Phytochemical Characteristics and Antimicrobial Effects of Nonea rossica (Boraginaceae) Extracts

Abstract

—A phytochemical and microbiological analysis of a widespread Russian species, Nonea rossica Steven (Boraginaceae) was carried out. As an object of study, we used the aerial part (herb) of N. rossica, harvested during flowering stage from a steppe meadow in the Novosibirsk region. The qualitative composition of biologically active compounds (BAC) was determined by thin layer chromatography, using two solvent systems: ethyl acetate–ethanol–dimexide and ethyl acetate–anhydrous formic acid–glacial acetic acid–water. The quantification of their amount was carried out by spectrophotometry (flavonoids expressed as rutin, hydroxycinnamic acids – as caffeic acid, and coumarin-like compounds – as coumarin). The raw material ethanolic extracts of different concentrations (20, 40, 70 and 95%) were used in pharmacological research. Antimicrobial activity was determined by the serial dilution method. Strains of gram-positive bacteria (Staphylococcus aureus ATCC 6538 FDA 209P and Bacillus cereus ATCC 10702) and fungi – Candida albicans NCTC 885-653 were used as test cultures. The presence of bioactive phenolic compounds (hydroxycinnamic acids, flavonoids, coumarins) was established and their quantitative content was determined. It was observed that the highest yield of bioactive phenolic compounds resulted from using 40–70% ethanol as extractant. The microbiological activity of hydroalcoholic extracts from Nonea rossica herb was studied. It was determined that antimicrobial activity against Staphylococcus aureus and Bacillus cereus, and antifungal activity against Candida albicans were exhibited by 40–70% ethanolic extracts of Nonea rossica, where equal content of caffeic acid and coumarin was measured. The synergistic interaction of these compounds determines the established bactericidal and fungistatic properties of such extracts.