Chemical profiling, antimicrobial, anti-enzymatic, and cytotoxic properties of Phlomis fruticosa L.

Structural diversity of biologically active compounds identified in plants after many years of storage is rarely reported in literature. Herein, we studied chemical profile and biological activities of Phlomis fruticosa L. after plant material storage for 20 years. Chemical analyzes were performed by UHPLC-LTQ-Orbitrap/MS, and revealed presence of 44 compounds: including 13 phenolic acids, 9 phenylethanoids, 20 flavonoids and 2 phenolic related compounds (a phenolic acid derivative and an aliphatic alcohol). The extract showed antimicrobial activity, being the most potent against Aspergillus fumigatus with minimum inhibitory concentration of 0.31 mg/mL. Also, the extract was able to inhibit biofilm formed by Candida species and to inhibit biofilm formation by Staphylococcus aureus. Obtained results revealed that the extract has potential to interfere with the cell membrane permeability of Candida albicans and to suppress production of virulence factor staphyloxanthin in S. aureus. Furthermore, the extract inhibited the activity of α-amylase which is one of the therapeutic targets for diabetes type II. Also, the antiproliferative effect of the extract was demonstrated on human cancer cell lines, while the extract did not exhibit any cytotoxic effect on primary human cells. Based on the obtained results, P. fruticosa could be an interesting source of biologically active compounds even after long term storage.