Antibacterial and antimutagenic activity of extracts aboveground parts of three Solidago species: Solidago virgaurea L., Solidago canadensis L. and Solidago gigantea Ait.

Hexane and ethanolic extracts obtained from aboveground parts of three Solidago species (Solidago virgaurea L., Solidago canadensis L. and Solidago gigantea Ait.) were analyzed by gas chromatography-mass spectrometry (GC-MS). Thirty nine and forty nine volatile compounds were detected, respectively in ethanolic and hexane extracts of S. virgaurea, sixty two and forty six in S. canadensis extracts, respectively and seventy three and forty five compounds in the ethanolic and hexane extracts of S. gigantea. Moreover, evaluation of the content of total secondary metabolites (flavonoides, o-dihydroxyphenols) was made. It was found that both ethanolic and hexane extracts showed an antibacterial activity and acted strongly to Gram-positive (Staphyllococcus aureus, Staphyllococcus faecalis and Bacillus subtilis) than Gram-negative (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa) bacteria. Hexane extract of S. canadensis acted the strongest of Gram-positive bacteria (minimal inhibitory concentration (MIC) values: 5 to 10 mg/ml), while the other hexane extracts showed rather weak effect (MIC values: 100 and > 100 mg/ml). In the case of ethanolic extracts relatively strong activity against Gram-positive bacteria were found in S. gigantea and S. canadensis (MIC values: from 10 to 50 mg/ml). In general, alcohol extracts had slightly stronger antibacterial properties compared with lipophilic ones. However, hexane extracts of the S. virgaurea, S. canadensis and S. gigantea herb exhibited antimutagenic activity (at a concentration of 2.5 mg/ml), whereas ethanolic extracts, in the applied range of concentrations, did not show antimutagenic activity.