A rapid RP-HPTLC densitometry method for simultaneous determination of major flavonoids in important medicinal plants

A simple, sensitive, selective, precise, and robust high-performance TLC (HPTLC) method was developed and validated for determination of flavonoids in herbal extracts Bauhinia variegata, Bacopa monnieri, Centella asiatica, Ginkgo biloba, Lonicera japonica, Rosa bourboniana, Rosa brunonii, and Rosa damascena. The HPTLC of flavonoids was performed on RP-18 F-254, TLC plates with dual run, water (5% formic acid)/methanol (70:30) and water (5% formic acid)/methanol (50:50) as mobile phases. Densitometric determination of flavonoids was performed at lambda = 280 nm in reflectance/ absorbance mode. The linear regression analysis data for the calibration plots showed a good linear relationship with r(2) = 0.998 +/- 0.0003 in the concentration range of 150-800 ng/spot for apigenin and rutin and 200-1000 ng/spot for quercetin, luteolin, and quercitrin with respect to peak area. The average recovery for apigenin, quercetin, rutin, luteolin, and quercitrin was 97-99.8% indicating the excellent reproducibility. Statistical analysis of the data showed that the method is reproducible and selective for determination of flavonoids.