Sesquiterpenlactones

Sesquiterpene lactones are an extensive group of natural sesquiterpene derivatives (aliphatic mono-, di-, or tricyclic terpenes) derived mainly from germacran (germacran type of sesquiterterpenes), eudesman (eudalin), guaian (guaianolides) and pseudoguaian. Of the more than2000 representatives of this group of substances, the majority are found in plants, especially in representatives of the Asteraceae family, less frequently in Magnoliaceae, liverworts, etc. Sesquiterpene lactones have a variety of biological and pharmacological effects. In plants they act primarily as defense substances. They have a toxic effect on bacteria, fungi, worms (e.g. santonin from Artemisia cina) and other parasites.

The spectrum of action on humans is described as antitumoral, antimicrobial, antirheumatic and antiphlogistic(helenalin from Arnica montana). The pharmacological effect of sesquiterpene lactones is probably due to the alkylation of proteins (enzymes), which are characterized by exposed sulfhydryl groups (SH groups).

Some representatives have properties that make them objects for pharmacological research. For example, the sesquiterpene lactones(helenalin, dihydrohelenalin) and their esters are to be regarded as the main active principle in the effect of arnica extracts. Arnica extracts have analgesic, antiseptic and above all antiphlogistic effects. An inhibition of inflammatory cytokines and cyclooxygenase is assumed to be the mechanism of action.

Sesquiterpene lactones play a major role in contact allergic reactions.

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