Fig. 1.
![Biosynthetic pathway for ectoine and hydroxyectoine. Author’s own modification following [77, 92].](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/6470923671e4585e08aa02f2/j_PM-2019.58.3.339_fig_001.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=ASIA6AP2G7AKPD7DO3RW%2F20251211%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251211T092435Z&X-Amz-Expires=3600&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEB0aDGV1LWNlbnRyYWwtMSJIMEYCIQCHH1Ft%2BnsekTrSd9fFl%2B%2FSQCxLLYRNaXLCIO1XfotP8AIhAKwTB8oux7yuk8ZbZzKjPwmNxiy5qQarbGIcJ5qQ84RTKsYFCOb%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEQAhoMOTYzMTM0Mjg5OTQwIgyF3Sk5hde3jE131F4qmgXuzwu9nCerGzXuV2%2FB5RWy3ED2Fnjz1gokoE5HIdBHeYEqgdbwzd0xvThcwlK1Q9NAsHolepTzWcvHKsVhxgzVewfZe%2BkRE2hv2PYAd9wPkOiSzapWMJ5KJiXniDjDjFt8E1Xz2pK8j7gqP4hhnnfVdYysvANGCVTS55GuZ24xiGUDZ0MqbD4lltzQch%2BHuCDzqT%2BbdOQI8k3551k8o2CXfs%2Bc1ieQKvMlYnzKsn3oaYVcGHSmHwjCSV7Ind2CJS01tEHR%2FVvPR6SBMQ4aJrsO%2B%2BlLM7eokUsurKCCax5ExbiDhVY7fNb85s8AzSvFKNyJEkAVpUQXfDNAVZ0EyIbstfwJRQ7fy6O8GDYjEKrIZZu948nlsHsEIzoxqOQLUfyzsW9Wc3UOIncIp80Und6TEb12M31tTLWX3%2BYrjrhBnHDdDJzQkJQnz96E%2Flp1MsT8IcmNIabSX2N58yE3txByCVhFv%2BX8YKwoLSj9auNM62kvHPSAcM05gepKeh6YhIhZAhupah24m0%2B%2FN9Wug%2Bp8yW6PNuCNAkkli7BxWeSYVc4OSTFVjiU2Y%2BCVVRja0ax%2BG%2BHVIW0mlnpH7pStjjN3DJbfpUE1ovXUvDvzLohi2LurgD6IgrzCRXkU9Tn%2Bibb7AVNZ6wjaL%2BvR2jzY5CFELGckY1kFGUf%2F56e27Pnk3lDhPScoijr4OcEAgfO8g5cMWVUyY31SgL7IHQWCRXSGrAQsRiP0qybz02TebeUsLogVP67V9BnSXgmPNFZvlBgTr5EjpTa0fzTTF76wBPE21TFu1OUKKBWjjU5LY41HVFCp%2BDMVbYCBCM1N28dpm657QufUsTNou1K8Yd70JePuVu9kE%2BxFTynKveYqiy%2B669iFTHbckttXkpYw0aPpyQY6sAHwHYAjPujBNItyESfO8wR1y%2F7C8r3ATn0jW8a71Ipk3cJfDBxa7wN00MC3zK35roRyb5os6%2FiWwbcBZFYD9TsQUIvhWM9pEKLrb7VzLbJZVazXsq1vbTtEvQa29ezp61kx%2BZgLL4SFsi0woL0yLeosu42YL2pj20UlF5mMnjFz99rhi9MRQRJYqpHIrdtuxD3%2Bc%2Fc0D2NggKUE5ZSn5P8e0iwBR7UQDd2End5Yc005yw%3D%3D&X-Amz-Signature=8c2479634011de3755f65fba6f501ac15d1dc5b25277fdd2b0319182b8e7bba3&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Potential possibilities of practical use of ectoine and hydroxyectoine to protect cells
| Effect | References |
| Ectoine | |
| Supporting the ethanol fermentation process by Zymomonas mobilis | [99] |
| Halomonas participation in phenol detoxification | [69] |
| Maintenance of E. coli respiratory activity (in vivo) | [72] |
| Osmoprotective effect on lactic acid bacteria | [5] |
| Tolerance to the salinity of transformed tobacco plants | [70] |
| Increase in the fluidity of cell membranes under extreme conditions | [40] |
| Increases the distance between lipid molecules and improves the membrane fluidity | [28] |
| Effect on the synthesis of chaperone proteins (in vivo and in vitro) | [7, 19] |
| Enterocytes protection against alpha haemolysin of Staphylococcus aureus (in vivo) | [15] |
| Hydroxyectoine | |
| Protection of Pseudomonas putida against desiccation | [65] |
| Protection of E. coli against desiccation | [66, 67] |
| Induction of thermotolerance in E. coli | [64] |
| Ectoine and hydroxyectoine | |
| Stabilization of E. coli during drying and storage | [63] |
Potential possibilities of practical use of ectoine in skin protection
| Effect | References |
| Anti-aging effect (in vivo) | [41] |
| Skin protection against desiccation (in vivo) | [35] |
| Anti-aging activity (in vitro), mitochondrial DNA protection and inhibition of skin inflammation caused by ceramides | [17] |
| Inducing thermal shock proteins and mediation in the proinflammatory response of human epidermal keratinocytes | [19] |
| Photoprotection against visible light (in vitro) | [13] |
| Moisturising factor (in vivo) | [71] |
| UV protection of Langerhans cells (in vivo) | [10] |
| Blocking the release of ceramides in human epidermal keratinocytes under the influence of UVA | [36] |
| Skin protection against dehydration caused by surfactants (in vivo) | [18] |
| Inhibition of melanogenesis | [96] |
Proteins protected under stress conditions by ectoine and hydroxyectoine
| Protein | Stress | Protein concentration | Concentration of osmolytes | Activity of protein (%) |
| Lactate dehydrogenase | fast freezing/slow defrosting (4x) | 52 μ/ml | 1.0 M hydroxyectoine | 100 |
| Phosphofructokinase | 75 μ/ml | 1.0 M ectoine | 100 | |
| Enolase | 50 μ/ml | 0.4 M ectoine | 100 | |
| Glutamate dehydrogenase | 350 μ/ml | 0.5 M hydroxyectoine | 85 | |
| Carboxylesterase | 200 μ/ml | 0.5 M hydroxyectoine | 100 | |
| Binding protein CD30 | 1 μ/ml | 1.0 M hydroxyectoine | 89 | |
| Lactate dehydrogenase | incubation at elevated temperature: | 52 μ/ml | 0.5 M hydroxyectoine | 90 |
| Phosphofructokinase | 75 μ/ml | 1.0 M hydroxyectoine | 100 | |
| Enolase | 50 μ/ml | 0.1 M hydroxyectoine | 88 | |
| Carboxylesterase | 200 μ/ml | 2.0 M hydroxyectoine | 65 | |
| Taq polymerase | 20 IU/ml | 1.0 M hydroxyectoine | 45 | |
| Monoclonal antibody | – | 0.5 M hydroxyectoine | active | |
| RNase A | melting | 1 mg/ml | 3.0 M hydroxyectoine | increase in Tm by 12 K |
| Lactate dehydrogenase | freeze-drying | 52 μ/ml | 1.0 M ectoine | 61 |
| Phosphofructokinase | 75 μ/ml | 1.0 M hydroxyectoine | 68 | |
| Enolase | 50 μ/ml | 0.4 M hydroxyectoine | 97 | |
| Lactate dehydrogenase | H2O2 oxidation | 200 μ/ml | 0.5 M hydroxyectoine | 95 |
Potential possibilities of the practical use of ectoine and hydroxyectoine for protecting macromolecules
| Effect | References |
| Ectoine | |
| Ensuring thermostability of cyanophycin synthetase | [39] |
| Ensuring the thermostability of the phytase (90° C) | [100] |
| Antibodies protection against proteolytic degradation | [9] |
| Lowering the melting temperature of DNA | [58] |
| Limiting the formation of infectious prions (PrP106–126) causing encephalopathy (in vitro) | [47] |
| Activation of proinflammatory reactions in the lung epithelium by stabilizing the membrane signalling platform (ex vivo) | [93] |
| Neutrophil apoptosis restoration during pneumonia (in vivo and in vitro) | [88, 89] |
| Limiting the penetration of neutrophils into the muscle layer of the intestine after transplantation (in vivo) due to the ability to stabilize macromolecules on the cell surface | [75] |
| Macromolecule protection against proteolytic factors (in vitro) | [54] |
| Inhibition of HIV replication | [58] |
| Stabilization of retrovirus vectors in gene therapy | [26] |
| Hydroxyectoine | |
| Recombinant proteins protection against degradation, aggregation, change of conformation and freezing | [6] |
| Protection of immunotoxins against stress related to freezing and defrosting | [6] |
| Increasing the melting temperature of DNA | [57] |
| Improving the quality of DNA microarrays | [68] |
| Lowering AST level after liver reperfusion (as an ingredient of organ storage solution), (ex vivo) | [11] |
| Increase in bile production after reperfusion (as an ingredient of organ storage solution), (ex vivo) | [11] |
| Pressure reduction in the portal vein after reperfusion (as an ingredient of the organ storage solution), (ex vivo) | [11] |
| Reduction of cellular apoptosis after liver transplantation (as an ingredient of organ storage solution), (ex vivo) | [11] |
| Ectoine and hydroxyectoine | |
| Enzymes protection against high temperature, freezing and desiccation | [62] |
| Reduction of protein fibrillation (Aß42) in Alzheimer’s disease (in vitro) | [47, 53, 81] |
| Cryoprotection of umbilical cord blood cells (ex vivo) | [12] |
| Reduction of ulcerative areas and inflammatory mediators during colitis due to the ability to stabilize macromolecules (in vivo) | [1] |