biostudies-literatureUnknown14(11)Bodalska APeppermint leaf, sage leaf, thyme herb, and their preparations are common components of herbal medicinal products (HMPs). According to the European Pharmacopoeia guidelines, the above-mentioned plant substances are standardized for the content of essential oils, omitting polyphenols, which also have a significant impact on their activities. The aim of this study was to evaluate the stability of the predominant polyphenols-rosmarinic acid, luteolin-7-O-β-glucuronide, and eriocitrin-in selected commercial liquid HMPs containing thyme, sage, and peppermint under long-term, intermediate, and accelerated testing conditions. Qualitative and quantitative analyses of these polyphenols were performed by the previously optimized and validated HPLC-DAD method. Rosmarinic acid stability was better in Pharmaceuticals (Basel, Switzerland)1139https://www.ebi.ac.uk/biostudies/studies/S-EPMC8624675biostudies-literatureStability of Rosmarinic Acid and Flavonoid Glycosides in Liquid Forms of Herbal Medicinal Products-A Preliminary Study.PMC8624675Fecka IKowalczyk ABodalska AfalseStability of Rosmarinic Acid and Flavonoid Glycosides in Liquid Forms of Herbal Medicinal Products-A Preliminary Study.Peppermint leaf, sage leaf, thyme herb, and their preparations are common components of herbal medicinal products (HMPs). According to the European Pharmacopoeia guidelines, the above-mentioned plant substances are standardized for the content of essential oils, omitting polyphenols, which also have a significant impact on their activities. The aim of this study was to evaluate the stability of the predominant polyphenols-rosmarinic acid, luteolin-7-O-β-glucuronide, and eriocitrin-in selected commercial liquid HMPs containing thyme, sage, and peppermint under long-term, intermediate, and accelerated testing conditions. Qualitative and quantitative analyses of these polyphenols were performed by the previously optimized and validated HPLC-DAD method. Rosmarinic acid stability was better in 2021-01-01T00:00:00Z2021 Nov2025-04-05T10:51:52.604Z2022-02-11T13:31:55.684ZS-EPMC86246753483292110.3390/ph14111139