Pre-clinical Evaluation of Shilajit in Cancer: A Systematic Review

Shilajit, an Ayurvedic herbo-mineral preparation containing fulvic acids and humic substances, has been studied for its anti-cancer potential; however, a precise summary of experimental evidence is not available. The purpose of this systematic review and qualitative synthesis was to analyse the preclinical and clinical evidence on the anticancer potential, mechanisms, and translational prospects of Shilajit. PubMed, Ovid Discovery, and Google Scholar were searched systematically, and only nine preclinical studies met predetermined inclusion and exclusion criteria. No clinical studies were eligible. Data on cytotoxicity, mechanisms of action, and selectivity were extracted by two independent reviewers. These included studies (eight in vitro and one in vivo osteosarcoma model) analysed the effect of Shilajit on various types of cancer. Despite differences in methodologies, all studies reported dose-dependent cytotoxicity with IC₅₀ values ranging from 31 to 1103 µg/mL for various cancer types, depending on the type of cancer and form of Shilajit preparation. Selectivity against cancer cells was observed as compared to normal cell lines. Molecularly, Shilajit mediated apoptosis through the generation of reactive oxygen species and inhibition of NF-κ B (Nuclear Factor kappa-light-chain-enhancer of activated B cells)/IKK (I-kappa-B kinase) signaling, as well as suppression of epithelial-mesenchymal transition and cell cycle arrest. In vivo findings suggested chemopotentiation and organ protection when administered together with standard therapy. Thus, Shilajit shows multitargeted anticancer activities in various experimental cancer models by several mechanisms. This evidence is preclinical, and standardization issues restrict clinical translation. The results support continued investigation through rigorous, blinded studies, recognising that no clinical trials currently exist and that any potential clinical translation remains speculative at this stage.