Anticancer Potential of Colebrookea oppositifolia Flower Extract Against Breast and Prostate Cancer: An Integrated LC-MS, Network Pharmacology, Molecular Dynamics, PCA, and MM-GBSA Approach

Cancer remains one of the most formidable challenges in modern medicine, characterized by cells that grow out of control and resist standard treatments. While chemotherapy and radiation have saved countless lives, they often come with severe side effects and the troubling reality that tumors can develop resistance to drugs over time. This has driven scientists to look back at nature for answers, exploring how plants used for centuries in traditional medicine might offer new ways to fight disease. The approach involves identifying specific chemical compounds within plants that can interfere with the biological machinery cancer cells use to survive and multiply. By understanding exactly how these natural compounds lock onto cancer targets, researchers hope to develop safer, more effective therapies that work with the body's own systems rather than just attacking it.

In this spirit, a team of researchers from universities in Nepal, Pakistan, Germany, and Saudi Arabia turned their attention to Colebrookea oppositifolia, a wild shrub known locally as "Dhurseli" in the subtropical regions of Asia. For generations, people in Nepal have used the flowers of this plant to treat various ailments, including tumors. The researchers wanted to move beyond tradition and find the specific scientific mechanism behind this healing power. They focused on breast and prostate cancers, two of the most common and deadly forms of the disease, to see if the flower extract could stop these cells from growing.

To begin their investigation, the team collected fresh flowers from the Kaski District in Nepal and processed them into a liquid extract using methanol. They then used a sophisticated analytical technique called liquid chromatography-mass spectrometry to separate and identify the chemical ingredients inside the mixture. This process revealed nine distinct compounds, but the researchers were particularly interested in three flavonoids—natural plant pigments known for their health benefits: apigenin, diosmetin, and a sugar-bound version of apigenin called apigetrin. Using computer models, they screened these compounds to see if they could be absorbed by the human body and if they looked like potential medicines. The results pointed to apigetrin as the most promising candidate, showing it had the right properties to enter cells and interact with biological targets.

The next step was to determine which parts of the cancer cells these compounds might attack. The researchers used network pharmacology, a method that maps the complex web of interactions between drugs and the thousands of proteins inside the human body. By cross-referencing the targets of the plant compounds with the genes known to drive breast and prostate cancers, they identified a specific set of seventy-four overlapping genes. From this group, they narrowed their focus to the top ten most critical targets, which included three key proteins: AKT1, EGFR, and SRC. These proteins act like switches in the cell, telling cancer cells when to grow, divide, and survive. If a drug can turn these switches off, it could stop the cancer in its tracks.

To see how well the plant compounds could lock onto these protein switches, the team built detailed 3D computer models of the proteins and the molecules. They simulated the physical docking process, watching how the shapes of the molecules fit into the pockets of the proteins. The simulations showed that apigetrin fit exceptionally well, particularly into the EGFR protein, forming strong bonds that would likely block the protein from functioning. The researchers then took this a step further by running a two-hundred-nanosecond molecular dynamics simulation. This is a computer experiment that watches how the protein and the drug move and wiggle over time, mimicking the conditions inside a living cell. The results showed that once apigetrin attached to the EGFR protein, it stayed firmly in place, keeping the protein stable and preventing it from sending growth signals to the cancer cell.

The team calculated the energy required to keep the drug and protein together, finding that the bond was extremely strong and energetically favorable. This suggested that the interaction was not just a temporary glitch but a robust, stable connection. To confirm these computer predictions, the researchers moved to the laboratory. They treated human breast cancer cells and prostate cancer cells with the flower extract in a petri dish. They observed that as the concentration of the extract increased, the number of living cancer cells dropped significantly. The extract killed about half of the cancer cells at a concentration of roughly 261 micrograms per milliliter for breast cancer and 286 micrograms per milliliter for prostate cancer. Importantly, when they tested the extract on normal, healthy kidney cells, it was much less toxic, suggesting that the plant material might be able to target cancer cells while sparing healthy tissue.

The study concludes that the flowers of Colebrookea oppositifolia contain powerful natural compounds, especially apigetrin, that can effectively target the specific molecular pathways driving breast and prostate cancers. While the computer simulations provided a detailed map of how these molecules interact with cancer proteins, and the lab tests confirmed that the extract can kill cancer cells, the researchers emphasize that this is a starting point. The findings validate the traditional use of the plant and identify a specific chemical lead for future development, but they also note that more extensive testing in living organisms is needed to fully understand the safety and effectiveness of this potential treatment before it could ever become a medicine for patients.