Betulinic Acid from the Bark of Platanus occidentalis L. (American Sycamore): Phytochemical Profiling, DNA Binding, and Electrochemical Characterization

High Resolution Image Download MS PowerPoint Slide The American sycamore ( Platanus occidentalis L.) concentrates bioactive compounds in its flowers and leaves. However, the presence, structural characterization, and utilization of triterpenoids in its bark have been least explored. In this study, bark extracts were systematically investigated through integrated phytochemical, spectroscopic, biophysical, and electrochemical analyses, with a focus on the isolation and functional characterization of betulinic acid (BA). Gas chromatography–mass spectrometry (GC-MS) revealed a triterpenoid-rich profile, including fatty acid methyl esters, dehydrotrametenolic acid, poricoic acid, and BA as the dominant constituents. Structural elucidation by 1 H-NMR, 13 C-NMR, and Fourier transform infrared (FTIR) spectroscopies confirmed characteristic functional groups of pentacyclic triterpenes. Building on this phytochemical foundation, UV–vis and circular dichroism spectroscopy demonstrated that BA interacts strongly with calf-thymus DNA (ctDNA), inducing conformational changes consistent with intercalative binding in Tris-HCl buffer (pH 7.43). Electrochemical studies further revealed that BA undergoes electron transfer interactions with an inorganic redox mediator, forming stable intermediate species during BA–ctDNA association. Together, these results link the phytochemical identity of sycamore-derived BA to its redox activity and DNA-binding behavior, highlighting its potential relevance in bioelectronic, sensing, and medicinal applications.