Effect of Extraction Conditions on the Antioxidant Activity of Olive Wood Extracts

Table 2

Extraction yields and radical scavenging percentages of several extracts prepared by the extraction procedures E1–E6 from the olive wood sample A.

Extract^a	Procedure^b	Solvent	Temperature	Yield^c	RSP ± SD^d
A1	E1	EtOH	r.t.	54.1	48.8 ± 0.2
A2	E2	EtOAc	r.t.	11.0	63.2 ± 0.8
A3	E2	EtOH	r.t.	51.4	42.1 ± 0.4
A4	E3	EtOAc	Reflux	14.2	64.9 ± 0.1
A5	E4	EtOAc	r.t.	8.6	48.5 ± 0.8
A6	E4	EtOH	r.t.	40.0	42.1 ± 1.1
A7	E4	EtOH : H2O 3 : 2	r.t.	111.4	27.1 ± 1.9
A8	E4	H2O	r.t.	80.0	17.1 ± 1.4
A9	E4	H2O : HCOOH 4 : 1	r.t.	122.9	25.9 ± 0.5
A10	E4	EtOAc	Reflux	11.4	50.9 ± 1.5
A11	E4	EtOH	Reflux	94.3	52.4 ± 1.7
A12	E4	EtOH : H2O 3 : 2	Reflux	145.7	39.6 ± 1.1
A13	E4	H2O	Reflux	108.6	44.0 ± 0.2
A14	E4	H2O : HCOOH 4 : 1	Reflux	211.4	33.7 ± 1.8
A15	E5	EtOAc	Reflux	22.6	54.3 ± 0.3
A16	E5	n-BuOH	Reflux	54.9	45.7 ± 1.3
A17	E5	H2O	Reflux	42.0	11.1 ± 0.8
A18	E6	Et2O	Reflux	4.0	48.5 ± 0.1
A19	E6	CHCl3	Reflux	4.0	26.1 ± 0.4
A20	E6	n-BuOH	Reflux	33.7	39.6 ± 0.1
Rosemary oleoresin (reference extract)^d					95.0 ± 0.3

aExtracts A1–A20 were prepared from the olive wood sample A, collected in April, 2003 (during the pruning period) at the village of Fuensanta, Jaén province, Spain.
bProcedures E1–E6 are detailed in Figures 1–6.
^cYield is expressed as grams of extract per kilogram of olive wood sample.
^dRadical scavenging percentage (RSP) is expressed as DPPH^• scavenging (%). Values are means of three replicates ± SD (standard deviation).
^dCommercially available rosemary extract was used as reference, at the same concentration (50 𝜇g mL⁻¹).