Three new 14-noreudesmane-type sesquiterpenoids from the roots of Hippophae rhamnoides

Hippophae rhamnoides L. (Elaeagnaceae), commonly known as sea buckthorn, is a medicinal plant valued for its diverse bioactive constituents and broad therapeutic potential. Phytochemical investigation of its roots led to the isolation of three new 14-noreudesmane-type sesquiterpenoids (1-3), together with sixteen known compounds (4-19). Their structures and absolute configurations were determined using comprehensive spectroscopic analyses and quantum chemical computations of electronic circular dichroism (ECD) spectra and ¹³C NMR shifts. Three new sesquiterpenoids (1-3) were tested for their antioxidant, anti-inflammatory, antibacterial, and α-glucosidase inhibitory activities. Unfortunately, none exhibited significant activity under the tested conditions. Among the isolated known compounds, all those displaying α-glucosidase inhibitory and antibacterial activities are pentacyclic triterpenoids. Hippophamide (17) showed significant DPPH and ABTS radical-scavenging activity. These results enriched the chemical profile of H. rhamnoides roots.