helenalin

Helenalin is a naturally occurring sesquiterpene lactone found in plants such as Arnica montana and Arnica chamissonis. It is primarily responsible for the toxicity of these species. Despite its toxicity to humans and animals if ingested in significant amounts, helenalin has demonstrated notable anti-inflammatory and antineoplastic (anti-cancer) effects in vitro. Its mechanism of action includes selective inhibition of the transcription factor NF-kappaB by modifying the NF-kappaB/IkappaB complex and preventing activation-driven gene expression. This effect differs from that of traditional NSAIDs. Helenalin also induces oxidative stress through reactive oxygen species generation and can inhibit enzymes such as 5-lipoxygenase and leukotriene C4 synthase. Additionally, it can interact with proteins via Michael addition to thiol groups on cysteine residues—disrupting protein function—and inhibits human cytochrome P450 enzymes (notably CYP3A4/3A5/2A13). While used traditionally as an anti-inflammatory agent in folk medicine (mainly topically), it is not approved as a pharmaceutical drug due to its toxicity profile[1][2][6][7].

Other names

(-)-4-Hydroxy-4a,8-dimethyl-3,3a,4a,7a,8,9,9a-octahydroazuleno[6,5-b]furan-2,5-dione6754-13-8