African Medicinal Plants Targeting Triple-Negative Breast Cancer (TNBC): A Systematic Review of Ethnobotanical Surveys, Phytochemistry and Anti-TNBC Studies.

Background: Triple-Negative Breast Cancer (TNBC) remains the most aggressive oncological challenge within the African continent, characterized by high molecular heterogeneity, early onset in African women, and the absence of hormonal receptors. Multi-drug resistance (MDR), driven by ATP-binding cassette (ABC) efflux pumps and supported by the persistence of cancer stem cells (CSCs) within the tumor microenvironment, significantly compromises clinical outcomes and traditional treatment efficacy. Objective: This systematic review evaluates the ethnobotanical relevance, phytochemical diversity, and toxicity of some medicinal plants from the African pharmacopoeia specifically utilized or investigated for their activity against the TNBC phenotype. Methods: Following PRISMA guidelines, a systematic search was executed across PubMed, ScienceDirect, Scopus, Web of Science, and AJOL. The study focuses on original research published between 2011 and 2026 utilizing TNBC-specific models (such as MDA-MB-231, BT-20, HCC1937, or 4T1) and analyses the growth habits, parts used, and traditional administration modes of the selected African plant species, distributed across Western, Central, Southern, and Eastern Africa. Following a rigorous multi-reviewer screening process, a final set of 52 primary articles representing 30 distinct genera and 22 botanical families was selected for qualitative and quantitative synthesis. Results: This review identifies plant species actively used or studied in Africa for their anti-TNBC potential, with the most representative botanical families being Asteraceae (13%), Fabaceae (7%), and Annonaceae (7%). These species are traditionally administered through various methods, including decoction, infusion, and mastication, utilizing diverse plant parts such as leaves, stem and root barks. Significant cytotoxic activities against TNBC cell lines (notably MDA-MB-231) were recorded, with IC50 values as low as 5.10 ± 0.28 µg/mL for Catharanthus roseus and 13.56 µg/mL for Nauclea pobeguinii. Furthermore, species such as Vernonia amygdalina and Curcuma longa demonstrated a capacity to enhance the effectiveness of conventional chemotherapy like Doxorubicin, suggesting a strong potential for chemosensitization and therapeutic synergy in managing resistant breast cancer phenotypes. Conclusions: Standardized African phytomedicines represent a promising frontier in overcoming TNBC chemoresistance. However, the lack of clinical trials and end-to-end drug development infrastructure on the continent remains a significant barrier. Transitioning to nano-formulated delivery systems and establishing regional drug discovery hubs under the ethical framework of the Nagoya Protocol are essential steps toward developing precise and equitable oncology treatments from Africa's rich biodiversity.