Prenyloxycoumarins and prenyloxyfuranocoumarins (isopentenyloxy-, geranyloxy-, linear and cyclic sesquiterpenyloxy compounds and their biosynthetic derivatives) represent a family of secondary metabolites that have been considered for years just as intermediates of other coumarin-based compounds. Only in the last two decades these secondary metabolites have been recognized as interesting and valuable biologically active natural products. Up to now more than 160 compounds have been isolated from plants mainly belonging to the families of Rutaceae and Umbelliferae, comprising common edible vegetables and fruits like lemons, oranges and grapefruits. In view of the biological activity of some natural prenyloxycoumarins, very recently syntheses of structurally related analogs aimed to establish detailed structure-activity relationships have also been carried out. Many of the isolated prenyloxy- and prenyloxyfuranocoumarins and their semisynthetic derivatives were shown to exert in vitro and in vivo remarkable antitumoral, anti-inflammatory and anti-viral effects. The object of this review is to examine in detail the different types of prenyloxycoumarins and prenyloxyfuranocoumarins from the chemical, phytochemical and biological point of view.

Today, the green synthesis of metal nanoparticles is a promising strategy in material science and nanotechnology. In this research, silver nanoparticles (AgNPs) were synthesized through the high-efficient, cost-effective green and facile process, using the Astragalus tribuloides Delile. root extract as a bioreduction and capping agent at room temperature. UV–Vis spectroscopy was applied for the investigation of the reaction proceedings. To characterize the greenly synthesized AgNPs, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), and transmission electron microscopy (TEM) analyses were utilized. In addition, the total phenolics and flavonoids contents, antioxidant, antibacterial, and anti-inflammatory activities of the greenly synthesized AgNPs and the A. tribuloides root extract were evaluated. The results indicated that the AgNPs had spherical morphology and crystalline structure with the average size of 34.2 ± 8.0 nm. The total phenolics and flavonoids contents of the greenly synthesized AgNPs were lower than those for the A. tribuloides root extract. The resultant AgNPs exhibited the appropriate antioxidant activity (64%) as compared to that for the A. tribuloides root extract (47%). The antibacterial test approved the higher bactericidal activity of the resulting AgNPs on the Gram-positive and Gram-negative bacteria in comparison to the A. tribuloides root extract. Considering the anti-inflammatory activity, the greenly synthesized AgNPs showed a stranger effect than the A. tribuloides root extract (82% versus 69% at 500 μg/mL). Generally, the AgNPs that were fabricated by using the A. tribuloides root extract had appropriate antioxidant, antibacterial, and anti-inflammatory activities and, therefore, can be considered as a promising candidate for various biomedical applications.