Paraaminobenzoic acid (PABA)

For the first time about the presence of a substance that has vitamin properties, Stemp reported (1939). This factor was necessary for the reproduction of microorganisms. Woods (1940) has shown that a substance released from Streptococcus haemoliticus can reduce the bacteriostatic effect of sulfonamide administration. This substance was paraminobenzoic acid (PABA).

[1], [2], [3], [4], [5], [6]

Physicochemical Properties of Paraaminobenzoic Acid (PABA)

Two structural analogs with the arrangement of radicals in the ortho- and meta-positions are biologically inactive. This crystalline substance is white, with a yellowish tint, has a melting point of 186-187 ° C, it is difficult to dissolve in water, it is easier - in alcohol and ether. Chemically resistant, can withstand boiling in acidic and alkaline environment. It is used in medicine for infectious diseases, as bacteriostatic agents. Also used are PABC derivatives (novocaine, anesthesin), which have a local anesthetic effect.

Metabolism of paraaminobenzoic acid (PABA)

Ingested, paraaminobenzoic acid (PABA) is partially absorbed in the upper intestine, partially used by the microflora of the large intestine for the synthesis of folic acid. In the blood, PABA is detected in significant amounts: 2-70 μg / dL, with urine it is excreted predominantly in acetylated form. The content in the blood and excretion from the body with urine varies with various diseases. The highest content in patients with cardiovascular diseases, the minimum for chronic hepatitis, Botkin's disease, ulcer disease, etc. With feces 250 μg of PABC are excreted.

Biological functions of para-aminobenzoic acid (PABA)

PABK has a wide range of physiological effects on the body, being an integral part of folic and folinic acids, contributes to the synthesis of purines and pyrimidines, and, consequently, RNA and DNA. It affects the exchange of some biogenic amines. Its antihistamine action is proved, which is important when using preparations of the postoperative period.

The inhibiting growth of microbes, the action of sulfonamides can be removed by the introduction of folic acid. In this case, the existence of a PABC is not necessary. They note the positive effect of PABA on the central nervous system (normal internal inhibition processes). It affects the function of the thyroid gland. Prolonged administration of toxic doses of the drug leads to suppression of secretion of thyroxine and hyperplasia of the thyroid gland. Small doses of 100-200 mg per reception, reduce hyperthyroidism, which is manifested in particular in the normalization of basal metabolism, decrease in gas exchange values and oxygen consumption. Paraaminobenzoic acid (PABA) affects the metabolism of hormones. It slows the oxidation of adrenaline. Under its influence, the cycle is normalized for oligomenorei.

Paraaminobenzoic acid (PABA) is practically non-toxic, hypervitaminosis is not described. However, overdose can be observed depressive state, hypotension. The use of acid in large doses of 4-6 g per day, in the complex therapy of rickettsiosis proved to be very effective, the mortality from this disease decreased. In comparison with conventional therapeutic methods, a decrease in temperature and recovery occurred earlier. PABC reduces the toxicity of certain substances, in particular arsenic and antimony. In connection with the photoprotective action, it is used in photodermatoses, in cosmetic ointments to protect against sunburn.

In a dose of 0.1-0.5 g was used in the treatment of patients with atherosclerosis, hypertensive disease. As a result of course therapy lasting 20 days, improvement in general well-being was noted, and work capacity increased. Intramuscular injection was effective in muscle bleeding. Its administration enhances the action of antitumor drugs of sarcolysin against sarcoma 45 and the Garning-Passy tumor. Simultaneously, there was a stimulating effect on erythropoiesis.

Widely used structural analogues of PABA, in particular sulfonamides, which possess antibacterial properties. It is suggested that sulfonamide preparations, due to structural similarity, can competitively replace PABA in the enzyme systems of microorganisms, followed by a halt in their growth and multiplication. Coenzyme functions of this acid are not established, but being an integral part of coenzymes of folic acid, PABA thereby participates in many metabolic processes.

[7], [8], [9]

Sources and need for para-amino benzoic acid (PABA)

Paraaminobenzoic acid (PABA) is widely distributed in food products. It was first isolated from yeast. In significant amounts, it is contained in the liver (2.5 μg / g), in the kidneys (1.8 μg / g), in the heart (1.35 μg / g), in yeast (4 μg / g) and fungi (1, 3 μg / g). In other products: cow's milk, chicken eggs, carrots, spinach, wheat contain much less.

The volume of daily needs is not set.