Determination of flavonoids in the aerial parts of lemon balm and catnip using capillary electrophoresis

An important aspect of modern analytical chemistry is the study of multicomponent objects, including medicinal plants with clinically proven pharmacological activity, and promising plants from the point of view of pharmacy, which are not officinal, but belong to the same family. In addition, it is of interest for pharmacy to determine the content of valuable types of flavonoids (rutin, cynaroside, luteolin) in these plants, due to their high antitumor activity. In this study, lemon balm (Melissa officinalis L.) and catnip (Nepeta cataria L.), both belonging to the Lamiaceae family, have been chosen as research objects. These plants have been collected from the botanical garden at Samara National Research University named after S. P. Korolev. The aim of the research was to quantify flavonoids such as rutin, cynaroside, and luteolin in dried samples of these plants. Using standard samples of rutin, cynaroside, and luteolin, we demonstrated the possibility of separating them selectively through capi llary zone electrophoresis with UV detection at a wavelength of 355 nm using a borate buffer as an electrolyte with a pH of 9,2 . A method for the determination of rutin, cynaroside, and luteolin, in dried botanical plant samples after extraction using an aqueous ethanol solution has been proposed. It has been found that the peaks of the main components of plants in electrophoregram spectra are located after the peaks of the studied flavonoids, and they do not interfere with the determination of these flavonoids at low concentrations in the plant samples under investigation. The content of flavonoids in lemon balm samples per 1 g of dry raw material is, mg/g: rutin – 0,351, luteolin – 0,011, cynaroside has not been detected. In catnip, the content of flavonoids is, mg/g: rutin – 0,218, luteolin – 0,027, cynaroside – 0,026.