Quantitative determination of bioactive phenylethanoid glycosides in Clerodendrum phlomidis using HPTLC

A new validated high performance thin layer chromatographic method has been developed for the simultaneous determination of three bioactive phenylethanoid glycosides verbascoside (1), leucosceptoside A (2) and martynoside (3) in the roots of Clerodendrum phlomidis. Extraction efficiency of marker compounds was studied using normal (cold and hot), ultrasonic as well as microwave assisted extraction techniques with various solvents. Well resolved separation of marker compounds was achieved on silica gel 60F₂₅₄ plates using the mobile phase consisting of chloroform–methanol–water (7.8:2.0:0.2, v/v/v). Quantitation of marker compounds was carried out using the densitometric reflection/absorption mode at 460 nm after post-chromatographic derivatization with vanillin–sulphuric acid reagent. Method was validated for peak purity, precision, robustness and sensitivity etc., as per ICH guidelines. Report on the occurrence of phenylethanoid glycosides for the first time in C. phlomidis is of chemotaxonomic importance.