Quantification of 4'-geranyloxyferulic acid and boropinic acid by HPLC-DAD in grapefruit skin from different country origins

Oxyprenylated natural products are a family of secondary metabolites featured by remarkable anti-cancer and anti-inflammatory effects. 4'-Geranyloxyferulic acid exerts valuable chemopreventive effects on several types of cancer, while its structural analogue boropinic acid avowed inhibitory effect against the growth of Helicobacter pylori. We wish to report herein, as a continuation of our studies [1], the validation of a new method for the selective determination of the title molecules in grapefruit skin extracts, after extraction with ethanol (1:3, m/v) using a ODS column at 10°C, water and methanol as mobile phase at 1.2 mL min^-1 flow rate in gradient elution mode. Quantitative analyses revealed LOQ of 0.5µg/mL and linearity up to 50µg/mL (r² ≥0.9960). Precision values ranged from 0.80% to 11.7% while trueness ones from -10.5% to 14.2%. This method was successfully applied and significant differences were observed depending on the country of origin of the vegetable material.