Ginseng Compound Rb1 Starves Pancreatic Tumors by Turning Off Their Macrophage Allies

Pancreatic ductal adenocarcinoma remains one of the most lethal cancers in the world, with a five-year survival rate below ten percent and a stubborn resistance to the immunotherapies that have transformed treatment for many other tumors. Now, a team of researchers led by Chang-Sheng Dong of Shanghai University of Traditional Chinese Medicine reports that a humble saponin drawn from ginseng, one of East Asia’s most widely consumed medicinal and edible plants, can slow the disease in preclinical models by an unexpected route: not by killing cancer cells directly, but by reprogramming the immune cells that surround and nourish them. The compound, ginsenoside Rb1, appears to block the polarization of tumor-promoting M2-like macrophages through the PI3K-AKT signaling pathway, stripping pancreatic tumors of a key layer of immunosuppressive protection.

The study, published in Food Science & Nutrition, was framed around the concept of medicine-food homology, a principle embedded in Chinese regulatory practice that classifies certain botanicals, including ginseng, as substances traditionally used as both food and medicine. In China, ginseng is officially listed in the medicine-food homology catalogue, permitting its use as a common food ingredient in soups, teas, beverages, and functional food products. The content of ginsenoside Rb1 in cultivated ginseng varies considerably with growing conditions, ranging from 2.22 to 11.22 milligrams per gram, but its long history of safe dietary exposure is precisely what makes it attractive as a candidate for nutrition-based cancer prevention rather than conventional pharmacology.

To identify the active substance responsible for the anti-pancreatic-cancer effects of a ginseng-containing herbal formula developed by the group, the researchers first applied ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. This profiling step singled out ginsenoside Rb1 as a core bioactive component, prioritized over other ginsenosides such as Rg1, Re, and Rg3 because of its high abundance in ginseng, its favorable safety profile as a food-derived saponin, and its documented antitumor and immunomodulatory activities. The team then deployed a network pharmacology screen, integrating three target-prediction platforms with five pancreatic cancer disease-target databases, to narrow the field of candidate mechanisms.

The computational pipeline was ambitious in scope. It identified 587 candidate targets for ginsenoside Rb1 and 905 pancreatic cancer-related targets, with intersection analysis revealing 110 shared targets. The resulting protein-protein interaction network contained 491 nodes and 3,728 edges, and topology analysis based on degree, betweenness, and closeness centrality surfaced a set of hub genes including STAT3, AKT1, CASP3, BCL2, HIF1A, MTOR, and SRC. KEGG enrichment analysis ultimately locked the PI3K-AKT signaling pathway as the priority candidate for experimental validation, a hypothesis the team then carried into the laboratory.

The in vivo evidence came from an orthotopic pancreatic cancer model established by inoculating KPC-derived cancer cells directly into the pancreas of C57BL/6 mice. Mice were randomly assigned to five groups receiving saline, the chemotherapy drug gemcitabine, or ginsenoside Rb1 at 25, 50, or 100 milligrams per kilogram per day. The results were striking: ginsenoside Rb1 reduced tumor growth in a dose-dependent fashion, with the high-dose group achieving efficacy comparable to gemcitabine. Ki67 staining confirmed reduced tumor cell proliferation, and high-dose treatment prolonged survival without any obvious loss of body weight, a signal that the compound was well tolerated at therapeutic doses.

Metastasis, the process that makes pancreatic cancer so deadly, was also blunted. In a syngeneic liver metastasis model, ginsenoside Rb1 treatment reduced liver metastatic burden, as shown by smaller tumor-invading areas, fewer metastatic lesions on histological staining, and a lower liver-to-body weight ratio. Immunohistochemistry revealed that the compound suppressed the expression of metastasis-related epithelial-mesenchymal transition markers, including Zeb-1 and Vimentin, in the liver lesions. Together with the primary tumor data, these findings suggested that ginsenoside Rb1 acts on more than just the cancer cells themselves.

That suspicion hardened into the study’s central insight when the researchers turned to the tumor microenvironment. Although ginsenoside Rb1 showed only limited direct cytotoxicity against pancreatic cancer cell lines and no toxicity toward normal pancreatic ductal epithelial cells, it produced dramatic changes in the immune landscape of the tumors. Multiplex immunofluorescence revealed that macrophages were a major immune population in pancreatic tumor tissue, and the most notable change after treatment was a dose-dependent reduction in M2-like macrophage markers, including CD206, CD163, and ARG1. Flow cytometry of tumor-infiltrating cells confirmed that ginsenoside Rb1 selectively decreased ARG1-positive CD11b-positive F4/80-positive M2 macrophages while leaving CD86-positive M1 macrophages untouched, indicating a selective suppression of the pro-tumoral polarization program rather than a wholesale depletion of macrophages.

The mechanism was traced to the PI3K-AKT pathway. Western blotting showed that ginsenoside Rb1 reduced phosphorylation of PI3K and AKT in a dose-dependent manner in both tumor tissues and macrophages, and molecular docking with AutoDock Vina suggested stable binding of the compound to AKT1 and PIK3CA with strong binding energies. In cell culture, the team generated M2-like macrophages from both THP-1 cells and human peripheral blood monocytes, and found that ginsenoside Rb1 had minimal effects on unpolarized macrophages but reduced the induction of M2 markers such as CD206, CD115, and TGFB1 in both models. The compound, in other words, appears to intervene at the point where resting macrophages are being converted into tumor-supporting ones.

Functional assays drove the point home. Conditioned medium from ginsenoside Rb1-treated M2-like macrophages reduced the growth of a patient-derived pancreatic tumor organoid compared with medium from untreated M2 macrophages, suggesting that the reprogrammed macrophages had lost much of their tumor-promoting activity. In a complementary in vivo test, KPC-derived pancreatic cancer cells were co-injected with either untreated or ginsenoside Rb1-treated M2-like macrophages into C57BL/6 mice, and the co-injection of treated macrophages was associated with reduced metastatic burden. Safety evaluations reinforced the compound’s tolerability: major organs showed no gross abnormalities, serum markers of liver and kidney function, including ALT, AST, BUN, creatinine, and uric acid, remained unchanged, and hepatic expression of pro-inflammatory cytokines such as TNF-alpha, IFN-gamma, and IL-6 was not significantly altered.

The authors are careful about the limits of their evidence. The study does not establish definitive causality between PI3K-AKT inhibition and macrophage modulation, which would require pathway rescue or genetic gain-of-function experiments. Tumor-associated macrophage characterization relied on conventional M2-associated markers that cannot fully resolve the heterogeneity of these cells in pancreatic cancer, and only one patient-derived organoid line was used, so inter-patient variability remains untested. Critically, the compound was administered intraperitoneally, meaning that oral bioavailability, gut microbiota-mediated deglycosylation to compound K, food-matrix effects, and processing stability all require separate investigation before ginsenoside Rb1 can be developed as a functional food ingredient or nutritional adjuvant. Standardization, toxicological evaluation, and GRAS determination also lie ahead. Still, the work offers a compelling proof of concept: a dietary botanical constituent with centuries of safe human consumption can engage tumor-immune signaling in a way that is compatible with long-term nutritional intervention, opening a preventive, low-toxicity avenue against one of medicine’s most intractable cancers.

Subject of Research: Ginsenoside Rb1 from Panax ginseng reprograms tumor-associated macrophages via PI3K-AKT signaling to suppress pancreatic cancer progression

Article Title: Ginsenoside Rb1 From the Functional Food Panax ginseng Suppresses Pancreatic Cancer Progression via Macrophage Reprogramming Through the PI3K‐AKT Pathway

Article References: Dong, C.-S., Wang, G., Niu, Y., Sun, X., Ren, W., Zhang, J., Zhang, Y., Wu, R.-X., & Wu, X. (2026). Ginsenoside Rb1 From the Functional Food Panax ginseng Suppresses Pancreatic Cancer Progression via Macrophage Reprogramming Through the PI3K ‐ AKT Pathway. Food Science & Nutrition, 14(10), Article e72468. https://doi.org/10.1002/fsn3.72468

Image Credits: AI Generated

DOI: 10.1002/fsn3.72468

Keywords: ginsenoside Rb1, Panax ginseng, pancreatic cancer, macrophage polarization, PI3K-AKT pathway, tumor microenvironment, medicine-food homology, functional food, liver metastasis, network pharmacology, immunomodulation, patient-derived organoids