Djenkolic acid (or sometimes jengkolic acid) is a

sulfur Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...

-containing non-protein

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

naturally found in the djenkol beans of the Southeast Asian plant '' Archidendron jiringa''. Its chemical structure is similar to

cystine Cystine is the oxidized derivative of the amino acid cysteine and has the formula (SCH2CH(NH2)CO2H)2. It is a white solid that is poorly soluble in water. As a residue in proteins, cystine serves two functions: a site of redox reactions and a mec ...

but contains a methylene (single carbon) unit in between the two sulfur atoms. There is about 20 grams of djenkolic acid per kilogram of dry djenkol beans, and it has also been reported in smaller amounts in the seeds of other leguminous plants such as ''

Leucaena esculenta ''Leucaena'' is a genus of flowering plants in the mimosoid clade of the subfamily Caesalpinioideae of the family Fabaceae. It contains about 24 species of trees and shrubs, which are commonly known as leadtrees. They are native to the Americas, ...

'' (2.2 g/kg) and '' Pithecolobium ondulatum'' (2.8 g/kg).D'Mello, J. P. Felix (1991). Toxic Amino Acids. In J. P. F. D'Mello, C. M. Duffus, J. H. Duffus (Eds.)
Toxic Substances in Crop Plants
'. Woodhead Publishing. pp. 21–48. . Google Book Search. Retrieved on November 15, 2008.

Toxicity

The toxicity of djenkolic acid in humans arises from its poor

solubility In chemistry, solubility is the ability of a chemical substance, substance, the solute, to form a solution (chemistry), solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form su ...

under acidic conditions after consumption of the djenkol bean. The amino acid precipitates into crystals which cause mechanical irritation of the renal tubules and

urinary tract The human urinary system, also known as the urinary tract or renal system, consists of the kidneys, ureters, bladder, and the urethra. The purpose of the urinary system is to eliminate waste from the body, regulate blood volume and blood pressu ...

, resulting in symptoms such as abdominal discomfort, loin pains, severe colic, nausea, vomiting,

dysuria Dysuria refers to painful or uncomfortable urination. It is one of a constellation of ''irritative'' bladder symptoms (also sometimes referred to as lower urinary tract symptoms), which includes nocturia and urinary frequency. Diagnosis The cl ...

, gross

hematuria Hematuria or haematuria is defined as the presence of blood or red blood cells in the urine. "Gross hematuria" occurs when urine appears red, brown, or tea-colored due to the presence of blood. Hematuria may also be subtle and only detectable with ...

, and

oliguria Oliguria or hypouresis is the low output of urine specifically more than 80 ml/day but less than 400ml/day. The decreased output of urine may be a sign of dehydration, kidney failure, hypovolemic shock, hyperosmolar Hyperglycemic Nonketotic Syndro ...

, occurring 2 to 6 hours after the beans were ingested.Barsoum, R. S., & Sitprija, V. (2007). Tropical Nephrology. In R. W. Schrier (Ed.)
Diseases of the Kidney and Urinary Tract: Clinicopathologic Foundations of Medicine
'. Lippincott Williams & Wilkins. p. 2037. . Google Book Search. Retrieved on November 15, 2008. Urine analysis of patients reveals erythrocytes, epithelial cells, protein, and the needle-like crystals of djenkolic acid.

Urolithiasis Kidney stone disease (known as nephrolithiasis, renal calculus disease, or urolithiasis) is a crystallopathy and occurs when there are too many minerals in the urine and not enough liquid or hydration. This imbalance causes tiny pieces of cr ...

can also happen, with djenkolic acid as the nucleus. In young children, it has also been reported to produce painful swelling of the genitalia. Treatment for this toxicity requires hydration to increase urine flow and alkalinization of urine by

sodium bicarbonate Sodium bicarbonate ( IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda (or simply “bicarb” especially in the UK) is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cat ...

. Furthermore, this poisoning can be prevented when consuming djenkol beans by boiling them beforehand, since djenkolic acid is removed from the beans.

Discovery and synthesis

Djenkolic acid was first isolated by Van Veen and Hyman in 1933 from the urine of the natives of

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

who had eaten the djenkol bean and were suffering from poisoning. They then isolated the djenkolic acid crystals by treating the djenkol beans with

barium hydroxide Barium hydroxide is a chemical compound with the chemical formula Ba(OH)2. The monohydrate (''x'' = 1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form. ...

at 30°C for a prolonged period. Du Vigneaud and Patterson managed to synthesize djenkolic acid by condensation of

methylene chloride Dichloromethane (DCM, methylene chloride, or methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odor is widely used as a solvent. Although it is not miscible with ...

with 2 moles of L-cysteine in liquid

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

. Later on, Armstrong and du Vigneaud prepared djenkolic acid by the direct combination of 1 mole of

formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

with 2 moles of L-cysteine in a strongly acidic solution.

References

{{reflist Alpha-Amino acids Sulfur amino acids Plant toxins Toxic amino acids