Tryptophol is an aromatic alcohol that induces sleep in humans. It is found in wine as a secondary product of ethanol fermentation. It was first described by Felix Ehrlich in 1912. It is also produced by the trypanosomal parasite in

sleeping sickness African trypanosomiasis is an insect-borne parasitic infection of humans and other animals. Human African trypanosomiasis (HAT), also known as African sleeping sickness or simply sleeping sickness, is caused by the species '' Trypanosoma b ...

. It forms in the liver as a side-effect of disulfiram treatment.

Natural occurrences

Tryptophol can be found in ''

Pinus sylvestris ''Pinus sylvestris'', the Scots pine (UK), Scotch pine (US), Baltic pine, or European red pine is a species of tree in the pine family Pinaceae that is native plant, native to Eurasia. It can readily be identified by its combination of fairly s ...

'' needles or seeds. It is produced by the trypanosomal parasite ('' Trypanosoma brucei'') in sleeping sickness (

African trypanosomiasis African trypanosomiasis is an insect-borne parasitic infection of humans and other animals. Human African trypanosomiasis (HAT), also known as African sleeping sickness or simply sleeping sickness, is caused by the species ''Trypanosoma bru ...

). Tryptophol is found in wine and beer as a secondary product of ethanol fermentation (a product also known as congener) by ''

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have be ...

''. It is also an autoantibiotic produced by the fungus '' Candida albicans''. It can also be isolated from the marine sponge '' Ircinia spiculosa''.

Metabolism

Biosynthesis

It was first described by Felix Ehrlich in 1912. Ehrlich demonstrated that yeast attacks the natural amino acids essentially by splitting off carbon dioxide and replacing the amino group with hydroxyl. By this reaction, tryptophan gives rise to tryptophol. Tryptophan is first deaminated to 3-indolepyruvate. It is then decarboxylated to indole acetaldehyde by indolepyruvate decarboxylase. This latter compound is transformed to tryptophol by alcohol dehydrogenase. It is formed from tryptophan, along with indole-3-acetic acid in rats infected by '' Trypanosoma brucei gambiense''. An efficient conversion of tryptophan to indole-3-acetic acid and/or tryptophol can be achieved by some species of fungi in the genus '' Rhizoctonia''.

Biodegradation

In '' Cucumis sativus'' (cucumber), the enzymes indole-3-acetaldehyde reductase (NADH) and indole-3-acetaldehyde reductase (NADPH) use tryptophol to form (indol-3-yl)acetaldehyde.

Glycosides

The unicellular alga '' Euglena gracilis'' converts exogenous tryptophol to two major metabolites: tryptophol galactoside and an unknown compound (a tryptophol ester), and to minor amounts of indole-3-acetic acid, tryptophol acetate, and tryptophol glucoside.

Biological effects

Tryptophol and its derivatives 5-hydroxytryptophol and 5-methoxytryptophol, induce

sleep Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain Sensory nervous system, sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with th ...

in mice. It induces a sleep-like state that lasts less than an hour at the 250 mg/kg dose. These compounds may play a role in physiological sleep mechanisms. It may be a functional analog of serotonin or melatonin, compounds involved in sleep regulation. Tryptophol shows genotoxicity ''in vitro''. Tryptophol is a quorum sensing molecule for the yeast ''

''. It is also found in the bloodstream of patients with chronic trypanosomiasis. For that reason, it may be a quorum sensing molecule for the trypanosome parasite. In the case of trypanosome infection, tryptophol decreases the immune response of the host. As it is formed in the liver after

ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula . It is an Alcohol (chemistry), alcohol, with its formula also written as , or EtOH, where Et is the ps ...

ingestion or disulfiram treatment, it is also associated with the study of

alcoholism Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World He ...

. Pyrazole and

have been shown to inhibit the conversion of exogenous tryptophol to indole-3-acetic acid and to potentiate the sleep-inducing hypothermic effects of tryptophol in mice. It is a growth promoter of cucumber hypocotyl segments. The auxinic action in terms of embryo formation is even better for tryptophol arabinoside on ''

Cucurbita pepo ''Cucurbita pepo'' is a cultivated plant of the genus ''Cucurbita''. It yields varieties of winter squash and pumpkin, but the most widespread varieties belong to the subspecies ''Cucurbita pepo'' subsp. ''pepo'', called summer squash. It has b ...

'' hypocotyl fragments.

References

{{Alcohols Auxins Human drug metabolites Hypnotics Indoles Hydroxyethyl compounds