Abstract

The present work was conducted to evaluate a simple effective technique for spectrophotometric determination of two flavonoids namely diosmin (1) and rutin (2) in the isolated fractions obtained from Persicaria salicifolia, authentic and pharmaceutical dosage forms, the method is based on the reduction of Ag⁺ cations to silver nanoparticles (Ag-NPs) by the effect of these flavonoids in the presence of polyvinylpyrrolidone (PVP) as a stabilizing agent which result in production of intense brown colour corresponding to the formation of the surface plasmon resonance of produced silver nanoparticles. The plasmon absorbance of the Ag-NPs allows quantitative spectrophotometric determination of these flavonoids where calibration curves derived from the changes in absorbance at λ=415 and 432 nm were linear with concentration range of diosmin and rutin 1-8 and 0.5-7.0 µg/mL while their detection limits (3σ) were 0.26 and 0.12, respectively. The method was applied successfully for the determination of flavonoids in extract, authentic and pharmaceutical dosage forms. The haemostatic activity of the total methanol extract, isolated fractions, authentic and dosage forms were investigated for their usual and silver nanoparticulated forms using tail bleeding time and amount of bleeding assays in rats, where the nanoparticulated samples exhibited more significant activities.

Key words: Persicaria, diosmin, rutin, silver nanoparticles, spectrophotometry, haemostatic.