Djenkolic acid (or sometimes jengkolic acid) is a

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

-containing non-protein

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

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 me ...

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 substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubil ...

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

renal tubules The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure ca ...

and

urinary tract The 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 pressure, con ...

, resulting in symptoms such as abdominal discomfort, loin pains, severe

colic Colic or cholic () is a form of pain that starts and stops abruptly. It occurs due to muscular contractions of a hollow tube ( small and large intestine, gall bladder, ureter, etc.) in an attempt to relieve an obstruction by forcing content out ...

, 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 clin ...

, 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 w ...

, and

oliguria Oliguria or hypouresis is the low output of urine specifically more than 80 ml/day but less than 400ml/day.Boon et al, Davidson's Principles & Practice of Medicine (20th Ed), p475 The decreased output of urine may be a sign of dehydration, kidney ...

, 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, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...

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, is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation ( Na+) and a bicarbonate anion ( HCO3−) ...

. 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 (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's List ...

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. P ...

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

methylene chloride Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour 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 compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

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

formaldehyde Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...

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

References

{{reflist Sulfur amino acids Plant toxins Toxic amino acids