Study of the antioxidant activity of Thymus sibthorpii Bentham (Lamiaceae)

Figures & data

Figure 1. Structures of the isolated compounds.

Rosmarinic acid methyl ester (8).

Table 1. Polyphenol content of different plant extracts.

Extracts	mg of GAE/1gr extract ± SD*
PE	1.5 ± 0.1*
DM	0.2 ± 0.005*
M	5.4 ± 0.25*
HE	2.5 ± 0.15*
ET	1.5 ± 0.008*
EA	3.5 ± 0.005*
BU	0.4 ± 0.0002**

*SD < 10% of the mean.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).

Table 2: % Interaction of different plant extracts with DPPH.

	±SD*
	(100 μl)		(10 μl)
Extracts	20 min	60 min	20 min	60 min
PE	38.4 ± 0.5*	62.2 ± 0.9**	17.9 ± 0.1*	34.2 ± 1.0*
DM	23.7 ± 0.2*	22.4 ± 0.7**	7.9 ± 0.3**	49.5 ± 0.4*
M	95.3 ± 1.9*	87.6 ± 1.0**	91.7 ± 1.3**	92.1 ± 0.6**
HE	89.8 ± 2.1*	91.1 ± 1.4**	39.8 ± 0.9**	60.2 ± 0.1**
ET	99.7 ± 1.8**	93.1 ± 1.9**	95.2 ± 2.1*	94.7 ± 2.1**
EA	92.8 ± 1.7*	92.1 ± 1.3*	92.4 ± 1.8*	95.9 ± 2.3**
BU	85.4 ± 1.2**	87.6 ± 1.6*	90.7 ± 0.9*	86.4 ± 1.8**
W	83.7 ± 1.0*	86.4 ± 1.1**	86.4 ± 1.3*	87.9 ± 1.2*
NDGA	94 ± 2.1**	97 ± 1.5**	88 ± 1.2*	96 ± 1.6*

*SD < 10% of the mean.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).

Table 3. Percentage soybean LOX inhibitory activity of extracts.

Extracts (10 μL)	% Inhibition ± SD*
PE	12.6 ± 1.0*
DM	48.3 ± 0.7*
M	14.1 ± 0.1*
HE	36.8 ± 0.9*
ET	27.1 ± 0.5*
EA	8 ± 0.3**
BU	13.5 ± 0.1*
W	9.7 ± 0.8*
NDGA	88 ± 2.1**

*SD < 10% of the mean.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).

Table 4. Percentage interaction of isolated compounds with DPPH.

Compounds (50 μΜ)	% interaction 20 min ± SD*	Interaction % 60 min ± SD*
1	31.3 ± 1.5*	54.4 ± 2.3*
2	5.8 ± 0.1*	16.4 ± 0.5*
3	17.3 ± 0.9*	21.1 ± 1.0**
4	54.3 ± 1.7**	53.7 ± 1.2**
5	61.9 ± 2.3*	58.9 ± 0.8**
6	78.8 ± 2.1*	79.9 ± 1.1**
7	81.6 ± 1.6**	81.2 ± 1.9*
8	65.0 ± 2.1*	70.2 ± 0.8**
NDGA	83 ± 1.1*	87 ± 1.5**

*SD < 10% of the mean.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).

Table 5. % Inhibition of linoleic acid peroxidation induced by the isolated compounds.

Compounds	10 μM	50 μM	100 μM
1	nt	nt	0.0
2	nt	Nt	46.6 ± 0.4*
3	nt	nt	0.0
4	79.2 ± 2.3*	100 ± 2.3**	100 ± 2.8**
5	22.7 ± 0.8*	nt	100 ± 3.3**
6	nt	0.0	50.2 ± 1.0*
7	45.8 ± 1.6**	nt	100 ± 1.8**
8	75.8 ± 3.1*	nt	100 ± 2.5**
Trolox	63 ± 1.3*	76 ± 2.5*	83 ± 1.2*

*SD < 10% of the mean; *SD < 10% of the mean; nt: not tested.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).

Table 6. Percentage soybean LOX inhibitory activity of the isolated compounds.

Compounds	10 μM	100 μM
1	0	29.2 ± 0.2**
2	0	34 ± 0.5**
3	19.8 ± 0.1*	72.4 ± 1.6**
4	nt	0
5	nt	39.3 ± 0.3*
6	22.9 ± 0.3**	87 ± 0.9*
7	25.9 ± 0.7**	92.4 ± 2.6*
8	10.6 ± 0.8**	79.4 ± 1.6**
NDGA	86 ± 1.9**	91 ± 2.1**

*SD < 10% of the mean; nt: not tested.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).

Table 7. Superoxide anion scavenging activity % of the isolated compounds.

Compounds	10 μM	100 μM
1	nt	15.2 ± 0.4
2	0	0
3	7.2 ± 0.5*	0
4	27.4 ± 1.1*	nt
5	nt	21.3 ± 1.1*
6	nt	13.7 ± 0.8**
7	nt	28.6 ± 1.3*
8	13.3 ± 0.25*	0
Caffeic acid	45% ± 0.3**IC50 = 600 μΜ ± 2.3**

*SD < 10% of the mean; nt: not tested.

In all cases, significant difference from control: *p < 0.1 **p < 0.01 (Student’s t-test).