Isolation, characterization, and biological evaluation of bioactive components from the stem bark of Broussonetia papyrifera: Antioxidant properties and apoptosis induction in breast cancer cells.

Five previously undescribed compounds, including broussopapyrin A (1), broussopapyrin B (2), broussopapyrin C (3), broussocoumarin (4), and (S)-broussonone A (5), were isolated and structurally elucidated from the stem bark of Broussonetia papyrifera. These isolated new compounds, along with known compounds 6-15, were evaluated for their antioxidant and anticancer properties. Among the bioactive components, broussopapyrin A (1) exhibited potent DPPH (SC = 22.33 ± 1.50 μM) and ABTS (SC = 15.15 ± 2.07 μM) scavenging activities, significantly greater than the commercially available antioxidant, butylated hydroxytoluene (BHT) (DPPH SC = 139.41 ± 2.26 μM; ABTS SC = 92.15 ± 5.46 μM). Notably, broussopapyrin A (1) exhibited higher cytotoxicity against breast cancer cell lines, including MCF-7 (IC = 7.51 ± 1.21 μM) and MDA-MB-231 (IC = 19.73 ± 3.51 μM), compared to 5-FU (IC = 16.33 ± 2.44 μM and 68.19 ± 10.32 μM against MCF-7 and MDA-MB-231, respectively), along with 2-2.5 folds greater safety at effective concentrations relative to doxorubicin. Furthermore, broussopapyrin A (1) demonstrated effectively apoptosis induction via regulating caspase-3, caspase-7, BAX, and Bcl-2 against breast cancer cell lines. These findings highlight bioactive components of B. papyrifera, especially for broussopapyrin A (1), as promising antioxidants and anticancer agents with both high efficacy and improved safety, paving the way for future development of therapeutic strategies targeting oxidative stress disorder and breast cancer.