Characterization of Phenolic Components in Polar Extracts of Eucalyptus globulus Labill. Bark by High-Performance Liquid Chromatography–Mass Spectrometry

Abstract

High-performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS) and tandem mass spectrometry (MS(n)) were used to investigate the phenolic constituents in methanol, water, and methanol/water extracts of Eucalyptus globulus Labill. bark. Twenty-nine phenolic compounds were identified, 16 of them referenced for the first time as constituents of E. globulus bark, namely, quinic, dihydroxyphenylacetic, and caffeic acids, bis(hexahydroxydiphenoyl (HHDP))-glucose, galloyl-bis(HHDP)-glucose, galloyl-HHDP-glucose, isorhamentin-hexoside, quercetin-hexoside, methylellagic acid (EA)-pentose conjugate, myricetin-rhamnoside, isorhamnetin-rhamnoside, mearnsetin, phloridzin, mearnsetin-hexoside, luteolin, and a proanthocyanidin B-type dimer. Digalloylglucose was identified as the major compound in the methanol and methanol/water extracts, followed by isorhamnetin-rhamnoside in the methanol extract and by catechin in the methanol/water extract, whereas in the water extract catechin and galloyl- HHDP-glucose were identified as the predominant components. The methanol/water extract was shown be the most efficient to isolate phenolic compounds identified in E. globulus bark.

Chemical composition and in vitro antioxidant and antitumor activities of Eucalyptus camaldulensis Dehn. leaves

“…Flavonoids, catechin (0.44 ± 0.07 g/mL) and quercetin (0.69 ± 0.11 g/mL) were observed in methanol extract only. The findings reported in current study confirm the presence of several polyphenolic compounds (phenolic acids and flavonoids) illustrated by Proestos and Komaitis (2013), Santos et al (2011) andBoulekbache-Makhlof et al (2013) in Euclayptus species.…”

Effect of the extraction technique on the recovery of bioactive compounds from eucalyptus (Eucalyptus globulus) wood industrial wastes

“…As shown in the chromatograms, the ellagic acid was the main compound in both extracts. Galloylglucoses, gallic acid and ellagic acid were also found in other parts of the eucalyptus tree, such as the bark (Santos et al, 2011).…”

Extraction of Polyphenolic Compounds from Eucalyptus globulus Bark: Process Optimization and Screening for Biological Activity

“…The temperature, time of extraction, type of solvent used and solid/liquid ratio are some of the factors to consider in optimizing the extraction efficiency in terms of quality and yield. 16−18 The existing literature discloses that an alcohol/water mixture is a better extractive medium for total phenolic content 19 and antioxidant activity 20,21 when compared to single solvents or aqueous solutions of Na 2 SO 3 or NaOH, confirming that the extractive medium is a key variable in the extractive process of the bark components. Table S1 (Supporting Information) summarizes some of the literature data concerning the yield and the content of a polar fraction of E. globulus bark.…”