Analysis of different extracts of Satureja hortensis L. obtained with various solvents (by supercritical CO 2 and by traditional extraction techniques) is presented in this study to identify and to determine the major constituents responsible for the antioxidant activity. The total polyphenol and total flavonoid contents of the extracts were determined by spectrophotometric method and no correlation was found with the antioxidant activites. HPLC was also used to measure two diterpenes as carnosol and carnosic acid in the extracts. Neither carnosol nor carnosic acid were identified. Individual antioxidants as rosmarinic and caffeic acids were identified and quantified with TLC-densitometry method. Rosmarinic acid was found in higher amount than caffeic acid. The content of rosmarinic acid was also determined with HPLC. A good correlation coefficient of 0.85 was found between the antioxidant activity and amount of rosmarinic acid, which leads to the conclusion that rosmarinic acid is among the main antioxidant compounds of S. hortensis L. plant.

The study has shown that the yield and total antioxidant activity of the marigold extracts were affected by the pressure and temperature of SC-CO(2) , and that online HPLC technique could be used as an efficient and rapid method for separation and identification of bioactive compounds from a complex mixture.

Qualitative and quantitative analysis was performed on supercritical-fluid and conventional Soxhlet extracts of Betula pendula Roth., Alnus glutinosa (L.) Gaertn., and Platanus hybrida Brot. bark. The effect of the two extraction methods on extraction yields was compared. Lupeol and β-sitosterol were identified in the bark extracts by TLC and by GC-MS. The main components were betulin and lupeol followed by βsitosterol; betulinic acid seemed to be a minor constituent. Betulin content was determined by RP-HPLC, with acetonitrile-water 80:20 (v/v) as mobile phase. Comparison of the extraction methods showed that supercritical-fluid (scCO 2 + EtOH) and ethanolic Soxhlet extraction resulted in the highest extraction yields. Accumulation of betulin derivatives was higher in supercritical-fluid extracts (scCO 2 + EtOH) than in conventional Soxhlet extracts.

Plane tree is planted as ornamental tree in urban areas. This tree naturally sheds its bark during the spring; however, the shed bark is commonly regarded as a waste material without any significant application.On the other hand, the bark of plane tree may be an important source of industrially relevant compounds, most notably betulinic acid. In our study a Supercritical Fluid Ultra Performance Convergence Chromatography (UPC2) system coupled with Evaporative Light Scattering Detector (ELSD), along with conventional HPLC, GC-MS and NMR were successfully utilized to analyze triterpenes in the extracts from the bark of plane tree. We show that not only betulinic acid, but other important triterpenes: betulin, betulinic aldehyde and β-sitosterol are also present in the extract of the plane tree bark. Among these the main compound is betulinic acid, with up to an order of magnitude larger concentration than the other constituents. The applied extraction method has a significant role on the concentration of the different compounds in the extracts. Most notably, neat scCO2 is not suitable to extract the polar betulinic acid, however betulin and betulinic aldehyde can be extracted selectively.