Antioxidant Activity of Pressafonin-A Isolated From Sicilian Ferulago nodosa (L.) Boiss. Roots and Its Proapoptotic Effect Through ROS-Dependent p53/p21Waf1/Cip1 Pathway in Human Melanoma A-375 Cells

Ferulago nodosa (L.) Boiss. is a species belonging to the Apiaceae family which grows spontaneously in the Balkan and southern Tyrrhenian areas of the Mediterranean Sea. Plants of the Ferulago genus are widely used in the ethnopharmacological field, mainly in the form of infusions, as remedies against panic attacks, to solve problems related to the gastrointestinal tract, and for ulcer complications. In this study, we assessed antioxidant and antiproliferative activities of the pressafonin-A (PA), extracted from F. nodosa roots, following its spectroscopical characterization. Among the assays conducted, reducing capacity tests and free radical scavenging assays showed that PA can act as an antioxidant. PA also exhibited time- and concentration-dependent antiproliferative activity against human cancer cell lines, including A-375 (melanoma), HCT-116 (colorectal carcinoma), and MCF-7 (breast adenocarcinoma). Selectivity index (SI) was calculated using normal 16-HBE cells. Among the cell lines tested, PA demonstrated an SI > 10 in A-375 cells. Treatment with PA 6.2 μM (IC₂₅) and 12.4 μM (IC₅₀) for 24-h induced apoptosis, as cytofluorimetrically evidenced by phosphatidylserine exposure, loss of mitochondrial membrane potential, and intracellular ROS production. Moreover, PA caused an arrest of cell cycle at the G1/S phase transition. Western blot analysis showed that PA caused an increase in protein levels of p53, p21^Waf1/Cip1, cytochrome c, and BAX, along with a decrease in Bcl-2 protein. In conclusion, natural PA demonstrated antioxidant and antiproliferative properties on A-375 by inducing apoptosis via ROS-dependent intrinsic mitochondrial pathway and cell cycle arrest. These results suggest that PA may have potential as a chemopreventive agent for skin diseases.