Host-dependent variations in antioxidant activity, metabolic profile, and phenolic content of the parasitic plant Phoradendron nervosum Oliv.

Phoradendron nervosum (hemiparasitic plant) exhibits remarkable metabolic plasticity, with significant variations in bioactive compound content, metabolite profiles, and antioxidant capacity depending on the host species (Laurus nobilis L., Hibiscus rosa-sinensis L., Populus alba L.) and organ type (leaves vs. fruits). A multi-method approach combining spectrophotometry, complementary antioxidant assays (ABTS, DPPH, FRAP), and complete metabolomic profiling by LC-MS was used to elucidate the biochemical interactions between P. nervosum and its hosts. The results obtained showed a differential distribution of total phenolic and flavonoid compounds, with leaves characterized by higher flavonoid concentrations (e.g., up to 0.286 mg QE/g DW). At the same time, fruits exhibited host-mediated modulations, especially in the species L. nobilis (e.g., the highest TPC at 2.723 mg GAE/g DW). Antioxidant activity was consistently higher in leaves (e.g., up to 41.26 µmol Trolox/g DW in DPPH assay), correlating with their enriched presence of phenolic acids and glycosylated flavonoids. The host species played a determining role in antioxidant capacity, as H. rosa-sinensis-associated plants exhibited the highest levels (e.g., 14.53 µmol Trolox/g DW in ABTS, 24.06 µmol Fe2+/g DW in FRAP). Correlation analysis suggested complex biochemical trade-offs influencing metabolic allocations. A diversity of bioactive compounds was identified by LC-MS, highlighting the synergistic interaction between metabolites in defining the physiological response of P. nervosum. Our results highlight its adaptive versatility and ecological significance, but also potential pharmacological applications, given that related mistletoe species from Europe are already used in antitumor treatments.