Integrated In Vitro and In Silico Exploration of Bioactive Compounds in Strychnos lucida Stem Extract: Revealing Mechanisms Against Breast Cancer

Breast cancer remains the most commonly diagnosed cancer and the leading cause of cancer death in women worldwide. Numerous studies have explored various plant extracts as anticancer agents, targeting specific and effective cancer cell death pathways. This study aims to utilize in vitro and in silico approaches to evaluate the anti-breast cancer activity of Strychnos lucida and predict the molecular mechanisms of its active compounds. In vitro studies were performed by determining the total content of phenolics, flavonoids, terpenoids and alkaloids, examining toxicity and selectivity, apoptosis assay using Annexin V/PI and apoptosis morphology analysis using SEM, mitochondrial membrane potential (MMP) analysis using MitoTracker on T47D cells. In silico studies were used for compound analysis, anticancer compound candidate selection, target protein prediction, functional annotation, molecular docking and molecular dynamics simulation. The results of the in vitro study showed that phenolics were the class of compounds with the highest content in the S. lucida stem extract. The extract exhibited toxicity against T47D cells with an IC₅₀ value of 734.79 µg/mL and general cytotoxicity against TIG-1 cells. The extract was able to induce apoptosis and changes in MMP in T47D cells. In silico study of S. lucida based on the KNApSAcK database contains 23 metabolites consisting of alkaloid, phenolic and glycoside groups. Six compounds are predicted to have anticancer activity, namely 3-O-caffeoylquinic acid, adenosine, loganine, secoxyloganin, sweroside and tachioside. These compounds target proteins associated with cancer development pathways, such as apoptotic pathways and the MAPK signaling pathway, and are predicted to inhibit cancer cell growth and induce apoptosis through their interaction with MAPK9 and MAPK3. S. lucida stem extract shows promising potential as an anticancer candidate; however, further in vitro studies are required to elucidate the specific mechanisms of action of its bioactive compounds in inhibiting breast cancer cells.