Phytochemical Characterization, Electronic Reactivity and Anticancer Evaluation of Symphyotrichum novi-belgii

Background: Symphyotrichum novi-belgii (syn. Aster novi-belgii) belongs to the Asteraceae family and remains comparatively underexplored from a phytochemical and pharmacological perspective. Symphyotrichum novi-belgii remains poorly characterized in terms of organ-specific phytochemistry and anticancer relevance. Methods: In this study, methanolic extracts of the leaves, stems and roots of Symphyotrichum novi-belgii were characterized using FTIR and GC-MS. Selected phytoconstituents were investigated using density functional theory (DFT) and molecular docking against HPV16 E6, while the effects of the crude extracts on HeLa cervical cancer cells were assessed using the MTT cell-viability assay following treatment with each extract at 100 µg/mL for 48 h. The chemical and computational findings were considered alongside the MTT cell-viability results to compare the leaf (Lf), stem (St) and root (Rt) extracts of S. novi-belgii and identify phytoconstituents warranting further investigation. Results: FTIR spectra revealed hydroxyl, carbonyl, aromatic, aliphatic, and C-O/C-O-C functionalities. GC-MS detected nine chromatographic features each in the Lf and St extracts and seven in the Rt extract, representing chemical classes such as organic and phenolic acids, flavonoid-type compounds, terpenoids, an alkaloid, nitrogen-containing heterocycles, lactones, ethers, and a fatty-acid ester. DFT calculations on selected proposed molecular structures indicated the highest calculated molecular softness for the sanguinarine model (Lf8; 0.831 eV−1) and the highest electrophilicity index for the caftaric-acid model (Rt6; 4.356 eV). Separately, the proposed flavonol-type molecular structure represented by Lf5 (leaf), St6 (stem), and Rt4 (root) was distinct from the sanguinarine model (Lf8). The original docking calculations reported predicted binding scores of −10.4 kcal/mol for the Lf5 and Rt4 model entries. However, discrepancies between the original library-search results and the corresponding literature-assisted GC-MS assignments prevent confirmation that these molecular structures were present in the extracts. The computational results therefore represent theoretical predictions for the selected structures rather than verified properties of experimentally identified plant constituents. In the preliminary MTT evaluation at 100 µg/mL following 48 h of exposure, the Lf extract showed 31.03% inhibition, whereas the Rt and St extracts yielded −12.98% and −10.61%, respectively. None of the extracts reached 50% inhibition at the concentration tested. Because no concentration–response series was performed, extract-specific IC50 values could not be determined. Doxorubicin, included as the positive drug control, showed 81.81% apparent MTT inhibition under the reported single-concentration conditions. Conclusions: FTIR and exploratory GC-MS analyses revealed differences in the detectable chemical features of the three extracts, while DFT and molecular docking provided theoretical predictions for selected proposed molecular structures. At 100 µg/mL following 48 h of exposure, the leaf (Lf) extract showed a higher apparent MTT percentage-inhibition value than the root (Rt) and stem (St) extracts. This single-concentration observation is descriptive and does not establish statistically significant differences, cytotoxicity, or anticancer efficacy.