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

authors	Mota, I; Pinto, PCR; Novo, C; Sousa, G; Guerreiro, O; Guerra, AR; Duarte, MF; Rodrigues, AE
nationality	International
journal	INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
keywords	RESPONSE-SURFACE METHODOLOGY; CASTANEA-SATIVA SHELL; ANTIOXIDANT ACTIVITY; NATURAL ANTIOXIDANTS; CHEMICAL-COMPOSITION; PHENOLIC-COMPOUNDS; MASS-SPECTROMETRY; STEM BARK; E-RUDIS; WOOD
abstract	The bark of Eucalyptus globulus is a promising source of polyphenolic compounds that could be extracted employing polar solvents. Extraction experiments were planned according to the Box-Behnken design to evaluate the effect of temperature and time of extraction and the ethanol/water ratio on the dependent variables total phenolic content (TPC; as gallic acid equivalents, GAE), antioxidant activity (AA; as millimoles of ascorbic acid equivalents, AAE), proanthocyanidins (Pac; as mimosa extract equivalents, MEE), Stiasny number (SN), and coextracted total carbohydrates (TC). Response surface models were developed, and statistical analysis of variance was performed. A maximum of TPC of 32% (W-GAE/W-extract) was achieved for 264 min, 82.5 degrees C, and 52% ethanol corresponding to about 2% of the bark weight. These conditions are close to those leading to maximum values of compounds with AA (2.1 mmol(AAE)/g(extract)) and Pac 14% (w(MEE)/w(extract)). TC in the extract and the SN predicted were 22.7% (w(TC)/w(extract)) and 37, respectively. Preliminary studies concerning the biological activity of some extracts have demonstrated their differential capacity to reduce human breast cancer cell proliferation.
publisher	AMER CHEMICAL SOC
issn	0888-5885
year published	2012
volume	51
issue	20
beginning page	6991
ending page	7000
digital object identifier (doi)	10.1021/ie300103z
web of science category	Engineering, Chemical
subject category	Engineering
unique article identifier	WOS:000304285400001