Determination of antioxidant potential and volatile compound profiles in some Sideritis taxa

In this study, the total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity, and volatile components were determined in some endemic Sideritis taxa naturally distributed in the highlands of Denizli and Antalya (Turkey). The aerial flowering parts of Sideritis galaticaBornm. (SG), Sideritis pisidicaBoiss.& Heldr. apud Bentham (SP), Sideritis libanotica Labill. subsp. linearis (Bentham) Bornm. (SL), and Sideritis stricta Boiss.& Heldr. (SS), which are commonly consumed as herbal tea, were extracted using 80% methanol. The highest TPC (30.41 mg GAE/g) was found in Sideritis galatica, while the highest TFC (25.89 mg QE/g) and antioxidant capacity (0.54 mg/mL) were observed in Sideritis stricta. Regarding volatile components determined by GC-MS (Headspace), -pinene was dominant in SG, -myrcene in SP, -pinene in SL, and -pinene in SS. Each of the four Sideritis taxa examined displayed distinct biological properties. Furthermore, each taxon showed unique profiles in terms of dominant volatile compounds. These findings shed light on the potential pharmacological and aromatic uses of the studied Sideritis taxa.