Quantification of the flavonoid glycosides in Passiflora incarnata by capillary electrophoresis

Capillary electrophoresis has been applied for the separation and quantification of the flavonoids in Passiflorae herba. Separations were performed using 25 mM sodium borate with 20 % methanol (pH 9.5). For the quantification quercetin 3-O-arabinoside was used as internal standard. The method was applied to the determination of the flavonoid glycosides in 10 different commercial samples of the drug and showed similar flavonoid patterns, but differences concerning the single and total amounts of flavonoids. The total flavonoid contents determined with the new method correlated satisfactorily with those achieved by the spectrophotometric assay according to the European Pharmacopoeia.