Improved high-performance liquid chromatography-DAD method for the simultaneous analysis of quercetin and kaempferol in the stems of Cissus quadrangularis Linn.

A simple, rapid, and specific reversed-phase HPLC method with DAD detection has been used for analysis of two flavonoids, quercetin and kaempferol, in Cissus quadrangularis Linn. The flavonoids were well resolved within 10 min, and quantification was achieved, on an endcapped C18 column at 370 nm with acetonitrile-phosphate buffer (pH 3.4, adjusted with glacial acetic acid) 60:40 (v/v) as isocratic mobile phase at a flow rate of 1.0 mL min−1. The method was validated for limit of detection, limit of quantification, linearity, precision, accuracy, and recovery. Linearity was demonstrated over the range 0.75 to 10 μg mL−1 for quercetin and 1.0 to 10 μg mL−1 for kaempferol with good correlation coefficients (r2 > 0.998). Detection limits were 0.075 and 0.10 μg mL−1 for quercetin and kaempferol respectively. Recovery was 98.0–105.3% for quercetin and 95.0–101.1% for kaempferol. The method was successfully applied to analysis of two flavonoids in four samples of Cissus quadrangularis Linn.