Coumarin-Hemiterpene Ethers of Plant Origin and Their Bioactivities

Natural coumarin-hemiterpene ethers (NCHEs) are secondary metabolites characterized by the attachment of an isoprenyl group to the coumarin scaffold via an ether bond. There is no review of the biological activities of these compounds. This paper reviews the various bioactivities of coumarin-hemiterpene ethers of plant origin, whether synthesized or isolated from plant species. Electronic databases (Google Scholar, Scopus, PubMed, and Science Direct) were searched for bioactivity reports of NCHEs. All relevant English-language articles up to June 2025 were collected. Diverse biological activities, including cytotoxicity, antitumor, antibacterial, antiviral, anti-inflammatory, neuroprotective, antinociceptive, anticonvulsive, choline esterase inhibitory, antimutagenic, and others, have been reported for NCHEs. Valuable in vivo studies have been carried out to confirm the antitumor, anti-inflammatory, neuroprotective, antinociceptive, and anticonvulsive effects of NCHEs. The biological effects of 7-isopentenyloxycoumarin (7-IPC) have been evaluated more extensively than those of other NCHEs. In particular, 7-IPC can be considered a promising natural compound with multiple therapeutic effects. Collectively, the evidence points to the significant anti-inflammatory and antitumor potential of some NCHEs. However, since many NCHEs have been subjected to limited biological evaluations, further biological studies on these compounds are essential and insightful.