Carnosine: biological role and prospects for use in medicine]

The biological role of the histidine-containing dipeptide carnosine (beta-alanyl-L-histidine) has been reviewed. The properties and putative biological role of the dipeptide in vertebrate tissues are considered. The antioxidative activity of carnosine and related compounds is described. The author's conception of the membranoprotective effect of carnosine on cells, tissues, and whole organism has been formulated. The properties of carnosine as an antistressory radioprotective agent are discussed. The data presented suggest that carnosine is a perspective immunomodulating tool which has many applications in medicine.     

A comparative study of synthetic carnosine analogs as antioxidants

1. The antioxidative activity of carnosine and 16 related compounds, both synthetic and natural, was determined. 2. The antioxidative effect was estimated by the ability of the dipeptides to prevent MDA accumulation in the course of LPO induced in rabbit sarcoplasmic reticulum membranes by the Fe2+ ascorbate system. 3. It was found that the antioxidative effect comparable to that of carnosine was exerted by water-soluble (cyclo-L-histidyl-L-proline) and alcohol-soluble (cyclo-L-histidyl-L-phenilalanine) dipeptides as well as by the histidine-free cyclodipeptides (cyclo-L-tyrosyl-L-proline). 4. However, in contrast to its synthetic analogs, carnosine not only inhibited the LPO, but also diminished the level of products accumulated during membrane lipid peroxidation.     

Antioxidative properties of histidine-containing dipeptides from skeletal muscles of vertebrates

1. Ascorbate-dependent peroxidation of lipid components of biological membranes is inhibited by the natural histidine-containing dipeptides, carnosine and anserine, used at physiological concentrations. 2. Carnosine and anserine exhibit an equal antioxidative activity, whereas the preventing effect of homocarnosine is manifested only at low concentrations of oxidized lipid material. 3. The inhibiting effect of the dipeptides is enhanced either by the rise in the dipeptide concentration or by the decrease in the level of membrane components. 4. Addition of the dipeptides results in a marked decrease in the level of primary molecular products of lipid peroxidation. 5. In this case the optical spectrum of primary molecular products of polyunsaturated fatty acids changes significantly.     

Carnosine protection of Ca2+ transport against damage induced by lipid peroxidation

The authors studied the protective action of carnosine on sarcoplasmic reticulum (SR) membranes from frog skeletal muscles destroyed by ascorbic acid-dependent lipid peroxidation (LPO). It was demonstrated that addition of carnosine to the incubation medium at a concentration of 25 mM sharply decelerated inactivation of Ca-ATPase of SR membranes, maintaining at the same time the coupling of hydrolysing and transport functions of the Ca-pump. When given at the same concentration carnosine inhibited the accumulation of LPO products reacting with 2-thiobarbituric acid. This effect of carnosine was followed by its utilization.     

The antioxidative properties of carnosine and other drugs

The antioxidative effect of various drugs on lipid peroxidation in rat serum in the presence of FeSO4 was studied. The concentration of TBA-active products decreased in the presence of carnosine and anticataract drugs (Japanese Catalin, Chinese Baineiting and Finnish Catachrom-OFTAN). Vita-iodurol (France) and Quinax (USA) were completely inert. One of feasible mechanisms underlying certain pathologies (cataract, rheumatism, etc.) is the damage of biomembranes by active oxygen species. The potent antioxidative activity of carnosine reflects the high therapeutic value of this compound.     

Protection of the monoamine oxidase in brain synaptosomes by fat- and water-soluble antioxidants during lipid peroxidation

The protective effects of alpha-tocopherol, carnosine and their mixtures on monoamine oxidase activity, accumulation of lipid peroxidation products, lipid fatty acid composition, hydrophobicity and microviscosity of synaptic membranes during lipid peroxidation were studied. It was shown that the protective efficiency is more higher when the mixture of water and liposoluble antioxidants was used.     

The effect of carnosine on indicators of free radical lipid oxidation during acute stress in rats

The effect of carnosine intraperitoneal injection in rats (in doses 0.2, 2.0 or 20 mg/kg) on the vegetative parameters (arterial blood pressure, Hildebrandt index), the content of free radical oxidation (FRO) products and superoxide dismutase activity in serum and brain homogenates and brain lipid composition under normal condition and after different stress forms have been investigated. The carnosine injection in dose 20 mg/kg preserves and increase in arterial pressure and Hildebrandt index at all steps of stress development. The phase non-unidirectional changes in studied biochemical parameters have been revealed depending on the level of stress development in animals under control. The unidirectional and dose-dependent changes of phospholipid content and the level of brain lipids, decrease of FRO products in tissue and brain cholesterol, the increase of the superoxide dismutase activity of serum and brain homogenates have been found in intact and stressed animals after carnosine injection. A comparison of carnosine pharmacokinetics with concentration dependences of the antioxidative effect under in vitro and in vivo experiments comes to conclusion concerning the carnosine indirect adaptogenic action.     

Synergistic antioxidative activities of hydroxycinnamoyl‐peptides

Antioxidants have become an important subject of study as an active ingredient for cosmetics and preservatives for food. We synthesized antioxidative peptide conjugates of hydroxycinnamic acids (HCAs) such as ferulic acid (FA), caffeic acid (CA), and sinapic acid (SA) by SPPS method. We measured their potential antioxidant properties by 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) scavenging test and lipid autoxidation inhibition test. When the antioxidative peptides, such as glutathione analogue (GS(Bzl)H) and carnosine (CAR), were conjugated to HCAs, their antioxidative activities were enhanced significantly. CA‐peptides exhibited the highest free radical scavenging activity by the DPPH test, and showed good antioxidative activity in the lipid autoxidation test. FA‐ and SA‐peptides showed excellent antioxidative activity in the lipid autoxidation test. Furthermore, we demonstrated a synergistic antioxidative activity of HCA‐peptide conjugates by comparing their antioxidative activity with that of a simple mixture of HCAs and the antioxidant peptides. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.     

Protective action of fat- and water-soluble antioxidants on the cytochrome P-450 system during lipid peroxidation in liver microsomes

The protective effects of alpha-tocopherol, carnosine and their mixture on monooxygenase system during lipid peroxidation in liver microsome membranes were studied. It was shown that for optimal protection effect of cytochrome P-450 system the mixture of water and liposoluble antioxidants is required.     

Prospects for designing medicines based on carnosine (several new applications)]

The perspectives in application of carnosine, its analogs (histidine-containing dipeptides), and their derivatives as components of medicinal drugs are reviewed. These applications are based on antioxidative properties of carnosine and its analogs, their chelating activity towards transient valency metals as well as on their specific neurotransmitter functions in the brain. Combination of carnosine with other antioxidants and the use of copper or zinc complexes with histidine-containing dipeptides are considered as perspective trends in the design of new drugs.     

Stability of lipid domains

Membranes with simple lipid composition exhibit complex phase behavior. Ordered and disordered liquid phases can coexist in cholesterol-containing membranes with lipid compositions resembling biological membranes and at physiological temperatures. Research during the last years suggests that these lipid domains play a role in the organization of biological membranes. Understanding the principles that govern the formation and stability of lipid domains is of great importance to build a model that properly describes membrane structure and function. In this review, we describe the current knowledge of the chemical and physical basis of lipid domains and its application to biological membranes.     

Muscle dipeptides--natural inhibitors of lipid peroxidation

The effects of carnosine (beta-alanyl-L-histidine) and anserine (beta-alanyl-1-methyl-L-histidine) on ascorbate-dependent lipid peroxidation in frog skeletal muscle sarcoplasmic reticulum were studied. It was found that the dipeptides (10-50 mM) cause a 25-90% inhibition of ascorbate-dependent lipid peroxidation and decrease the reaction rate and the amount of end products. The nature of lipid peroxidation primary products in the presence of the dipeptides changes which can be evidenced from changes in their spectral properties. Unlike other known natural antioxidants, skeletal muscle dipeptides do not only inhibit lipid peroxidation but also decrease the level of accumulated lipid peroxidation products. Histidine and beta-alanine, similar to imidazole, glycyl-glycine, arginyl-phenyl alanine and alpha-alanyl-D-histidine do not inhibit lipid peroxidation. At the same time, the carnosine stereoisomer D-carnosine which does not exist in nature exhibits a far greater inhibiting effect as compared to its natural counterpart. It is assumed that the skeletal muscle dipeptides carnosine and anserine are highly effective as natural antioxidants.     

Carnosine Protects the Brain of Rats and Mongolian Gerbils against Ischemic Injury: After-Stroke-Effect

Carnosine, a specific constituent of excitable tissues of vertebrates, exhibits a significant antioxidant protecting effect on the brain damaged by ischemic-reperfusion injury when it was administered to the animals before ischemic episode. In this study, the therapeutic effect of carnosine was estimated on animals when this drug was administered intraperitoneally (100 mg/kg body weight) after ischemic episode induced by experimental global brain ischemia. Treatment of the animals with carnosine after ischemic episode under long-term (7–14 days) reperfusion demonstrated its pronounced protective effect on neurological symptoms and animal mortality. Carnosine also prevented higher lipid peroxidation of brain membrane structures and increased a resistance of neuronal membranes to the in vitro induced oxidation. Measurements of malonyl dialdehyde (MDA) in brain homogenates showed its increase in the after brain stroke animals and decreased MDA level in the after brain stroke animals treated with carnosine. We concluded that carnosine compensates deficit in antioxidant defense system of brain damaged by ischemic injury. The data presented demonstrate that carnosine is effective in protecting the brain in the post-ischemic period. Special issue dedicated to Dr. Bernd Hamprecht     

Carnosine: An Endogenous Neuroprotector in the Ischemic Brain

1. The biological effects of carnosine, a natural hydrophilic neuropeptide, on the reactive oxygen species (ROS) pathological generation are reviewed.2. We describe direct antioxidant action observed in the in vitro experiments.3. Carnosine was found to effect metabolism indirectly. These effects are reflected in ROS turnover regulation and lipid peroxidation (LPO) processes.4. During brain ischemia carnosine acts as a neuroprotector, contributing to better cerebral blood flow restoration, electroencephalography (EEG) normalization, decreased lactate accumulation, and enyzmatic protection against ROS.5. The data presented demonstrate that carnosine is a specific regulator of essential metabolic pathways in neurons supporting brain homeostasis under unfavorable conditions.     

Peptides as antioxidants and carbonyl quenchers in biological model systems

Subjecting selected peptides to in vitro analyses covering their ability to interfere with the lipid oxidation chain reaction as well as to protect proteins from direct and indirect oxidation has provided the basis for a more detailed understanding of peptide-mediated protection in biological systems. The efficiency of peptides as radical scavengers and chain-breaking antioxidants in oxidizing lipid membranes was found to be low. Previous studies on antioxidative activity of peptides tend not to include comparisons with efficiencies of more well-documented antioxidants and/or use irrelevantly high dosages of peptides. The present study demonstrates that the effect of the investigated peptides towards oxidation in biological membrane systems is mainly a protection of vital proteins from being oxidatively modified. This protection is obtained through a prevention of lipid oxidation derived carbonylation (indirect protein oxidation) and through interference with aqueous radical species (direct protein oxidation), and it is only achieved if the peptides are present in high concentrations as sacrificial antioxidants.     

Carnosine: New concept for the function of an old molecule

In this review, the development of understanding of the biological functions of carnosine is briefly discussed. Carnosine was first described as a component of meat in 1900 by V. S. Gulevitch. Changes in the concepts of the role of carnosine in metabolism are followed starting from the early suggestion that it is the end product of protein degradation to the modern ideas based on demonstrating its specific involvement in intracellular signaling regulation in excitable tissue cells. The discovery of the ability of carnosine to regulate expression of early response genes broadens the concept about carnosine as a cellular peptide regulator. The first attempts for application of carnosine in sport and medical practice are described.     

Carnosine: endogenous physiological corrector of antioxidative system activity

The results of research of camosine as an antioxidative system corrector in conditions of oxidative stress caused by the action of damaging factors (y-rays, overcooling, hypobaric hypoxia, brain ischemia, neurotoxin impact) are summarized in the present review. The effects of carnosine are characterized not only at the level of the whole organism but also in "in vitro" models with use of a whole series of enzymatic systems. The results of the experiments conducted displayed the ability of carnosine to protect animals from oxidative stress based on the combination of direct antioxidative effects and a modulation of enzymes' activities which participate in controlling of reactive oxygen species level in tissues.     

A re-evaluation of the antioxidant activity of purified carnosine

The antioxidant activity of carnosine has been re-evaluated due to the presence of contaminating hydrazine in commercial carnosine preparations. Purified carnosine is capable of scavenging peroxyl radicals. Inhibition of the oxidation of phosphatidylcholine liposomes by purified carnosine is greater in the presence of copper than iron, a phenomenon likely to be due to the copper chelating properties of carnosine. Purified carnosine is capable of forming adducts with aldehydic lipid oxidation products. Adduct formation is greatest for alpha,beta-monounsaturated followed by polyunsaturated and saturated aldehydes. While the ability of carnosine to form adducts with aldehydic lipid oxidation products is lower than other compounds such as glutathione, the higher concentrations of carnosine in skeletal muscle are likely to make it the most important molecule that forms aldehyde adducts. Monitoring changes in carnosine concentrations in oxidizing skeletal muscle shows that carnosine oxidation does not occur until the later stages of oxidation suggesting that carnosine may not be as effective free radical scavenger in vivo as other antioxidants like alpha-tocopherol.     

In vitro and in vivo inhibition of muscle lipid and protein oxidation by carnosine.

Carnosine, a beta-alanyl-L-histidine dipeptide with antioxidant properties is present at high concentrations in skeletal muscle tissue. In this study, we report on the antioxidant activity of carnosine on muscle lipid and protein stability from both in vitro and in vivo experiments. Carnosine inhibited lipid peroxidation and oxidative modification of protein in muscle tissue prepared from rat hind limb homogenates exposed to in vitro Fenton reactant (Fe2+, H2O2)-generated free radicals. The minimum effective concentrations of carnosine for lipid and protein oxidation were 2.5 and 1 mM, respectively. Histidine and beta-alanine, active components of carnosine, showed no individual effect towards inhibiting either lipid or protein oxidation. Skeletal muscle of rats fed a histidine supplemented diet for 13 days exhibited a marked increase in carnosine content with a concomitant reduction in muscle lipid peroxidation and protein carbonyl content in skeletal muscle caused by subjecting rats to a Fe-nitrilotriacetate administration treatment. This significant in vitro result confirms the in vivo antioxidant activity of carnosine for both lipid and protein constituents of muscle under physiological conditions.