Determination of psoralen and plumbagin from its polyherbal oil formulations by an HPTLC densitometric method

Many polyherbal oil formulations in Indian and Chinese traditional systems of medicine used for control of skin diseases contain seeds of Psoralea corylifolia and roots of Plumbago zeylanica L. Psoralen and plumbagin are the reliable markers for Ps. corylifolia and Pl. zeylanica, respectively. However, no attempt is made to standardize the polyherbal oil formulations containing Ps. corylifolia and Pl. zeylanica in terms of their active ingredients or marker compounds. In this paper, a simple, rapid, and sensitive HPTLC method is described for the first time to identify and quantify psoralen and plumbagin from such polyherbal oil formulations. The methanolic extract of oil formulations was used for analysis of markers. Psoralen gives a sharp UV absorbance peak at 302 nm and plumbagin at 275 nm. Good resolution of psoralen (Rf = 0.37) and plumbagin (Rf = 0.77) was attained using toluene-ethyl acetate (7.5 + 2.5, v/v) mobile phase. The method was validated in terms of calibration curve, limits of detection and quantification, precision, accuracy, and robustness following a standard protocol. Polyherbal oil formulations were analyzed with reasonable accuracy, and no matrix interference was observed. The method developed can be used for marker-based quality assurance of oil formulations containing Ps. corylifolia and Pl. zeylanica as one active ingredient.