GAS CHROMATOGRAPHY-MASS SPECTROMETRY ANALYSIS OF FOUR FRACTIONS FROM COMFREY ROOTS AND EVALUATION OF THEIR ANTIMICROBIAL ACTIVITY

The current study aimed to evaluate the metabolite profile of four subsequent extracts from comfrey roots (hexane, chloroform, ethyl acetate, and 95% ethanol) and its antimicrobial potential. The extracts were obtained by subsequent maceration in each solvent for a duration of each extraction 24 hours. The resulting extracts were evaporated to dryness and analyzed by gas chromatography coupled with mass spectrometry (GC-MS). The agar diffusion method was used to evaluate the antimicrobial potential of comfrey root extracts against Gram-positive and Gram-negative bacteria, yeasts, and fungi. The highest extractive yield was found in 95 % ethanol fraction of 2.12%. It was detected high extractable contents of fatty acids, sterols, phenolic acids, amino acids, organic acids, sugars, and polyols in the obtained fractions; ethyl acetate and ethanol fractions showed the highest number of compounds—32 and 29, respectively. In the hexane and chloroform fractions dominated fatty acids and sterols. The results from antimicrobial activity showed that hexane and chloroform fractions showed moderate antimicrobial activity against Bacillus subtilis ATCC 6633, Bacillus amyloliquefaciens 4BCL-YT, Micrococcus luteus 2YC-YT, and Pseudomonas aeruginosa ATCC 9027. In general, hexane and ethyl acetate fractions showed low activity against fungi, against which other fractions were inactive. Only ethyl acetate and ethanol fraction showed antimicrobial against Candida albicans NBIMCC 74. In general, hexane and ethyl acetate fractions showed the highest range of antimicrobial activity against tested microorganisms. This research enriched the knowledge for metabolite composition of comfrey root extracts and demonstrated their potential antimicrobial effect for future application in cosmetics and pharmacy.