This is a working overview of ACTH fragment, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-03 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
==== Immunohistochemistry Approaches ==== As an antibody technique, immunohistochemistry (IHC) allows for validating protein presence. It, and immunocytochemistry, allow for surveying the localization of proteases on a tissue or cellular scale respectively. It also can evaluate for the localization of cleavage products using monoclonal antibodies raised against neo-epitopes of cleavage sites produced by protease processing. Unfortunately, in addition to providing little functional information, IHC is also non-quantitative, making it an unappealing option for describing degradomics on system-wide scales.
=== Progestogenic activity === CPA is a highly potent progestogen. It is described as the most potent progestin of the 17α-hydroxyprogesterone group, being about 1,200-fold more potent than hydroxyprogesterone acetate, 12-fold more potent than medroxyprogesterone acetate, and 3-fold more potent than chlormadinone acetate in animal bioassays. Based on results in the animal bioassays, CPA has also been said to be the most potent progestin known, with 1,000 times the potency of progesterone. With oral administration in humans however, CPA is distinctly less potent as a progestogen than various other progestins such as the 19-nortestosterone derivatives. The effective dosage of CPA needed to inhibit ovulation by itself in women (i.e., to act as a contraceptive) is 1 mg/day, and the medication is marketed as a contraceptive (combined with low-dose ethinylestradiol) at a dosage of 2 mg/day. For comparison, the ovulation-inhibiting dosage of levonorgestrel is 50 μg/day. At the dosages typically used clinically, CPA is described as a "strong" and "powerful" progestogen. Its endometrial transformation dosage is 20 to 30 mg per cycle and its menstrual delay test dosage has been estimated to be less than 1 mg/day. CPA is not well-balanced in terms of its activities; relative to the progestogenic potency of CPA, its potency as an androgen receptor antagonist is quite weak. In order to take full advantage of its antiandrogenic activity, CPA must be administered at a dosage of 50 to 100 mg per day, which is 2 to 3 times the cyclical endometrial transformation dose per day.
== External links == Clinical trial number NCT02896192 for "Setmelanotide for the Treatment of Early-Onset POMC Deficiency Obesity" at ClinicalTrials.gov Clinical trial number NCT03287960 for "Setmelanotide for the Treatment of LEPR Deficiency Obesity" at ClinicalTrials.gov
Prior to widespread use of air-conditioning, salt shakers with caps containing silica gel beads to keep the salt dry enough to prevent clumping were marketed in the US, replacing the practice of including a few grains of rice in salt shakers to effect the same drying. Silica gel is sometimes used as a preservation tool to control relative humidity in museum and library exhibitions and storage. Other applications include diagnostic test strips, inhalation devices, syringes, drug test kits, and hospital sanitation kits. Silica gel is commonly described as a way to remove moisture from phones and electronics accidentally exposed to water, but there are no known controlled studies that compare its actual efficacy compared to simple air or fan exposure. The average person is also unlikely to have a sufficient quantity of ready-to-use activated or regenerated silica gel.
Sources: en.wikipedia.org
=== Natural === Natural metallopeptides with antibiotic, antimicrobial and anticancer properties have been of particular interest to the scientific community (e.g. the divalent bacitracin, histatin and Fe/Cu-bleomycin). At the same time there is an increasing attention to the role of metalloppeptides in disease development. For example, metallochemical interactions in brain tissue can contribute to neurodegenerative conditions due to the naturally high concentration of metal ions in the brain. Hence the metallochemical reactions occurring outside the physiologically healthy concentrations, can contribute to the development of diseases such as Alzheimer's disease. The condition is related to the β-amyloid metallopeptides. Another example are infectious prion polypeptides and specific isoforms of prion protein which contribute to disease transmission and development.
Fibronectin is important for guiding cell attachment and migration during embryonic development. In mammalian development, the absence of fibronectin leads to defects in mesodermal, neural tube, and vascular development. Similarly, the absence of a normal fibronectin matrix in developing amphibians causes defects in mesodermal patterning and inhibits gastrulation. Fibronectin is also found in normal human saliva, which helps prevent colonization of the oral cavity and pharynx by pathogenic bacteria.
==== Initial loans ==== Townsend entered the senior Tottenham team under manager Harry Redknapp. In August 2009, he went on a month's loan to League One club Leyton Orient, extended at the end of the month to the end of December, after which he returned to Tottenham. In 26 appearances for Orient, Townsend scored twice, including a "great goal" in a 3–3 draw against Yeovil, passing three opposing players with a run that began in his own half, leading the opposition manager to lament that his players had not been more ruthless and taken him down with a professional foul. Having not yet made his Tottenham debut, on 14 January 2010, Townsend was again taken on loan by a League One club, Milton Keynes Dons, until the end of the season, although he was recalled after just two months due to injuries. In nine matches for the Dons he had scored twice. The season ended without Townsend having made his debut for Tottenham. On 12 August 2010, Townsend signed another season-long loan, moving up to the Championship level with Ipswich Town, but this was terminated on 20 December, as Redknapp believed he had not been playing regularly enough. He had played 16 times, scoring once.
{\displaystyle {\begin{cases}{\ce {^{244}_{96}Cm ->[{\ce {(\alpha,n)}}] ^{247}_{98}Cf ->[\epsilon][3.11 \ {\ce {h}}] ^{247}_{97}Bk}}\\{\ce {^{244}_{96}Cm ->[{\ce {(\alpha,p)}}] ^{247}_{97}Bk}}\end{cases}}}
== Modern cultivation == Seed yield varies depending on cultivars, mode of cultivation, and growing conditions by geographic region. For example, commercial fields in Argentina and Colombia vary in yield range from 450 to 1,250 kg/ha (400 to 1,120 lb/acre). A small-scale study with three cultivars grown in the inter-Andean valleys of Ecuador produced yields up to 2,300 kg/ha (2,100 lb/acre), indicating that favorable growing environment and cultivar interacted to produce such high yields.[20] Genotype has a larger effect on yield than on protein content, oil content, fatty acid composition, or phenolic compounds, whereas high temperature reduces oil content and degree of unsaturation, and raises protein content.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.