Quencher procedure for analysis of biologically active compounds of hop (Humuluslupulus L.) leaves and cones

This project was financed by Research Council of Lithuania project No. 09.3.3-LMT-K-712-03-0133Hop (Humulus lupulus L.) is a plant, which is probably the best known for being used in brewery for bittering. Bitter a- and p-acids found in cones of hops have antibacterial and antkmdant properties. However, it is knovvn that hops contain other biologically active compounds (i.e. xanthohumoį 8-prenylnaringenin and others) that have anti-cancer, radical scavenging, peroxide reducing and antioxidant properties [1,2]. It is very likely, that biologically active compounds can be found in different proportions across the whole plant. It is also possible that various parts of hop plant contain biologically active compounds that are insoluble in some solvents. There is lack of information about biologically active compounds of the leaves of hops. The QUENCHER procedure, standing for QUick, Easy, New, CHEap and Reproducible, is the method, which relies on the surface reaction phenomenon between solid (bound or trapped antioxidant compounds) and dissolved materials [3]. The purpose of this study was to apply QUENCHER procedure for determination of phenolic compounds, flavonoid compounds and radical scavenging activity of hop leaves and cones as well as to compare the results with that obtained using extract of raw materiaį which prepared by conventional liąuid extraction. Five different Lithuanian hop varieties (Raudoniai, Fredos taurieji, Fredos derlingieji, Kauno ankstyvieji, Kauno gražieji) growing in Kaunas Botanical Garden of Vytautas Magnus University were analyzed. To our knowledge, it is the first study on the application of QUENCHER procedure for the analysis of phenolic compounds of different parts of hops. The totai amount of phenolic compounds, the amount of flavonoids and radical scavenging activity using DPPH (l,l-diphenyl-2-picrylhydrazyl) were determined using spectrophotometric methods [4]. Results were expressed as rutin eąuivalents mg/g of plant. [...]Biochemijos katedraBotanikos sodasGamtos mokslų fakultetasVytauto Didžiojo universiteta