Densitometric determination of flavonoids in methanolic and aqueous extracts of Epilobii angustifolii herba by use of HPTLC

Separation and quantitative analysis of quercetin glycosides in methanolic and aqueous extracts of Epilobii angustifolii herba have been achieved by HPTLC with densitometric detection. The compounds were separated on silica gel 60F(254) HPTLC plates with ethyl acetate-formic acid-water, 68 + 2.5 + 3 (v/v), as mobile phase; densitometric detection of the flavonoids was performed at lambda = 350 nm. The amounts of the compounds were calculated by use of regression equations obtained from calibration plots. The flavonoids were more abundant in the aqueous extract than in the methanolic extract. Quercetin glucuronide was the most abundant compound in both extracts (21.22 mg g(-1) and 17.85 mg g(-1), respectively). The method is rapid, easy, and selective, particularly for quercetin glucuronide analysis.