Bioactivities of Salvia nemorosa L. inflorescences are influenced by the extraction solvents

Salvia nemorosa L. is a rich source of bioactive constituents. We have used different solvents to obtain 14 different extracts in order to evaluate solvents impact on S. nemorosa inflorescences bioactivities. Firstly, the extraction yield, chemical composition and cytotoxic properties towards HaCaT cell line were elaborated. Afterwards, we have studied the extracts bioactivity in terms of wound healing, antioxidant and antidiabetic potentials as well as antimicrobial and antibiofilm capacities; followed by the determination of the antimicrobial mechanism. The extracts yield ranged from 3.03% to 15.75% and they were dominated by epigallocatechin gallate and rosmarinic acid. The majority of extracts did not possess cytotoxic properties towards human keratinocytes. Butanol was the most appropriate solvent for the improvement of wound healing capacity. Combined extraction with ethanol and water resulted in the highest antioxidant potential of the extracts that could be attributed to the high abundance of detected polyphenols. Extraction with butanol led to the increased inhibition towards enzymes linked to type 2-diabetes and increase in antimicrobial capacities. The extracts have shown antibiofilm potential towards Staphylococcus lugdunensis biofilms with more than 90% inhibition for the most active ones. The selected extract EB7 reduced bacterial ability to adhere to human keratinocytes and provided immunomodulatory action in HaCaT cells exposed to S. lugdunensis. The antibacterial mechanism of action of the same extract was associated with moderate perturbation in the cell membrane integrity and with the reduction in bacterial mitochondrial activity. S. nemorosa inflorescences were abundant sources of bioactive polyphenols and with different extraction solvents their bioactivities were further improved. This study reported for the first time the effects of extraction solvents on various bioactivities of S. nemorosa inflorescences, supporting S. nemorosa role as a natural bioactive therapeutic agent with possible antioxidant, antidiabetic and antimicrobial applications