Volatile constituents, phenolic compounds, and antioxidant activity of Calamintha glandulosa (Req.) Bentham.

BACKGROUND Calamintha glandulosa (Req.) Bentham is an aromatic perennial plant belonging to the family Lamiaceae, mostly found on rocky pastures, dry meadows, and abandoned places of the Mediterranean area. Plants belonging to this genus are known as highly aromatic and to possess significant antimicrobial and antifungal properties. The aim of this study was to provide clear picture of the volatiles of this plant species, and, for the first time, to present C. glandulosa from Croatia in terms of its antioxidant activity. RESULTS The essential oil and headspace obtained from odorous parts of C. glandulosa were subjected to capillary gas chromatography-mass spectrometry analysis. More than 50 volatile compounds were identified in six samples obtained using different extraction techniques. The most abundant components in all the samples examined were oxygenated monoterpenes, with piperitone (19.9-59.5%) and piperitenone (7.1-42.6%) as the main representatives. The total phenolic content of extracts obtained by successive Soxhlet extraction was measured, and the scavenging potency of the samples, indicated as IC50 values, were examined using four different spectrophotometric and spectrofluorimetric methods. In all cases the essential oil showed the lowest antioxidant activity, while the aqueous extract showed the highest. This can be explained by the levels of the phenolic compounds in the samples examined. CONCLUSIONS A clear picture of aroma profile of C. glandulosa is presented, and the results obtained differ from those published previously. The high antioxidant potential of C. glandulosa from Croatia was established for the first time. Results from the present study suggest further analysis on this plant species in order to define its medicinal properties.