Variation of essential oils, phenolic compounds composition andradical scavenging activity of introduced plants in Lithuania Cercidiphyllum Japonicum Siebold et Zucc., Liriodendron Tulipifera L. and Ginkgo biloba L. extracts during the vegetation periods

Abstract

Cercidiphyllum japonicum siebold et Zucc., Liriodendron tulipifera L. and Ginkgo biloba L. are woody, introduced plants in Lithuania. The aim of the work is to evaluate variation of essen­ tial oils, phenolic compounds composition and radical scavenging activity of C. japonicum siebold et Zucc., L. tulipifera L. and G. biloba L. extracts during different vegetation periods. raw material of investigated plants was prepared using different sample preparation methods (maceration, in tube extraction, static headspace solid phase microextraction and direct head­ space injection) and analysis methods (spectrophotometry, high performance liquid chroma­ tography, gas chromatography with mass spectrophotometry). While analysing the samples it was determined that the highest amount of phenolic com­ pounds, flavonoids and radical scavenging activity are in C. japonicum siebold et Zucc. leaves. The analysis of phenolic compounds in extracts of plants was carried out using a high per­ formance liquid chromatography which allows identification of these phenolic compounds: chlorogenic, gallic, o­coumaric, sinapic, protocatechuic acids and rutin in extracts. comparing different sample preparation methods for gas chromatography, it was determined that static headspace solid phase microextraction is the most effective method. The highest concentration of volatile compounds of analysed samples was in C.japonicum siebold et Zucc. leaves; the low­ est concentration of essential oils was in G. biloba L. leaves.