L-Histidine

Safe in the present practices of use and concentration. Ingredient, concentration, and use information are available in documents discoverable at https://cir-reports.cir-safety.org

Since the actions of supplemental L-histidine are unclear, any postulated mechanism is entirely speculative. However, some facts are known about L-histidine and some of its metabolites, such as histamine and trans-urocanic acid, which suggest that supplemental L-histidine may one day be shown to have immunomodulatory and/or antioxidant activities. Low free histidine has been found in the serum of some rheumatoid arthritis patients. Serum concentrations of other amino acids have been found to be normal in these patients. L-histidine is an excellent chelating agent for such metals as copper, iron and zinc. Copper and iron participate in a reaction (Fenton reaction) that generates potent reactive oxygen species that could be destructive to tissues, including joints. <br/>L-histidine is the obligate precursor of histamine, which is produced via the decarboxylation of the amino acid. In experimental animals, tissue histamine levels increase as the amount of dietary L-histidine increases. It is likely that this would be the case in humans as well. Histamine is known to possess immunomodulatory and antioxidant activity. Suppressor T cells have H2 receptors, and histamine activates them. Promotion of suppressor T cell activity could be beneficial in rheumatoid arthritis. Further, histamine has been shown to down-regulate the production of reactive oxygen species in phagocytic cells, such as monocytes, by binding to the H2 receptors on these cells. Decreased reactive oxygen species production by phagocytes could play antioxidant, anti-inflammatory and immunomodulatory roles in such diseases as rheumatoid arthritis. <br/>This latter mechanism is the rationale for the use of histamine itself in several clinical trials studying histamine for the treatment of certain types of cancer and viral diseases. In these trials, down-regulation by histamine of reactive oxygen species formation appears to inhibit the suppression of natural killer (NK) cells and cytotoxic T lymphocytes, allowing these cells to be more effective in attacking cancer cells and virally infected cells.

/SRP:/ Basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poison A and B/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poison A and B/

L-Histidine is a food additive permitted for direct addition to food for human consumption, as long as 1) the quantity of the substance added to food does not exceed the amount reasonably required to accomplish its intended physical, nutritive, or other technical effect in food, and 2) any substance intended for use in or on food is of appropriate food grade and is prepared and handled as a food ingredient.

CIR ingredient: Histidine

An essential amino acid; [Merck Index] Used as a medicine, feed additive, dietary supplement, in biochemical research, infusion solutions, diagnostic aids, and as a starting material for peptide drugs; [HSDB] Used as a flavoring agent and nutritional supplement for foods; [FDA]

Farming (Feed Additives) [Category: Industry]

Medicine, feed additive, biochemical research, dietary supplement

Infusion solutions/diagnostic aids; raw material (peptide drugs)

Use (kg; approx.) in Germany (2009): >10000

ISOLATED FROM BLOOD CORPUSCLES BY METHOD OF ELECTRICAL TRANSPORT... BY PRECIPITATION WITH MERCURIC CHLORIDE... CONVENIENT LAB PROCEDURES: FOSTER, SHEMIN, ORG SYN COLL VOL II, 330 (1943). SYNTHESIS BY CONDENSING 4-CHLOROMETHYLGLYOXALINE WITH ETHYLCHLOROMALONATE: PYMAN, J CHEM SOC 99, 668, 1386 (1911)...

...BY CONDENSING GLYOXALINE FORMALDEHYDE WITH HIPPURIC ACID: PYMAN, J CHEM SOC 109, 186 (1916).

From blood corpuscles, organic synthesis

ECRISTIDINE; & LAROSTIDIN. /L-HISTIDINE MONOHYDROCHLORIDE/

Available commercially as L(+)-histidine hydrochloride and as the free base.

Found naturally in the L(-) form.

Flavouring Agent -> FLAVOURING_AGENT -> JECFA Functional Classes

Flavoring Agents -> JECFA Flavorings Index

Cosmetics -> Skin conditioning; Humectant; Antistatic

L-Histidine: ACTIVE

Histidine: ACTIVE