Development of natural diterpenoid Eriocalyxin B as an anti-tumor agent for breast cancer

The natural ent- kaurane diterpenoid eriocalyxin B (Eri B), isolated from Isodon eriocalyx var. laxiflora , has been reported to possess anti-tumor and anti-inflammatory activities. Here, we aimed to illustrate the potent anti-tumor and anti-metastatic effects of Eri B in breast cancer preclinical models. Our previous studies demonstrated that Eri B was an autophagy inducer and could diminish tumor growth in human breast xenograft-bearing mice via inhibition of Akt/mTOR/p70S6K signaling pathway [ 1 ]. Eri B was shown to inhibit angiogenesis through modulating VEGFR-2 signaling pathway in zebrafish embryos and breast tumor-bearing mice [ 2 ]. Furthermore, our transcriptome analysis in zebrafish embryos revealed two major pathways (glutathione metabolism and tight junctions) which may be related to the anti-tumor activities of Eri B [ 3 ]. In our recent studies, the anti-metastatic effects of Eri B have also been demonstrated. Eri B could significantly suppress lung and liver metastasis in both human breast xenograft- and syngeneic breast allograft-bearing mice [ 4 ]. While in immune-competent mice treated with Eri B, the diversity and composition of gut microbiome were found to be changed, from which the potential pathways involved in the anti-cancer efficacy of Eri B were projected [ 4 ]. Our latest findings revealed the regulatory role of mast cells in breast cancer and the inhibitory effect of Eri B on mast cells in breast cancer [ 5 ]. In conclusion, with the promising anti-tumor and anti-metastatic efficacies of Eri B as demonstrated in our breast cancer preclinical models, further investigations on the potential molecular targets and formulation development are currently in progress. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany