Pinealon (Glu-Asp-Arg): A Khavinson Tripeptide in the Research Literature

Research-use-only context. This article summarizes published third-party scientific literature and laboratory practice. It is not medical advice, not a therapeutic or performance claim, and not a usage guide. US Prime Peptides products are supplied strictly for in vitro laboratory research and are not for human or veterinary use.

This article surveys what has been published about Pinealon, the tripeptide Glu-Asp-Arg, sorted by model: cell-culture work on reactive oxygen species and proliferation, biophysical studies of the peptide binding DNA, rodent models, and the small Russian human record. It explains the "bioregulator" hypothesis behind the Khavinson short peptides, assesses how much of the evidence has been replicated, and states the compound's regulatory position.

Pinealon is the tripeptide Glu-Asp-Arg

Pinealon is the synthetic tripeptide Glu-Asp-Arg (one-letter code EDR), molecular formula C15H26N6O8, molecular weight about 418.4 daltons, PubChem CID 10273502, CAS 175175-23-2. It belongs to a family of di-, tri- and tetrapeptides designed at the St. Petersburg Institute of Bioregulation and Gerontology under Vladimir Khavinson, which also includes Epitalon (Ala-Glu-Asp-Gly), Vilon (Lys-Glu), Vesugen (Lys-Glu-Asp) and Testagen (Lys-Glu-Asp-Gly). In the Russian literature the sequences were chosen to reflect the amino-acid composition of tissue extracts; Pinealon is grouped with the pineal and brain-derived peptides, and in several papers it is tested alongside Cortexin, a brain-extract polypeptide fraction.

Chemically it is unusual among research peptides. Two acidic residues (glutamate and aspartate) and one strongly basic residue (arginine) make it a highly polar zwitterion with net negative charge near neutral pH, no aromatic ring, no sulfur, and essentially no hydrophobic surface. That has practical consequences: it dissolves readily in water, elutes very early on reverse-phase HPLC, gives weak absorbance at 280 nanometers (so purity must be read at 214 or 220 nanometers), and tends to be hygroscopic as a lyophilized salt. The counter-ion can be a large share of vial mass for a peptide this small, which is why net peptide content, not just HPLC purity, is the number to read on a certificate; the arithmetic is in Net Peptide Content vs Purity.

Pinealon is not an approved drug in the United States and holds no FDA, EU or pharmacopeial status. Unlike Semax and Selank, it does not carry a Russian medicinal registration; the Khavinson short peptides have been marketed in Russia mainly outside the drug category. A research vial is documented by its lot certificate. The Pinealon 10 mg listing shows that certificate for the lyophilized form, and the Pinealon liquid spray 10 mg / 10 mL listing shows the solution-format certificate with content per bottle.

Cell-culture findings: reactive oxygen species and proliferation

The most-cited paper is Khavinson and colleagues (2011, Rejuvenation Research), which exposed three cell types, rat cerebellar granule cells, neutrophils, and PC12 pheochromocytoma cells, to oxidative stress triggered by receptor-dependent or receptor-independent stimuli and measured reactive oxygen species by fluorescent probe and necrotic death by propidium iodide. The authors reported concentration-dependent restriction of ROS accumulation and fewer propidium-iodide-positive cells, a delayed time course of ERK1/2 activation, and changes in cell-cycle distribution. They noted that the ROS and death effects saturated at lower concentrations than the cell-cycle effect, and inferred from that separation that the peptide might act on the genome directly, a hypothesis rather than a measurement.

Two organotypic-culture papers from the same institute give a more mixed picture. Khavinson and colleagues (2011, Bulletin of Experimental Biology and Medicine) grew pineal gland explants from 3-month-old rats and reported that Ala-Glu-Asp-Gly and Lys-Glu-Asp raised Ki-67 staining, while Glu-Asp-Arg and Lys-Glu did not change Ki-67 or the apoptosis marker AIF; only Ala-Glu-Asp-Gly raised CGRP. Voicekhovskaya and colleagues (2012, same journal) tested five tripeptides on skin explants from young and old rats; Glu-Asp-Arg (coded T-33) was among those that raised proliferation in young-rat explants, while Lys-Glu-Asp stood out in old-rat explants, with less p53 staining accompanying the proliferation change. A 2014 paper by Khavinson and colleagues reported higher serotonin immunostaining in aging rat cortical cultures exposed to Glu-Asp-Arg or Lys-Glu-Asp, and paired it with a molecular-docking prediction that the peptides match a CCTGCC sequence in the tryptophan hydroxylase gene.

These are all immunocytochemical or fluorescence endpoints in primary or explant cultures, scored by one institute, often with small replicate numbers. The negative Ki-67 result in pineal explants is worth noting because it shows the peptide is not a general proliferation stimulus even within this group's own assays.

Biophysics: does a tripeptide bind DNA?

The distinctive claim in the bioregulator literature is that very short peptides enter the nucleus and bind DNA in a sequence-selective way. Fedoreyeva and colleagues (2011, Biochemistry (Moscow)) labeled Epitalon, Pinealon and Testagen with fluorescein isothiocyanate, incubated HeLa cells with them, and reported fluorescence in cytoplasm, nucleus and nucleolus. In cell-free assays they measured Stern-Volmer quenching constants for the unlabeled peptides against fluorescein-labeled single- and double-stranded oligonucleotides and DNA-ethidium complexes, and reported that the constants differed by peptide and by oligonucleotide sequence, with Epitalon, Pinealon and Testagen quenching CAG-containing sequences most and discriminating cytosine-methylated from unmethylated CNG sites.

The only study from outside the Khavinson institute is physical rather than biological. Silanteva and colleagues (2019, Journal of Physical Chemistry B), at St. Petersburg State University, used UV spectroscopy, NMR, viscometry and molecular dynamics to examine Glu-Asp-Arg with DNA in solution. They reported that the peptide can partly enter the major groove and interact with guanine N7 and O6 atoms, and that magnesium ions promote the interaction by screening phosphate charge, an effect that persisted at higher salt. This is a careful solution-chemistry result; it shows a weak, ion-dependent association, not sequence-specific gene regulation.

Three cautions apply. Fluorescein labeling adds a large aromatic group to a 418-dalton peptide and may itself drive uptake. Quenching constants demonstrate contact, not functional binding at a promoter. And no chromatin immunoprecipitation, reporter-gene, or footprinting experiment with Pinealon has been published by any group. The broader bioregulator hypothesis, and the wider peptide family it covers, is discussed in Khavinson Short Peptides Explained.

Rodent models

Arutjunyan and colleagues (2012, International Journal of Clinical and Experimental Medicine) produced hyperhomocysteinemia in pregnant rats by methionine loading, then tested the offspring in spatial-orientation and learning tasks and isolated their cerebellar neurons to measure ROS accumulation and necrotic-cell counts. The offspring of peptide-exposed dams scored higher on the behavioral tasks and their isolated neurons showed lower ROS and fewer necrotic cells than offspring of methionine-only dams. Kozina (2008, Advances in Gerontology) compared Vilon, Epitalon, Vesugen and Pinealon in a hypobaric hypoxia model and reported Pinealon as the most active of the four, proposing that the effect runs through endogenous antioxidant enzymes rather than direct radical scavenging.

A series from Mendzheritskii and colleagues at Rostov (2011, 2013, 2015, Advances in Gerontology) compared Pinealon with Cortexin in old rats under carotid artery occlusion, hypoxia and hypothermia, scoring survival, behavior and caspase-3 activity in brain tissue. In the 2011 occlusion study, Pinealon-exposed animals survived the procedure more often, but the authors also reported a moderate rise in caspase-3 activity in both sham and occluded animals exposed to the peptide, a result that complicates the simple anti-apoptotic reading. All of these are Russian-language papers with abstracts in English, from two groups, with group sizes typical of exploratory animal work.

The bioregulator hypothesis and the quality of the evidence

The framework behind Pinealon is Khavinson's "peptide bioregulation" hypothesis, set out most fully for this peptide in a 2020 review in Molecules by Khavinson, Linkova, Kozhevnikova and Trofimova. The proposal is that short peptides released from tissue proteins enter cells, bind histones or DNA at specific sites, and shift transcription of genes for antioxidant enzymes (SOD2, GPX1), pro-apoptotic proteins (caspase-3, p53), transcription factors (PPARA, PPARG) and the MAPK/ERK pathway. The review assembles the papers above plus molecular-docking predictions; it is explicit that the histone and DNA binding step is "assumed."

Judged by ordinary evidence standards, the Pinealon record has four limits. First, nearly every biological paper has an author from the originating institute, and the one fully independent study is a physical-chemistry paper that found weak, ion-dependent DNA contact. Second, no study has been replicated by a laboratory outside Russia. Third, most primary data appear in Advances in Gerontology and Bulletin of Experimental Biology and Medicine, journals with short formats that rarely report full statistics. Fourth, the human record consists of small open studies in Russian occupational-health and gerontology journals (for example, Umnov 2013 and Bashkireva 2012 in Advances in Gerontology) that lack blinding and placebo control. None of this makes the findings wrong; it makes them preliminary, which is a different thing from established.

For a laboratory, the useful takeaways are narrower than the hypothesis: the peptide is stable and water-soluble, the ROS assays in cerebellar granule cells and PC12 cells are reproducible protocols that a lab could rerun, and the DNA-binding work gives a defined physical question (groove association in the presence of magnesium) that a biophysics group could test with its own material. How the tripeptide compares with the better-studied tetrapeptide from the same family is covered in Pinealon vs Epithalon and the Epithalon research overview.

Frequently Asked Questions

What is Pinealon?

Pinealon is the synthetic tripeptide Glu-Asp-Arg (EDR), molecular weight about 418 daltons, one of the short "bioregulator" peptides designed at the St. Petersburg Institute of Bioregulation and Gerontology. It is highly polar, dissolves easily in water, and is studied mainly in Russian cell-culture and rodent work.

Is Pinealon an approved drug anywhere?

No. Pinealon is not approved by the FDA or any EU regulator, and unlike Semax and Selank it has no Russian medicinal registration; the Khavinson short peptides have been sold in Russia mainly outside the drug category. In the United States it is a research chemical.

What did the Pinealon cell studies actually measure?

The 2011 Rejuvenation Research paper measured reactive oxygen species, propidium-iodide necrosis, ERK1/2 phosphorylation timing and cell-cycle distribution in rat cerebellar granule cells, neutrophils and PC12 cells under oxidative stress. Explant studies measured Ki-67, AIF, p53 and CGRP immunostaining, with Glu-Asp-Arg negative for Ki-67 in pineal explants.

Does Pinealon bind DNA?

A 2019 Journal of Physical Chemistry B study reported weak association with the DNA major groove at guanine N7 and O6, promoted by magnesium ions. A 2011 fluorescence study reported nuclear localization of a fluorescein-labeled version and sequence-dependent quenching with oligonucleotides. No reporter, footprinting or chromatin study has confirmed functional, sequence-specific binding.

Citations

1. Khavinson V, Ribakova Y, Kulebiakin K, et al. Pinealon increases cell viability by suppression of free radical levels and activating proliferative processes. Rejuvenation Res. 2011;14:535-541. PMID 21978084
2. Khavinson VKh, Linkova NS, Chalisova NI, Dudkov AV, Koncevaya EA. Effect of short peptides on expression of signaling molecules in organotypic pineal cell culture. Bull Exp Biol Med. 2011;152:138-141. PMID 22803060
3. Voicekhovskaya MA, Chalisova NI, Kontsevaya EA, Ryzhak GA. Effect of bioregulatory tripeptides on the culture of skin cells from young and old rats. Bull Exp Biol Med. 2012;152:357-359. PMID 22803085
4. Khavinson VKh, Lin'kova NS, Tarnovskaya SI, Umnov RS, Elashkina EV, Durnova AO. Short peptides stimulate serotonin expression in cells of brain cortex. Bull Exp Biol Med. 2014;157:77-80. PMID 24909721
5. Fedoreyeva LI, Kireev II, Khavinson VKh, Vanyushin BF. Penetration of short fluorescence-labeled peptides into the nucleus in HeLa cells and in vitro specific interaction of the peptides with deoxyribooligonucleotides and DNA. Biochemistry (Mosc). 2011;76:1210-1219. PMID 22117547
6. Silanteva IA, Komolkin AV, Morozova EA, Vorontsov-Velyaminov PN, Kasyanenko NA. Role of Mono- and Divalent Ions in Peptide Glu-Asp-Arg-DNA Interaction. J Phys Chem B. 2019;123:1896-1902. PMID 30762356
7. Arutjunyan A, Kozina L, Stvolinskiy S, Bulygina Y, Mashkina A, Khavinson V. Pinealon protects the rat offspring from prenatal hyperhomocysteinemia. Int J Clin Exp Med. 2012;5:179-185. PMID 22567179
8. Kozina LS. Investigation of antihypoxic properties of short peptides [in Russian]. Adv Gerontol. 2008;21:61-67. PMID 18546825
9. Mendzheritskii AM, Karantysh GV, Ivonina KO. Effects of introduction of short peptides before carotid artery occlusion on behaviour and caspase-3 activity in the brain of old rats [in Russian]. Adv Gerontol. 2011;24:74-79. PMID 21809624
10. Mendzheritskii AM, et al. Regulation of content of cytokines in blood serum and of caspase-3 activity in brains of old rats in model of sharp hypoxic hypoxia with Cortexin and Pinealon [in Russian]. Adv Gerontol. 2014;27:94-97. PMID 25051764
11. Mendzheritsky AM, et al. Pinealon and Cortexin influence on behavior and neurochemical processes in 18-month aged rats within hypoxia and hypothermia [in Russian]. Adv Gerontol. 2015;28:532-539. PMID 28509493
12. Khavinson V, Linkova N, Kozhevnikova E, Trofimova S. EDR Peptide: Possible Mechanism of Gene Expression and Protein Synthesis Regulation Involved in the Pathogenesis of Alzheimer's Disease. Molecules. 2020;26:159. PMID 33396470
13. Umnov RS, et al. Neuroprotective effects of peptides bioregulators in people of various age [in Russian]. Adv Gerontol. 2013;26:671-678. PMID 24738258
14. Bashkireva AS, et al. The peptide correction of neurotic disorders among professional truck-drivers [in Russian]. Adv Gerontol. 2012;25:718-728. PMID 23734521

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