The invention relates to a method for the reduction of the concentration of amines and salts thereof, wherein the amines have the general formula I R1R2R3N, and the salts have the formula II R1R2R3N—H. The method is suitable for use in food preparation and in the manufacture of foods. The inventive idea is also useful in the manufacture of medical products for absorbing and for removing amines from the digestive tract or skin area of humans or animals.
Structurally, amines are derived from ammonia wherein one, two or three hydrogen atoms of the ammonia can be substituted for same or different organic radicals. Amines and their salts have been known for a long time to chemists and are being used in various applications in the laboratory as well as for technical synthesis processes. Amines are also present in humans and animals. They serve as regulatory and control substances in such a vast number of biological processes that to date, their classification into substances that are either harmful, tending to be stressful, or even harmless is impossible and neither useful nor sensible. Rather, in order to judge whether a substance of a given concentration has a harmful or a rather harmless effect has to be determined for each substance individually in light of its biological effect and concentrations that are relevant for the organism. Further, a growing number of amines enters the human body either as pharmaceutically active substances in pharmaceutical products (for instance as blood pressure lowering substances), in trace amounts as herbicides or their remnants, or as contaminants in food products. An industrial, chemical processing of amines results among others in the synthesis of azo dyes: this class of dyes can be found almost everywhere in the human living space, including labels on technical installations, product packaging, or dying of foods, sometimes in trace amounts and sometimes in larger amounts. Other sources of amines are cooking, baking, grilling and frying processes, which are commonly used for the preparation of meals and represent mainly thermal processes. The amines are formed through reaction of amino acids with carbohydrates, fats and other reactants at high temperature. In addition, plants and their extracts contain significant amounts of amines. Examples are the large group of alkaloids, narcotic drugs, and toxins of mushrooms.
A further significant source of amines in humans or animals is digestion: under anaerobic conditions in the intestine proteins are broken down through the activity of bacterial acylases into shorter peptide sequences and eventually into amino acids which are normally resorbed through the intestine and used by the organism. However, some of these amino acids are either broken down into carbon dioxide and amine by bacterial amino acid decarboxylase or are further degraded through other steps. In the literature these amines are referred to as “biogenic amines”.
A further significant source of amines is microbial activity. All foods produced by or through the use of microorganisms contain amines. Examples are cheese, wine, sauerkraut, beer, yogurt and kefir. In addition amines are also produced during the storage of meat, fish, sausages, poultry and game. Normally, the amount of amines increases strongly in cases where food is stored for too long or becomes spoiled. In these cases, beside the increasing microbial load, amine concentrations that were tolerable in the beginning become encumbering or toxic for the body. To avoid excessive amounts of encumbering bacterial amines, food should always be produced, prepared and consumed freshly. A critical situation arises, however, in cases where bacterial amines carry out the function of a tissue hormone which itself is involved in a specific regulatory function in human or animal organisms. In these cases the organism is forced to chemically alter the respective amine which is present in the chyme, completely in order to prevent its resorbtion through the intestinal mucosa into the body. Otherwise, uncontrollable reactions would occur which would override the organism's ability to initiate and control these reactions in the respective tissues. Such a chemical alteration is achieved by the ferment system monoamine oxidase or diamine oxidase respectively. The ferment system is able to break down a large number of mainly primary amines through hydrogen peroxide via oxidative deamination into the respective carbonyl compound and ammonia, and its activity in the intestinal mucosa is sufficiently high to allow higher organisms to protect themselves from biogenic amines. This reaction is an oxidative deamination with elimination of ammonia. It is the reverse reaction of the reductive amination, which is known in chemistry as Leukart-Wallach-reaction for about 100 years. Several factors can contribute to the reduction or, in rare cases almost complete loss of the diamino or aminooxidase activity in parts of the intestine of humans and animals, such as aging processes, enzyme defects, and pathological changes in the intestinal mucosa, numerous aminooxidase inhibiting drugs, as well as auxiliary materials and preservatives in food. For instance, in case of ingestion of uncontrolled amounts of 2-(4′-imidazolyl)-ethylamine, which functions as tissue hormone and neurotransmitter in the human body, the affected persons contract severe intestinal inflammation or multiple food intolerance. The course of the disease can span over years, sometimes decades and, because of the particular severity of the disease causes strong psychological stress. The number of affected persons has risen strongly in the last thirty years. In the case of the more common and less severe form of the disease, its cause is mostly not recognized and affected persons intermittently suffer from painful and quite unpleasant digestive complications. In the human and animal body 2-(4′-imidazolyl)-ethylamine plays a central role in allergic reactions and is involved in the defense against foreign substances and microorganisms through the immune system. 2-(4′-imidazolyl)-ethylamine is very important in the gastrointestinal tract for the regulation of gastric acid production as well as in the central nervous system for the regulation of the sleep-wake-rhythm. 2-(4′-imidazolyl)-ethylamine is stored in mast cells, basophile granulocytes and nerve cells. If needed 2-(4′-imidazolyl)-ethylamine can be released from mast cells and basophile granulocytes very rapidly as for instance in allergic reactions or after mechanical injuries. The physiological effect of 2-(4′-imidazolyl)-ethylamine is based on dilation of the small vessels which manifests itself in redness of the skin, increased permeability of vessels, and contraction of the smooth musculature in the bronchia, intestine, uterus and large vessels. The unwanted effects of allergic reactions include headache, runny nose, difficulty of breathing and asthma, and skin reactions such as itching and formation of wheals. Further, heart function is also influenced by 2-(4′-imidazolyl)-ethylamine which can manifest itself in tachycardia or arrhythmia. Blood pressure drops significantly. The effect on the gastro-intestinal tract consists of soft stool and diarrhea.
The most important function of the body's own 2-(4′-imidazolyl)-ethylamine is its participation in the defense against foreign substances and its pathological participation in the symptoms of allergies and asthma. Further, 2-(4′-imidazolyl)-ethylamine is a mediator substance in inflammations and burns. In these cases 2-(4′-imidazolyl)-ethylamine leads to itching and pain, contraction of the smooth musculature in the bronchia and the large blood vessels. An increased permeability of the vascular walls leads to urticaria. In addition, 2-(4′-imidazolyl)-ethylamine leads to the release of adrenaline. The body tries to guard against resorbtion of 2-(4′-imidazolyl)-ethylamine from the intestine by a high activity of the enzyme monoamine oxidase or diamine oxidase respectively, and by an as complete as possible degradation of 2-(4′-imidazolyl)-ethylamine.
Two further amines, which can be generated through microbial activity in the intestine during digestion are 2-phenyl-ethylamine and 2-(4′-hydroxyphenyl)-ethylamine. Resorbtion of 2-phenyl-ethylamine leads to a rise of blood sugar levels. At the same time 2-phenyl-ethylamine is an amphetamine derivative and thus an amine which causes addiction and increased appetite and, through sustained high blood sugar levels can lead to type II diabetes. It is commonly found in larger amounts in chocolate and the human body can produce it endogenously under certain circumstances. It is created in the intestine through bacterial degradation of the amino acid phenylalanine. 2-(4′-hydroxyphenyl)-ethylamine causes a strong rise of blood pressure through stimulation of the sympathetic nervous system. Systolic blood pressures of 250 to 300 mmHg caused by 2-(4′-hydroxyphenyl)-ethylamine are not uncommon. The health risks are easy to imagine and are commonly summarized with the term hypertonic crisis. 2-(4′-hydroxyphenyl)-ethylamine is generated from the amino acid tyrosine through bacterial degradation under the influence of decarboxylases.
A further, very important biologically active amine is dimethylamine, a secondary amine. It is generated in relatively large amounts in muscle tissue and reaches the intestine directly mainly through consumption of fish. It is also generated partly through bacterial degradation during digestion often with sarcosine as intermediate, but also as a result of trans-methylation reactions, involving for instance methionine. Increased concentrations of dimethylamine compromise neurophysiological functions. Especially in persons with limited kidney function and older age this circumstance is significant. Beside its property to lower blood pressure, diethylamine is able to react with nitrite, which is generated in the intestine through microbial reduction of nitrate which is present in drinking water or in consumed vegetables. The reaction of diethylamine with nitrite occurs spontaneously at pH 5.0 and is catalyzed in bacterial species at a pH of 7.2. The result of the reaction is dimethylnitrosamine, a highly carcinogenic substance which belongs to the group of nitrosamines. The majority of these nitrosamines have the ability to cause tumors in animal experiments. Thus, already 30 to 40 years ago dimethylamine was suspected to function as a potential pre carcinogen in humans and animals. The degradation of dimethylamine through aminooxidases in the intestinal mucosa is not possible, and therefore the entire amount of dimethylamine present or generated in the intestine is resorbed and distributed within the entire body through the bloodstream. Through the activity of the kidneys diethylamine becomes a component of the urine in healthy humans and can be excreted from the body. It can best be detected by gas chromatography, 1H-NMR-spectroscopy or photometrically in the urine. The predominant amount of dimethylamine is generated through degradation of methylated arginine. The healthy human being excretes about 17.5 milligrams of dimethylamine per day through urine. Males excrete 21.2 milligrams while females excrete 13.5 milligram on average.
A further important secondary amine is pyrrolidine. It can be generated through bacterial decarboxylation of the amino acid proline. As an amino acid proline is a component of proteins. In analogy to dimthylamine, pyrrolidine reacts with nitrite to form nitrosopyrrolidinee, a substance which is also highly carcinogenic. pyrrolidine was found in some organisms.
A number of other carcinogenic amines is generated in the intestine under strongly reducing conditions during digestion. Especially members of the group of azo dyes through splitting of the azo group form aromatic amines, such as benzidine, aniline and naphtylamine, or substituted derivatives thereof. The production and use of several of these aromatic amines has been banned. However, production and trade of azo dyes that are chemically accessible though these substances are still permitted internationally. The German industry has voluntarily abandoned production of these potentially dangerous azo dyes for several years. However, all azo dyes in question can still reach the internal market through imports of finished products, as long as no similar, as far as possible voluntary, production restrictions exist in countries of origin and production.
In analogy to the intestine, substances especially amines, can be taken up by the body through the skin: minor injuries, insect bites, abrasions, but also more severe injuries can become populated by infectious germs. The wounds become infected and some microorganisms are capable to release amines, especially 2-(4′-imidazolyl)-ethylamine, in this environment as well. The activity of the amine degrading oxidases is relatively lower compared to that in the intestinal mucosa. Partly, microorganisms are capable to produce additional toxic compounds which enter the surrounding tissue and in this way can destroy the tissue and lead to its lysis. The lyzed tissue in turn forms the basis for the microorganisms' further development and propagation. The wound becomes larger. The infection progresses. In many cases such infections are caused by the bacterium Staphylococcus aureus, which is commonly found on the skin or in the nose of humans. Many species of Staphylococcus aureus have become resistant to antibiotics. The result of the resistance against antibiotics is that treatment with one or with a combination of several antibiotics has little or no effect and the bacteria are still able to propagate in the wound. In this way the wounds continue to develop further and expand deeper into the tissue, until eventually a clinically effective antibiotic is found. If there is no effective antibiotic and none can be found in time, affected persons mostly die of ensuing sepsis.
The disulfidic cystamine, which is also a biogenic amine, has the characteristic to inhibit blood clotting and, in higher concentration, to prevent blood clotting altogether. In the 1960ies efforts were made to use this characteristic for the development of new inhibitors of thrombocyte aggregation. However, these efforts failed because of the formation of skin abscesses and lung complications. Moreover, cystamine leads to lack of appetite, drowsiness, increased salivation and lowers the blood glucose level. A number of diseases are connected to spontaneous bleeding, for instance in the intestine or other mucous membranes. Frequent spontaneous bleeding of mucous membranes for example in the intestine, nose or lung can have an infection as the underlying cause. If, after infection, cystamines are released in high concentrations and/or the human has pathological monoamine or diamine oxidase weaknesses with regard to cystamine in the affected tissues, spontaneous local bleeding or hemorrhaging into the tissue can occur due to local inhibition of blood clotting. Very strong bleedings of the mucous membranes occur in hemorrhagic fevers that flare up sporadically in the tropics. Lassa fever, Ebola fever and Dengue fever are mentioned here in particular. In addition, nosocomial infections play an increasing role and require the highest safety measures during treatment.
Tryptamine has the characteristic to cause nightmares in affected persons, when it reaches the blood stream through routes mentioned above. This is not surprising since tryptamine is structurally closely related to LSD=lysergic acid diethylamide. Tryptamine is often a natural component of heavy red wines and can sometimes also be found in good lager wines.
As can be seen from the above discussion, amines have the ability to influence the metabolism and with that the health of humans and animals. It is important in this context to realize that a reduction of enzymatic activity of the monoamine and diamine oxidases or generation of large amounts of amines in the intestine or through the skin, can lead to an uncontrolled assimilation of a large number of amines into the human or animal body. This can then lead to the health consequences mentioned above. A number of amines are not or only hardly degraded in the intestine, and others are even only produced in the intestine during digestion. This creates the task to develop a process to reduce the uptake of amines through the intestine or skin.