UV–Vis and fluorescence spectroscopy of <i>Ammi visnaga</i> extracts: influence of ethanol–water composition on extraction efficiency and optical fingerprinting

Ammi visnaga (L.) Lam. is a medicinal plant rich in furanochromones and flavonoids. A rapid UV–Vis absorption and fluorescence spectroscopy approach was used to evaluate the influence of ethanol–water composition on extraction efficiency and optical properties of A. visnaga extracts. Hydroalcoholic mixtures (10–90% v/v ethanol) were investigated. UV–Vis spectra showed three absorption bands at 195–198 nm, 274–279 nm, and 329–332 nm, attributed to aromatic compounds, flavonoids, and furanochromones (khellin and visnagin), respectively. Maximum extraction was obtained at 30–70% ethanol, with semi-quantitative estimates of khellin (∼1.76 mg g−1) and visnagin (∼2.35 mg g−1). Fluorescence emission spectra (λexc = 330–340 nm) exhibited broad emission centered at 430–450 nm, with intensity variations governed by solvent polarity and solute–solvent interactions. UV–Vis and fluorescence spectroscopy provide a rapid and cost-effective tool for extraction assessment and optical fingerprinting of A. visnaga extracts.