Organosulfur-rich essential oils from flower parts of three Allium species: chemical composition, enzyme inhibitory effects and in silico interactions

The essential oils obtained from the flowers of Allium paniculatum subsp. paniculatum (EOP), A. guttatum subsp. sardoum (EOS), and A. scorodoprasum subsp. waldsteinii (EOW) were evaluated in the present study, providing a comparative insight into their chemical composition and biological properties. The results from the GC–MS analysis indicated a notable abundance of sulfur-containing compounds across three samples. The major components identified included dimethyl trisulfide at 23.64% and dimethyl disulfide at 23.01% in the EOP and, cis-1-propenyl propyl trisulfide (11.99%, 17.33%, respectively) and trans-1-propenyl propyl trisulfide (15.40%, 22.41%, respectively) in the EOS and EOW. Enzyme inhibitory assays demonstrated that the essential oils exerted notable bioactivity, especially against tyrosinase, with IC₅₀ values of 14.27, 19.46, and 18.21 µg/mL for EOP, EOS, and EOW, respectively. In addition, the samples exhibited considerable antioxidant properties in DPPH, ABTS, CUPRAC, and FRAP assays. Molecular docking studies supported the experimental findings by demonstrating favourable binding interactions between major organosulfur constituents and the active sites of tyrosinase, α-amylase, α-glucosidase, AChE, and BuChE. Overall, these findings suggest that organosulfur-rich essential oils may represent promising natural sources for further investigation of antioxidant and enzyme inhibitory properties and provide insight into the biological relevance of organosulfur metabolites within the genus Allium.