TLC-densitometry of rosmarinic and caffeic acids in the evaluation of lamiaceae species growing in central Europe

A thin-layer chromatographic (TLC)-densitometric method was used for the parallel quantification of rosmarinic acid (RA) and caffeic acid (CA) in crude extracts of Salvia species (Family Lamiaceae), obtained by ultrasonic extraction with 60% methanol. The densitometric measurement was performed in fluorescent mode as it has been published earlier. The applicability of the method has been investigated mainly from the viewpoint of the starting material. Questions are discussed like, what kind of factors should be taken into account, if the drugs are to be characterized, and how the RA and CA contents of samples vary in the plants are discussed. The drugs (plant material) show great differences due to the time of harvest, to the organ composition of drugs, and to the extraction and storage conditions of the stock-solutions prepared from them. The importance of these parameters is illustrated on Salvia species native to Hungary.