Spectrophotometric determination of antioxidant capacity among diverse Jasminum species via ABTS⁺ and Fe³⁺/Fe²⁺ reducing systems

The present study employed two complementary in vitro chemical assays, namely Ferric Reducing Antioxidant Power (FRAP) and ABTS⁺ radical scavenging, to evaluate and compare the antioxidant potential of methanolic extracts derived from five distinct Jasminum species. The electron-donating capacity of the extracts, mediated through redox-based mechanisms, as well as their ability to neutralize free radicals, was determined using spectrophotometric analysis. Results revealed significant interspecific variation in antioxidant activity. Based on absorbance values, FRAP measurements (µmol Fe²⁺/g), and antioxidant power indices, J. azoricum and J. nudiflorum exhibited the highest antioxidant potential, whereas J. sambac demonstrated the lowest activity across both assays. Specifically, the FRAP assay quantified the extracts’ capacity to reduce Fe³⁺ to Fe²⁺, while the ABTS assay measured their ability to scavenge ABTS⁺ radical cations. The observed variability is likely attributable to differences in phytochemical composition, particularly in phenolic and flavonoid content. Overall, this comparative evaluation underscores the promise of certain Jasminum species as potential natural sources of antioxidants for pharmaceutical and nutraceutical applications. KEY WORDS: Jasminum species, Spectrophotometric analysis, Antioxidant activity, ABTS assay, FRAP assay Bull. Chem. Soc. Ethiop. 2026, 40(3), 679-689. DOI: https://dx.doi.org/10.4314/bcse.v40i3.14