It is used as a fragrance and fixative in many perfumes and as an aroma compound. Its name derives from the Greek root skato-, meaning feces. Skatole was discovered in 1877 by the German physician Ludwig Brieger (1849–1919).[2][3][4]
Original: "Ich habe mich zuerst mit der Untersuchung der flüchtigen Bestandtheile der Excremente aus sauerer Lösung beschäftigt. Es wurden dabei die flüchtigen Fettsäuren: Essigsäure, normale und Isobuttersäure, sowie die aromatischen Substanzen: Phenol, Indol und eine neue dem Indol verwandte Substanz, die ich Skatol nennen werde, erhalten."
Translation: "I was occupied initially with the investigation of the volatile components of excrement in acidic solution. One obtained thereby volatile fatty acids; acetic acid; normal and isobutyric acid; as well as the aromatic substances: phenol, indole and a new substance which is related to indole and which I will name 'skatole'." - Brieger (1878), page 130
Skatole, along with the fecal odorant indole, can be neutralized by combining it with other scents, by producing perfumes or air fresheners that lack skatole and indole. In a manner similar to noise-cancelling headphones, the scent produced by the resultant concentrations of skatole and indole relative to other substances in the freshener is thus "in-phase" and perceived as pleasant.[8]
Skatole is one of many compounds that are attractive to males of various species of orchid bees, which apparently gather the chemical to synthesize pheromones; it is commonly used as bait for these bees for study.[9] It is also known for being an attractant for the Tasmanian grass grub beetle (Aphodius tasmaniae).[10]
Skatole has been shown to be an attractant to gravidmosquitoes in both field and laboratory conditions. Because this compound is present in feces, it is found in combined sewage overflows (CSO), as streams and lakes containing CSO water have untreated human and industrial waste. CSO sites are thus of particular interest when studying mosquito-borne diseases such as West Nile virus.[11]
Animal studies
Skatole occurs naturally in the feces of all species of mammals and birds, and in the bovinerumen.[12]
Skatole has been shown to cause pulmonary edema in goats, sheep, rats, and some strains of mice. It appears to selectively target club cells, which are the major site of cytochrome P450 enzymes in the lungs. These enzymes convert skatole to a reactive intermediate, 3-methyleneindolenine, which damages cells by forming protein adducts (see fog fever).[13]
With the testicular steroid androstenone, skatole is regarded as a principal determinant of boar taint.[14]
^Brieger, Ludwig (1879). "Über Skatol" [On skatole]. Berichte der Deutschen Chemischen Gesellschaft. 12 (2): 1985–1988. doi:10.1002/cber.187901202206. Retrieved 3 November 2020.
^Emil Fischer (1886) "Indole aus Phenylhydrazin" (Indole from phenylhydrazine), Annalen der Chemie, vol. 236, pages 126-151; for Fischer's synthesis of skatole, see page 137. (Fischer was not the first to prepare skatole. It was prepared, via other methods, in 1880 by von Baeyer, and in 1883 by Otto Fischer and German and by Fileti.)
^Beechler, J W., J G Miller, and M S Mulla (1994). "Field evaluation of synthetic compounds mediating oviposition in Culex mosquitoes (Diptera: Culicidae)". J Chem Ecol. 20 (2): 281–291. doi:10.1007/BF02064436. PMID24242053. S2CID23784247.((cite journal)): CS1 maint: multiple names: authors list (link)
