Identification and quantification of glycoside flavonoids in the energy crop Albizia julibrissin.

Oxygen radical absorbance capacity (ORAC) values showed that methanolic extracts of Albizia julibrissin foliage displayed antioxidant activity. High performance liquid chromatography (HPLC) and mass spectrometry (MS) techniques were utilized in the identification of the compounds. The analysis confirmed the presence of three compounds in A. julibrissin foliage methanolic extract: an unknown quercetin derivative with mass of 610 Da, hyperoside (quercetin-3-O-galactoside), and quercitrin (quercetin-3-O-rhamnoside). Fast performance liquid chromatography (FPLC) was employed to fractionate the crude A. julibrissin foliage methanolic extract into its individual flavonoid components. The flavonoids were quantified in terms of mass and their respective contribution to the overall ORAC value. Quercetin glycosides accounted for 2.0% of total foliage.

Extraction of hyperoside and quercitrin from mimosa (Albizia julibrissin) foliage.

Mimosa, an excellent energy crop candidate because of its high growth yield, also contains, on a dry basis, 0.83% hyperoside and 0.90% quercitrin. Hyperoside has been documented as having anti-inflammatory and diurectic properties, whereas quercitrin may play a role in intestinal repair following chronic mucosal injury. Thus, mimosa might first be extracted for important antioxidant compounds and then used as a feedstock for energy production. This article presents results from studies aimed at determining the effect of three extraction parameters (temperature, solvent composition, and time) on the yield of these important quercetin compounds. Conditions are sought which maximize yield and concentration, whereas complementing subsequent biomass pretreatment, hydrolysis and fermentation.