Antioxidant, cytotoxic activity, chemical composition and molecular docking ofthe stembark of Breonadia salicina Hepper and J. R. I. Wood

The study aimed to evaluate the antioxidant properties, chemical composition, and total phenolic and flavonoid contents of the stembark from Breonadia salicina. Furthermore, lead compounds were studied for their possible antioxidant and anticancer effects using in silico analysis. Antioxidant activity was measured using the ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic) acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assays. The chemical composition was analyzed with LCMS/LC-HRM (Liquid Chromatography-High Resolution Mass Spectrometry) technique. The ethyl acetate (EAS) fraction derived from Stembark exhibited significant antioxidant properties, as evidenced by its total phenolic content (146.8 ± 1.2 mg GAE/g), flavonoid contents (84.7 ± 4.6 mg Rutin/g), DPPH and ABTS radical scavenging activity, yielding values of 279.7 and 259 μg/mL, respectively. A total of twenty-one compounds were identified within the EAS fraction. Notably, compounds 7, 18, and 19 recorded the highest docking scores of -9.2, -9.2, and -9.3 (kcal/mol, respectively. Compounds 1, 5, 8, 9, and 13 demonstrated significant cytotoxicity against ovarian cancer, with a probability (Pa) greater than 0.92. Furthermore, compounds 1, 2, 3, 6, 8, 9, 10, 12, 15, 19, and 21 exhibited strong IC50 values of less than 1 µM. Among these, compounds 1 and 19 received the highest predictive scores from the three in silico assessment tools employed. Anacardic acid (compound 1) and SSR161421 (compound 19) achieved the best results, being recognized by two of the three anticancer in silico tools. These lead compounds may serve as promising candidates for the development of therapeutic agents aimed at specifically targeting cancer cells.