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

Phytochemical characteristics and antimicrobial properties of extracts were studied in Nonea rossica Steven (Boraginaceae), which is widespread in Russia. The aerial part (herb) of N. rossica was harvested from a steppe meadow in the Novosibirsk region during flowering. The qualitative composition of biologically active compounds (BACs) was determined by thin-layer chromatography. Quantitative assays were carried out by spectrophotometry; flavonoids, hydroxycinnamic acids, and coumarin-like compounds were measured with reference to rutin, caffeic acid, and coumarin, respectively. Antimicrobial activity was determined by the serial dilution method. Gram-positive bacterial (Staphylococcus aureus ATCC 6538 FDA 209P and Bacillus cereus ATCC 10702) and fungal (Candida albicans NCTC 885-653) strains were used as test cultures. Phenolic BACs (hydroxycinnamic acids, flavonoids, and coumarins) were detected, and their quantitative contents determined. The highest yield of phenolic BACs was achieved using 40-70% ethanol as an extractant. Antimicrobial activity against S. aureus and B. cereus and antifungal activity against C. albicans were detected in N. rossica herb extracts prepared using 40-70% ethanol. The extracts were tested for the contents of caffeic acid and coumarin. Synergistic interactions of these compounds determined the bactericidal and fungistatic properties of the extracts.