Quality of herbal medicinal products based on sage and thyme preparations

Abstract

Sage and thyme are herbs that have been traditionally used in various forms for upper respiratory tract infections and inflammation of mucous membranes. The activity of these medicinal plants was mainly attributed to the essential oil. Its lowest content in herbal substances approved for pharmaceutical use is defined by the respective monographs of the European Pharmacopoeia or national pharmacopeias. Studies carried out in recent years emphasize also the importance of non-volatile compounds present in these plants – polyphenols, which also have a versatile beneficial therapeutic potential for health. Our study included a qualitative analysis of polyphenols in commercial herbal medicines based on sage and thyme and quantification of levels of the most important non-volatile components using the U(H) PLC-ESI-MS and HPLC-DAD methods along with the analysis of variance (ANOVA). This research highlighted the great diversity of the most abundant compounds – rosmarinic acid and luteolin-7-O-βglucuronide. Since polyphenols are present in the tested herbal medicines in considerable amounts, their concentration and participation in the therapeutic effect should not be ignored. Therefore, the content of rosmarinic acid and luteolin-7-O-β-glucuronide in sage leaf and thyme herb is proposed as another parameter for quality control purposes.