Development and validation of a method for quantitative determination of the flavonoid content in the herb of yellow loosestrife (Lysimachia vulgaris L.)

Introduction. The study of the qualitative and quantitative composition of plants and the identification of promising medicinal species is one of the most important tasks of modern pharmacognosy. Yellow loosestrife ( Lysimachia vulgaris L.) of the Primulaceae family is a perennial herbaceous plant. The main group of active substances in the herb of L. vulgaris are phenolic compounds. L. vulgaris is widely distributed in Russia, is known in traditional medicine, its biological activities have been examined in vitro and in vivo experiments. A search of scientific literature in the Russian segment did not reveal sufficient information on the quantitative content of biologically active substances. Aim. Development and validation of an analytical procedure for assessing the quantitative content of flavonoids in the herb of yellow loosestrife ( L. vulgaris ) in terms of rutin using spectrophotometry. Materials and methods. The object of the study was alcohol extracts from the aerial part of L. vulgaris , harvested during the flowering period in the Leningrad region. Quantitative determination was carried out by spectrophotometry. The proposed analytical procedure was validated in accordance with the requirements of the State Pharmacopoeia XV in terms of specificity, linearity, range, repeatability (intra-assay precision), precision and accuracy (trueness). Results and discussion. For the proposed analytical procedure, rutin was proposed as a standard sample. It was found that the maximum extraction of flavonoids from the herb of L. vulgaris is achieved by using a single extraction with 70 % ethyl alcohol for 30 min at a raw material : extractant ratio of 1 : 100 and a raw material grinding of 2–1 mm. A 1 % alcohol solution of aluminum chloride was proposed as a complexing agent, and the complexation conditions were selected (aliquot of aluminum chloride 1 % solution 2 ml, complexation time 30 min). The analytical procedure meets the requirements of the validation characteristics. According to the developed method, it was found that the amount of flavonoids in the herb of L. vulgaris , harvested in the Leningrad region, is 2,97 ± 0,05 % expressed in rutin. Conclusion. A method for the quantitative determination of the flavonoid content in the herb of yellow loosestrife ( L. vulgaris ) by spectrophotometry expressed in rutin has been developed and validated.