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Twenty-one samples of Sideritis species (S. scardica, S. raeseri, S. taurica, S. syriaca and S. perfoliata) from various locations on the Balkan Peninsula were evaluated for their chemical constituents. Chemical analyses were focused on secondary metabolites, particularly phenolic compounds, which have several roles in the plant physiological processes and have demonstrated significant health beneficial effects. The occurrence of hydroxycinnamic acids, phenylethanoid glycosides and flavonoids has been investigated in taxonomically related taxa of the genus Sideritis. A systematic method for phenolic compounds identification was developed using tandem mass spectrometry coupled to high performance liquid chromatography with diode array detection. Scanning for precursor ions of commonly found phenolics in Sideritis species using LC/MS n with an ion trap instrument permitted the specific determination of hydroxycinnamic acid derivatives, and phenylethanoid and flavonoid glycosides. Further characterization of each phenolic compound was performed using MS/MS production analysis and commonneutral-loss analysis. This on-line technique allowed identification of three hydroxycinnamic acid derivatives, eight phenylethanoid glycosides, and twenty-four flavonoid glycosides. All thе taxa analysed produced very similar phenolic patterns characterized by the presence of 5-caffeoylquinic acid, lavandulifolioside, verbascoside, hypolaetin 7-O-[6′′′-O-acetyl]-allosyl(1→2)glucoside, apigenin 7-(4"-p-coumaroylglucoside), 4'-O-methylisoscutellarein 7-O-[6′′′-O-acetyl]-allosyl(1→2)glucoside, and minor amounts of isoverbascoside, apigenin 7-O-allosyl(1→2)glucoside, isoscutellarein 7-Oallosyl-(1→2)-[6′′-O-acetyl]-glucoside, hypolaetin 7-O-allosyl-(1→2)-[6′′-O-acetyl]-glucoside and 4'-O-methylhypolaetin 7-O-[6′′′-Oacetyl]-allosyl-(1→2)-[6′′-O-acetyl]-glucoside. These results show that the investigated species are systematically very closely related. Phenylethanoid glycosides and flavonoid acetylglycosides are dominant and constitute 90% of the total phenolic compounds compared with hydroxycinnamic acid and flavonoid 7-O-glycosides.

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Chemical composition and antioxidant activity of essential oils and methanol extracts of needles of Pinus mugo native to R. Macedonia were investigated. Plant material was collected on Karadzica Mountain during two seasons. Essential oil was obtained by steam distillation and was analyzed by GC/FID/MS. 8 major constituents were identified:  3 -carene, -pinene, limonene+-phellandrene, germacrene D, transcaryophyllene, -cadinene, bicyclogermacrene and -cadinol. Identification of flavonoids and phenolic compounds in methanol extracts was made by LC-DAD/ESI-MS n . 14 compounds were identified (2 phenolic acids, 2 procyanidins, 7 flavonol glycosides and 3 flavonol acylated glycosides). Total phenolic content (TPC) and total flavonoid content (TFC) were measured by Folin-Ciocalteau and aluminum chloride assay, respectively. TPC and TFC values ranged from 11.41-12.17 mgGAE/g and from 4.65-6.03 mgCE/g for dried plant material, respectively. Evaluation of antioxidant activity was made using DPPH and TBARS test. IC50 values for the methanol extract ranged from 11.58-16.01 mg/mL for DPPH and from 9.41-15.76 mg/mL for TBARS assay. IC50 values for the essential oil ranged from 2.51-4.26 mg/mL and 2.59-4.14 mg/mL for DPPH and TBARS assay, respectively. The needles from Macedonian P. mugo could be considered as a potential plant source for isolation of essential oil as well as flavonoids and other phenolics as they exhibit promising antioxidant activity. Additionally, further investigation and evaluation of chemical composition as well as biological activity should be done in order to provide more data for their possible medicinal, pharmaceutical and commercial utilization.