A comparative study on chemical composition and antimicrobial activity of essential oils from three Phlomis species from Uzbekistan.

Essential oils obtained from the aerial parts of Phlomis bucharica, P. salicifolia and P. sewerzowii were determined using GC-FID and GC-MS methods. A total of 76 components were identified in the three species representing 97.12, 88.34, and 96.41% of the whole oil, respectively. High percentages of thymol (20.41%) and camphor (14.46%) exist in P. bucharica oil. Methyl palmitate predominates in P. salicifolia oil representing 51.15% whereas thymol (35.76%) is the major constituent in P. sewerzowii essential oil. GC-MS analyses showed that P. bucharica and P. sewerzowii are more closely related comparable to P. salicifolia. The antimicrobial activity of the essential oils was assessed against different microorganisms using agar-disc diffusion and broth microdilution assay. Among the three tested species, the essential oil of P. salicifolia showed the highest antibacterial activity.