The aim of this study is to analyze the volatile composition and antimicrobial and antioxidant activities of the essential oils of Polytrichum commune and Antitrichia curtipendula. The essential oils obtained by hydro-distillation (HD) from each species were identified by GC-MS/FID. The main components were biformene (13.06%), α-pinene (6.53%), and bornyl acetate (8.10%) in P. commune. Nonanal and tetradecanal as major compounds were 19.96% and 20.23% in A. curtipendula essential oils, respectively. Antioxidant activity of obtained essential oils was evaluated using in-vitro antioxidant models. There was no significant difference within the groups according to DPPH activity. Also, the essential oil from P. commune showed higher metal-ion chelating activities than that of the essential oil of A. curtipendula. Metal-ion chelating activities varied between 4.1% and 67.4% at the 800 µg/mL concentration, respectively. The antimicrobial activity was tested by a minimal inhibition concentration test. Each moss species showed good antimicrobial activity against microorganisms according to the results of minimal inhibition concentration experiments.

Chemical compositions of the essential oil of Sedum pallidum Bieb. var. bithynicum (Boiss.) and S. spurium Bieb. (Crassulaceae) from Turkey were investigated by GC-MS, and antimicrobial activity of the oil samples were assessed against Gram-positive/negative bacteria and yeast-like fungi. Thirty-eight and thirty-five components were identified in the essential oils and the main components of these species were found to be caryophyllene oxide from S. pallidum var. bithynicum and hexahydrofarnesyl acetone from S. spurium in the ratios of 12.8% and 15.7%, respectively. The isolated essential oils of the plants showed low antimicrobial activity against Gram-negative/positive bacteria and yeast-like fungi, having the MIC values of 500-2000 μg/mL. Antibacterial activity was not observed against Bacillus cereus.

The volatile constituents of the essential oils from the flower, leaf, and stem of Verbascum wiedemannianum were analysed by GC and GC-MS. A total of forty-three compounds were identified, constituting over 99.1%, 94.3%, and 98.7% of oil composition of the flower, leaf, and stem of V. wiedemannianum, respectively. Hydrocarbons were shown to be the main group of constituents of the flower and stem part in the ratio of 83.3% and 32.1%, respectively. But, the major group in the leaf oil was found to be aldehydes (46.8%). The main components of the flower, leaf and stem oils of V. wiedemannianum were pentadecane (58.2%), (2E)-hexenal (33.2%), and hexadecanoic acid (24.6%), respectively.