Bronchogen

What it is. Bronchogen is Ala-Glu-Asp-Leu, designed from lung tissue extract amino acid composition in the Khavinson programme [4].

The lung work. Two Russian-language studies used a rat model of obstructive lung pathology. The first reported that peptide therapy modulated the morphofunctional state of bronchial epithelium [1]; the second reported anti-inflammatory and regenerative effects in the same model [2]. This is more organ-appropriate evidence than Livagen has for the liver, though it remains two reports from one programme, available in English only as abstracts.

The calorimetry, which is the most interesting result. Differential scanning microcalorimetry measured the thermodynamics of DNA melting with bronchogen present. The peptide raised the melting temperature of both calf thymus and mouse liver DNA by 3.1 °C - but only within a narrow band of peptide-to-base-pair ratios, from 0.01 to 0.055. Above that, no further change. The melting enthalpy did not change across the range [3].

This is worth dwelling on because it is the kind of evidence the rest of this programme mostly lacks: a physical measurement, on a benchtop instrument, showing that the peptide binds DNA and stabilises it. It is also strictly a statement about purified DNA in a cuvette. It says nothing about whether the peptide reaches DNA in a living cell, and the saturation at low ratios suggests a limited number of binding sites rather than a general coating effect.

Sequence specificity. In the fluorescence-quenching study that examined several of these peptides together, bronchogen preferred CTG-containing sequences while epithalon, testagen and pinealon preferred CAG [5]. Different peptides, different preferences - again, evidence against a generic charge-driven effect.

Human evidence. None.

Bronchogen offers the clearest physical support in this family for the shared mechanistic claim. The DNA thermostability work shows binding directly: a 3.1 °C rise in melting temperature is a substantial stabilisation, and the saturation above a ratio of 0.055 implies discrete binding sites [3]. The fluorescence work adds sequence preference [5]. Together these make "short peptides bind DNA in a sequence-dependent way" a demonstrated statement rather than an assertion.

What remains undemonstrated is every subsequent step. That binding changes transcription in a cell; that the peptide reaches nuclear DNA after a dose; that any of this produces the bronchial epithelial changes seen in the rat model [1]. Those are three separate claims and none has been tested directly.

The CNG binding preference is proposed to matter because CNG sites are targets for cytosine methylation [5], which would give the peptides an epigenetic route. That is a hypothesis in the source paper, not a finding.

The free tetrapeptide Ala-Glu-Asp-Leu, supplied lyophilised. Given by injection in the rat work; oral products are sold in Russia without a published absorption study.

No adverse effects are reported and no safety or toxicology study has been published. There is no pharmacokinetic data in any species and no human exposure data.

The DNA-binding evidence cuts both ways as a safety matter. It is the strongest support for the mechanism and it is also the reason to want toxicology: a molecule demonstrated to bind and stabilise DNA is one where genotoxicity testing would be standard for any compound entering development. None has been published here.

The provenance caveat applies as across this group.

No interaction studies exist. Bronchogen has been examined alongside epithalon, pinealon and testagen in the DNA-binding work [5] and among the peptides stimulating tissue-specific differentiation [6], as comparisons rather than combinations.