Determination of bioactive compounds in the extracts of yellow tea by high-performance liquid chromatography

U ovom radu ispitana je učinkovitost različitih otapala (voda, 10%-tni, 25%-tni, 50%-tni, 75%-tni i 100%-tni etanol) na ekstrakciju polifenola i alkaloida žutog čaja („rinfuzni“ oblik, filter vrećica i kuglica) tijekom različitog vremena trajanja ekstrakcije (3, 5, 10, 15 i 30 minuta). Također je uspoređena klasična ekstrakcija vodom i 75%-tnim etanolom s ekstrakcijom primjenom ultrazvučne kupelji i istih otapala. Na ekstrakciju istraživanih spojeva značajno utječe vrijeme ekstrakcije i primijenjeno otapalo. Među istraživanim otapalima, 50%-tni etanol se pokazao kao najučinkovitije otapalo prilikom ekstracije kafeina i EGCG-a iz „rinfuznog“ oblika i filter vrećice, dok je 75%-tni etanol bio najbolje otapalo za ekstrakciju istih iz čaja u kuglici. Primjena ultrazvučne kupelji nije rezultirala povećanim udjelom ekstrahiranih polifenola i alkaloida.In this study, efficiency of different solvents (water, 10, 25, 50, 75 and 100% ethanol) in extraction of polyphenols and alkaloids of yellow tea (loose form, bagged and tea ball) after different extraction time (3, 5, 10, 15 and 30 minutes) was investigated. Also classical extraction with water and 75% ethanol was compared with application of ultrasound bath with same solvents. On the extraction efficiency significantly affected prolonged time of extraction and applied solvent. Among the examined solvents, 50% ethanol was the best solvent for the extraction of caffeine and EGCG in loose form and bagged and 75% ethanol as the most efficient solvent for the extraction from tea ball. The use of ultrasound bath did not result with increased bonus rate of extracted polyphenols and alkaloids