Bioactivity Profile of Datura stramonium L. Seed Extracts: Collagenase and Tyrosinase Inhibition and Antioxidant Activity

Datura stramonium L., a member of the Solanaceae family, contains diverse phytochemicals with potential pharmacological applications, yet its enzyme inhibitory and antioxidant properties remain insufficiently characterized. In this study, ethanol and aqueous extracts of D. stramonium seeds collected from Belmebük village (Amasya, Turkey) were evaluated for collagenase and tyrosinase inhibition, as well as antioxidant capacity. Enzyme inhibition assays conducted at 20 μg/mL revealed that the ethanol extract inhibited collagenase and tyrosinase by 26.8 ± 0.099% and 59.5 ± 0.025%, respectively, while the aqueous extract showed higher activity with 52.1 ± 0.09% and 70.5 ± 0.012% inhibition. Compared to positive controls (epigallocatechin gallate: 88.09% collagenase inhibition; kojic acid: 98.13% tyrosinase inhibition), the extracts demonstrated moderate but significant activities. Antioxidant evaluations using DPPH and ABTS assays indicated IC₅₀ values of 0.0962 ± 0.0299 and 0.241 ± 0.052 mg/mL for the ethanol extract, and 0.0522 ± 0.0254 and 0.1974 ± 0.0156 mg/mL for the aqueous extract, respectively. Although less potent than standard antioxidants (BHT: 0.0148 ± 0.001 mg/mL; Trolox: 0.0153 ± 0.001 mg/mL), both extracts displayed notable radical scavenging effects, with the aqueous extract consistently outperforming the ethanol extract. These findings highlight that D. stramonium seed extracts possess dual bioactivity by inhibiting collagenase and tyrosinase while exerting antioxidant effects, suggesting their potential in preventing collagen degradation, hyperpigmentation, and oxidative damage. To the best of our knowledge, this is the first report on enzyme inhibitory activities of D. stramonium seed extracts, providing novel evidence for their potential utilization in pharmaceutical and dermocosmetic formulations.