Solidago gigantea Aiton is an invasive plant species rich in bioactive secondary metabolites. The aim of this study was to characterize the phytochemical profile of an ethanolic S. gigantea extract and to evaluate its antibacterial and chemoprotective potential using in vitro models. Chemical analysis revealed a high content of phenolic compounds, dominated by chlorogenic acid, along with other phenolic acids and flavonoids, including rutin and quercitrin. The extract also contained saponins and a diverse lipophilic fraction composed of long-chain hydrocarbons, alcohols, fatty acids, phytosterols, and triterpenoids. The extract exhibited strong antibacterial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus strains, while Gram-negative bacteria and yeasts were less susceptible. In cancer cell models, the extract showed selective antiproliferative and cytotoxic effects, particularly in colorectal and breast cancer cell lines, including doxorubicin-resistant phenotypes, with minimal effects on normal fibroblasts. The extract also showed antioxidant and cytoprotective properties, reflected by a reduction in intracellular reactive oxygen species under both basal and oxidative stress conditions. Increased accumulation of rhodamine 123 in resistant cancer cells suggested a potential inhibition of P-glycoprotein-mediated efflux. Overall, the results indicate that S. gigantea extract exhibits multi-target biological activity associated with its polyphenolic composition, supporting its potential application in chemoprevention, adjuvant cancer therapy, and the control of Gram-positive bacterial infections.
Gębarowska et al. (Thu,) studied this question.