Indian Journal of Agricultural Biochemistry

Walnut (Juglans regia L.) shells, often considered agro-industrial waste, were evaluated for their phytochemical composition and diverse biological activities. Methanolic extracts of the shells exhibited strong antioxidant capacity, as demonstrated by DPPH, FRAP and metal chelation assays. Antibacterial analysis revealed broad-spectrum activity against five bacterial strains, with a notably low MIC of 1512 μg/mL against Bacillus subtilis. The extract also showed significant cytotoxic effects, particularly against the HCT-116 human colon cancer cell line, alongside promising antidiabetic potential. These findings position walnut shell extract as a rich source of bioactive compounds with multifunctional therapeutic properties. In conclusion, the study focuses on the extract's diverse biological attributes and highlights its potential as a versatile, natural agent for future applications in oxidative stress management, antimicrobial therapy, cancer treatment and metabolic disorder regulation.