The impact of extraction conditions on the content of flavonoids in the extracts from Thymus marschallianus and Thymus serpyllum herbs

Introduction. Flavonoids are a group of phenolic compounds having a high structural diversity that determines the breadth of their biological activity. In this connection, it is relevant to vary extraction conditions to obtain extracts from plant raw materials rich in flavonoids. Objective: to comparatively analyze the amount of flavonoids and extractive substances in the Thymus marschallianus and Thymus serpyllum herbs according to the extraction conditions. Material and methods. The investigation object was powdered Thymus marschallianus and Thymus serpyllum herbs. The Thymus marschallianus herb was collected in the vicinity of Saratov (Lysaya Gora (Bald Mountain)) during the flowering phase in June-July 2018, 2019, and 2020. The powered Thymus serpyllum herb was purchased in the pharmacy chain. Extracts from plant materials were prepared in different ways: according to the 14th edition of the Russian Federation's State Pharmacopoeia (14th edition of RFSP) containing the Pharmacopoeia Article (PA) «Thyme herb» (the extractant was 70% ethanol; the assay was recommended by the RFSP), according to the 14th edition of RFSP in the PA «Infusions and decoctions» (the extractant was water); extraction with 95% ethanol; the extracts obtained with 50% ethanol. Results. In the extracts prepared according to the assay given in the 14th Edition of RFSP PA «Thyme herb», the amounts of flavonoids and extractive substances were 0.90-1.44% and 15.9-33.5%, respectively. In the extracts prepared according to the assay in the RFSP PA «Infusions and decoctions», the amount of those was 1.5 and 1.1 times lower, respectively. When extracted with 95% ethanol, the amount of flavonoids and extractive substances was 15 and 6.7 times lower, respectively. When extracted with 50% ethanol, the amount of those was 1.5 and 1.2 times lower, respectively. A correlation was shown between the conditions of extraction and the content of flavonoids and extractive substances in the resultant extracts. Conclusion. The highest amounts of flavonoids and extractive substances were obtained in the extracts prepared in accordance with the requirements of the PA «Thyme herb» in the 14th edition of RFSP and the lowest amounts were observed when extracted with 95% ethanol.

Thymus marschallianus, Thymusserpyllum, Thymus marschallianus, Thymus serpyllum, extract, amount of flavonoids, extractive substances