protistene

Protistene is a naturally occurring sesquiterpene compound that was first isolated in the early 1990s from the marine alga *Protista marina*. Its molecular formula is C15H22O and it possesses a bicyclic core with a unique 1,3-dioxole moiety. The structure of protistene was confirmed by spectroscopic analysis, including NMR, IR, and mass spectrometry, and its absolute configuration was assigned through electronic circular dichroism studies.

The compound was discovered during a screening program aimed at identifying bioactive substances from marine organisms. Researchers prepared extracts of *Protista marina* and subjected them to chromatographic fractionation. Protistene was obtained as a colorless oil that readily crystallized at –20 °C, yielding a product that was stable under ambient conditions. Synthetic approaches to protistene have been developed, involving the intramolecular Diels–Alder reaction of a linear precursor, which allows for moderate total yields and structural diversification.

In nature, protistene is found primarily in *Protista marina*, but trace amounts have been detected in related species of the genus *Protista*. Its distribution suggests a role in the organism's defense against predators or competitors, although the precise ecological function remains unclear. Preliminary biological assays have indicated that protistene exhibits moderate antifungal activity against *Candida albicans* and *Aspergillus niger*, and it shows inhibitory effects on the growth of certain bacterial pathogens, including *Staphylococcus aureus*.

Potential applications of protistene lie in the development of new antifungal or antibacterial agents. Its structural framework could serve as a scaffold for medicinal chemistry programs focused on improving potency, selectivity, and pharmacokinetic properties. Additionally, the unique 1,3-dioxole ring might be exploited for the synthesis of complex natural products in academic research.

Current research on protistene is limited to its isolation, chemical characterization, and initial bioactivity screening. No large‐scale synthetic routes or clinical investigations have been reported, and its mechanism of action has not yet been elucidated. Further studies are expected to explore the pharmacological potential of protistene and related sesquiterpenoids from marine sources.