GC-MS metabolite profiling and multi-target Docking analysis of Calotropis procera and Euphorbia tirucalli stem extracts for cytotoxicity and antioxidant activity.

C. procera and E. tirucalli are traditionally used to treat infections, inflammation, skin disorders, and tumors. This study evaluated their cytotoxic and antioxidant activities, analyzed chemical profiles via GC-MS, and performed molecular docking against breast cancer target proteins. The methanol extracts of C. procera and E. tirucalli stems inhibited the growth of MCF-7 breast cancer cells by 31.0 ± 0.98% and 36.0 ± 0.31%, respectively, at a concentration of 200 µg/mL, with corresponding IC₅₀ values of 102.31 and 130.12 µg/mL. Both methanol and n-hexane stem extracts showed significant antioxidant activity in DPPH and ABTS assays. In the DPPH assay, IC₅₀ values for C. procera were 10.79 µg/mL (methanol) and 18.52 µg/mL (n-hexane), while for E. tirucalli, values were 33.76 µg/mL and 12.37 µg/mL, respectively. In the ABTS assay, IC₅₀ values were 7.24 µg/mL (methanol) and 11.98 µg/mL (n-hexane) for C. procera, and 8.97 µg/mL (methanol) and 23.52 µg/mL (n-hexane) for E. tirucalli. GC-MS analysis revealed key phytochemicals including α-amyrin, β-amyrin, lanosterol, germanicol, lupeol, olean-18-ene, linoleic acid, and oleic acid. Compounds with relative abundance ≥ 1% were analyzed using SwissADME and ProTox II, revealing compliance with Lipinski’s rule of five and no predicted hepatotoxicity, carcinogenicity, mutagenicity, or cytotoxicity. Molecular docking analysis showed that lupeol, β-amyrin, α-amyrin, lanosterol, olean-18-ene, and germanicol had strong binding affinities with human myeloperoxidase (-10.1 to -10.8 kcal/mol) and estrogen receptor alpha (-7.5 to -9.9 kcal/mol), outperforming reference compounds ascorbic acid (-5.8 kcal/mol) and gefitinib (-7.5 kcal/mol). These findings suggest C. procera and E. tirucalli are promising sources of bioactive compounds, supporting their potential for further in vivo and mechanistic investigations in drug development.