Cottonization of Decorticated and Degummed Flax Fiber - A Novel Approach to Improving the Quality of Flax Fiber and its Biomedical Applications

Figures & data

Table 1. UPLC separation conditions of phenolic and terpenoid compounds.

PHENOLICS (0.4 mL/min)			TERPENOIDS (0.5 mL/min)
eluents time	0.1%(v/v) formic acid	acetonitrile	eluents time	50% methanol : 40% acetonitrile : 10% water	50% methanol : 50% acetonitrile
0’ − 1’	95%	5%	0’ − 1’	100%	0%
1’ − 12’	70%	30%	1’ − 9’	0%	100%
12’ − 16’	0%	100%	9’ − 10’	100%	0%
16’ − 17’	95%	5%

Table 2. The content of total free and bound to the cell wall phenolic compounds, terpenoic compounds, and polyamines in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the UPLC analysis. Results are mean ± SD (n = 5). Statistically significant changes are marked with asterisks (p < .05). bdl – below detection limit.

Compounds	Type	Retting	Decortication	Wet degumming	Cottonization
Free phenolic compounds [µg/g DW]	Nike	bdl	322.12 ± 43.40	bdl	8.54 ± 0.96
	B14	bdl	98.07 ± 2.64*	bdl	21.13 ± 1.30*
Bound phenolic compounds [µg/g DW]	Nike	82.75 ± 5.38	95.10 ± 9.78	25.82 ± 1.09	41.36 ± 3.50
	B14	91.38 ± 3.13	108.15 ± 6.00	31.98 ± 2.11*	58.71 ± 1.53*
Terpenoid compound: Lutein [µg/g DW]	Nike	2.22 ± 0.29	7.75 ± 0.55	1.07 ± 0.03	0.35 ± 0.01
	B14	2.68 ± 0.61	2.48 ± 0.15*	3.30 ± 0.31*	0.39 ± 0.02*
Poliamines [µg/g DW]	Nike	5.66 ± 0.48	103.16 ± 5.42	3.03 ± 0.60	0.081 ± 0.005
	B14	5.29 ± 0.51	74.18 ± 5.36*	2.58 ± 0.04	0.113 ± 0.016*

Table 3. The content of free phenolic compounds in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the UPLC analysis. Results are mean ± SD (n = 5). Statistically significant changes are marked with asterisks (p < .05). bdl – below detection limit.

Free phenolic compounds [µg/g DW]	Type	Retting	Decortication	Wet degumming	Cottonization
Caffeic acid	Nike	bdl	5.20 ± 1.12	bdl	bdl
	B14	bdl	0.64 ± 0.06*	bdl	bdl
Vanillin	Nike	bdl	bdl	bdl	0.82 ± 0.07
	B14	bdl	bdl	bdl	0.79 ± 0.08
Orientin-glycoside	Nike	bdl	13.91 ± 1.26	bdl	bdl
	B14	bdl	3.92 ± 0.18*	bdl	bdl
Apigenin-diglycoside	Nike	bdl	9.50 ± 1.03	bdl	bdl
	B14	bdl	4.00 ± 0.20*	bdl	bdl
Orientin-glycoside	Nike	bdl	22.19 ± 1.58	bdl	bdl
	B14	bdl	5.71 ± 0.20*	bdl	bdl
Orientin-glycoside	Nike	bdl	29.84 ± 4.47	bdl	bdl
	B14	bdl	10.17 ± 0.49*	bdl	bdl
Isoorientin	Nike	bdl	189.55 ± 28.07	bdl	4.21 ± 0.51
	B14	bdl	53.06 ± 0.23*	bdl	12.06 ± 0.69*
Orientin	Nike	bdl	33.17 ± 4.68	bdl	2.61 ± 0.30
	B14	bdl	13.07 ± 0.95*	bdl	5.92 ± 0.39*
Vitexin	Nike	bdl	18.76 ± 2.87	bdl	0.90 ± 0.08
	B14	bdl	7.57 ± 0.52*	bdl	2.35 ± 0.15*

Table 4. The content of bound to the cell-wall phenolic compounds in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the UPLC analysis. Results are mean ± SD (n = 5). Statistically significant changes are marked with asterisks (p < .05). bdl – below detection limit.

Bound phenolic compounds [µg/g DW]	Type	Retting	Decortication	Wet degumming	Cottonization
Vanillic acid	Nike	9.06 ± 1.63	bdl	bdl	bdl
	B14	6.46 ± 0.72*	bdl	bdl	bdl
4-hydroxybenzoic aldehyde	Nike	5.86 ± 0.48	1.16 ± 0.29	bdl	22.25 ± 3.24
	B14	4.56 ± 0.46*	1.18 ± 0.87	bdl	37.78 ± 0.98*
Vanillin	Nike	19.96 ± 2.77	8.83 ± 1.60	12.10 ± 0.66	4.69 ± 0.49
	B14	20.52 ± 0.69	10.37 ± 0.15	13.93 ± 1.79	4.75 ± 0.20
Coumaric acid	Nike	4.77 ± 0.58	5.77 ± 2.02	1.35 ± 0.21	1.38 ± 0.06
	B14	5.08 ± 0.21	4.81 ± 0.35	1.65 ± 0.05*	1.05 ± 0.19
Syringic aldehyde	Nike	16.02 ± 1.70	bdl	2.40 ± 0.34	3.20 ± 1.00
	B14	14.38 ± 2.66	bdl	2.54 ± 0.24	5.55 ± 1.13
Ferulic acid	Nike	22.54 ± 3.48	32.22 ± 5.37	7.51 ± 0.76	7.17 ± 0.72
	B14	28.36 ± 1.02*	28.89 ± 1.73	10.15 ± 1.06*	6.76 ± 0.19
Vitexin	Nike	10.39 ± 1.82	10.35 ± 2.97	2.45 ± 0.12	2.66 ± 0.17
	B14	16.59 ± 0.81*	14.73 ± 2.11	3.71 ± 0.19*	2.81 ± 0.02
Caffeic acid	Nike	bdl	6.61 ± 2.07	bdl	bdl
	B14	bdl	5.22 ± 0.56	bdl	bdl
Isoorientin	Nike	bdl	18.77 ± 4.77	bdl	bdl
	B14	bdl	20.87 ± 2.79	bdl	bdl
Orientin	Nike	bdl	12.55 ± 4.94	bdl	bdl
	B14	bdl	23.26 ± 4.51	bdl	bdl

Table 5. The content of free polyamines (PA1) conjugated polyamines (PA2) and cell wall-bound polyamines (PA3), including individual polyamines: putrescine, spermidine, and spermine in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stem. Data were obtained from the UPLC analysis. Results are mean ± SD (n = 4). Statistically significant changes are marked with asterisks (p < .05). bdl – below detection limit.

Polyamines [µg/g DW]		Type	Retting	Decortication	Wet degumming	Cottonization [ng/g DW]
PA1	Putrescine	Nike	0.84 ± 0.07	7.38 ± 0.07	0.91 ± 0.03	12.80 ± 0.69
		B14	0.39 ± 0.04*	10.78 ± 0.72*	0.71 ± 0.06	4.95 ± 0.38*
	Spermidine	Nike	1.05 ± 0.07	3.05 ± 1.19	1.09 ± 0.54	0.02 ± 0.03
		B14	0.69 ± 0.07*	3.03 ± 0.30	0.68 ± 0.33	0.19 ± 0.16
	Spermine	Nike	0.02 ± 0.00	0.34 ± 0.04	0.22 ± 0.05	bdl
		B14	0.02 ± 0.00	0.82 ± 0.13*	0.26 ± 0.03	bdl
PA2	Putrescine	Nike	1.00 ± 0.01	1.08 ± 0.38	0.14 ± 0.17	11.61 ± 0.93
		B14	0.63 ± 0.07*	1.46 ± 1.02	0.05 ± 0.16	7.22 ± 4.19
	Spermidine	Nike	1.33 ± 0.05	11.90 ± 0.84	bdl	2.78 ± 0.22
		B14	1.27 ± 0.18	6.38 ± 0.93*	bdl	4.25 ± 1.36
	Spermine	Nike	0.04 ± 0.01	0.11 ± 0.04	0.12 ± 0.00	bdl
		B14	0.07 ± 0.03	bdl*	0.05 ± 0.00	bdl
PA3	Putrescine	Nike	0.84 ± 0.15	13.64 ± 1.15	0.48 ± 0.13	15.98 ± 1.97
		B14	0.73 ± 0.14	15.26 ± 1.91	0.39 ± 0.09	20.98 ± 0.43*
	Spermidine	Nike	0.54 ± 0.25	63.41 ± 5.15	0.08 ± 0.02	44.02 ± 8.06
		B14	1.46 ± 0.19*	35.82 ± 3.98*	0.09 ± 0.02	75.16 ± 0.33*
	Spermine	Nike	bdl	0.73 ± 0.15	0.20 ± 0.03	0.18 ± 0.03
		B14	0.03 ± 0.01*	0.63 ± 0.10	0.16 ± 0.02	0.33 ± 0.06*
PA1		Nike	1.91 ± 0.07	10.77 ± 1.23	2.22 ± 0.54	12.82 ± 0.03
		B14	1.10 ± 0.07*	14.63 ± 0.44*	1.65 ± 0.33	5.13 ± 0.16*
PA2		Nike	2.37 ± 0.05	13.09 ± 0.87	0.26 ± 0.00	14.38 ± 0.22
		B14	1.97 ± 0.22	7.38 ± 1.09*	0.10 ± 0.08	11.47 ± 1.36
PA3		Nike	1.39 ± 0.25	77.78 ± 5.30	0.76 ± 0.02	60.18 ± 8.09
		B14	2.22 ± 0.20*	51.71 ± 4.08*	0.65 ± 0.02	96.47 ± 11.66*

Figure 1. The antioxidant potential of extracts from fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems determined by DPPH (Figure 1a) and FRAP (Figure 1b) methods. Statistically significant changes are marked with asterisks (p < .05).

Figure 2. The content of cell wall polymers (cellulose, lignin, pectin, and hemicellulose) in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Statistically significant changes are marked with asterisks (p < .05).

Table 6. The content of fatty acids in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the GC-FID analysis. Results are mean ± SD (n = 4). Statistically significant changes are marked with asterisks (p < .05).

Fatty acids (mg/100 g DW)	Type	Retting	Decortication	Wet degumming	Cottonization
C16:0	Nike	290.05 ± 2.28	212.97 ± 5.13	282.08 ± 9.29	123.02 ± 1.81
	B14	269.34 ± 8.95	201.58 ± 6.02	242.58 ± 6.31*	152.20 ± 6.04*
C18:0	Nike	172.23 ± 2.02	121.56 ± 3.60	177.96 ± 6.25	76.78 ± 1.41
	B14	163.97 ± 4.60	111.93 ± 3.59*	158.93 ± 4.07*	85.96 ± 5.40*
C18:1	Nike	64.80 ± 0.11	40.96 ± 1.96	40.77 ± 3.22	14.25 ± 0.36
	B14	52.68 ± 1.89	39.29 ± 1.15	34.53 ± 0.88*	14.34 ± 2.70
C18:2	Nike	63.38 ± 0.46	29.21 ± 1.82	17.41 ± 0.79	4.86 ± 0.25
	B14	47.91 ± 1.32*	14.94 ± 1.12*	12.10 ± 0.19*	16.54 ± 0.41*
C18:3	Nike	26.89 ± 0.01	7.18 ± 0.43	6.34 ± 0.50	2.23 ± 0.46
	B14	17.91 ± 0.66*	4.02 ± 0.45*	6.25 ± 0.18	4.90 ± 0.20*
sum	Nike	617.36 ± 4.88	411.88 ± 12.94	524.56 ± 7.36	221.14 ± 3.69
	B14	551.80 ± 17.42	371.76 ± 12.33*	454.39 ± 8.56*	273.95 ± 11.68*

Table 7. The content of phytosterols in fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the GC-FID analysis. Results are mean ± SD (n = 4). Statistically significant changes are marked with asterisks (p < .05).

Phytosterols (mg/100 g)	Type	Retting	Decortication	Wet degumming	Cottonization
Campesterol	Nike	21.62 ± 0.96	10.94 ± 0.42	15.82 ± 1.90	9.16 ± 1.19
	B14	22.07 ± 1.67	8.63 ± 0.92*	14.89 ± 0.80	8.56 ± 0.65
Stigmasterol	Nike	20.18 ± 0.77	14.39 ± 0.57	20.41 ± 2.33	10.96 ± 1.09
	B14	17.97 ± 0.94*	10.73 ± 0.21*	16.37 ± 1.57	11.23 ± 0.36
Β-sitosterol	Nike	82.87 ± 3.52	42.88 ± 1.21	69.76 ± 6.60	43.95 ± 3.45
	B14	101.33 ± 3.07*	36.04 ± 6.27	70.69 ± 5.99	45.60 ± 3.98

Table 8. The influence of extracts from fibers obtained by retting, decortication, wet degumming, and cottonization of flax stems on microorganisms’ growth was presented as the percentage of non-treated microorganisms (100%) ± standard deviation. Statistically significant changes are marked with asterisks (p < .05).

		Strain	Type	Retting	Decortication	Wet degumming	Cottonization
Methanolic extraction		S. aureus	Nike	115.78 ± 3.10	101.17 ± 7.83	81.51* ± 0.84	74.22* ± 3.31
			B14	101.36 ± 0.06	85.13 ± 3.88	94.84 ± 6.79	74.97* ± 1.70
		E. coli	Nike	117.58 ± 2.10	108.18 ± 1.25	93.48 ± 0.63	90.80 ± 3.65
			B14	114.79 ± 4.47	100.81 ± 1.98	95.45 ± 11.34	107.36 ± 2.33
		P. aeruginosa	Nike	99.24 ± 10.63	79.48 ± 6.50	79.49* ± 3.2	54.29* ± 17.37
			B14	85.87* ± 2.95	68.65* ± 15.81	77.70* ± 3.08	71.47 ± 11.99
		C. albicans	Nike	101.50 ± 10.04	99.12 ± 1.76	108.51 ± 12.04	111.82 ± 2.95
			B14	100.68 ± 1.35	92.64 ± 0.87	103.81 ± 6.86	92.23 ± 8.36
Extraction after hydrolysis	(10× diluted)	S. aureus	Nike	100.58 ± 1.32	76.50* ± 1.34	69,50 ± 37.93	11.50* ± 4.83
			B14	56.57 ± 14.55	70.95* ± 1.03	74,00 ± 16.71	32.63* ± 2.94
		E. coli	Nike	86.74* ± 1.84	102.40 ± 0.79	97,67 ± 7.61	12.13* ± 2.20
			B14	92.63* ± 0.59	93.74 ± 3.07	106,55 ± 3.38	74.67* ± 1.87
		P. aeruginosa	Nike	71.10 *± 2.09	94.65 ± 5.89	76,36 ± 41.85	8.86* ± 2.57
			B14	75.58 ± 31.36	97.21 ± 2.90	114,24 ± 0.88	8.27* ± 5.80
		C. albicans	Nike	107.64 ± 5.47	93.55 ± 4.14	75,64* ± 7.69	82.75 ± 8.37
			B14	73.41 ± 10.09	89.61 ± 9.57	92,31 ± 6.41	71.99* ± 2.66

Table 9. The content of free phenolic compounds in aqueous extract no. 1 from fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the UPLC analysis.

Extract 1 [µg/g DW]	Type	Retting	Decortication	Wet degumming	Cottonization
Vanillic acid	Nike	15.01	48.55	7.47	bdl
	B14	15.20	56.24	5.53	0.28
Apigenin-glycoside	Nike	4.92	42.97	3.38	0.23
	B14	11.98	123.47	2.09	0.69
Vanillin	Nike	3.61	0.00	2.77	0.14
	B14	16.23	0.00	1.21	0.11
Orientin-glycoside	Nike	5.17	643.97	3.43	bdl
	B14	15.19	265.83	1.40	0.69
Apigenin-diglycoside	Nike	2.50	233.35	1.37	bdl
	B14	8.23	71.60	bdl	bdl
Orientin-glycoside	Nike	7.57	737.87	3.12	bdl
	B14	19.52	229.31	1.42	0.24
Orientin-glycoside	Nike	bdl	354.42	bdl	bdl
	B14	10.42	71.63	bdl	0.33
Isoorientin	Nike	2.51	1816.32	1.56	0.20
	B14	6.18	342.14	bdl	5.92
Orientin	Nike	12.39	1101.54	5.01	bdl
	B14	35.84	462.57	3.40	0.77
Vitexin	Nike	bdl	155.77	1.61	bdl
	B14	0.48	30.19	1.85	1.81

Table 10. The content of bound to the cell wall phenolic compounds in aqueous extract no. 2 from fibers obtained by retting, decortication, wet degumming, and cottonization of B14 and Nike flax stems. Data were obtained from the UPLC analysis.

Extract 2 [µg/g DW]	Type	Retting		Decortication	Wet degumming	Cottonization
Vanillic acid	Nike	52.33		87.22	35.06	0.89
	B14	88.69		47.97	30.44	1.35
4-hydroxybenzoic aldehyde	Nike	19.95		20.75	16.24	1.02
	B14	24.35		15.89	12.10	1.44
Vanillin	Nike	113.45		166.97	86.75	4.07
	B14	201.16		91.47	63.81	5.69
Coumaric acid	Nike	bdl		21.61	bdl	0.16
	B14	26.51		54.78	4.44	0.07
Syringic aldehyde	Nike	158.82		205.06	89.71	2.21
	B14	245.56		141.29	64.44	3.76
Ferulic acid	Nike	51.87		386.88	36.75	1.30
	B14	326.94		81.23	41.49	1.30
Vitexin	Nike	14.88		70.50	7.37	0.20
	B14	75.07		23.22	7.89	0.15
Isoorientin	Nike	bdl		39.67	bdl	bdl
	B14	bdl		bdl	bdl	bdl
Orientin	Nike	bdl		73.25	bdl	bdl
	B14	bdl		23.57	bdl	bdl

Figure 3. The influence of extracts from fibers obtained by retting, decortication, wet degumming, and cottonization of flax stems on fibroblast cell growth presented as the percentage of non-treated fibroblast cells (100%) ± standard deviation. Statistically significant changes are marked with asterisks (p < .05).

Figure 4. Transcript levels of pro-inflammatory (IL6 and MCP1), anti-inflammatory (IL10 and ICAM), and redox (CAT and SOD) genes in the V79 cell line treated with extracts (extract type 1 - 4A and extract type 2 - 4B) containing phenolic compounds from fibers obtained by retting, decortication, wet degumming, and cottonization of flax stems compared to control (untreated cells = 1). Statistically significant changes are marked with asterisks (p < .05).