Genotoxicity and cytotoxicity screening of ethanol and water extracts of Lonicera caerulea leaf

Lonicera caerulea L. (haskap) leaves represent an abundant agricultural by-product rich in bioactive phenolic compounds and secondary metabolites, yet their safety for food industry applications remains largely unknown. In this study, we evaluated the genotoxicity and cytotoxicity of ethanol and aqueous extracts of haskap leaves using the UMU-ChromoTest™, a bacterial SOS chromotest. A serial two-fold dilutions ranging from undiluted to 1:8192 were prepared for both extract types, and the assay was performed according to the EBPI UMU-ChromoTest™ procedure. Bacterial growth factor (GF) and β-galactosidase (β-Gal) induction ratio (IR) were calculated from absorbance readings at 600 nm and 420 nm, respectively. Results showed that for the ethanol extract, GF values ranged from 0.983 to 1.017 (mean 1.005 ± 0.011) and IR values from 0.983 to 1.017 (mean 1.006 ± 0.012). For the water extract, GF values ranged from 0.983 to 1.017 (mean 1.007 ± 0.011) and IR values from 0.977 to 1.023 (mean 0.993 ± 0.013). All values remained well within the established safety thresholds (GF > 0.5; IR < 1.5) across the entire dilution series. Neither extract exhibited a dose-dependent genotoxic or cytotoxic response. These findings demonstrate that both ethanol and water extracts of L. caerulea leaves are non-genotoxic and non-cytotoxic under the tested conditions, thereby supporting their potential as safe bioactive ingredients in food and pharmaceutical industries and offering a sustainable route to valorize an abundant agricultural byproduct.