digplanet beta 1: Athena
Share digplanet:

Agriculture

Applied sciences

Arts

Belief

Business

Chronology

Culture

Education

Environment

Geography

Health

History

Humanities

Language

Law

Life

Mathematics

Nature

People

Politics

Science

Society

Technology

4-Aminobenzoic acid
4-Aminobenzoic acid.svg PABA molecule
Identifiers
CAS number 150-13-0 YesY
PubChem 978
ChemSpider 953 YesY
UNII TL2TJE8QTX YesY
DrugBank DB02362
KEGG D02456 YesY
ChEBI CHEBI:30753 YesY
ChEMBL CHEMBL542 YesY
Jmol-3D images Image 1
Properties
Molecular formula C7H7NO2
Molar mass 137.14 g mol−1
Appearance White-grey crystals
Density 1.374 g/mL
Melting point 187–189 °C
Boiling point 340°C
Solubility in water 1 g/170 mL (25 °C)
1 g/90 mL (90 °C)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

4-Aminobenzoic acid (also known as para-aminobenzoic acid or PABA because the number 4 carbon in the benzene ring is also known as the para position) is an organic compound with the formula H2NC6H4CO2H. PABA is a white-grey crystalline substance that is only slightly soluble in water. It consists of a benzene ring substituted with an amino group and a carboxyl group.

Production and occurrence[edit]

In industry, PABA is prepared mainly by two routes: reduction of 4-nitrobenzoic acid and the Hoffman degradation of the monoamide derived from terephthalic acid.[1] (Toluene + HNO3/H2SO4) = nitro-toluene. Then oxidation of the nitrotoluene (with sodium dichromate, sulfuric acid, and heat), and reduction of the nitro group.

Food sources of PABA include liver, brewer's yeast (and unfiltered beer), kidney, molasses, mushrooms, and whole grains.[2]

Biology[edit]

Biochemistry[edit]

Tetrahydrofolate synthesis pathway

PABA is an intermediate in the bacterial synthesis of folate. PABA has been referred to as Vitamin Bx.[3] Some bacteria in the human intestinal tract such as E. coli generate PABA from chorismate.[4] Humans lack the enzymes to convert PABA to folate, and therefore require folate from dietary sources such as green leafy vegetables. Although some intestinal bacteria can synthesize folate from PABA[5] and some E. coli can synthesize folate,[6] this requires six enzymatic activities in folate synthesis which are not all done in the same bacteria. In humans PABA is considered nonessential and is not recognized as a vitamin.[3]

Sulfonamide drugs are structurally similar to PABA, and their antibacterial activity is due to their ability to interfere with the conversion of PABA to folate by the enzyme dihydropteroate synthetase. Thus, bacterial growth is limited through folate deficiency without effect on human cells.[citation needed]

Medical use[edit]

The potassium salt is used as a drug against fibrotic skin disorders, such as Peyronie's disease, under the trade name Potaba.[7] PABA is also occasionally used in pill form by sufferers of irritable bowel syndrome to treat its associated gastrointestinal symptoms, and in nutritional epidemiological studies to assess the completeness of 24-hour urine collection for the determination of urinary sodium, potassium, or nitrogen levels.

Nutritional supplement[edit]

Despite the lack of any recognized syndromes of PABA deficiency in humans, many claims of benefit are made by commercial suppliers of PABA as a nutritional supplement. Benefit is claimed for fatigue, irritability, depression, weeping eczema (moist eczema), scleroderma (premature hardening of skin), patchy pigment loss in skin (vitiligo), and premature grey hair.[8] It is also sometimes claimed that oral supplements of PABA can make the skin less sensitive to sun damage.[citation needed]

Commercial and industrial use[edit]

PABA finds use mainly in the biomedical sector. Other uses include its conversion to specialty azo dyes and crosslinking agents.

In the past, PABA was widely used in sunscreens as a UV filter. It is a UVB absorber, meaning that it can absorb wavelengths between 290 and 320 nm. [9] Patented in 1943, PABA was one of the first active ingredients to be used in sunscreen.[10] The first in vivo studies on mice showed that PABA reduced UV damage. In addition, PABA was shown to protect against skin tumors in rodents.[11] Animal and in vitro studies in the early 1980s suggested PABA might increase the risk of cellular UV damage.[12] On the basis of these studies as well as problems with allergies and clothing discoloration, PABA fell out of favor as a sunscreen. However, water-insoluble PABA derivatives such as padimate O are currently used in some products.

Safety considerations[edit]

PABA is largely nontoxic; the median lethal dose of PABA in dogs (oral) is 2 g/kg.[1] Allergic reactions to PABA can occur. PABA is formed in the metabolism of certain ester local anesthetics, and many allergic reactions to local anesthetics are the result of reactions to PABA.[13]

References[edit]

  1. ^ a b Maki, T.; Takeda, K. (2000). "Benzoic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH. doi:10.1002/14356007.a03_555.  edit
  2. ^ Nutritional Health Resource
  3. ^ a b "Para-aminobenzoic acid". Medline Plus Medical Encyclopedia. United States National Institutes of Health. Retrieved 24 January 2014. 
  4. ^ Folate Synthesis (Abstract)
  5. ^ Wegkamp A, Oorschot W, de Vos WM, and Smid EJ, "Characterization of the role of para-aminobenzoic acid biosynthesis in folate production by Lactococcus Iactic, Appl Environ Microbiology, April 2007, 73(8), pp 2673-2681
  6. ^ In vivo Folate Production
  7. ^ "Compound Summary on PubChem". PubChem. National Institute of Health: National Library of Medicine. 2006. Retrieved 2006-04-05. 
  8. ^ Health Library (Supplements) PABA
  9. ^ Melanoma Madness The scientific flap over sunscreens and skin cancer -- Chemical studies, Science News Online, 6/6/98 (accessed 10/1/2009, 2009)
  10. ^ F. P.; Mitchnick, M.; Nash, J. F. A Review of Sunscreen Safety and Efficacy Photochem. Photobiol. 1998, 68, 243 <last_page> 256.
  11. ^ H.; Thune, P.; Eeg Larsen, T. The inhibiting effect of PABA on photocarcinogenesis Arch. Dermatol. Res. 1990, 282, 38 <last_page> 41
  12. ^ Osgood, Pauline J.; Moss, Stephen H.; Davies, David J. G. (1982). "The Sensitization of Near-Ultraviolet Radiation Killing of Mammalian Cells by the Sunscreen Agent Para-aminobenzoic Acid". Journal of Investigative Dermatology 79 (6): 354–7. doi:10.1111/1523-1747.ep12529409. PMID 6982950. 
  13. ^ Toxicity, Local Anesthetics: eMedicine Emergency Medicine

External links[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/4-Aminobenzoic_acid — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
119 videos foundNext > 

Vitamin PABA (Para Aminobenzoic Acid)

http://www.thecornucopia-store.net.

PABA Para Amino Benzoic Acid ceramide jun2010

Para Amino Benzoic Acid sounds longer than it is! and the Schroeder Diamonds makes it a breeze to draw. this is like an arrow with the carboxylate tail and t...

FOLIC ACID

https://www.facebook.com/DwarozhIVF Folic acid (also known as folate, vitamin M, vitamin B9,[3] vitamin Bc[4] (or folacin), pteroyl-L-glutamic acid, pteroyl-...

Acide benzoïque et brûlures aiguës de la face - Aminobenzoic acid and acute face burns

PABA Supplement Benefits - An Overview of Things You Need to Be Aware Of

http://www.amazon.com/gp/product/B00CX7Q548 Other important PABA health advantages are: it efficiently alleviates anxiety and fatigue and also battles the di...

Pronounce Medical Words ― Para―Aminobenzoic Acid

This video shows you how to say Para―Aminobenzoic Acid. How would you pronounce Para―Aminobenzoic Acid?

Argan Fig Shampoo and Conditioner from Blackbox Cosmetics

ORDER YOURS TODAY https://shop.blackboxcosmetics.com/DT0489 Argan-Fig Shampoo is the most luxurious Sulfate and Paraben Free shampooing experience ever devel...

#35 Biochemistry Lecture (Nitrogen and Amino Acid Metabolism) from Kevin Ahern's BB 350

1. Contact me at kgahern@davincipress.com / Friend me on Facebook (kevin.g.ahern) 2. Download my free biochemistry book at http://biochem.science.oregonstate...

All about...solari: Filtri chimici vs. Filtri fisici

Grazie mille a Francesca e Lida per le preziose informazioni che mi hanno dato! Ecco qua i nomi dei filtri chimici e fisici che possiamo trovare nelle creme ...

#35 BB 350 Nitrogen Metabolism - Kevin Ahern's Biochemistry Online

1. Contact me at kgahern@davincipress.com / Friend me on Facebook (kevin.g.ahern) 2. Download my free biochemistry book at http://biochem.science.oregonstate...

119 videos foundNext > 

We're sorry, but there's no news about "4-Aminobenzoic acid" right now.

Loading

Oops, we seem to be having trouble contacting Twitter

Support Wikipedia

A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia. Please add your support for Wikipedia!