Investigation of Physico-Chemical Properties of Usnic Acid for Standardization of Extracts From Plant Raw Materials of the Cetraria Species

Modern realities dictate the need to search for and create new medicines derived from plant raw materials. Among the extracted components, usnic acid is considered one of the most promising. A large amount of it is contained in lichens. It has antibacterial, anti-inflammatory and other properties. The aim of the study was to study the solubility of usnic acid in various solvents with an assessment of its stability. The aim of the study was to study the solubility of usnic acid in various solvents with an assessment of its stability. Solubility in various solvents was assessed by spectrophotometric analysis in the UV region (200-400 nm). Usnic acid showed the best solubility in formic and glacial acetic acids, alkalis, and the following organic solvents: chloroform, acetonitrile, and dimexide. It is slightly soluble in alcohol, acetone and ethyl acetate. The absorption maxima in the wavelength range were in the range of 230-320 nm. Thus, to standardize extracts of usnic acid from vegetable raw materials, it is more profitable to use solvents: formic acid, glacial acetic acid, chloroform, acetonitrile, dimexide, and a 10% sodium hydroxide solution. In the latter case, it is necessary to take into account the stability of the usnic acid solution for no more than a day.