Approaches to standardization of Pyrolae folia raw materials

Introduction. Medicinal plant raw materials are of interest for the development of new medicines, for evaluating their effectiveness, safety, as well as the methodology of their study, and the use of new analytical methods. There are 12 species of the genus Pyrola in Russia, the most common are round-leaved wintergreen (Pyrola rotundifolia L.), pink wintergreen (Pyrola asarifolia (DC.) Freyn, synonym of Pyrola incarnata (DC.) Freyn). These species are similar in chemical composition and contain flavonoids and simple phenolic compounds, which determine their pharmacological effects and are promising for use in medical practice as anti-inflammatory and diuretic agents. These two species are included in the Pyrolae folia raw material as the producing plants.

The purpose of the study. To develop methods for the quantitative determination of the amount of flavonoids, the amount of simple phenolic compounds for the standardization of Pyrola raw materials (Pyrolae folia).

Material and methods. Raw material samples (leaves) of P. incarnata and P. rotundifolia species were collected during the fruiting period in the Irkutsk region in 2022-2024. Spectral studies were carried out using SF-2000 (Russia) and Leki (Finland) instruments. The results of quantitative analysis were statistically processed at P=95.

Results. Spectral studies of alcohol extracts of Pyrolae folia showed the presence of a maximum at 410±2 nm, which coincides with the standard sample (SS) of rutin. The spectrum of the alcohol extract purified by passing it through an aluminum oxide chromatographic column, which contains simple phenolic compounds, is characterized by a maximum absorption peak at 280±2 nm and corresponds to the SS of arbutin. The technological factors that contribute to the maximum yield of flavonoids and simple phenols from the raw material have been identified. These parameters are used as conditions for the developed methods of quantitative analysis and calculation of the amount of these compounds. The relative error in determining the amount of flavonoids and the amount of simple phenols was ±2,42% and ± 2,15% (respectively). The developed spectrophotometric techniques are valid. It has been shown that it is necessary to set the lower limits of the flavonoid content at 1,7% and the simple phenol content at 4,5% (based on the dry weight of Pyrolae folia).

Conclusions. The methods of quantitative determination by spectrophotometry of the amount of flavonoids and the amount of simple phenols in the raw materials of pear leaves – Pyrolae folia have been developed and the norms of the content of these indicators have been established.