Estrogenicity of octyl glucoside synthesized by direct glucosidation as non-endocrine disruptive surfactant

Article abstract of DOI:10.1166/jnn.2018.14875

The estrogenicity of octyl glucoside was studied with its preparation method using microporous zeolites. Its estrogenicity was estimated using E-assay method to confirm the possibility as nonendocrine disruptive surfactant. The octyl glucoside was synthesized from D-glucose with 1-octanol by direct glucosidation. The high conversion of D-glucose was obtained on H-FAU zeolite which has a mild acid strength. The conversion and yield were improved with increasing of acid site amount of the zeolite catalysts. The octyl glucopyranoside is more hydrophilic than nonylphenol and has a high wettability. The octyl glucosides represented extremely lower estrogenic cell proliferation compared with nonylphenol.

Full text of DOI:10.1166/jnn.2018.14875

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Nanoscience and Nanotechnology
Vol. 18, 1478–1481, 2018
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Estrogenicity of Octyl Glucoside Synthesized by Direct
Glucosidation as Non-Endocrine Disruptive Surfactant
Kyong-Hwan Chung1, Hangun Kim2, Young-Kwon Park3, Byung-Hoon Kim4,
Jung-Sik Kim5, and Sang-Chul Jung1ꢀ∗
1Department of Environmental Engineering, Sunchon National University, Suncheon 57922, Korea
2College of Pharmacy, Sunchon National University, Suncheon 57922, Korea
3School of Environmental Engineering, University of Seoul, Seoul 02504, Korea
4Department of Dental Materials, Chosun University, Gwangju 61452, Korea
5Department of Materials Science and Engineering, University of Seoul, Seoul 02504, Korea
The estrogenicity of octyl glucoside was studied with its preparation method using microporous
zeolites. Its estrogenicity was estimated using E-assay method to confirm the possibility as non-
endocrine disruptive surfactant. The octyl glucoside was synthesized from D-glucose with 1-octanol
by direct glucosidation. The high conversion of D-glucose was obtained on H-FAU zeolite which has
a mild acid strength. The conversion and yield were improved with increasing of acid site amount of
the zeolite catalysts. The octyl glucopyranoside is more hydrophilic than nonylphenol and has a high
wettability. The octyl glucosides represented extremely lower estrogenic cell proliferation compared
IP: 77.186.71.175 On: Thu, 14 Jun 2018 20:49:38
with nonylphenol.
Copyright: American Scientific Publishers
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Keywords: Estrogenicity, Octyl Glucoside, Direct Glucosidation, Zeolite, Surfactant.
1. INTRODUCTION
Therefore, they have recently been considered as alterna-
tive surfactants to alkylphenols. Octyl glucoside (n-octyl-
ꢀ-D-glucoside) is a detergent frequently used to solubilise
integral membrane proteins for studies in biochemistry.
It has become one of the most important detergents for
purification of membrane proteins because it generally
does not denature the protein and can readily be removed
from final protein extracts. Octyl glucoside (OG) been also
proposed as a conditioning agent to prevent microbial col-
onization of contact lenses, due to its ability to lower the
hydrophobicity of contact lenses and prevent adhesion of
cells.
In this study, the estrogenicity of OG was evaluated
compared with that of nonylphenol using E-assay method.
The preparation method of OG was also suggested. The
OG from D-glucose with 1-octanol was prepared by direct
glucosidation reaction on microporous zeolite catalysts.
The catalytic activities of the zeolite catalysts were eval-
uated in the direct glucosidation reaction. The physical
properties of octyl glucopyranoside were analyzed com-
pared with nonylphenol. We also estimated the character-
istics of cell proliferation of human breast cancer cell line
(MCF-7) to the octyl glucopyranosides and nonylphenol
to compare their estrogenicities.
Surfactants have been used as emulsifiers, detergents,
foaming agents, wetting agents, and dispersants.1 Some
of the surfactants are noted to be toxic to humans and
ecosystems. The toxic surfactants have been restricting by
proposal or spontaneous restrictions. Alkyl phenol ethoxy-
lates have been used as major surfactants. They break
down in the aerobic conditions found in sewage treatment
plants and in the metabolite, nonylphenol, which has been
found to be an endocrine disruptor.2 Concerns have been
expressed about alkylphenols owing to their environmental
prevalence and their potential effect as xenoestrogen and
endocrine disruptors.3 Nonylphenol has been reported to
have estrogenic activity based on its proliferation induction
and up-regulation of the progesterone receptor I human
estrogen-sensitive breast tumor cells.4 It has been estab-
lished recently that nonylphenol has antiandrogenic activ-
ity, which means that it affects the appropriate functioning
of the androgens which are necessary to the normal growth
and reproductive organs of males.5
Long-chain alkyl glucosides have excellent surfac-
tant properties with biodegradability and low toxicity.6
∗Author to whom correspondence should be addressed.
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doi:10.1166/jnn.2018.14875

Chung et al.
Estrogenicity of Octyl Glucoside Synthesized by Direct Glucosidation as Non-Endocrine Disruptive Surfactant
2. EXPERIMENTAL DETAILS
2.1. Catalysts
controls and octyl-ꢁ-glucopyranoside (99%, Sigma-
Aldrich), octyl-ꢀ-glucopyranoside (99%, Sigma-Aldrich)
were used as the object controls in evaluation of
estrogenicity.
FAU (zeolite Y, Si/Al = 3) was purchased from Zeobuilder
Co. The MOR (Mordenite, Si/Al = 10) zeolite was also
purchased from Tosoh Co. The cations of zeolites were
exchanged with H+ ion. We denote the H+ ion exchanged
zeolites following the zeolite code names, H-FAU and
H-MOR.
3. RESULTS AND DISCUSSION
3.1. Catalytic Activities of the Zeolite Catalysts
The acidities of the zeolites differed considerably accord-
ing to their framework, as shown in Figure 1. The FAU
zeolite has a lot of weak acid sites. On the contrary, the
MOR zeolite has strong acid sites. In this glucosidation
reaction, two OGs isomers i.e., the ꢂꢁꢃꢀꢄ-octyl glucopy-
ranoside and ꢂꢁꢃꢀꢄ-octyl glucofuranoside isomers, were
produced mainly as an anomeric mixture. A small amount
of short-chain alcohols and their derivatives were also
formed as byproducts through the decomposition of 1-
octanol.
The catalytic activities of the zeolite catalysts are listed
in Table I. Conversions of D-glucose were obtained above
80% on the two catalysts. The H-FAU catalyst showed
a high yield of OGs. The yields of OG on the catalysts
exceed 70%, but that on H-MOR zeolite was lower. The
yield of OG and OGP selectivity were higher over the
H-FAU zeolite catalysts. These results mean that the weak
acid sites concentration of the zeolites can induce higher
catalytic activity in the reaction.
2.2. Direct Glucosidation Reaction
OGs were prepared from D-glucose (Sigma, 99%) with
1-octanol (Aldrich, 99%) by direct glucosidation on the
zeolite catalysts. D-glucose (2.5 g) and 1-octanol (50 mL)
were introduced as the reactants. The reactants were put
into the reactor with the zeolite catalyst. The reaction was
ꢀ
carried out directly in the reactor with stirring at 130 C.
The compositions of the products were measured by GC
equipped HP-1 capillary column and detected by an FID
analyzer. The conversion was determined as the percentage
of D-glucose consumed. The OG yields were determined
as the percentage of the amount produced with respect to
the sum of total products.
2.3. Characterization of the Zeolite
Catalysts and Products
NH3-temperature programmed desorption (NH3-TPD) pro-
files were measured using a chemisorption apparatus. Sur-
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face tensions were measured using a ring and plate method
3.2. Effect of Acidities and Pore Topologies of the
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tensiometer (Kruss K100, Germany) and maxmum bub-
ble pressure tensiometer (Kruss BP2, Germany). Critical
micelle concentration (CMC) was determined from the
value of surface tension. Contact angles (CA) were mea-
sured using pendant drop tensiometer (Kruss DSA 100,
Germany).
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Zeolite Catalysts
The FAU zeolite has tri-directional channels and super
cavities in the pores. The MOR zeolite has narrow pore
entrances and a straight pore channel. The yields of OGP
and OGF exceeded 80% on the H-FAU zeolite catalysts.
2.4. Estimation of Estrogenicities of
OGPs and Nonylphenol
MCF-7 (Michigan Cancer Foundation-7) cell line as a
human breast cancer cell line was induced in the esti-
mation of estrogenicity. The cell line was cultivated on
Dulbecco’s modified Eagle’s medium (DMEN) including
10% charcoal dextran treated fetal bovine serum (CDT-
FBS) for 6 days. The sex hormone in a serum of CDT-FBS
was removed by adsorption with a charcoal and dextran.
Chemical stock solution dissolved in dimethylsulfoxide
(DMSO) was diluted again to 0.1% solvent concentration
with DMSO. The cell line was evaluated the MTT (2-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetra zolium bromide,
Sigma) assay after cultivation in an incubator for 144 h.
MTT was distributed as 0.1 mg/well and then cultivated
again for 4 h. After DMSO injection to the cultivation
medium, the sample was estimated the absorbance at
540 nm by spectrophotometer. The control was consisted
of cultivation medium only. 17ꢀ-estradiol (99%, Sigma)
and nonylphenol (99%, Sigma) were induced as positive
Figure 1. NH3-TPD profiles of the zeolite catalysts.
J. Nanosci. Nanotechnol. 18, 1478–1481, 2018
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Estrogenicity of Octyl Glucoside Synthesized by Direct Glucosidation as Non-Endocrine Disruptive Surfactant
Chung et al.
Table I. Catalytic activities of the zeolite catalysts in the glucosidation.
Yield (%) Selectivity (%)
3
2.5
2
Catalyst
Conversion (%)
OGP
OGF
OGP
OGF
H-FAU
H-MOR
93.1
81.2
63.2
20.5
18.3
23.1
77.5
47.0
22.5
53.0
1.5
1
The high catalytic activities were derived from weak acid
sites. The yield of OGP was larger than that of OGF on
the H-FAU zeolite catalyst. The selectivities of the two
isomers depending on the pore structure of the zeolites are
insensitive to the activation conditions. The furanosides are
formed from the attack of the alcohol on the glucosyl oxo-
nium intermediate. The more stable pyranosides are pro-
duced from them through a process of ring opening. In this
process, the selectivities of the isomers are affected by the
pore topologies. This suggests that the product selectivity
may be closely dependent on the pore structure.
0.5
0
Nonylphenol
17β-estradiol
Octyl-β-glucopyranoside
Octyl-α-glucopyranoside
105
104
103
102
101
1
10–1 10–2
DMSO
Concentration (pM)
Figure 3. Estrogenicities of 17ꢀ-estradiol, nonylphenol, and OGPs
compared with that of control.
The H-FAU catalyst showed a high OGP selectivity.
This is attributed to its high pore volume and numerous
weak acid sites, leading the production of OGP. Its pore
structure provides sufficient space volume to form pyrano-
sides by the isomerization of the furanosides in the pore
channels. On the contrary, the yield of OGF was higher
than that of OGP on the H-MOR catalyst.
from the values of concentration at surface tension
unchanging despite of increasing of their concentration.
From the results, the CMC of OGP was determined
as 2.2 × 10−2 mol/L and surface tension at CMC was
31.2 mN/m. The CMC of nonylphenol was measured as
1.2 × 10−4 mol/L, respectively. The CMC of OGP was
higher than that of nonylphenol. The contact angle of OGP
was lower than those of nonylphenol and water. This indi-
cates that the OGP is more hydrophilic than nonylphenol
3.3. Physical Properties of OGPs and Nonylphenol
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Figure 2 shows the surface tensions and contact angles
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of OGP and nonylphenol. The CMCs of were determined
and has a high wettability.
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70
60
50
40
30
20
10
0
(A)
3.4. Estrogenicities of OGPs and Nonylphenol
CA=31.1°
Figure 3 shows the cell proliferation of MCF-7 in 17ꢀ-
estradiol, nonylphenol, and OGPs compared to the control.
The cell proliferation rate of 17ꢀ-estradiol at 10 pM was
increased 2.5 fold and that of nonylphenol was increased to
2.1 fold at 100 nM compared with that of control. Hence,
those of OGPs are nothing but ca. 1.7 fold, respectively.
Table II lists relative proliferation effect (RPE) and rel-
ative proliferation potency (RPP) of OGPs and nonylphe-
nol compared with those of 17ꢀ-estradiol as a relative
basis. In this result, RPE and RPP of OGPs were rep-
resented lower than those of nonylphenol. The OGPs
did not influence to the cell proliferation effect above
10 pM concentration compared with 17ꢀ-estradiol and
nonylphenol. It means that the OGPs show low estro-
gen cell proliferation compared with 17ꢀ-estradiol and
nonylphenol.
10–4
10–3
10–2
10–1
1
Concentration (mol/L)
70
60
50
40
30
20
10
0
(B)
CA=48.7°
Table II. RPE and RPP of 17ꢀ-estradiol, nonylphenol, and OGPs.
Compounds
Concentration (nM) RPE (%) RPP (%)
10–6
10–5
10–4
10–3
10–2
17ꢀ-estradiol
Nonylphenol
Octyl-ꢁ-glucopyranoside
Octyl-ꢀ-glucopyranoside
10
105
10
100
85ꢅ3
59ꢅ1
66ꢅ3
100
20
10
Concentration (mol/L)
Figure 2. Surface tensions and contact angles of OGP (A) and
nonylphenol (B).
10
10
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Chung et al.
Estrogenicity of Octyl Glucoside Synthesized by Direct Glucosidation as Non-Endocrine Disruptive Surfactant
4. CONCLUSION
the National Research Foundation of Korea (NRF) funded
by the Ministry of Science, ICT and Future Planning
(2015M3C8A6A06012988).
The H-FAU catalyst has shown a high catalytic activ-
ity and OGP selectivity in the glucosidation. The con-
version and yield were improved with increasing of acid
sites of the catalysts. The catalytic activities are depended
on the amount of weak acid sites of the zeolite cata-
lysts. The OGP was more hydrophilic than nonylphenol
and has a high wettability. The OGPs did not influence
to the cell proliferation effect even a high concentration.
The OGP show extremely low estrogenicity compared with
nonylphenol.
References and Notes
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2. M. Scott and M. N. Jones, Biochimica et Biophysica Acta 1508, 235
(2000).
3. R. Thiruvenkatachari, S. Vigneswaran, and I. S. Moon, Korean J.
Chem. Eng. 25, 64 (2008).
4. A. M. Soto, H. Justicia, J. Wray, and C. Sonnenschein, Environ.
Health Perspect. 92, 167 (1991).
5. S. Kim and J. Kim, Korean J. Chem. Eng. 23, 747 (2006).
6. N. Ferlin, L. Duchet, J. Kovensky, and E. Grand, E. Carbohydrate
Research 343, 2819 (2008).
Acknowledgment: This research was supported by the
Civil research projects for solving social problems through
Received: 1 December 2016. Accepted: 30 April 2017.
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