Preparations and antioxidant activities of sesamol and it's derivatives

Article abstract of DOI:10.1016/j.bmcl.2020.127716

Antioxidants is a kind of substances that can effectively inhibit the oxidation reaction of free radicals. There are many chemical components with antioxidant activity in natural products. Sesamol is one of the natural products with antioxidant activity,

Full text of DOI:10.1016/j.bmcl.2020.127716

Bioorg. Med. Chem. Lett. 31 (2021) 127716
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Preparations and antioxidant activities of sesamol and it’s derivatives
,
,
,*
Shiyang Zhoua b, Huiying Zoua, Gangliang Huangb *, Guangying Chena
a College of Chemistry and Chemical Engineering, Key Laboratory of Tropical Medicinal Resource Chemistry of Ministry of Education, Hainan Normal University, Haikou
571158, China
b Active Carbohydrate Research Institute, Chongqing Key Laboratory of Inorganic Functional Materials, College of Chemistry, Chongqing Normal University, Chongqing
401331, China
A R T I C L E I N F O
A B S T R A C T
Keywords:
Antioxidants is a kind of substances that can effectively inhibit the oxidation reaction of free radicals. There are
many chemical components with antioxidant activity in natural products. Sesamol is one of the natural products
with antioxidant activity, and it is often used as an antioxidant in food, medicine and other fields. In the present
study, sesame was used as the extraction raw material for the extraction and separated of sesamol with anti-
oxidant activity. On this basis, a total 10 of sesamol derivatives were synthesized by two steps reaction with
sesamol as starting material. The antioxidant activity of these sesamol derivatives were tested, and the test results
showed that these sesamol derivatives had a good antioxidant activity, among them, compound 4d had the best
antioxidant activity. Sesamol derivatives can be used as an antioxidant in food, medicine and other fields and it
needs a further study.
Antioxidant
Natural product
Sesamol derivatives
The strategy of resources, environment and sustainable development
has become a global hot issues facing human society, which requires
people to make efficient and precise use of useful resources1 Because of
the uniqueness and the important Socioeconomic value, biological re-
sources are widely used in all fields of society. There are many kinds of
natural products, which are widely existed in nature. The research, deep
processing and utilization of chemical substances in natural products
have an important Socioeconomic value.2,3 Due to environmental fac-
tors such as pollution, the abuse of additives and the increase of social
pressure, the proliferation of free radicals in the human body, all of them
are destructing the balance of antioxidant system. The excessive active
free radicals can attack the human cells, causing cell damage and even
death. The study shows that many serious diseases and aging are asso-
ciated with the production of excess free radicals. The research of
antioxidant substances from natural products and their applications
have aroused people’s attention.4–6 At present, the antioxidant active
ingredients have been screened out from the natural products, including
polysaccharides, flavonoids, polyphenols (lignans), alkaloids, saponins
and vitamins.7 The study on the extraction and separation of antioxidant
active components of natural products and the synthesis of derivatives is
of a great significance for the development of new antioxidants and the
study on antioxidant mechanism of antioxidants.8–10
compound. It is an important aroma component of sesame oil and an
important quality stabilizer of sesame oil. Sesamol was found in sesame
seeds, sesame oil and sesame meal, and it can be continuously decom-
posed by sesamin during hot processing. The maximum value in sesame
oil was up to 64.4 mg/100 g.10–12 As a natural food functional factor,
sesamol has a very strong antioxidant capacity and it is often used as an
antioxidant in food and medicine. Through its antioxidant activity,
sesamol has a certain inhibitory effect on the oxidation of oil and it can
prolong the shelf life of meat products, improve their quality and pre-
vent meat products from oxidation and deterioration during storage.
Sesamol is an expensive chemical, pharmaceutical intermediate raw
material, which has a good development and utilization value and
application prospect.13–15 It was an important starting material or in-
termediate for the synthesis of antihypertensive, cardio-cerebrovascular
and anticancer drugs, as well as a raw material for the pesticide syner-
gistic agent pepper butyl ether. There is a great international demand for
sesamin, especially in the field of drug synthesis.16–20 There are three
main ways to obtain sesamol: the first one is to extract it from sesame oil
(sesame); the second one is completely synthesized from 3, 4-(methyl-
enedioxy) aniline; the third one is semi-synthetic from piperonal. In this
study, the commercial sesame seed was used as the raw material to
extract the sesamol, a convenient and efficient extraction and separation
process was adopted to successfully obtain the sesamol with antioxidant
Sesamol, 3, 4-(methylenedioxy) phenol, is a natural fat-soluble lignin
* Corresponding authors.
E-mail addresses: huangdoctor226@163.com (G. Huang), chgying123@163.com (G. Chen).
https://doi.org/10.1016/j.bmcl.2020.127716
Received 2 September 2020; Received in revised form 18 November 2020; Accepted 21 November 2020
Available online 26 November 2020
0960-894X/© 2020 Elsevier Ltd. All rights reserved.

S. Zhou et al.
Bioorganic & Medicinal Chemistry Letters 31 (2021) 127716
Fig. 1. Extraction and derivatization of sesamol.
Fig. 2. The technological process of extraction and separation of sesamol.
function (Fig. 1). On the basis of the obtained sesamol, prepared by
chemical synthesis, and two derivatives of sesamol were successfully
synthesized. In the process of synthesis of sesamol derivatives, sesamol
was used as raw material to prepare the desired target compounds
through esterification and closed-loop reaction. The antioxidant activ-
ities of sesamol derivatives were studied, including hydroxyl radical
scavenging capacity, superoxide anion scavenging capacity, reducing
capacity and anti lipid peroxidation capacity.21 Sesamol derivatives can
be used as an antioxidant in food, medicine and other fields, which
needs further study.
the separation of sesamol with silica gel was completed, in order to
further purify, we selected petroleum ether for crystallization treatment,
and finally obtained pure sesamol. Under the optimal extraction and
separation conditions, the extraction rate of sesamol was 30.2 mg/100 g
(0.30‰).
Natural products and their synthetic derivatives had been recognized
as the most important source of a new class of biological activity sub-
stances and therapeutic agents for a long time. We herein present the
synthesis of sesamol derivatives and the results of the antioxidant ac-
tivity assays. Ten sesamol derivatives were synthesized by two steps
reaction with sesamol as starting material (Scheme 1). These sesamol
derivatives include open-loop structures (compounds 3a-3e) and closed-
loop structures (compounds 4a-4e). In the process of synthesis, the
sesamol (obtained by extraction and separation from sesame samples)
was esterified with substituted 2-chlorobenzoyl chloride (compounds
2a-2e) to obtain its open-loop derivatives (compounds 3a-3e). In this
step, with tetrahydrofuran (THF) as the reaction solvent, the compounds
3a-3e with high yield (yield more than 95%) could be obtained by
refluxing for 2 h without using any catalyst. Based on the derivatives of
open-loop structure, the closed-loop structure compounds 4a-4e were
synthesized. In the second step, the dimethylacetamide (DMA) was used
as the reaction solvent and anhydrous potassium carbonate (K2CO3) was
used as the acid application agent, and the closed-loop process could be
completed within 6 h of refluxing. As the closed-loop reaction was
relatively difficult, palladium acetate (Pd(OAc)2) was appropriately
added as the reaction catalyst.23 The yield of the closed-loop structure
derivatives 4a-4e were significantly lower than that of the previous
derivatives, which was approximately 50%–60%. In general, the syn-
thetic route has the advantages of simple operation, mild reaction con-
ditions, moderate to good total yield, and certain industrialization
potential.
In general, the sesamol was obtained from sesame samples through
two processes of extraction and separation.22 The specific extraction and
separation process was shown in Fig. 2. Sesamol mainly exists in sesame
seeds in the form of sesamin. During the hot processing of sesame seeds,
the sesamin was continuously decomposed into sesamol. Sesamin was a
compound of free lignans which was lipophilic. Therefore, sesamin
could be easily dissolved in chloroform, ether, ethyl acetate and other
organic solvents. However, these low-polarity organic solvents have a
hard time penetrating into the plant cells, it was necessary to extract
with hydrophilic organic solvents such as ethyl alcohol and acetone, and
then extract with organic solvents such as chloroform and ether. As
sesamin could be decomposed into sesamol during heat treatment, the
sesamol could be extracted by proper heat treatment during the
extraction process. In the extraction process of sesamol, we systemati-
cally screened the solvent, concentration, extraction temperature and
extraction time. Ethyl alcohol was finally determined as the extraction
solvent. The ethyl alcohol concentration used for extraction was 70%
(volume fraction), the extraction temperature was 60 ◦C and the
extraction length of time was 4 h. After the extraction of sesamol, the
extraction was carried out with ether. The main separation method of
lignin was adsorption chromatography. The commonly used adsorption
separation material was silica gel, eluted by solvent systems such as
petroleum ether-ethyl acetate, petroleum ether-acetone, chloroform-
acetone, chloroform–methanol. During the separation of sesamol,
chloroform/methanol = 95:5 (volume fraction) was used as eluent. After
Free radicals are constantly produced in the body due to continuous
contact with the outside world, including respiration (oxidation reac-
tion), external pollution, radiation exposure and other factors. Scientific
research shows that cancer, aging or other diseases are mostly linked to
2

S. Zhou et al.
Bioorganic & Medicinal Chemistry Letters 31 (2021) 127716
Scheme 1. The synthetic route of sesamol derivatives compounds 3a-3e and 4a-4e. Reagents and conditions: (a) THF, reflux, 2 h; (b) DMA, K2CO3, Pd(OAc)2, reflux,
6 h.
the production of excess free radicals.24 Research on antioxidants can
effectively overcome the harm brought by them, so antioxidants have
been listed as one of the main research and development directions of
health products and cosmetics enterprises. Also one of the most impor-
tant functional appeals of the market.25 Antioxidation was any sub-
stance that can effectively inhibit the oxidation reaction of free radicals
in the presence of low concentration. Its action mechanism can be direct
ed action on free radicals or indirect consumption of substances which
are easy to generate free radicals to prevent further reactions.26 While
the body inevitably produces free radicals, it also naturally produces
antioxidant substances that resist free radicals to counteract their
oxidative attacks on human cells. Studies have shown that the body’s
antioxidant system is a system with perfect and complex functions
comparable to the immune system. The stronger the body’s antioxidant
capacity was, the healthier it was and the longer it lives. The chemical
composition of natural flavor was very complex, which was generally
composed of nearly a hundred chemical components, and some are even
composed of hundreds of chemical components. The main antioxidant
chemical constituents are phenols, flavonoids, terpenoids, aldehydes,
ketones, acids, alcohols, esters, alkaloids and unsaturated hydrocarbons.
Different spice plants contain different chemical components of the main
antioxidant properties. The chemical composition of natural flavor
plants, in the process of storage or use will also occur a series of
biochemical reactions, forming many new compounds. Sesamol was an
important ingredient in sesame oil and sesamol was a free radical
scavenger with a strong antioxidant activity. In this study, 10 kinds of
sesamol derivatives were synthesized by taking the sesamol extracted
and separated from sesame as the starting material (Fig. 1 and Scheme
1). On this basis, the antioxidant activities of the 10 sesamol derivatives
were studied, including hydroxyl radical scavenging capacity, super-
oxide anion scavenging capacity, hydrogen peroxide scavenging ca-
pacity, reducing ability and anti lipid peroxidation capacity. Sesamol
was used as a positive control during the determination of antioxidant
activity. The antioxidant activity test results showed that the activity of
these 10 sesamol derivatives was mostly better than that of the positive
control (sesamol).
Hydroxyl radical was generated by Fenton reaction: H2O2 + Fe2+
→
⋅OH + H2O + Fe3+. Salicylic acid was added into the reaction system, the
hydroxyl produced by Fenton reaction was based on the reaction of
salicylic acid, and 2, 3-dihydroxybenzoic acid with special absorption
was generated at 510 nm. If the hydroxyl radical scavenging hydroxyl
radical is added to the reaction system, the hydroxyl radical will be
reduced, so as to reduce the production of colored compounds. The
absorbance of the reaction solution was measured at 510 nm by fixed
reaction time method to determine the hydroxyl radical scavenging ef-
fect.25 As shown in Table 1, the results of 10 sesamol derivatives showed
that they had scavenging activity under low concentration (Table 1). As
could be seen from the results in Table 1, under the same test concen-
tration, the hydroxyl radical scavenging ability of most derivatives was
better than that of the positive control group. At the high concentration,
the hydroxyl radical scavenging activity of the closed loop derivatives
(compounds 4a-4e) were significantly higher than that of the open loop
derivatives (compounds 3a-3e) and the positive control group (ses-
amol). Among them, the compound 4d showed the best biological
3

S. Zhou et al.
Bioorganic & Medicinal Chemistry Letters 31 (2021) 127716
Table 1
Table 3
Hydroxyl radical scavenging rate of sesamol derivatives.
Eliminate efficiency of sesamol derivatives.
Compounds
Hydroxyl radical scavenging ratea (%) ±SD
Compounds
Eliminate efficiencya (%) ±SD
Concentration (g.Lꢀ 1
)
Concentration (g.Lꢀ 1
)
0.2
0.4
0.6
0.8
1
1.2
0.2
0.4
0.6
0.8
1
1.2
3a
14.23
34.35
± 0.22
32.67
± 0.23
32.61
± 0.21
30.71
± 0.26
26.41
± 0.23
38.92
± 0.31
40.61
± 0.33
40.84
± 0.36
42.93
± 0.32
38.72
± 0.30
30.22
± 0.24
61.47
73.76
± 0.66
72.73
± 0.67
70.65
± 0.65
66.56
± 0.60
57.49
± 0.58
83.20
± 0.72
89.89
± 0.71
88.23
± 0.73
92.74
± 0.73
83.20
± 0.71
67.44
± 0.68
77.45
78.23
3a
14.56
± 0.11
14.34
± 0.12
12.95
± 0.11
12.88
± 0.12
11.26
± 0.13
15.43
± 0.13
16.36
± 0.13
16.05
± 0.15
16.99
± 0.14
15.93
± 0.13
12.36
± 0.10
34.94
66.39
± 0.55
65.39
± 0.56
59.05
± 0.54
58.73
± 0.58
51.34
± 0.52
70.36
± 0.66
74.60
± 0.65
73.18
± 0.65
77.47
± 0.68
72.64
± 0.69
56.36
± 0.53
77.01
84.71
85.56
± 0.13
14.03
± 0.55
60.60
± 0.66
76.36
± 0.67
77.13
± 0.26
34.41
± 0.68
75.85
± 0.83
83.43
± 0.85
84.27
3b
3b
± 0.11
13.63
± 0.56
58.88
± 0.68
74.19
± 0.70
74.93
± 0.25
31.08
± 0.67
68.50
± 0.82
75.35
± 0.83
76.10
3c
3c
± 0.10
12.84
± 0.51
55.46
± 0.65
69.89
± 0.69
70.58
± 0.24
30.91
± 0.66
68.13
± 0.84
74.94
± 0.67
75.69
3d
3d
± 0.10
11.09
± 0.50
47.90
± 0.61
60.36
± 0.62
60.96
± 0.21
27.02
± 0.68
59.56
± 0.86
65.51
± 0.66
66.17
3e
3e
± 0.11
16.05
± 0.49
69.33
± 0.61
87.36
± 0.63
88.23
± 0.22
37.03
± 0.56
81.61
± 0.60
89.78
± 0.56
90.67
4a
4a
± 0.13
17.34
± 0.58
74.90
± 0.83
94.38
± 0.89*
95.32
± 0.29
39.26
± 0.86
86.53
± 0.86*
95.19
± 0.86*
96.14
4b
4b
± 0.13
17.02
± 0.67
73.52
± 0.88*
92.64
± 0.91*
93.56
± 0.30
38.52
± 0.84
84.89
± 0.90*
93.38
± 0.89*
94.32
4c
4c
± 0.15
17.89
± 0.59
77.28
± 0.87*
97.37
± 0.90*
98.35
± 0.29
40.77
± 0.87
89.87
± 0.89*
98.85
± 0.90*
99.84
4d
4d
± 0.14
16.05
± 0.53
69.33
± 0.89*
87.36
± 0.92*
88.23
± 0.30
38.23
± 0.83*
84.26
± 0.93*
92.68
± 0.91*
93.61
4e
4e
± 0.14
13.01
± 0.55
56.20
± 0.85
70.81
± 0.81*
71.52
± 0.31
29.66
± 0.82
75.37
± 0.91*
81.91
± 0.90*
82.63
Sesamolb
Sesamolb
± 0.10
± 0.56
± 0.66
± 0.68
± 0.26
± 0.62
± 0.65
± 0.76
a
a
Data represent the mean values from at least eight independent experiments
each in triplicate (n = 3). Statistical significance was measured by T-tests (*p <
0.05).
Data represent the mean values from at least eight independent experiments
each in triplicate (n = 3). Statistical significance was measured by T-tests (*P <
0.05).
b
b
The positive control group.
The positive control group.
intermediate has the maximum absorption wavelength at 320 nm. The
production of superoxide anion could be judged according to the pro-
duction of colored intermediate. If superoxide anion scavenging sub-
stances were added to the system, the formation of colored substances
will be reduced and the absorbance will be reduced.26 The lower the
absorbance, the better the superoxide removal. The superoxide anion
scavenging test results of 10 sesamol derivatives are shown in Table 2. It
could be seen from Table 2, within the range of 0.2–1.2 g.Lꢀ 1, all ses-
amol derivatives showed effective superoxide anion scavenging activity.
At the same concentration, most of the derivatives had better superoxide
anion scavenging activity than the positive control group (sesamol). At
the same time, the activity of three ring structure derivatives (com-
pounds 4a-4e) were better than that of two ring structure derivatives
(compounds 3a-3e). In addition, the scavenging ability of superoxide
anions in closed-loop structure derivatives 4a-4e were significantly
higher than that in open-loop structure derivatives 3a-3e and positive
control group. Among them, the compound 4d showed the best bio-
logical activity at a high concentration of 1.2 g/L. The superoxide anion
scavenging rate was 96.65 ± 0.85%, while that of the positive control
group was 70.32 ± 0.71%.
Table 2
Superoxide anion scavenging rate of sesamol derivatives.
Compounds
Superoxide anion scavenging ratea (%) ±SD
Concentration (g.Lꢀ 1
)
0.2
0.4
0.6
0.8
1
1.2
3a
13.26
30.49
± 0.23
29.92
± 0.22
27.85
± 0.21
26.17
± 0.22
23.89
± 0.21
35.94
± 0.29
37.51
± 0.30
36.91
± 0.29
38.15
± 0.31
34.84
± 0.28
27.76
± 0.26
57.94
69.53
± 0.66
68.22
± 0.63
63.50
± 0.60
59.67
± 0.59
54.48
± 0.51
81.96
± 0.71
85.52
± 0.73
84.16
± 0.73
86.99
± 0.72
79.44
± 0.70
63.29
± 0.67
76.48
77.25
± 0.11
13.01
± 0.45
56.85
± 0.71
75.04
± 0.70
75.79
3b
± 0.12
12.11
± 0.49
52.92
± 0.73
69.85
± 0.72
70.55
3c
± 0.10
11.38
± 0.50
49.73
± 0.70
65.64
± 0.71
66.30
3d
± 0.10
10.39
± 0.50
45.40
± 0.71
59.93
± 0.70
60.53
3e
± 0.12
15.63
± 0.44
68.30
± 0.61
90.16
± 0.60
91.06
4a
± 0.15
16.31
± 0.51
71.27
± 0.81*
94.08
± 0.82*
95.02
4b
± 0.13
16.05
± 0.63
70.13
± 0.80*
92.58
± 0.83*
93.50
4c
± 0.13
16.59
± 0.64
72.49
± 0.76*
95.69
± 0.84*
96.65
4d
Antioxidants (reducing agents) were scavenging free radicals by
giving electrons through their own reduction. The stronger the reduc-
tion ability was, the stronger the antioxidant ability will be. Experiment,
the samples of the antioxidant can make potassium ferricyanide triva-
lent iron reduction into bivalent iron (potassium ferrocyanide), ferrous
iron (potassium ferrocyanide) further under the reaction of ferric tri-
chloride and generate a maximum absorbance at 700 nm Prussian blue
(Fe4[Fe (CN)6]3). Therefore, the determination of the height at 700 nm
can indirectly reflect the reduction ability of antioxidants.26 The greater
the absorbance, the stronger the reduction ability. The reduction ca-
pacity of 10 sesamol derivatives was determined in Table 3. According
to the data in Table 3, these sesamol derivatives show effective reducing
capacity within the concentration range of 0.2–1.2 g/L. When
comparing the reduction capacity of the derivatives of sesamol (two-ring
structure and three-ring structure) with that of sesamol (positive control
group), most sesamol derivatives showed a certain improvement in
± 0.12
15.15
± 0.62
66.20
± 0.80*
87.39
± 0.85*
88.26
4e
± 0.13
12.07
± 0.60
52.74
± 0.79
69.62
± 0.80*
70.32
Sesamolb
± 0.12
± 0.53
± 0.68
± 0.71
a
Data represent the mean values from at least eight independent experiments
each in triplicate (n = 3). Statistical significance was measured by T-tests (*p <
0.05).
b
The positive control group.
activity at a high concentration of 1.2 g/L. The hydroxyl radical scav-
enging rate was 98.35 ± 0.92%, while that of the positive control group
was 71.52 ± 0.68%.
In weak alkaline medium, pyrocatechol could be oxidized and
decomposed to produce colored intermediate and superoxide anion, and
superoxide anion catalyzes oxidation. The colored substance of the
4

S. Zhou et al.
Bioorganic & Medicinal Chemistry Letters 31 (2021) 127716
and efficient chemical synthesis method. The antioxidant activity of
these sesamol derivatives were tested, and the results showed that the
antioxidant activity of most sesamol derivatives was higher than that of
the positive control group (sesamol). Among the compounds tested,
compound 4d showed the best antioxidant activity. For specific per-
formance: hydroxyl radical scavenging rate was 98.35 ± 0.92%,
peroxide anion scavenging rate was 96.65 ± 0.85%, eliminate efficiency
was 99.84 ± 0.91% and antiperoxide index was 99.43 ± 0.90% in high
concentration of 1.2 g/L. Analysis of the available data suggests that
compound 4d could be used a candidate antioxidant drug requiring
further study. In the future, we will further study the mechanism of
action and pharmacokinetic properties of compound 4d, as well as the
structure–activity relationship (SAR) of this series of compounds, to
obtain more sesamol derivatives or analogues with antioxidant activity.
Table 4
Antiperoxide index of sesamol derivatives.
Compounds
Antiperoxide indexa (%) ±SD
Concentration (g/L)
0.2
0.4
0.6
0.8
1
1.2
3a
14.22
34.12
± 0.23
33.76
± 0.22
31.15
± 0.21
30.43
± 0.23
27.12
± 0.21
37.87
± 0.24
39.11
± 0.26
39.70
± 0.25
40.63
± 0.24
38.35
± 0.26
30.62
± 0.23
61.43
73.71
± 0.61
72.93
± 0.62
67.28
± 0.59
65.73
± 0.58
58.57
± 0.59
81.80
± 0.71
84.49
± 0.73
85.79
± 0.80
87.76
± 0.76
82.84
± 0.56
66.14
± 50
81.08
83.52
± 0.11
14.07
± 0.45
60.78
± 0.73
80.23
± 0.73
82.63
3b
± 0.11
12.98
± 0.46
56.07
± 0.72
74.01
± 0.76
76.23
3c
± 0.12
12.68
± 0.44
54.77
± 0.76
72.30
± 0.68
74.47
3d
± 0.13
11.30
± 0.45
48.81
± 0.70
64.43
± 0.70
66.37
3e
± 0.12
15.78
± 0.39
68.16
± 0.71
89.98
± 0.59
92.68
4a
± 0.12
16.31
± 0.39
70.41
± 0.81*
92.94
± 0.84*
95.73
4b
Declaration of Competing Interest
± 0.14
16.55
± 0.50
71.49
± 0.80*
94.37
± 0.81*
97.20
4c
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to influence
the work reported in this paper.
± 0.12
16.93
± 0.45
73.13
± 0.86*
96.54
± 0.90*
99.43
4d
± 0.13
15.98
± 0.51
69.03
± 0.90*
91.12
± 0.90*
93.85
4e
± 0.12
12.76
± 0.45
55.12
± 0.86*
72.76
± 0.92*
74.94
Sesamolb
Acknowledgements
± 0.11
± 0.45
± 0.70
± 0.78
a
The Project was Sponsored by the National Natural Science Foun-
dation of China (21662012, 41866005). The Project was also Sponsored
by the Postgraduate Research and Innovation Project of Hainan Normal
University (Hsyx2018-8), Open Foundation Project of Key Laboratory of
Tropical Medicinal Resource Chemistry of Ministry of Education
(RDZH2019002), key project of science and technology research pro-
gram of Chongqing Education Commission of China (No. KJZD-
K202000503), the Scientific Research Foundation for the Returned
Overseas Chinese Scholars, State Education Ministry (No. 2015-1098),
and Chongqing Key Research Project of Basic Science & Frontier Tech-
nology (No. cstc2017jcyjBX0012), China.
Data represent the mean values from at least eight independent experiments
each in triplicate (n = 3). Statistical significance was measured by T-tests (*P <
0.05).
b
The positive control group.
reducing capacity under the same concentration. Among them, the
compound 4d showed the best biological activity at a high concentration
of 1.2 g/L. The eliminate efficiency was 99.84 ± 0.91%, while that of the
positive control group was 82.63 ± 0.76%.
Lipid peroxides were very unstable and could spontaneously degrade
into complex products with small molecules, such as aldehydes, ketones,
alkanes, olefins, acids and polymers. Detection of these degradation
products were considered to be the most effective indicator of lipid
peroxidation levels. Malondialdehyde was the most typical end product
of lipid peroxidation. Thiobarbituric acid method was based on the free
radical reaction of unsaturated fatty acids to form oxidative radicals,
oxidizing to epoxides, which decompose to malondialdehyde. Malon-
dialdehyde reacts with thiobarbituric acid to form thiobarbituric acid
dye complexes. The complex has a maximum absorption value at 532
nm, so the formation of thiobarbituric acid dye complex was a marker to
measure the degree of free radical oxidation reaction.22 The determi-
nation results of the anti-lipid peroxidation ability of 10 sesamol de-
rivatives was shown in Table 4. As shown in Table 4, within the selected
concentration range of 0.2–1.2 g/L, these sesamol derivatives were
effective against lipid peroxidation. At the same concentration, the anti-
lipid peroxidation ability of most sesamol derivatives was improved
compared with the positive control group (sesamol). When comparing
the anti-lipid peroxidation ability of open-loop derivatives (compounds
3a-3e) and closed-loop derivatives (compounds 4a-4e), it was found
that the activity of closed-loop structure was better than that of open-
loop structure. Among them, the compound 4d showed the best bio-
logical activity at a high concentration of 1.2 g/L. The antiperoxide
index was 99.43 ± 0.90%, while that of the positive control group was
74.94 ± 0.78%.
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In general, we reported a method of extracting and separating ses-
amol with antioxidant activity from sesame, systematically screened and
optimized the technological conditions of the extraction and separation
of sesamol. The extraction rate of sesamol was 30.2 mg/100 g (0.30‰)
under the optimal technological conditions.27 On the basis of the ob-
tained sesamol, ten sesamol derivatives were synthesized by the simple
27 Sesamol: 1H NMR (600MHz, DMSO-d6) δ: 5.90 (2H, s, -CH2-), 6.20 (1H, dd, J = 8.4,
2.5 Hz, Ph-H), 6.39 (1H, d, J = 2.4 Hz, Ph-H), 6.70 (1H, d, J = 8.3 Hz, Ph-H), 9.12
(1H, s, -OH); 13C NMR (100MHz, DMSO-d6) δ: 98.3, 101.0, 106.7, 108.6, 140.1,
148.2, 153.0.
5