Vernodalin and Gymnanthemum extensum Crude Extracts Exhibit In Vitro Anticancer Activity with Differential Regulation of Cancer-Associated Signaling Proteins in Breast and Ovarian Cancer Cells

Background/Objectives: Vernodalin (VD) and crude extracts from Gymnanthemum extensum leaves have previously demonstrated anticancer activity; however, their underlying molecular effects remain incompletely understood. This study investigated the anticancer activities of VD and G. extensum extracts and characterized their associated molecular responses in breast (MDA-MB-231) and ovarian (A2780) cancer cells. Methods: G. extensum leaves were extracted with dichloromethane and ethyl acetate to obtain DEGE and EAGE, respectively. VD was isolated from EAGE and characterized by 1H-NMR and HPLC. Phytochemical profiles of the extracts were analyzed by GC-MS and HPLC. Cytotoxicity, clonogenic survival, cell cycle progression, migration, and protein expression were evaluated using MTT assay, colony formation assay, flow cytometry, wound healing assay, and Western blotting. Results: GC–MS analysis revealed distinct phytochemical compositions between DEGE and EAGE, although both extracts contained high levels of neophytadiene and phytol. VD, DEGE, and EAGE inhibited cell proliferation and migration in both cancer cell lines. VD suppressed proteins associated with cancer progression, including SMYD3, BRAF, MELK, FOXM1, Cyclin B1, MDR1/ABCB1, and MMP-9, with molecular responses differing between MDA-MB-231 and A2780 cells. DEGE and EAGE exhibited molecular regulatory patterns distinct from those of purified VD, suggesting contributions from multiple phytochemical constituents. Conclusions: VD and G. extensum crude extracts exhibit significant in vitro anticancer activity against breast and ovarian cancer cells and induce distinct molecular responses. The differential effects of DEGE and EAGE may be attributable to differences in their phytochemical constituents.