A New Saponin From <i>Tridax procumbens</i> L.: In Vitro and In Silico Studies Reveal Broad Spectrum of Bioactivities

A new triterpenoid saponin designated as Sigmastane, 5(6), 9(11), 22(23), E, triene-3-O-β-glycoside, along with a mixture of known compounds, was isolated from the aerial part of the methanol extract of Tridax procumbens L. The structure of the compound was elucidated through one and two-dimensional nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry. The in vitro cytotoxic potential of the isolated compound was evaluated against two human cancer cell lines, MCF-7 and MDA-MB-249, using doxorubicin as a standard. The saponin displayed strong cytotoxic effects across both tested cell lines (MCF-7 and MDA-MB-249 cell lines, yielding half-maximal inhibitory concentration (IC₅₀) values of 6.55 and 3.96 µg/mL, respectively). Additionally, the antioxidant activity of the compound was evaluated using the DPPH assay, resulting in an IC₅₀ value of 1.46 µg/mL. In-vitro antibacterial activity showed significant minimum inhibitory concentration (MIC) at 62.5 and 250 µg/mL against Pseudomonas aeruginosa and Staphylococcus aureus, respectively. The compound showed activity against Mycobacterium tuberculosis (vaccine strain, H37RV strain) with MIC = 50 µg/mL. The molecular docking study for P. aeruginosa and breast cancer cell lines targeted proteins of 1a exhibited a binding energy range of -10.1 to -7.4 kcal/mol. These isolated saponins may serve as promising drug candidates for future research and the development in the pharmaceutical industry.