certificate of analysis 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 2025-09-25. Numbers and descriptions here follow the published literature rather than marketing material.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
The most widely cited claim is that epitalon activates telomerase and thereby extends telomere length. Supporting evidence comes largely from cultured human cells, where treatment was associated with increased telomerase activity and delayed replicative senescence. Telomerase activation is a biologically consequential effect, since the enzyme is largely silenced in most somatic cells. However, the route by which a short peptide would reach and act on the enzyme's regulatory machinery has not been established. Independent replication in human trials is scarce, so the link between cell-culture observations and whole-body aging remains an open question.
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.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Ala-Glu-Asp-Gly | Single-letter form AEDG |
| Compound class | Synthetic tetrapeptide | Not a natural free peptide |
| Research origin | Russian gerontology institutes | Developed during the 1990s |
| Main research claim | Telomerase activation | Evidence mainly from cultured cells |
| Regulatory status | Not an approved drug | Handled as a research material |
Between 25 and 28 July, the evaluation indices of the Lula government increased and surpassed disapproval, with 50.3% approval. According to AtlasIntel/Bloomberg, the recovery in Lula's popularity ratings took place amid the firm stance adopted by the Brazilian president in the face of the increase in tariffs announced by Donald Trump, then president of the United States, and the sanctions imposed by the U.S. government on Brazil, largely articulated by Eduardo Bolsonaro.
=== Discontinued === ABT-436 – vasopressin V1b receptor antagonist – alcoholism Adrogolide (ABT-431; DAS-431) – dopamine D1 receptor agonist – cocaine-related disorders ADX-629 – aldehyde inhibitor / reactive aldehyde species (RASP) inhibitor – alcoholism, alcoholic hepatitis ADX-10061 (CEE-310; CEE-03-310; NNC-010687; NNC-687) – dopamine D1 receptor antagonist – smoking withdrawal, substance-related disorders ADX-71441 – GABAB receptor positive allosteric modulator – alcoholism, cocaine-related disorders, substance-related disorders Anatabine (RCP-006) – nicotinic acetylcholine receptor agonist – smoking withdrawal ANS-6637 (GS-6637; GS-6673) – aldehyde dehydrogenase 2 (ALDH2) inhibitor – alcoholism, opioid-related disorders, smoking withdrawal, substance-related disorders Arbaclofen placarbil (R-baclofen placarbil; XP-19986) – GABAB receptor agonist – alcoholism ASP-8062 – GABAB receptor modulator – opioid-related disorders Aticaprant (AVTX-501; CERC-501; JNJ-3964; JNJ-67953964; JNJ-67953964-AAA; LY-2456302) – κ-opioid receptor antagonist – alcoholism, cocaine-related disorders, smoking withdrawal Azasetron (nazasetron; Serotone; Y-25130) – serotonin 5-HT3 receptor antagonist – cocaine-related disorders AZD-4041 – orexin OX1 receptor antagonist – smoking withdrawal Baclofen/samidorphan (ALKS-29; ALKS-33/baclofen; baclofen/ALKS-33) – combination of baclofen (GABAB receptor agonist) and samidorphan (μ-opioid receptor antagonist) – alcoholism Befloxatone (MD-370503) – monoamine oxidase A (MAO-A) inhibitor – smoking withdrawal BP-897 – dopamine D3 receptor agonist – cocaine-related disorders BR-9003 (BR-9003A) – undefined mechanism of action – smoking withdrawal BTRX-246040 (LY-2940094) – nociceptin receptor agonist – alcoholism Buprenorphine/naloxone (NanoBUP; NTC-0510; NTC-510) – combination of buprenorphine (non-selective opioid receptor modulator) and naloxone (orally/sublingually inactive opioid receptor antagonist) – opioid-related disorders Buprenorphine/samidorphan (ALKS 33-BUP; ALKS 33/buprenorphine; ALKS-5461; BUP-ALKS 33; buprenorphine/ALKS-33; buprenorphine/RDC 0313; RDC 0313/buprenorphine; samidorphan/buprenorphine) – combination of buprenorphine (non-selective opioid receptor modulator) and samidorphan (μ-opioid receptor antagonist) – cocaine-related disorders Cannabidiol (CBD; synthetic cannabidiol; RAD-011) – cannabinoid/various actions – substance-related disorders CVL-936 – dopamine D2 and D3 receptor antagonist – substance-related disorders CX-1739 – AMPA receptor positive allosteric modulator (ampakine) – substance-related disorders Deudimethyltryptamine (HLP004; HLP-004; CYB004; CYB-004; DMT-d10; deuterated dimethyltryptamine; dDMT) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and serotonergic psychedelic – substance-related disorders Deupsilocin (HLP003; HLP-003; CYB003; CYB-003; psilocin-d10; deuterated psilocin) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and serotonergic psychedelic – alcoholism Dianicline (SSR-591813) – nicotinic acetylcholine receptor agonist – smoking withdrawal Drinabant (AVE-1625; INDV-5004; OPNT-004) – cannabinoid CB1 receptor antagonist – substance-related disorders Ecopipam (EBS-101; PSYRX-101; SCH-39166) – dopamine D1 receptor antagonist – cocaine-related disorders Eglumetad (eglumegad; LY-354740) – metabotropic glutamate mGlu2 and mGlu3 receptor agonist – smoking withdrawal Elinzanetant (BAY-3427080; GSK-1144814A; GSK-1144814; Lynkuet; NT-814) – neurokinin NK1 and NK3 receptor antagonist – opioid-related disorders Femoxetine (femoxitine; FG-4963; Malexil; NNC-204963) – selective serotonin reuptake inhibitor (SSRI) – alcoholism Gabapentin enacarbil (ASP8825; Gabapentin-XP; GSK-1838262; Horizant; Regnite; Solzira; XP13512) – gabapentinoid (α2δ subunit-containing voltage-gated calcium channel blocker) – alcoholism Gepirone (Ariza; BMY-13805; Exxua; MJ-13805; Org-33062; TGFK07AD; Travivo; Variza) – serotonin 5-HT1A receptor agonist – cocaine-related disorders Istradefylline (KW-6002; Nourianz; Nouriast) – adenosine A2 receptor antagonist ITI-333 – serotonin 5-HT2A receptor antagonist, dopamine D1 receptor antagonist, α1A-adrenergic receptor antagonist, μ-opioid receptor partial agonist – substance-related disorders JNJ-39393406 – α7 subunit-containing nicotinic acetylcholine receptor positive allosteric modulator – smoking withdrawal JZP-150 – fatty acid amide hydrolase (FAAH) inhibitor – alcoholism Lisdexamfetamine (LDX; Elvanse; NRP-104; S-877489; SHP-489; SPD-489; Tyvense; Venvanse; Vyvanse) – norepinephrine–dopamine releasing agent (NDRA) – cocaine-related disorders Lorcaserin (APD-356; Belviq; E2023; Venespri) – serotonin 5-HT2C receptor agonist – smoking withdrawal Manifaxine (BW-1555U88; GW-320659) – norepinephrine–dopamine reuptake inhibitor (NDRI) – smoking withdrawal Mavoglurant (AFQ-056; STP-7) – metabotropic glutamate mGlu5 receptor antagonist – smoking withdrawal Nalmefene (CPH-101; JF-1; Lu AA36143; Nalmetrene; NIH-10365; ORF-11676; Selincro; Soberal) – μ-opioid receptor antagonist, κ-opioid receptor weak partial agonist – smoking withdrawal Nepicastat oral (APL-1401; SYN-117) – dopamine β-hydroxylase (DBH) inhibitor – cocaine-related disorders Neramexane (KRP-209; MRZ-2/579) – NMDA receptor antagonist, nicotinic acetylcholine receptor antagonist – alcoholism NIC-002 (NIC002; CYT002-NicQβ; Nicotine-Qβ) – immunostimulant (nicotine vaccine) – smoking withdrawal NicVAX – immunostimulant (nicotine vaccine) – smoking withdrawal Nornicotine – nicotinic acetylcholine receptor agonist – smoking withdrawal NS-2359 (GSK-372475) – serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI) – alcoholism NYX-783 – ionotropic glutamate NMDA receptor modulator – alcoholism, opioid-related disorders OREX-1019 – μ-opioid receptor agonist, δ-opioid receptor antagonist, κ-opioid receptor antagonist, nociceptin receptor agonist – cocaine-related disorders OREX-1038 – μ-opioid receptor agonist – cocaine-related disorders, opioid-related disorders Oxytocin intranasal (Syntocinon Nasal Spray; TUR-001) – oxytocin receptor agonist – alcoholism Quetiapine (FK-949; FK949E; ICI-204636; Seroquel) – atypical antipsychotic (non-selective monoamine receptor modulator) – alcoholism Rimonabant (Acomplia; SR-141716; SR-141716A; Zimulti) – cannabinoid CB1 receptor antagonist – smoking withdrawal Risperidone (JNJ-410397-AAA; R-64766; R064766; Risperdal; Risperdal Consta; Risperdal Depot) – atypical antipsychotic (non-selective monoamine receptor modulator) – substance-related disorders RTI-113 – dopamine reuptake inhibitor (DRI) (cocaine analogue) – cocaine-related disorders Samidorphan (ALKS-33; RDC-0313; RDC-0313-00) – μ-opioid receptor antagonist – alcoholism, substance-related disorders Sembragiline (EVT-302; RG-1577; RO-4602522) – monoamine oxidase B (MAO-B) inhibitor – smoking withdrawal Serlopitant (JTS-661; MK-0594; VPD-737) – neurokinin NK1 receptor antagonist – alcoholism Surinabant (SR-147778; SR147778) – cannabinoid CB1 receptor antagonist – alcoholism, smoking withdrawal TA-NIC – immunostimulant (nicotine vaccine) – smoking withdrawal Tradipitant (LY-686017; Nereus; VLY-686) – neurokinin NK1 receptor antagonist – alcoholism Verucerfont (GSK-561679; NBI-77860) – corticotropin-releasing factor 1 (CRF1) receptor antagonist Vigabatrin (γ-vinyl-GABA; gamma-vinyl-GABA; GVG; M071754; MDL-71754; RMI-71754; Sabril; Sabrilex) – GABA transaminase (GABA-T) inhibitor – cocaine-related disorders, substance-related disorders
Pasteur solved the mystery of polarized light acting differently with chemically identical crystals and solutions by discovering the phenomenon of molecular asymmetry, that is that molecules could be chiral and exist as a pair of enantiomers. Pasteur's method was to physically separate the crystals of a racemic mixture of sodium ammonium tartrate into right- and left-handed crystals, and then dissolve them to make two separate solutions which rotated polarized light in opposite directions. Pasteur's research was in part informed by considerations of molecular symmetry. Pasteur also proposed two other methods for the isolation of optically active enantiomers from racemic mixtures: by the use of optically active bases, e.g. strychnine, or by means of living organisms, e.g. bacteria or yeasts. William Thomson (Lord Kelvin) introduced the word "chiral" in 1904 to describe handed figures. Objects that do not exhibit optical isomerism are said to be "achiral", that is their image in a plane mirror can be made congruent with itself. The term chirality has almost completely displaced the term "dissymmetry" which was used by Pasteur.
Structural proteins that bind DNA are well-understood examples of non-specific DNA-protein interactions. Within chromosomes, DNA is held in complexes with structural proteins. These proteins organize the DNA into a compact structure called chromatin. In eukaryotes, this structure involves DNA binding to a complex of small basic proteins called histones, while in prokaryotes multiple types of proteins are involved. The histones form a disk-shaped complex called a nucleosome, which contains two complete turns of double-stranded DNA wrapped around its surface. These non-specific interactions are formed through basic residues in the histones, making ionic bonds to the acidic sugar-phosphate backbone of the DNA, and are thus largely independent of the base sequence. Chemical modifications of these basic amino acid residues include methylation, phosphorylation, and acetylation. These chemical changes alter the strength of the interaction between the DNA and the histones, making the DNA more or less accessible to transcription factors and changing the rate of transcription. Other non-specific DNA-binding proteins in chromatin include the high-mobility group proteins, which bind to bent or distorted DNA. These proteins are important in bending arrays of nucleosomes and arranging them into the larger structures that make up chromosomes. A distinct group of DNA-binding proteins is the DNA-binding proteins that specifically bind single-stranded DNA.
Sources: en.wikipedia.org
== Actin in cells == Intracellular actin cytoskeletal assembly and disassembly are tightly regulated by cell signaling mechanisms. Many signal transduction systems use the actin cytoskeleton as a scaffold, holding them at or near the inner face of the peripheral membrane. This subcellular location allows immediate responsiveness to transmembrane receptor action and the resulting cascade of signal-processing enzymes. Because actin monomers must be recycled to sustain high rates of actin-based motility during chemotaxis, cell signalling is believed to activate cofilin, the actin-filament depolymerizing protein which binds to ADP-rich actin subunits nearest the filament's pointed-end and promotes filament fragmentation, with concomitant depolymerization in order to liberate actin monomers. In most animal cells, monomeric actin is bound to profilin and thymosin beta-4, both of which preferentially bind with one-to-one stoichiometry to ATP-containing monomers. Although thymosin beta-4 is strictly a monomer-sequestering protein, the behavior of profilin is far more complex. Profilin enhances the ability of monomers to assemble by stimulating the exchange of actin-bound ADP for solution-phase ATP to yield actin-ATP and ADP. Profilin is transferred to the leading edge by virtue of its PIP2 binding site, and it employs its poly-L-proline binding site to dock onto end-tracking proteins. Once bound, profilin-actin-ATP is loaded into the monomer-insertion site of actoclampin motors.
Drug-related violence remained at previous levels during the first months of López Obrador's presidency. In October 2019, a National Guard operation in Culiacán, Sinaloa to capture Ovidio Guzmán López, responding to a U.S. extradition request, failed after cartel gunmen took hostages and forced his release. Guzmán was released after approximately 700 cartel enforcers took multiple hostages, including the housing unit where military families live in Culiacán. López Obrador defended the decision to release Guzmán López, arguing it prevented further loss of life, and insisted that he wanted to avoid more massacres, and that even though they underestimated the cartel's forces and ability to respond, the criminal process against Ovidio is still ongoing. Guzmán López was captured in a 2023 operation and extradited to the U.S. The strategy of avoiding armed confrontations while drug organizations have continued violent altercations has been controversial. The Jalisco New Generation Cartel (CJNG) expanded aggressively during López Obrador's presidency, and its territorial disputes were linked to significant increases in homicide rates in Colima, Zacatecas, Guanajuato, and Jalisco. In July 2022, authorities captured Rafael Caro-Quintero, a former leader of the Guadalajara Cartel. Despite his campaign promises, military deployments and expenditures have risen, with troop levels 76% higher and defense spending up 87% between 2012 and 2022.
== Structure == Moroidin, a bicyclic octapeptide, has been isolated from Dendrocnide moroides (also called Laportea moroides) and Celosia argentea. The structure of moroidin was confirmed in 2004 by X-ray crystallography. It contains two unusual crosslinks, one between leucine and tryptophan and the other between tryptophan and histidine. These linkages are also present in an analogous family of compounds, the celogentins.
Sources: en.wikipedia.org
=== History === It is said that Cleopatra, Queen of Ancient Egypt, took baths in donkey milk to preserve the beauty and youth of her skin. Legend has it that no less than 700 donkeys were needed to provide the quantity of milk necessary for her daily bath. This was also the case for Poppaea Sabina (30–65), second wife of Roman Emperor Nero, who is referred to in Pliny's description of the virtues of ass milk for the skin: "It is generally believed that ass milk effaces wrinkles in the face, renders the skin more delicate, and preserves its whiteness: and it is a well-known fact, that some women are in the habit of washing their face with it seven times daily, strictly observing that number. Poppaea, the wife of Emperor Nero, was the first to practice this; indeed, she had sitting baths, prepared solely with ass milk, for which purpose whole troops of she-asses used to attend her on her journeys." In his poem Medicamina Faciei Femineae, Roman poet Ovid (43 BC–18 AD) suggests beauty masks made with donkey milk. Pauline Bonaparte (1780–1825), Napoleon's sister, is reported to have used ass milk for her skin care.
In cancer, the genomes of affected cells are rearranged in complex or unpredictable ways. In addition to single-nucleotide polymorphism arrays identifying point mutations that cause cancer, oligonucleotide microarrays can be used to identify chromosomal gains and losses (called comparative genomic hybridization). These detection methods generate terabytes of data per experiment. The data is often found to contain considerable variability, or noise, and thus Hidden Markov model and change-point analysis methods are being developed to infer real copy number changes. Two important principles can be used to identify cancer by mutations in the exome. First, cancer is a disease of accumulated somatic mutations in genes. Second, cancer contains driver mutations which need to be distinguished from passengers. Further improvements in bioinformatics could allow for classifying types of cancer by analysis of cancer driven mutations in the genome. Furthermore, tracking of patients while the disease progresses may be possible in the future with the sequence of cancer samples. Another type of data that requires novel informatics development is the analysis of lesions found to be recurrent among many tumors.
However, the results of the 2012 presidential elections gave the PS wins in both districts with a smaller margin in the 7th (Hollande: 51.71% / Sarkozy: 48.29%) than in the 8th (Hollande 64.21% / Sarkozy: 35.79%).
== Post-retirement == De retired in 1973 from the Calcutta Medical College at the age of 58. After his retirement, he showed no interest in higher positions but continued his research at the Bose Institute, Calcutta. De's desire to purify the cholera toxin did not progress any further as the protein purification technology was not well established in his research settings. During his time of research, De worked with hypertoxin-producing classical strains of V. cholerae O1, which was abruptly replaced by El Tor biotype [producing less cholera toxin] in Calcutta from 1963. This new development was another reason why De could not continue his research on purification of cholera toxin. In 1978, the Nobel Foundation invited De to participate in the 43rd Nobel Symposium on Cholera and Related Diarrhoeas. De died on 15 April 1985 at the age of 70.
Sources: en.wikipedia.org
Vladimir Khavinson and colleagues at research institutes in Saint Petersburg developed and studied the peptide. Their program examined short peptides as regulators of aging and neuroendocrine function. Epitalon was one of several compounds produced by that group.
That question is not settled. Cell culture studies have reported increased telomerase activity after treatment, but comparable evidence from controlled human trials is lacking. Any claim about telomere lengthening in people should be treated as unproven.
It has not completed the large, controlled trials required for drug approval in major jurisdictions. Most human reports involve small samples and limited follow-up. As a result, it is sold as a research chemical rather than a licensed pharmaceutical product.
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.