The study, published in Frontiers in Nutrition, was designed to investigate the pharmacological activity of nuciferine and identify possible molecular targets involved in its effects against bladder cancer. The investigators described bladder cancer as a refractory malignant tumor and noted that chemotherapy agents including cisplatin, methotrexate, doxorubicin and vinblastine can be accompanied by adverse effects. The present work did not compare nuciferine with those treatments, assess clinical outcomes or test the compound in patients; it focused instead on isolating the molecule, modeling a possible protein interaction and measuring the response in tumor-bearing mice.

For the chemical work, researchers obtained 0.5 kilograms of N. nucifera leaves from Guigang in China’s Guangxi Zhuang Autonomous Region and deposited a voucher specimen under the number 2026NNG001. The leaves were finely powdered and extracted with 80% ethanol by refluxing. The ethanol distillate was then extracted with ethyl acetate and fractionated by silica-gel column chromatography using a dichloromethane-methanol gradient with ratios of 100:1 and 50:1 by volume, producing three fractions. Fraction 3 weighed 110.0 milligrams and was further purified by preparative high-performance liquid chromatography on a C18 column with a methanol-water mobile phase of 82:18 by volume. This procedure yielded 5.0 milligrams of a white powder identified as nuciferine.

The researchers tracked the compound through the plant material with thin-layer chromatography, high-performance liquid chromatography and liquid chromatography-mass spectrometry. They also used high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance spectroscopy to establish its structure. The mass-spectrometric analysis yielded the molecular formula C19H21NO2 and a detected protonated molecular ion at a mass-to-charge ratio of 296.1640. Proton and carbon-13 nuclear magnetic resonance measurements then supported the assignment of the isolated material to nuciferine. These characterization steps mean that the tumor experiment involved chemically identified nuciferine rather than an unquantified mixture of compounds extracted from lotus leaves.

To look for a possible molecular target, the team performed an in silico molecular-docking analysis of nuciferine against signal transducer and activator of transcription 3, or STAT3. The compound structure was retrieved from PubChem, while a three-dimensional structure of STAT3 was obtained from the Protein Data Bank under the identifier 6NJS. The researchers prepared the protein and compound through AutoDock, screened their interaction with AutoDock Vina and visualized the predicted complex in PyMOL. The docking analysis produced a free binding energy of −6.2 kcal/mol and placed nuciferine in hydrogen-bonding contact with the glutamine-644 and tyrosine-657 residues in the modeled STAT3 structure.

The docking result was a computational prediction, not a demonstrated molecular interaction. It suggested that the geometry of nuciferine was compatible with a binding site in the STAT3 structure and provided a hypothesis for subsequent experiments. Docking alone cannot establish that nuciferine binds STAT3 inside intact cells, changes the protein’s function or causes any downstream effect on a tumor. The researchers therefore used a tumor-bearing mouse model to examine whether biological changes observed after treatment were consistent with the proposed pathway, alongside direct measurements of tumor growth and molecular labeling.

For the in vivo experiment, the investigators used mature male C57BL/6 mice that were six weeks old at purchase and allowed them one week to adapt to their surroundings. They injected 1 × 10^6 stably cultured mouse MB49 bladder-cancer cells into the right axilla of each animal to establish cell-based xenograft tumors. Once the tumors had grown for seven days, six mice received nuciferine at 40 milligrams per kilogram of body weight and six mice received solvent alone. The treatment was administered by intragastric gavage once daily for 10 days. All mice were then euthanized, and the solid tumors were collected, weighed and fixed in 4% paraformaldehyde. The protocol was approved by the Experimental Animal Ethics Committee of Guangxi Medical University under approval number 202509025.

Nuciferine treatment significantly reduced tumor growth relative to the untreated controls at a reported significance threshold of p < 0.05. Immunofluorescence analysis of tumor sections showed corresponding shifts in cell-death markers: TUNEL-positive cells increased, as did Bax-positive cells, while Bcl-2-positive cells decreased. TUNEL labeling identifies DNA fragmentation commonly associated with apoptosis, and Bax and Bcl-2 participate in the regulation of mitochondrial cell death. Taken together, the measured changes were consistent with greater apoptotic activity in the treated tumors. The experiment did not directly quantify every stage of apoptosis, so the staining pattern supports that interpretation without establishing the complete process by which tumor growth declined.

STAT3 labeling was also lower in tumors from nuciferine-treated mice than in controls, with the difference reported at p < 0.05. STAT3 is a transcription factor implicated in inflammatory reactions, tumorigenesis and several cancer-associated processes, including cell proliferation, angiogenesis, stemness and drug tolerance. The decline in STAT3-labeled cells was therefore consistent with the docking-based proposal that nuciferine might affect an apoptosis-related STAT3 pathway. However, the study did not include a direct binding assay, a genetic loss-of-function experiment or a separate intervention that blocked STAT3. It consequently could not determine whether reduced STAT3 caused the tumor response, was a consequence of it or reflected another process.

Several features limit the scope of the result. Each comparison group contained only six mice, and all were male animals bearing tumors derived from one mouse bladder-cancer cell line. The authors also noted that detailed cell-culture experiments were lacking and that the pharmacological mechanism remained incompletely explored. The design likewise did not establish how nuciferine would be absorbed, metabolized or distributed in humans, what doses might be safe or effective in clinical settings, or whether the observed activity would extend to human bladder tumors. No human participants were enrolled, and the results therefore cannot be interpreted as evidence of a clinical benefit from lotus-leaf nuciferine.

Within those limits, the reported experiment provides a coherent preclinical signal: chemically characterized nuciferine was associated with reduced bladder-cancer tumor growth after 10 days of oral administration in a mouse model, accompanied by increased apoptosis-related labeling, reduced Bcl-2 and STAT3 labeling, and a computationally favorable interaction with STAT3. The study advances nuciferine from a compound with previously reported biological activities to one tested against bladder tumors in vivo. Establishing its mechanism would require further in vitro and in vivo investigation of STAT3, including functional loss-of-function tests, while any assessment of clinical use would depend on evidence beyond this single short mouse experiment.

Subject of Research: Preclinical mouse and molecular-docking evaluation of lotus-derived nuciferine against bladder cancer

Article Title: Anti-bladder cancer effects of nuciferine, a bioactive compound extracted from Nelumbo nucifera leaves

Article References: Qin, B., Liang, H., Kuang, T., Wei, C., Qin, M., Li, J., Lu, H., & Guo, C. (2026). Anti-bladder cancer effects of nuciferine, a bioactive compound extracted from Nelumbo nucifera leaves. Frontiers in Nutrition, 13, Article 1881388. https://doi.org/10.3389/fnut.2026.1881388

Image Credits: AI Generated

DOI: 10.3389/fnut.2026.1881388

Keywords: nuciferine, Nelumbo nucifera, bladder cancer, mouse xenograft, STAT3, apoptosis, molecular docking, preclinical research, Anti-bladder, cancer, effects, bioactive