Approaches to standardization of common raspberry leaves (Rubus idaeus L.)

Introduction. Common raspberry (Rubus idaeus L.) is one of the representatives of the genus Rubus L., belonging to the Rosaceae family, which is widespread and cultivated in the Russian Federation. The fruits and leaves of common raspberry, due to their rich chemical composition (flavonoids, phenylpropanoids, saponins, organic acids and tannins), are used in folk practice as an anti-inflammatory, antipyretic and diaphoretic agent. Common raspberry leaf was included in the British Pharmacopoeia, but in the Russian Federation there is no regulatory documentation that regulates the quality of common raspberry leaves. The aim of the work was to develop methods for the qualitative and quantitative determination of the amount of flavonoids in common raspberry leaves. Material and methods. The object of the study is the leaves of common raspberry, harvested during the flowering phase in different areas of the Samara region in June – July 2024. Qualitative determination of flavonoids was carried out by thin-layer chromatography (TLC) using chromatographic carriers of Sorbfil brand plates (PTLC-AF-A-UV). To separate the substances, a solvent system was used: n-butyl alcohol – glacial acetic acid – water in a ratio of 4:1:2. Quantitative determination of the amount of flavonoids in aqueous-alcoholic extracts of common raspberry leaves was carried out by differential spectrophotometry on a Specord 40 device (AnalytikJena AG, Germany) calculated on standard sample of rutin. Results and discussion. The developed method of quantitative determination was used to calculate the content of total flavonoids in common raspberry leaves, which varied from 2.08±0.06 to 2.11±0.06%. A validation assessment of the developed method was carried out. The error of a single determination with a confidence probability of 95% is ±2.86%. Conclusion. A method of quantitative determination of total flavonoids in common raspberry leaves by differential spectrophotometry was developed. A method of qualitative determination of flavonoids in common raspberry leaves was developed using thin-layer chromatography in the solvent system n-butyl alcohol – glacial acetic acid – water in a ratio of (4:1:2) with a witness substance, a standard sample of rutin. The obtained research results can be used in the development of regulatory documentation for a promising type of raw material «Common raspberry leaves» for introduction into the State Pharmacopoeia of the Russian Federation.