Journal of Food Bioactives, ISSN 2637-8752 print, 2637-8779 online
Journal website www.isnff-jfb.com

Original Research

Volume 8, December 2019, pages 92-98


Wood extracts as unique sources of soluble and insoluble-bound phenolics: reducing power, metal chelation and inhibition of oxidation of human LDL-cholesterol and DNA strand scission

Figures

Figure 1.
Figure 1. Agarose gel electrophoresis of inhibition of peroxyl radical-induced DNA scission by soluble wood extracts. N (nicked), S (supercoiled) DNA. TA, tannic acid; BW, banana wood; PW, pinewood; QW, quibracho wood; OW, oak wood; OPW, old date palm wood; SPW, seedling date palm wood.
Figure 2.
Figure 2. Agarose gel electrophoresis of inhibition of hydroxyl radical-induced DNA scission by soluble wood extracts. N (nicked), S (supercoiled) DNA. ; SPW, seedling date palm wood; OPW, old date palm wood; OW, oak wood; PW, pinewood; QW, quibracho wood; BW, banana ; TA, tannic acid.
Figure 3.
Figure 3. Inhibition of cupric ion-induced human low-density lipoprotein (LDL) peroxidation. TA, tannic acid; SA, syringic acid; CAT, catechin; GA, gallic acid; SPW, seedling date palm wood; OPW, Saudi old date palm wood; OW, oak wood; PW, pinewood; QW, quibracho wood; BW, banana wood.

Tables

Table 1. Total phenolic contents (TPC) of woods extracts (mg GAE/g of WE)*
 
FeedstockFraction
solubleinsoluble-bound
*GAE, gallic acid equivalents; WE, wood extract; OPW, old date palm wood; SPW, seedling date palm wood; OW, oak wood; PW, pinewood; QW, quibracho wood; BW, banana wood. Data represent mean values ± standard deviation (n = 3). Values followed by the same letters within a column are not significantly different (p > 0.05).
OPW74.65 ± 2.62b19.67 ± 0.87a
SPW80.03 ± 4.47a21.05 ± 0.60a
OW59.45 ±4.82c10.80 ± 0.10b
PW24.76 ± 0.26d7.54 ± 0.33d
QW43.34 ± 0.72c12.41 ± 0.14b
BW19.76 ± 1.01d5.98 ± 0.01c

 

Table 2. Phenolic compounds identified in woods by MALDI-TOF-MS
 
MWIdentificationOPWSPWOWPWQWBW
OPW, old date palm wood; SPW, seedling date palm wood; OW, oak wood; PW, pinewood; QW, quibracho wood; BW, banana wood.
110catechol++++
154protocatechuic acid++++
178coniferilaldehyde+++
182homovanillic acid++++
196hydroxycaffeic acid++
198syringic acid+++++
208sinapaldehyde++
2723′-hydroxydihydrodaidzein++++
286kaempferol++++
290(+)-catechin+++++
306(+)-gallocatechin+++++
316rhamnetin+++
326p-coumaric acid 4-O-glucoside++++

 

Table 3. Reducing power (RP) and iron (II) chelation capacity (CC) of wood extracts
 
FeedstockRP (mmoles TE/g WE)CC (μmoles EE/g WE)
SolubleInsoluble-boundSolubleInsoluble-bound
TE, trolox equivalent; EE, EDTA equivalents; OPW, old date palm wood; SPW, seedling date palm wood; OW, oak wood; PW, pinewood; QW, quibracho wood; BW, banana wood. Data represent mean values ± standard deviation (n = 3). Values followed by the same letters within a column are not significantly different (p > 0.05).
OPW1.18 ± 0.32a0.13 ± 0.004d10.82 ± 1.60b11.42 ± 1.67b
SPW1.37 ± 0.02a0.81 ± 0.03a21.17 ± 1.44a12.95 ± 1.85a
OW0.55 ± 0.04b0.30 ± 0.008c10.68 ± 1.33b10.28 ± 2.44c
PW0.59 ± 0.14b0.70 ±0.05b6.94 ± 1.65c3.08 ± 4.46d
QW1.15 ± 0.27a0.68±0.007b9.86 ± 1.55b8.59 ± 7.48c
BW0.35±0.03c0.10±0.004d5.54 ± 1.25c2.28 ± 2.48d

 

Table 4. Inhibition of DNA strand scission (%) of soluble wood phenolics towards hydroxyl- and peroxyl-induced oxidation*
 
FeedstockDNA strand scission inhibition (%)
Hydroxyl radicalPeroxyl radical
OPW, old date palm wood; SPW, seedling date palm wood; OW, oak wood; PW, pinewood; QW, quibracho wood; BW, banana wood. Data represent mean values ± standard deviation (n = 3). Values followed by the same letters within a column are not significantly different (p > 0.05).
SPW36.54 ± 2.39a98.42 ± 0.91a
OPW38.64 ± 0.74 a86.39 ± 1.94 b
OW29.85 ± 1.93 b69.41 ± 1.97 c
PW19.05 ± 0.63 c51.85 ± 2.66 c
QW27.07 ± 3.69 b89.06 ± 0.89 b
BW24.88 ± 4.66 b77.89 ± 2.13 c