isoalantolactone

Isoalantolactone is a natural product belonging to the sesquiterpene lactones, a class of plant-derived compounds known for reactive lactone moieties. It is found in several Asteraceae species, most notably the root of Inula helenium (elecampane). It is an isomer of alantolactone, sharing the characteristic α-methylene-γ-lactone group that underpins much of its chemistry and bioactivity.

Chemically, isoalantolactone has a germacrane-type sesquiterpene skeleton with an exocyclic methylene lactone, which makes it a Michael acceptor and capable of covalently modifying thiol groups in proteins.

Biological studies report antiproliferative and pro-apoptotic effects in cancer cell lines, anti-inflammatory activity, and antimicrobial properties. The proposed mechanism commonly involves alkylation of cellular thiols, disruption of redox signaling, and modulation of NF-κB, STAT, or MAPK pathways, though effects vary by cell type and concentration.

Isoalantolactone has been investigated mainly in vitro and in preclinical models, with potential as an anti-cancer or anti-inflammatory agent. It is not approved for medical use, and its covalent reactivity raises considerations for safety and toxicity in pharmacological contexts.

Inula helenium root and other Inula species are typical sources; isoalantolactone can be extracted from plant material and analyzed by chromatographic methods such as HPLC. The compound is part of essential oil fractions and crude extracts rather than a stand-alone drug.