke in association with use of methylephedrine have been reported. Methylephedrine shows reinforcing effects, a measure of addiction and misuse potential, in monkeys.
Sources: en.wikipedia.org
== Institutional responses to criticism of the impact factor == Given the growing criticism and its widespread usage as a means of research assessment, organisations and institutions have begun to take steps to move away from the journal impact factor. In November 2007 the European Association of Science Editors (EASE) issued an official statement recommending "that journal impact factors are used only—and cautiously—for measuring and comparing the influence of entire journals, but not for the assessment of single papers, and certainly not for the assessment of researchers or research programmes". In July 2008, the International Council for Science Committee on Freedom and Responsibility in the Conduct of Science issued a "statement on publication practices and indices and the role of peer review in research assessment", suggesting many possible solutions—e.g., considering a limit number of publications per year to be taken into consideration for each scientist, or even penalising scientists for an excessive number of publications per year—e.g., more than 20.
== Significance == AKH has become an important area of study, particularly in insect crop pests and insects that act as intermediate or vector hosts for parasites that can affect humans or animals . In experiments where locusts were injected with AKH and lipopolysaccharide (LPS–an immune elicitor found in the cell walls of bacteria) a stronger immune response was observed than in locusts that only received an LPS injection. The spread of malaria by the female mosquito, Anopheles gambiae, is partly dependent on the adipokinetic hormone, Anoga-HrTH (pGlu-Leu-Thr-Phe-Thr-Pro-Ala-Trp-NH2). No crystal structure of this important neuropeptide is available. The NMR restrained molecular dynamic was used to investigate its conformational space in aqueous solution and when bound to a membrane surface. The results showed that Anoga-HrTH has an almost cyclic conformation that is stabilized by a hydrogen bond between the C-terminus and Thr3. When the agonist docks to its receptor, this H-bond is broken and the molecule adopts a more extended structure. Preliminary AKHR docking calculations give the free energy of binding to be −47.30 kJ/mol. Information about the 3D structure and binding mode of Anoga-HrTH to its receptor are vital for the design of suitable mimetics which can act as insecticides.
== Background == Pedro Cuatrecasas was born in Madrid, Spain on 27 September 1936. He completed his A.B. from Washington University in St. Louis in 1958. He completed his M.D. from Washington University School of Medicine in 1962. Cuatrecasas died in La Jolla, California on 19 March 2025, at the age of 88.
== Advantages of chemoenzymatic synthesis == -Enzymes are environmentally benign, being completely degraded in the environment. -Most enzymes typically function under mild or biological conditions, which minimizes problems of undesired side-reactions such as decomposition, isomerization, racemization and rearrangement, which often plague traditional methodology. -Enzymes selected for chemoenzymatic synthesis can be immobilized on a solid support. These immobilized enzymes demonstrate improved stability and re-usability. -Through the development of protein engineering, specifically site-directed mutagenesis and directed evolution, enzymes can be modified to enable non-natural reactivity. Modifications may also allow for a broader substrate range, enhance reaction rate or catalyst turnover. -Enzymes exhibit extreme selectivity towards their substrates. Typically enzymes display three major types of selectivity:
In a Michelson interferometer adapted for FTIR, light from the polychromatic infrared source, approximately a black-body radiator, is collimated and directed to a beam splitter. Ideally 50% of the light is refracted towards the fixed mirror and 50% is transmitted towards the moving mirror. Light is reflected from the two mirrors back to the beam splitter and some fraction of the original light passes into the sample compartment. There, the light is focused on the sample. On leaving the sample compartment the light is refocused on to the detector. The difference in optical path length between the two arms to the interferometer is known as the retardation or optical path difference (OPD). An interferogram is obtained by varying the OPD and recording the signal from the detector for various values of the OPD. The form of the interferogram when no sample is present depends on factors such as the variation of source intensity and splitter efficiency with wavelength. This results in a maximum at zero OPD, when there is constructive interference at all wavelengths, followed by series of "wiggles". The position of zero OPD is determined accurately by finding the point of maximum intensity in the interferogram. When a sample is present the background interferogram is modulated by the presence of absorption bands in the sample. Commercial spectrometers use Michelson interferometers with a variety of scanning mechanisms to generate the path difference. Common to all these arrangements is the need to ensure that the two beams recombine exactly as the system scans.
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.
The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.