Natural populations of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi
Arabia may be a rich source of natural polyphenols with potential biological activities. Therefore,
tentative high-performance liquid chromatography–diode array detection was used to analyze the
polyphenol contents of leaf extracts. R. graveolens mainly contained the phenolic acids chlorogenic
acid and p-coumaric acid and the flavonoids rutoside and quercetin, whereas those of A. abrotanum
mainly contained the phenolic acids isochlorogenic acid and rosmarinic acid and the flavonoid
quercetin. Leaf extracts of both species showed antioxidant activities due to the presence of quercetin,
chlorogenic acid, and p-coumaric acid as well as antiproliferative and cytotoxic activities against
cancer cells, which may be attributed to necrotic cell accumulation during the early and late apoptotic
periods. Both species also exhibited antibacterial activity, although the activity was higher in
R. graveolens due to the high contents of quercetin and other polyphenols. Finally, both species
exhibited antifungal activities, which were associated with specific polyphenols. This is the first
study to confirm the richness of polyphenols and wide spectrum of biological activities in natural
populations of R. graveolens and A. abrotanum in northern Saudi Arabia
