Simultaneous determination of epicatechin, syringic acid, quercetin-3-O-galactoside and quercitrin in the leaves of Rhododendron species by using a validated HPTLC method

A rapid and sensitive reverse phase high-performance thin-layer chromatographic (RP-HPTLC) method has been developed for the simultaneous determination of four bioactive phenolics, viz. epicatechin (1), syringic acid (2), quercetin-3-O-galactoside (3) and quercitrin (4) in the leaves of Rhododendron arboreum, Rhododendron campanulatum and Rhododendron anthopogon. HPTLC was performed on pre-coated RP-18 F254S TLC plates. For achieving good separation, the mobile phase of methanol–5% formic acid in water, 50:50 (v/v) was used and densitometric determination of compounds was carried out at 290 nm in reflection/absorption mode. The method was validated in terms of linearity, precision, accuracy, and sensitivity. The calibration curves were linear in the range of 200–1200 ng for compounds 1, 3 and 4 and 400–2400 ng for compound 2. Lower limits of detection obtained for compounds 1–4 were 20, 40, 25 and 25 ng respectively, while the limit of quantification obtained were 50, 115, 75 and 70 ng respectively. The method was found to be reproducible and convenient for quantitative analysis of these compounds in Rhododendron species.