Biomedical Applications of Humic Substances: From Natural Biopolymers to Therapeutic Agents

Humic substances, which include humic acid and fulvic acid, are natural biopolymers formed from the decomposition of organic matter. There is growing interest in them because of their diverse potential in the biomedical field. Their complex structures, rich in various functional groups, provide antioxidant, anti-inflammatory, antimicrobial, antiviral, and immunomodulatory properties. Recent studies demonstrate that humic substances can scavenge reactive oxygen species, modulate cytokine production, inhibit viral fusion, promote wound healing, and enhance gut microbiota balance. Humic acid and fulvic acid also exhibit anticancer activity by inducing apoptosis in tumor cells, while protecting healthy tissues from oxidative stress. Furthermore, their chelating capacity underlies detoxifying activity and heavy metal binding effects. Despite promising research, variability in composition and potential cytotoxicity under certain conditions emphasize the need for standardized extraction methods and rigorous preclinical evaluation. This review offers a comprehensive overview of the biological effects of humic substances, exploring the mechanisms behind their actions and their potential biomedical applications. It highlights both the benefits and the limitations associated with their use in drug delivery systems.