Effect of glycyrrhizic acid on the bioavailability of resveratrol after oral administration in rabbit plasma using HPLC with fluorescence detection

Resveratrol is a chemical found in red wine, red and black grapes, pineapple, peanuts and many different plants. It is most commonly used for high cholesterol, cancer, heart disease, and many other conditions. In this study, the effect of glycyrrhizic acid on the oral bioavailability of resveratrol was investigated. The bioavailability study was performed on rabbits. An HPLC method by fluorescence detection was developed for the analysis of the plasma samples. Resveratrol in the plasma was measured analyzed in the C18 column by acetonitrile-0.2% formic acid (35:65, v/v) mobile phase system at 30 degrees C with a flow rate of 1 mL/min and detected by using fluorescence detection. Excitation and emission wavelengths were determined as 320 nm and 400 nm, respectively, and quercetin was used as the internal standard in the method. The validation of the developed method was performed according to ICH rules. The calibration curve showed linearity at 10-800 ng/mL range. The method greenness was assessed using the automated AGREE tool and the overall score value of 0.61 referred to a relatively green HPLC method. Cmax values of pure and combined resveratrol were found 101.29 ng/mL and 273.46 ng/mL, respectively. While AUC0-infinity value was 9.0764 mg.h/mL for resveratrol, it was found 39.3351 mg. h/mL when taken with glycyrrhizic acid. The increase AUC0-infinity and Cmax values obtained from the combined resveratrol were 433% and 270%, respectively. These values showed glycyrrhizic acid significantly increases the bioavailability of resveratrol.