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Bioassay-Guided Isolated Compounds from Morinda officinalis Inhibit Alzheimer's Disease Pathologies

Authors:

Abstract

Due to the side effects of synthetic drugs, the therapeutic potential of natural products for Alzheimer's disease (AD) has gained interest. Morinda officinalis has demonstrated inhibitory effects on geriatric diseases, such as bone loss and osteoporosis. However, although AD is a geriatric disease, M. officinalis has not been evaluated in an AD bioassay. Therefore, M. officinalis extracts and fractions were tested for AD-related activity, including inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), β-site amyloid precursor protein cleaving enzyme 1 (BACE1), and advanced glycation end-product (AGE) formation. A bioassay-guided approach led to isolation of 10 active compounds, eight anthraquinones (1-8), one coumarin (9), and one phytosterol (10), from n-hexane and ethyl acetate fractions of M. officinalis. The five anthraquinones (4-8) were stronger inhibitors of AChE than were other compounds. Compounds 3 and 9 were good inhibitors of BChE, and compounds 3 and 8 were good inhibitors of BACE1. Compounds 1-5 and 7-9 were more active than the positive control in inhibiting AGE formation. In addition, we first suggested a structure-activity relationship by which anthraquinones inhibit AChE and BACE1. Our findings demonstrate the preventive and therapeutic efficacy of M. officinalis for AD and its potential use as a natural alternative medicine.
molecules
Article
Bioassay-Guided Isolated Compounds from Morinda
officinalis Inhibit Alzheimer’s Disease Pathologies
Yoon Kyoung Lee ID , Hyo Jeong Bang, Jeong Bin Oh and Wan Kyunn Whang *
Pharmaceutical Botany Laboratory, College of Pharmacy, Chung-Ang University, Heukseok-dong, Dongjak-gu,
Seoul 151-756, Korea; dbsrudaks486@naver.com (Y.K.L.); bhj1027@hanmi.co.kr (H.J.B.);
ojb6911@naver.com (J.B.O.)
*Correspondence: whang-wk@cau.ac.kr; Tel.: +82-2-820-5611
Received: 20 September 2017; Accepted: 28 September 2017; Published: 29 September 2017
Abstract:
Due to the side effects of synthetic drugs, the therapeutic potential of natural products
for Alzheimer’s disease (AD) has gained interest. Morinda officinalis has demonstrated inhibitory
effects on geriatric diseases, such as bone loss and osteoporosis. However, although AD is a geriatric
disease, M. officinalis has not been evaluated in an AD bioassay. Therefore, M. officinalis extracts and
fractions were tested for AD-related activity, including inhibition of acetylcholinesterase (AChE),
butyrylcholinesterase (BChE),
β
-site amyloid precursor protein cleaving enzyme 1 (BACE1), and
advanced glycation end-product (AGE) formation. A bioassay-guided approach led to isolation of
10 active compounds, eight anthraquinones (
1
8
), one coumarin (
9
), and one phytosterol (
10
), from
n-hexane and ethyl acetate fractions of M. officinalis. The five anthraquinones (
4
8
) were stronger
inhibitors of AChE than were other compounds. Compounds
3
and
9
were good inhibitors of
BChE, and compounds
3
and
8
were good inhibitors of BACE1. Compounds
1
5
and
7
9
were
more active than the positive control in inhibiting AGE formation. In addition, we first suggested
a structure-activity relationship by which anthraquinones inhibit AChE and BACE1. Our findings
demonstrate the preventive and therapeutic efficacy of M. officinalis for AD and its potential use as a
natural alternative medicine.
Keywords:
Morinda officinalis; bioassay-guided isolation; Anthraquinone; Alzheimer’s diseases;
structure-activity relationship
1. Introduction
Morinda officinalis How. is a member of the Rubiaceae family and grows widely in
subtropical and tropical climates [
1
]. M. officinalis is distributed in Southern China and Northeast
Asia and is used to treat sexual impotence, spermatorrhea, irregular menstruation, menstrual
disorders, osteoporosis, diabetes mellitus, and inflammatory diseases such as rheumatoid arthritis
and dermatitis [
2
,
3
]. Moreover, several studies have reported that M. officinalis has various
biological activities, including protecting against bone loss [
4
], osteoporosis [
5
,
6
], age-induced bone
degeneration [
7
], and has anti-oxidant [
8
], anti-fatigue [
9
], and anti-inflammatory actvities [
10
].
The compounds isolated from M. officinalis include polysaccharides, flavone glycosides, iridoid
glycosides, anthraquinones, coumarins, and phytosterols, such as rubiadin, rubiadin-1-methyl
ether, 2-hydroxy-1-methoxy-anthraquinone, 1,3,8-trihydroxy-2-methoxy-anthraquinone, morindolide,
morofficinaloside, asperuloside, asperulosidic acid, monotropein, scopoletin, stigmasterol, daucosterol,
and β-sitosterol [3,11,12].
Alzheimer’s disease (AD) is major form of dementia and one of the most common age-related
progressive and irreversible neurodegenerative diseases. It is accompanied by memory loss, cognitive
dysfunction, disorientation, behavioral disturbances, and personality changes [
13
15
]. The two most
Molecules 2017,22, 1638; doi:10.3390/molecules22101638 www.mdpi.com/journal/molecules
Molecules 2017,22, 1638 2 of 12
common hypotheses that characterize AD pathology are the cholinergic and amyloid hypotheses [
16
].
According to the cholinergic hypothesis, AD is caused by a deficiency of the neurotransmitter
acetylcholine, which is hydrolyzed by acetylcholinesterase (AChE) and butyrylcholinesterase
(BChE) [
17
,
18
]. Therefore, cholinesterases, including AChE and BChE, are key enzymes in AD
pathogenesis [
19
,
20
]. The amyloid hypothesis suggests that amyloid-
β
peptide (A
β
) accumulation
in the brain is critical in AD pathogenesis [
21
,
22
]. A
β
is formed from sequential proteolytic cleavage
of amyloid precursor protein (APP) by the aspartic protease
γ
- and
β
-secretase (BACE1) in the
amyloidogenic pathway [
23
25
]. APP cleavage by BACE1 increases the production and accumulation
of neurotoxic forms of A
β
in the brain and causes neurodegeneration [
26
,
27
]. In addition, a previous
study reported that advanced glycation end-products (AGEs) contribute to neuronal dysfunction
and death in the progression of various neurodegenerative diseases including AD [
28
]. Accordingly,
inhibiting cholinesterases, AGE formation, and Aβaccumulation are important in preventing AD.
To treat AD, synthetic drugs, such as tacrine, rivastigmine, donepezil, and galantamine, are usually
prescribed. However, these drugs have side effects (e.g., hepatotoxic gastrointestinal disturbances) and
problems with bioavailability [
29
31
]. Due to these side effects, the therapeutic potential of natural
products has received great interest. Although studies have assessed the activity of anthraquinones on
AD [
27
], the effects of M. officinalis, which contains anthraquinones, on AD have not been evaluated.
Therefore, we isolated major components from M. officinalis and tested their inhibitory activities on
AChE, BChE, BACE1, and AGE formation.
2. Results
2.1. Identification of Compounds 110 Isolated from M. officinalis
According to the bioassay-guided isolation method, we chromatographically separated the
M. officinalis Hx and EA fractions. As a result, eight anthraquinones (
1
8
), one coumarin (
9
), and one
phytosterol (
10
) were isolated. Compounds
1
10
isolated from M. officinalis were identified as
alizarin-1-methyl ether (
1
), 1,2-dimethoxy-3-hydroxy anthraquinone (
2
), 2-methoxy anthraquinone
(
3
), 2-hydroxymethyl-3-methoxy anthraquinone (
4
), 2-hydroxymethyl-3-hydroxy anthraquinone (
5
),
rubiadin-1-methyl ether (
6
), 1-hydroxy-3-hydroxymethyl anthraquinone (
7
), rubiadin (
8
), scopoletin (
9
),
and
β
-sitosterol (
10
) [
3
,
5
,
12
,
32
,
33
] by comparison with spectroscopic (
1
H-,
13
C-NMR) and LC-MS data
from the literature (Figure 1). The m/zdata and retention time of each compound were provided in
Table 1. Observed mass value accuracies of compounds
1
10
were credible to 5 ppm. After identifying
compounds
1
10
, HPLC analysis was conducted to determine the major components of M. officinalis
extracts (Figure 2).
Table 1.
Identification of compounds
1
10
in M. officinalis by UHPLC-ESI/LTQ-Orbitrap-HRMS analysis.
No. Compound Rt (min) Formula Mass
Mode
Theoretical
Mass
Observed
Mass
Mass
Error
(Da)
Mass
Accuracy
(ppm)
1Alizarin-1-methyl ether 7.84
C
15
H
10
O
4Positive 255.0652 255.0652
0.0000
0.0
21,2-dimethoxy-3-hydroxy
anthraquinone 7.95
C
16
H
12
O
5Positive 285.0757 285.0758
0.0001
0.4
3
2-methoxy anthraquinone
8.61
C
15
H
10
O
3Positive 239.0703 239.0706
0.0003
1.3
4
2-hydroxymethyl-3-methoxy
anthraquinone 7.15
C
16
H
12
O
4Negative 267.0653 267.0655
0.0002
0.7
5
2-hydroxymethyl-3-hydroxy
anthraquinone 7.16
C
15
H
10
O
4Positive 253.0573 253.0574
0.0001
0.4
6Rubiadin-1-methyl ether 8.29
C
15
H
10
O
4Positive 269.0808 269.0808
0.0000
0.0
7
1-hydroxy-3-hydroxymethyl
anthraquinone 8.70
C
16
H
12
O
4Negative 253.0452 253.0455
0.0003
1.2
8Rubiadin 9.26
C
15
H
10
O
4Positive 255.0652 255.0654
0.0002
0.8
9Scopoletin 5.65 C10H8O4Positive 193.0495 193.0497
0.0002
1.0
10 β-sitosterol 13.42 C29H50 O Positive 437.3754 437.3768
0.0014
3.2
Molecules 2017,22, 1638 3 of 12
Molecules 2017, 22, 1638 3 of 12
Figure 1. Structures of compounds 110.
Figure 2. Chromatograms of standards mixture (A) and M. officinalis crude MeOH extract (B).
Figure 1. Structures of compounds 110.
Molecules 2017, 22, 1638 3 of 12
Figure 1. Structures of compounds 110.
Figure 2. Chromatograms of standards mixture (A) and M. officinalis crude MeOH extract (B).
Figure 2. Chromatograms of standards mixture (A) and M. officinalis crude MeOH extract (B).
Molecules 2017,22, 1638 4 of 12
2.2. AChE, BChE, BACE1, and AGE Formation Inhibitory Activities of the Extracts and Fractions from
M. officinalis
To demonstrate the potential of M. officinalis to prevent AD, we examined the effects of
M. officinalis
root extracts and fractions on AChE, BChE, BACE1, and AGE formation. The results are summarized
in Table 2. The IC
50
values of positive control in AChE, BChE, BACE1, and AGEs formations
were judged suitable compared with previous literatures [
16
,
26
,
27
,
34
]. The M. officinalis extracts,
Hx, and EA fractions significantly inhibited AChE activity (IC
50
of 58.82
±
9.13, 33.66
±
4.73,
and
80.14 ±16.65 µg/mL
, respectively). Although M. officinalis extracts slightly inhibited BChE
activity, the Hx fraction showed the highest inhibition with an IC
50
of 105.99
±
0.69
µ
g/mL.
The extracts, Hx, and EA fractions were the most potent BACE1 inhibitors with IC
50
values of
24.40 ±2.84
, 42.36
±
3.94, and 64.45
±
4.22
µ
g/mL, respectively. Finally, the Hx fraction (IC
50
of
166.03
±
7.76
µ
g/mL) most strongly inhibited AGE formation, followed by the EA fraction (IC
50
of
417.92 ±14.29 µg/mL), and the extracts had no activity.
Table 2.
IC
50
of the M. officinalis extracts and fractions for acetylcholinesterase (AChE), butyrylcholinesterase
(BChE),
β
-site amyloid precursor protein cleaving enzyme 1 (BACE1), and advanced glycation end-product
(AGE) formation.
Sample IC50 a(µg/mL)
AChE BChE BACE1 AGE Formation
Ext. 58.82 ±9.13 ** 445.55 ±32.05 ** 24.40 ±2.84 *** ND e
Hx fr. 33.66 ±4.73 ** 105.99 ±0.69 *** 42.36 ±3.94 ** 166.03 ±7.76 ***
EA fr. 80.14 ±16.65 * >500 64.45 ±4.22 ** 417.92 ±14..29 ***
BuOH fr. 188.83 ±2.44 *** >500 ND eND e
Water fr. >500 ND eND eND e
Berberine b0.14 ±0.01 *** 1.70 ±0.07 ** - -
AG c- - - 104.87 ±6.94 ***
Quercetin d- - 6.87 ±0.36 ** -
Data are presented as the mean
±
S.D. (n = 3);
a
IC
50
calculated from the least-squares regression line of the
logarithmic concentrations plotted against the residual activity;
b
Berberine was used as a positive control of AChE
and BChE inhibition.;
c
AG was used as a positive control of inhibition of AGE formation;
d
Quercetin was used as
a positive control of BACE1 inhibition;
e
ND was not detectable; * indicates a significant difference from control;
*p< 0.05, ** p< 0.005, *** p< 0.001
2.3. AChE, BChE, BACE1, and AGE Formation Inhibitory Activities of Compounds 110 Isolated from
M. officinalis
Compounds
1
10
were tested for their ability to inhibit AChE, BChE, BACE1, and AGE formation.
The results were shown in Table 3. The IC
50
values of positive control in AChE, BChE, BACE1,
and AGEs formations were also judged suitable compared with the previous literature [
16
,
26
,
27
,
35
].
β
-sitosterol (
10
) did not inhibit any of the tested activities with IC
50
values > 500
µ
M or ND (not
detected). Five anthraquinones (
4
8
) were stronger AChE inhibitors than were the other compounds.
The IC
50
values of compounds
4
8
were 27.05
±
1.49, 19.06
±
3.58, 87.19
±
6.56, 96.38
±
17.23,
and 44.31 ±12.20 µM
, respectively. Compounds
3
and
9
, had mild activity toward AChE and inhibited
AChE more significantly than did the other compounds with IC
50
values of 230.18
±
5.97 and
50.43 ±1.61 µM
, respectively. Furthermore, compounds
3
(IC
50
of 9.29
±
1.92
µ
M) and
8
(IC
50
of 19.82
±
3.05
µ
M) showed greater BACE1 inhibition than did quercetin (IC
50
of 22.75
±
1.20
µ
M), the positive
control. Compound
6
had activity similar to the positive control with an IC
50
of
25.89 ±2.11 µM
.
Compounds
1
5
and
7
9
inhibited AGE formation more than AG, the positive control. Compound
9
was the best inhibitor of AGE formation with an IC50 of 5.43 ±0.11 µM.
Molecules 2017,22, 1638 5 of 12
Table 3.
IC
50
of the compounds
1
10
for acetylcholinesterase (AChE), butyrylcholinesterase (BChE),
β
-site amyloid precursor protein cleaving enzyme 1 (BACE1), and advanced glycation end-product
(AGE) formation.
Compound IC50 a(µM)
AChE BChE BACE1 AGEs Formation
1174.83 ±10.71 ** 450.47 ±8.82 *** 192.41 ±7.32 *** 292.37 ±2.28 **
2147.00 ±13.33 ** 441.53 ±10.58 ** 114.63 ±21.62 * 437.86 ±23.94 **
3187.20 ±20.12 * 230.18 ±5.97 ** 9.29 ±1.92 ** 88.40 ±3.28 **
427.05 ±1.49 ** >500 >200 529.79 ±15.53 **
519.06 ±3.58 * 459.02 ±13.11 ** >200 355.03 ±12.00 **
687.19 ±6.56 ** >500 25.89 ±2.11 ** >1000
796.38 ±17.23 ** >500
178.43
±
12.15 ***
178.43 ±12.15 ***
844.31 ±12.20 * >500 19.82 ±3.05 * 522.42 ±10.11 **
9235.70 ±21.17 ** 50.43 ±1.61 *** >200 5.43 ±0.11 ***
10 >500 >500 ND eND e
Berberine b0.42 ±0.03 * 5.05 ±0.21 ** - -
AG c- - - 762.05 ±69.10 ***
Quercetin d- - 22.75 ±1.20 *** -
Data are presented as the mean
±
S.D. (n = 3);
a
IC
50
calculated from the least-squares regression line of the
logarithmic concentrations plotted against the residual activity;
b
Berberine was used as a positive control of AChE
and BChE inhibition.;
c
AG was used as a positive control of inhibition of AGE formation;
d
Quercetin was used as a
positive control of BACE1 inhibition;
e
ND was not detectable; * indicates a significant difference from control; * p<
0.05, ** p< 0.005, *** p< 0.001
3. Discussion
In recent years, the aging society and increasing life span have increased the number of people
over 65 years old worldwide. As a result, degenerative and geriatric diseases are increasing. Dementia,
a major symptom of cognitive disorders, is a significant social problem [
36
]. While dementia can result
from degenerative dementia, senile dementia, Parkinson's disease, and AD, AD is the most common,
accounting for 50% to 60% of all dementia [
37
]. M. officinalis has already been demonstrated to inhibit
geriatric diseases such as bone loss and osteoporosis. Although AD is a geriatric disease, M. officinalis
has not been evaluated in an AD bioassay. Therefore, we aimed to assess whether M. officinalis has the
potential to treat AD by inhibit AChE, BChE, BACE1, and AGE formation.
M. officinalis extracts and fractions were investigated for their ability to inhibit AChE, BChE,
BACE1, and AGE formation. The M. officinalis extracts were good inhibitors of AChE, BChE,
and BACE1. The extracts inhibited BACE1 more strongly than did the other fractions. The Hx
fraction was a stronger inhibitor in all assays. The Hx fraction inhibited AChE, BChE, and AGE
formation significantly more than the other fractions. The EA fraction mildly inhibited AChE, BACE1,
and AGE formation. In contrast, the BuOH and water fractions had no, or slight, activity in all assays.
These results demonstrated that the potential of M. officinalis extracts to prevent AD was derived from
the Hx and EA fractions.
Therefore, we conducted bioassay-guided isolation from the Hx and EA fractions. We isolated
bioactive compounds, including eight anthraquinones (
1
8
), one coumarin (
9
), and one phytosterol
(
10
). The isolated compounds
1
10
were investigated for inhibition of AChE, BChE, BACE1, and AGE
formation. Previous literatures studied AD activities of various natural products, for examples,
cholinesterase activities of flavonoid isolated from Kaempferia parviflora,Maclura pomifera, essential
oils of Salvia species, and their crude extracts [
35
,
38
,
39
]. When we compared previous articles with
our data, it could know that anthraquinones had more potential than the natural products kind of
flavonoids and fatty acids. Taken together, our study was significant to have accessed the anti-AD
activities of anthraquinones.
Compounds
4
8
were stronger AChE inhibitors than other compounds. Of these, compound
5
was the most active. Furthermore, we uncovered the following relationships between the
Molecules 2017,22, 1638 6 of 12
anthraquinone structure and AChE inhibitory activity: (1) anthraquinones with no substituent on
C-1 (compounds
4
and
5
) were more active than those with a substituent in C-1 (compounds
1
3
and
6
8
); (2) anthraquinone with a substituted methyl group on C-2 (compounds
6
and
8
) were
more active than those with a methoxy group (compounds
2
and
3
); (3) anthraquinones with a
substituent on C-3 (compounds
2
and
4
8
) had stronger activity than those without (compounds
1
and
3
); (4) anthraquinones with a hydroxy group at C-3 (compounds
5
and
8
) were more active than those
with a methoxy group (compounds
4
and
6
); and (5) the anthraquinone with no hydroxy group was a
minor inhibitor (compound 3).
Compound
9
significantly inhibited BChE, and compound
3
slightly inhibited AChE, making
them the most active among the isolated anthraquinones. According to bioassay-guided isolation,
the EA fraction also showed low potential, because most anthraquinones isolated from the EA fraction
had weak activity. The Hx fraction was the most active because compound
3
, a good inhibitor, was
isolated from Hx fraction.
Compounds
3
and
8
were stronger BACE1 inhibitors than quercetin, a positive control. Compound
6
showed similar activity to the positive control. Compound
3
was the best BACE1 inhibitor.
We suggested
the following structure-activity relationship for BACE1 inhibition by anthraquinones:
(1) anthraquinones with only one substituent (compound
3
) were more active than those with more
substituents (compounds
1
,
2
, and
4
8
); (2) anthraquinones with all substituents on C-1, 2, or 3
(compounds
2
,
6
, and
8
) were more active than those with two substituents (compounds
1
,
4
,
5
, and
7
);
(3) hydroxy (compound
8
), methyl (compound
6
), and methoxy group (compound
2
) substituents had
the highest activity in that order; and (4) when anthraquinones have two substituents, the substituent
position determines the activity. C-1 and 3 (compound
7
), C-1 and 2 (compound
1
), and C-2 and 3
(compounds 4and 5) were the most active in that order.
Finally, compounds
1
5
,
7
, and
8
were stronger inhibitors of AGE formation than AG, the positive
control. Compound
9
showed the best activity. Previous studies have indicated that scopoletin (
9
)
is a remarkable inhibitor of AGE formation [
40
]. Our results indicated that anthraquinones with
only one substituent (compound
3
) were the most effective, anthraquinones with a hydroxy group
(compounds
5
and
8
) had more activity than those with other substituents (compounds
4
and
6
),
and anthraquinones
with a methoxy group (compound
2
) were stronger inhibitors than those with a
methyl group (compound 6).
In conclusion, this study used bioassay-guided isolation to identify 10 compounds from
M. officinalis. The isolated compounds inhibited AChE, BChE, BACE1, and AGE formation, which are
related to AD. In addition, we suggested a structure-activity relationship for AChE and BACE1
inhibition by anthraquinones. These results demonstrated that M. officinalis root extracts were
therapeutic and may be a natural medicine for treating AD.
4. Materials and Methods
4.1. Plant Materials
M. officinalis roots were purchased from Kyung-Dong market, Seoul, Korea. Prof. Whang Wan
Kyunn identified the M. officinalis.
4.2. Instruments and Reagents
n-Hexane (Hx), ethyl acetate (EA), n-butanol (BuOH), methanol (MeOH), ethanol (EtOH),
and distilled
water were used for extraction, fractionation, and open column chromatography. Open
column chromatography used Sephadex LH-20 (25–100
µ
m; Pharmacia, Stockholm, Sweden), MCI
CHP 20P (Supelco, St. Louis, MO, USA), and ODS gel (400–500 mesh; Waters, Milford, MA, USA).
Dimethyl sulfoxide-d
6
(DMSO-d
6
) and chloroform-d(CDCl
3
) were used for the NMR solution. MS was
performed with ultra-high performance liquid chromatography and high-resolution mass spectrometry
(UHPLC-HRMS) coupled with electrospray ionization hybrid linear trap-quadruple-Orbitrap MS
Molecules 2017,22, 1638 7 of 12
(ESI/LTQ-Orbitrap) on an Ultimate 3000 rapid separation liquid chromatography (RSLC) system
(Thermo, Darmstadt, Germany).
1
H- and
13
C-nuclear magnetic resonance (NMR) spectra were
collected at 600 and 150 MHz, respectively, with a JEOL spectrometer. Chemical shifts are expressed
as parts per million (ppm) on the
δ
scale, and coupling constants (J) are shown in Hertz. HPLC
was conducted with Empower Pro 2.0 software (Waters, Milford, MA, USA), and determination
was performed with a Waters 2695 system pump and Waters 996 Photodiode array detector (Waters,
Milford, MA, USA). The separation column was a Waters Sunfire
C18 column (4.6
×
250 mm,
5
µ
m). HPLC-grade solvents, such as acetonitrile (ACN), methanol (MeOH), and distilled water
(H
2
O), were purchased from J. T. Baker
®
(Phillipsburg, PA, USA). HPLC-grade phosphoric acid
and dimethyl sulfoxide (DMSO) were obtained from DEAJUNG Chemical (Siheung, Gyeonggi,
Korea). Reagents and solvents including electric eel AChE (EC3.1.1.7), horse serum BChE (EC3.1.1.8),
acetylthiocholine iodide (ACh), butyrylthiocholine chloride (BCh), 5,5
0
-dithiobis [2-nitrobenzoic
acid] (DTNB), berberine, bovine serum albumin, aminoguanidine (AG), glucose, and fructose were
purchased from Sigma-Aldrich Chemical Company (St. Louis, MO, USA). The BACE1 FRET assay kit
(β-secretase) was purchased from PanVera Co. (Madison, WI, USA).
4.3. Extraction, Fractionation, and Isolation of M. officinalis
Dried and powdered M. officinalis roots (3.9 kg) were extracted in MeOH (20 L
×
3) at room
temperature. The filtrate was concentrated to dryness (613.4 g) in vacuo; suspended in water (H
2
O);
and partitioned in Hx, EA, and BuOH depending on solvent polarity. The result yielded Hx (3.84 g),
EA (7.23 g), BuOH (192.81 g), and water (270.42 g) fractions. Among these three fractions,
the Hx
and EA fractions showed the most potent activities in the four anti-AD model assays. Therefore,
we executed isolation from Hx and EA fractions.
The Hx fraction was subjected to Sephadex LH-20 chromatography and eluted in increasing
MeOH:water (60:40 to 100:0) solutions yielding eight sub-fractions. Sub-fraction 3 was separated
on a Sephadex LH-20 column (Pharmacia, Stockholm, Sweden) with 50% MeOH to obtain fractions
3-1 to 3-3. Sub-fraction 3-2 was separation on an MCI gel with 80% MeOH to yield four fractions.
Sub-fractions 3-2-2 and 3-2-3 were separated on an ODS column and eluted with 60% MeOH. Fraction
3-2-2-2 was separated on Sephadex LH-20 with 50% MeOH to isolate compound
1
. Sub-fraction 3-2-3-3
was separated on Sephadex LH-20 with 40% MeOH, and sub-fraction 3-2-3-3-3 was separated on ODS
(50% MeOH) to yield compound 2. Compound 3was isolated from fraction 5-2.
A portion of the EA fraction was separated on a Sephadex LH-20 column with an elution gradient
of 60% to 100% MeOH to give nine sub-fractions. Sub-fraction 3 was separated on a Sephadex LH-20
column with 40% MeOH to yield sub-fractions 3-1 to 3-11. Sub-fraction 3-6 was separated by MCI
column chromatography with 50% MeOH, and three fractions (3-6-1 to 3-6-3) were collected. Fraction
3-6-2 was separated by ODS eluted with 60% MeOH. Sub-fraction 3-6-2-2 was separated on Sephadex
LH-20 with 50% MeOH leading to the isolation of compounds
4
and
5
. Fraction 3-7 was separated by
MCI eluted with 80% MeOH to yield compound
6
and sub-fractions 3-7-1 to 3-7-8. Fraction 3-7-7 was
applied to an ODS column with 60% MeOH, yielding compound
7
. Sub-fraction 3-10 was separated
by MCI (50% MeOH), MCI (80% MeOH), and ODS (60% MeOH) yielding compound
8
. Fractions
2 and 8 were recrystallized to isolated compounds 9and 10, respectively.
4.4. Identification of Compounds Isolated from M. officinalis
4.4.1. NMR
Compound
1
: C
15
H
10
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 255.0652 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
)
δ
: 8.05 (2H, m, H-5, 8), 7.83 (1H, d, J= 8.4 Hz, H-3), 7.78 (2H, m, H-6, 7), 7.17 (1H, d, J= 8.4
Hz, H-4), 3.78 (3H, s, 1-OMe); 13C-NMR (150 MHz, DMSO-d6)δ: 182.6 (C-10), 180.9 (C-9), 160.9 (C-2),
148.2 (C-1), 134.5 (C-13), 133.6 (C-6, 7), 132.7 (C-14), 126.5 (C-3), 126.4 (C-11, 12), 125.9 (C-5), 125.2 (C-8),
121.9 (C-4), 57.8 (1-OMe).
Molecules 2017,22, 1638 8 of 12
Compound
2
: C
15
H
10
O
3
; ESI/LTQ-Orbitrap-HRMS m/z: 285.0758 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.02 (1H, d, J= 7.2 Hz, H-8), 7.96 (1H, d, J= 7.2 Hz, H-5), 7.75 (1H, t, J= 7.8, 7.2 Hz, H-7),
7.67 (1H, t, J= 7.8, 7.2 Hz, H-6), 7.11 (1H, s, H-4), 3.79 (3H, s, 1-OMe), 3.72 (3H, s, 2-OMe);
13
C-NMR
(150 MHz, DMSO-d
6
): 184.2 (C-10), 178.6 (C-9), 155.5 (C-1, 3), 148.8 (C-2), 136.1 (C-12), 134.4 (C-7), 132.8
(C-6), 132.7 (C-11), 131.4 (C-14), 126.6 (C-8), 126.1 (C-5), 115.2 (C-4, 13), 61.1 (1-OMe), 59.9 (2-OMe).
Compound
3
: C
15
H
10
O
3
; ESI/LTQ-Orbitrap-HRMS m/z: 239.0706 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.11 (1H, d, J= 6.3 Hz, H-8), 8.05 (1H, d, J= 6.2 Hz, H-5), 7.82 (2H, m, H-6, 7), 7.49 (2H, s,
H-1, 3), 7.12 (1H, s, H-4), 3.78 (3H, s, 2-OMe);
13
C-NMR (150 MHz, DMSO-d
6
): 185.4 (C-10), 181.8 (C-9),
157.1 (C-2), 134.4 (C-12), 134.2 (C-7), 134.0 (C-6), 133.5 (C-11), 132.9 (C-14), 129.9 (C-1), 129.1 (C-3), 126.7
(C-8), 126.5 (C-5), 126.2 (C-13), 111.3 (C-4), 59.8 (2-OMe).
Compound
4
: C
16
H
12
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 267.0653 [M
H]
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.06 (1H, d, J= 7.8 Hz, H-8), 7.98 (1H, d, J= 7.2 Hz, H-5), 7.78 (1H, t, J= 7.8, 7.2 Hz,
H-7), 7.69 (1H, t, J= 7.8, 7.2 Hz, H-6), 6.97 (2H, s, H-1, 4), 4.56 (2H, s, 2-CH
2
OH), 3.68 (3H, s, 3-OMe);
13
C-NMR (150 MHz, DMSO-d
6
): 184.4 (C-10), 182.8 (C-9), 137.2 (C-3), 135.6 (C-14), 135.1 (C-7), 134.0
(C-6), 132.3 (C-11), 132.1 (C-12), 128.1 (C-1), 126.2 (C-5, 8), 125.5 (C-2, 13), 114.7 (C-4), 62.3 (2-CH
2
OH),
61.0 (3-OMe).
Compound
5
: C
15
H
10
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 253.0503 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.08 (1H, d, J= 7.2 Hz, H-8), 8.05 (1H, d, J= 7.2 Hz, H-5), 7.97 (1H, s, H-4), 7.79 (1H, t,
J= 7.8
, 7.2 Hz, H-7), 7.74 (1H, t, J= 7.8, 7.2 Hz, H-6), 7.12 (1H, s, H-1), 4.49 (2H, s, 2-CH
2
OH);
13
C-NMR
(150 MHz, DMSO-d
6
): 184.6 (C-10), 180.4 (C-9), 160.3 (C-3), 134.7 (C-14), 134.5 (C-7), 134.4 (C-6), 133.7
(C-11), 133.4 (C-12), 126.8 (C-1), 126.7 (C-5, 8), 126.6 (C-2, 13), 114.1 (C-4), 60.4 (2-CH2OH).
Compound
6
: C
16
H
12
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 269.0808 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.08 (1H, d, J= 6.6 Hz, H-8), 8.02 (1H, d, J= 6.6 Hz, H-5), 7.82 (1H, t, J= 6.6, 7.2 Hz, H-7),
7.76 (1H, t, J= 6.6, 7.2 Hz, H-6), 7.41 (1H, s, H-4), 3.72 (3H, s, 1-OMe), 2.09 (3H, s, 2-Me);
13
C-NMR
(150 MHz, DMSO-d
6
): 183.5 (C-10), 180.1 (C-9), 164.8 (C-1), 161.2 (C-3), 135.2 (C-7), 134.9 (C-6), 134.2
(C-12), 133.5 (C-11), 132.6 (C-14), 127.0 (C-8), 126.7 (C-5), 126.4 (C-4), 116.9 (C-13), 110.4 (C-2), 60.9
(1-OMe), 9.6 (2-Me).
Compound
7
: C
15
H
10
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 253.0495 [M
H]
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.13 (1H, d, J= 7.2 Hz, H-8), 8.06 (1H, d, J= 7.2 Hz, H-5), 7.83 (1H, t, J= 6.6, 7.2 Hz, H-7),
7.77 (1H, t, J= 6.6, 7.2 Hz, H-6), 6.98 (2H, s, H-2, 4), 4.35 (2H, s, 3-CH
2
OH);
13
C-NMR (150 MHz,
DMSO-d
6
): 183.5 (C-9), 183.2 (C-10), 177.2 (C-1), 165.2 (C-3), 134.9 (C-6), 134.6 (C-7), 134.0 (C-14), 133.9
(C-11), 133.3 (C-12), 127.1 (C-5), 126.0 (C-8), 126.5 (C-2), 116.5 (C-4), 112.5 (C-13), 57.9 (3-CH2OH).
Compound
8
: C
15
H
10
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 255.0654 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
): 8.14 (1H, d, J= 7.8 Hz, H-8), 8.07 (1H, d, J= 6.6 Hz, H-5), 7.84 (1H, t, J= 7.2 Hz, H-7), 7.80
(1H, t, J= 7.2 Hz, H-6), 7.11 (1H, s, H-4), 1.99 (3H, s, 2-Me);
13
C-NMR (150 MHz, DMSO-d
6
): 185.1
(C-10), 183.0 (C-9), 165.6 (C-1), 163.1 (C-3), 134.9 (C-7), 134.3 (C-6), 134.1 (C-12), 133.4 (C-11), 132.2
(C-14), 127.0 (C-8), 126.6 (C-5), 117.4 (C-4), 110.0 (C-13), 107.9 (C-2), 8.7 (2-Me).
Compound
9
: C
10
H
8
O
4
; ESI/LTQ-Orbitrap-HRMS m/z: 193.0497 [M + H]
+
;
1
H-NMR (600 MHz,
DMSO-d
6
)
δ
: 7.83 (1H, d, J= 9.0 Hz, H-4), 7.14 (1H, s, H-5), 6.72 (1H, s, H-8), 6.16 (1H, d, J= 9.6 Hz,
H-3), 3.76 (3H, s, 6-OMe);
13
C-NMR (150 MHz, DMSO-d
6
)
δ
: 161.2 (C-2), 151.6 (C-7), 150.0 (C-9), 145.7
(C-6), 144.9 (C-4), 112.1 (C-3), 111.0 (C-10), 110.0 (C-5), 103.2 (C-8), 56.4 (6-OMe).
Compound
10
: C
29
H
50
O; ESI/LTQ-Orbitrap-HRMS m/z: 437.3768 [M + Na]
+
;
1
H-NMR (600 MHz,
CDCl
3
)
δ
: 5.35 (1H, m, H-6), 3.51 (1H, m, H-3), 1.99 (2H, m, H-11) 1.01 (3H, s, H-19), 0.93 (3H, m, H-21),
0.86 (3H, m, H-27), 0.83 (3H, m, H-26), 0.81 (3H, m, H-29), 0.68 (3H, s, H-18);
13
C-NMR (150 MHz,
CDCl
3
)
δ
: 140.8 (C-5), 121.7 (C-6), 71.8 (C-3), 56.9 (C-14), 56.0 (C-17), 50.1 (C-9), 45.8 (C-24), 42.3 (C-13),
40.4 (C-12), 39.8 (C-4), 37.3 (C-1), 36.5 (C-10), 36.1 (C-20), 33.9 (C-22), 31.9 (C-7, 8), 31.7 (C-2), 29.1 (C-25),
Molecules 2017,22, 1638 9 of 12
28.2 (C-16), 26.1 (C-23), 24.3 (C-15), 23.1 (C-28), 21.2 (C-11), 19.8 (C-26), 19.4 (C-19), 19.1 (C-27), 19.0
(C-21), 12.2 (C-29), 12.0 (C-18).
4.4.2. UHPLC-ESI/LTQ-Orbitrap-HRMS Conditions
Molecular weights of the isolated compounds were confirmed by UHPLC-ESI/LTQ-
Orbitrap-HRMS. Samples were dissolved in MeOH. The column (Hypersil GOLD C18,
2.1 ×50 mm
,
1.9
µ
m, Thermo) and sampler temperatures were 30
C and 15
C, respectively. UV was not used.
The mobile phase was 0.1% formic acid in water (solvent A) and 0.1% formic acid in acetonitrile
(solvent B). The flow rate was 0.3 mL/min. The gradient conditions were 0–18 min, 0–50% B;
18–20 min
,
50–100% B. The injection volume was 5.0
µ
L for the standard solution. The optimal analysis conditions
were as follows: heater temperature, 300
C; capillary temperature, 360
C; auxiliary gas flow rate,
10 L/h; sheath gas flow rate, 45 L/h; S-lens RF level, 50.0 V; spray capillary voltage, 3.0 kV; full MS
resolution, 35,000 (FWHM @ m/z200); full MS AGC target, 3e6; and full MS maximum IT, 200 ms.
4.5. HPLC Analysis
To analyze the major compounds from M. officinalis, a Waters Sunfire
C18 column (
4.6 ×250 mm
,
5
µ
m) was used. Solvents A (0.2% formic acid in water) and B (acetonitrile) were used in linear
gradients as the mobile phase (0–5 min, 15–30% B; 5–10 min, 30–40% B; 10–25 min, 40–60% B;
18–30 min
,
60–80% B
) at a flow rate of 1 mL/min. All eluents were filtered with a 0.45
µ
m PVDF syringe filter.
The injection volume was 10 µL, and compounds were detected at a wavelength of 280 nm.
4.6. Bioactivities Assay
4.6.1. Measurement of ChE Inhibitory Activities
ChE activity was detected by AChE- or BChE-mediated hydrolysis of DTNB for 15 min to form
thiocholine and the yellow 5-thio-2-nitrobenzoate anion. The result was quantified by measuring
the absorbance 412 nm. The assay mixture contained 0.1 M potassium phosphate buffer (pH 7.8),
0.3 U/mL
AChE or BChE, 0.5 mM DTNB, 0.6 mM ACh or BCh, and the sample for a total volume
of 0.2 mL. All tested samples were dissolved in 10% DMSO at five different final concentrations
(
10–500 µg/mL
for extracts and fractions or 10–500
µ
M for isolated constituents). The reaction was
performed in a 96-well plate. Berberine, a typical ChE inhibitor, was used as a positive control [
16
].
Inhibitory activity was calculated with the following formula: (Ac
As/Ac)
×
100, where Ac is the
change in absorbance for the control after 15 min and As is the change in absorbance for the sample
after 15 min.
4.6.2. Measurement of BACE1 Inhibition
BACE1 inhibition was measured with a commercially available spectrophotometric method
according to the manufacturer’s recommended protocol. The assay mixture contained 50 mM sodium
acetate buffer (pH 4.5), 1.0 U/mL BACE1, substrate (750 nM Rh-EVNLDAEFK-Quencher in 50 mM
ammonium bicarbonate), and sample. All tested samples were dissolved in 10% DMSO at five
different final concentrations (2.5–1250
µ
g/mL for extracts and fractions or 2.5–1250
µ
M for isolated
constituents). The reaction was incubated for 60 min at room temperature in the dark. BACE1 activity
was determined by measuring the proteolysis of two fluorophores (Rh-EVNLDAEFK-Quencher) to
form a fluorescent donor (Rh-EVNL) with an excitation of 545 nm and emission of 585 nm in a black
96-well plate. Quercetin, a typical BACE1 inhibitor, was used as a positive control [
16
,
26
,
27
]. Inhibition
was calculated with the following formula: (Ac
As/Ac)
×
100, where Ac is the change in fluorescence
for the control after 60 min, and As is the change in fluorescence for the sample after 60 min.
Molecules 2017,22, 1638 10 of 12
4.6.3. Measurement of Inhibition of AGE Formation
Inhibition of AGE formation was measured with a spectrophotometric method developed
previously [
34
]. All tested samples were dissolved in 10% DMSO at five different final concentrations
(10–500
µ
g/mL for extracts and fractions or 10–500
µ
M for isolated constituents). The assay mixture
contained bovine serum albumin (10 mg/mL), 50 mM phosphate buffer (pH 7.4) with 0.02% sodium
azide, and 0.4 M fructose and glucose. The reaction was incubated at 60
C for 2 days. After incubating,
fluorescence was measured at an excitation wavelength of 350 nm and emission of 450 nm in a black
96-well plate. Aminoguanidine (AG), a typical inhibitor of AGE formation, was used as a positive
control. The inhibitory activity was calculated with the following formula: (Ac
As/Ac)
×
100, where
Ac is the fluorescence of the control, and As is the fluorescence of the sample.
4.7. Statistical Analysis
All assays were performed in triplicate. Data are presented as the mean
±
standard deviation
(SD) and were analyzed by one-way ANOVA. Data were considered statistically significant at p< 0.05.
Acknowledgments:
This research was supported by the Chung-Ang University Research Scholarship Grants
in 2017.
Author Contributions:
Y.K.L. and W.K.W. conceived and designed the experiments; Y.K.L. performed the
extraction, isolation, bioactivities experiments, and quantitative analysis, analyzed the data, and wrote the paper;
and H.J.B. and J.B.O. assisted in the isolation.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
Potterat, O.; Hamburger, M. Morinda citrifolia (noni) fruit-phytochemistry, pharmacology, safety. Planta Med.
2007,73, 191–199. [CrossRef]
2.
Wang, M.Y.; West, B.J.; Jensen, C.J.; Nowichi, D.; Su, C.; Palu, A.; Anderson, G. Morinda citrifolia (Noni):
A literature review and recent advances in Noni research. Acta Pharmacol. Sin. 2002,23, 1127–1141.
3.
Zhang, H.L.; Zhang, Q.W.; Zhang, X.Q.; Ye, W.C.; Wang, Y.T. Chemical constituents from the roots of Morinda
officinalis.Chin. J. Nat. Med. 2010,8, 192–195. [CrossRef]
4.
Zhu, M.Y.; Wang, C.J.; Wang, X.; Chen, S.H.; Zhu, H.; Zhu, H.M. Extraction of polysaccharides from
Morinda officinalis by response surface methodology and effect of the polysaccharides on bone-related genes.
Carbohydr. Polym. 2011,85, 23–28. [CrossRef]
5.
Wu, Y.B.; Zheng, C.J.; Qin, L.P.; Sun, L.N.; Han, T.; Jiao, L.; Zhang, Q.Y.; Wu, J.Z. Antiosteoporotic activity of
anthraquinones from Morinda officinalis on osteoblasts and osteoclasts. Molecules
2009
,14, 573–583. [CrossRef]
6.
Bao, L.; Qin, L.; Liu, L.; Wu, Y.; Han, T.; Xue, L.; Zhang, Q. Anthraquinone compounds from Morinda officinalis
inhibit osteoclastic bone resorption in vitro. Chem. Biol. Interact. 2011,194, 97–105. [CrossRef] [PubMed]
7.
Wang, Z.B.; Lu, Q.Y.; Lu, H.Y.; Liao, W.M.; Wu, Z.P.; Kuang, G.Z.; Feng, H.J. Protective effect of Morinda
officinalis polysaccharides on bone degeneration in the aged rats. Int. J. Phys. Sci. 2011,6, 112–115.
8.
Zhu, M.Y.; Wang, C.J.; Gu, Y.; He, C.S.; Teng, X.; Zhang, P.; Lin, N. Extraction, characterization of
polysaccharides from Morinda officinalis and its antioxidant activities. Carbohydr. Polym. 2009,78, 497–501.
9.
Zhang, H.L.; Li, J.; Li, G.; Wang, D.M.; Zhu, L.P.; Yang, D.P. Structural characterization and anti-fatigue
activity of polysaccharides from the roots of Morinda officinalis.Int. J. Biol. Macromol.
2009
,44, 257–261.
[CrossRef] [PubMed]
10.
Choi, J.W.; Lee, K.T.; Choi, M.Y.; Nam, J.W.; Jung, H.J.; Park, S.K.; Park, H.J. Antinociceptive
anti-inflammatory effect of monotropein isolated from the root of Morinda officinalis.Biol. Pharm. Bull.
2005,28, 1915–1918. [CrossRef] [PubMed]
11.
Liu, Q.; Kim, S.B.; Ahn, J.H.; Hwang, B.Y.; Kim, S.Y.; Lee, M.K. Anthraquinones from Morinda officinalis roots
enhance adipocyte differentiation in 3T3-L1 cells. Nat. Prod. Res.
2012
,26, 1750–1754. [CrossRef] [PubMed]
12.
Yoshikawa, M.; Yamaguchi, S.; Nishisaka, H.; Yamahara, J.; Murakami, N. Chemical constituents of Chinese
natural medicine, Morindae Radix, the dried roots of Morinda officinalis How: Structures of morindolide and
morofficinaloside. Chem. Pharm. Bull. 1995,43, 1462–1465. [CrossRef] [PubMed]
Molecules 2017,22, 1638 11 of 12
13. Adams, R.L.; Crai, P.L.; Parsons, O.A. Neuropsychology of dementia. Neurol. Clin. 1984,4, 387–405.
14.
Aisen, P.S.; Davis, K.L. The search for disease-modifying treatment for Alzheimer’s disease. Neurology
1997
,
48, 35–41. [CrossRef]
15. Jann, M.W. Preclinical pharmacology of metrifonate. Pharmacotherapy 1998,18, 55–67. [PubMed]
16.
Ali, M.Y.; Jannat, S.; Jung, H.A.; Choi, R.J.; Roy, A.; Choi, J.S. Anti-Alzheimer’s disease potential of coumarins
from Angelica decursiva and Artemisia capillaris and structure-activity analysis. Asian Pac. J. Trop. Med.
2016
,9,
103–111. [CrossRef] [PubMed]
17.
Mukherjee, P.K.; Kumar, V.; Mal, M.; Houghton, P.J. Acetylcholinesterase inhibitors from plants. Phytomedicine
2007,14, 289–300. [CrossRef] [PubMed]
18.
Schliebs, R.; Arendt, T. The cholinergic system in aging and neuronal degeneration. Behav. Brain Res.
2011
,
221, 555–563. [CrossRef] [PubMed]
19.
Massoulie, J.; Pezzementi, L.; Bom, S.; Krejci, E.; Vallette, F.M. Molecular and cellular biology of
cholinesterases. Prog. Neurobiol. 1993,41, 31–91. [CrossRef]
20.
Liang, Y.; Rihui, C.; Wei, Y.; Qin, Y.; Zhiyong, C.; Lin, M.; Wenile, P.; Huacan, S. Synthesis of
4-[(diethylamino)methyl]-phenol derivatives as novel cholinesterase inhibitors with selectivity towards
butyrylcholinesterase. Bioorg. Med. Chem. Lett. 2010,20, 3254–3258.
21.
Querfurth, H.W.; LaFerla, F.M. Mechanisms of disease: Alzheimer ’s disease. N. Engl. J. Med.
2010
,362,
329–344. [CrossRef] [PubMed]
22.
Moon, M.; Hong, H.S.; Nam, D.W.; Baik, S.H.; Song, H.; Kook, S.Y.; Kim, Y.S.; Lee, J.; Mook, J.I. Intracellular
amyloid-b accumulation in calcium-binding protein-deficient neurons leads to amyloid-
β
plaque formation
in animal model of Alzheimer’s disease. J. Alzheimers Dis. 2012,29, 1–4.
23.
Pereira, C.; Agostinho, P.; Moreira, P.I.; Cardoso, S.M.; Oliveira, C.R. Alzheimer’s disease-associated
neurotoxic mechanisms and neuroprotective strategies. Curr. Drug Targets CNS Neurol. Disord.
2005
,
4, 383–403. [CrossRef] [PubMed]
24.
Yan, R.; Bienkowski, M.J.; Shuck, M.E.; Miao, H.; Tory, M.C.; Pauley, A.M.; Brashler, J.R.; Stratman, N.C.;
Mathews, W.R.; Buhl, A.E. Membrane-anchored aspartyl protease with Alzheimer’s disease
β
-secretase
activity. Nature 1999,402, 537–540. [CrossRef] [PubMed]
25.
Vassar, R.; Bennett, B.D.; Babu-Khan, S.; Kahn, S.; Mendiaz, E.A.; Denis, P.; Teplow, D.B.; Ross, S.;
Amarante, P.; Loeloff, R.
β
-Secretase cleavage of Alzheimer
'
s amyloid precursor protein by the
transmembrane aspartic protease BACE. Sciences 1999,286, 735–741. [CrossRef]
26.
Kuk, E.B.; Jo, A.R.; Oh, S.I.; Sohn, H.S.; Seong, S.H.; Roy, A.; Choi, J.S.; Jung, H.A. Anti-Alzheimer’s disease
activity of compounds from the root bark of Morus alba L. Arch. Pharm. Res.
2017
,40, 338–349. [CrossRef]
[PubMed]
27.
Jung, H.A.; Ali, M.Y.; Jung, H.J.; Jeong, H.O.; Chung, H.Y.; Choi, J.S. Inhibitory activities of major
anthraquinones and other constituents from Cassia obtusifolia against
β
-secretase and cholinesterases. J.
Ethnopharmacol. 2016,191, 152–160. [CrossRef] [PubMed]
28.
Sasaki, N.; Fukatsu, R.; Tsuzuki, K.; Hayashi, Y.; Yoshida, T.; Fujii, N.; Koike, T.; Wakayama, I.; Yanagihara, R.;
Garruto, R.; et al. Advanced glycation end products in Alzheimer’s disease and other neurodegenerative
diseases. Am. J. Pathol. 1998,153, 1149–1155. [CrossRef]
29.
Schulz, V. Ginkgo extract or cholinesterase inhibitors in patients with dementia: What clinical trials and
guidelines fail to consider. Phytomedicine 2003,10, 74–79. [CrossRef] [PubMed]
30.
Small, G.W.; Robins, R.V.; Barry, P.P.; Buckholts, N.S.; Dekosky, S.T.; Ferris, S.H.; Finkel, S.I.; Gwyther, L.P.;
Khachaturian, Z.S.; Lebowitz, B.D.; et al. Diagnosis and treatment of Alzheimer’s disease and related
disorder. JAMA 1997,278, 1363–1371. [CrossRef] [PubMed]
31.
Melzer, D. New drug treatment for Alzheimer’s disease: Lesson for healthcare policy. BMJ
1998
,316, 762–764.
[CrossRef] [PubMed]
32.
Lee, H.W.; Park, S.Y.; Choo, B.K.; Chun, J.M.; Lee, A.Y.; Kim, H.K. Standardization of Morinda officinalis How.
Kor. J. Pharmacogn. 2006,37, 241–245.
33.
Sun, P.; Huo, J.; Kurtan, T.; Mandi, A.; Antus, S.; Tang, H.; Draeger, S.; Schulz, B.; Hussain, H.; Krohn, K.; et al.
Structural and stereochemical studies of hydroxyanthraquinone derivatives from the endophytic fungus
Coniothyrium sp. Chirality 2013,25, 141–148. [CrossRef] [PubMed]
Molecules 2017,22, 1638 12 of 12
34.
Lee, Y.K.; Hong, E.Y.; Whang, W.K. Inhibitory effect of chemical constituents isolated from Artemisia iwayomogi
on polyol pathway and simultaneous quantification of major bioactive compounds. Biomed. Res. Int.
2017
,
2017, 1–12. [CrossRef] [PubMed]
35.
Savelev, S.U.; Okello, E.J.; Perry, E.K. Butyryl- and acethyl-cholinesterase inhibitory activities in essential oils
of Salvia species and their constituents. Phytother. Res. 2004,18, 315–324. [CrossRef] [PubMed]
36. Katzman, R. Early detection of senile dementia. Hosp. Pract. 1981,16, 61–76.
37.
Heuvel, C.V.D.; Thornton, E.; Vink, R. Traumatic brain injury and Alzheimer’s disease: A review. Prog. Brain
Res. 2007,161, 303–316.
38.
Orhan, I.; Senol, F.S.; Kartal, M.; Dborska, M.; Zemlicka, M.; Smejkal, K.; Mokry, P. Cholinesterase inhibitory
effects of the extracts and compounds of Maclura pomifera (Rafin.) Schneider. Food Chem. Toxicol.
2009
,47,
1747–1751. [CrossRef] [PubMed]
39.
Sawasdee, P.; Sabphone, C.; Sitthiwongwanit, D.; Kokpol, U. Anticholinesterase activity of 7-methoxyflavones
isolated from Kaempferia parviflora.Phytother. Res. 2009,23, 1792–1794. [CrossRef] [PubMed]
40.
Jung, H.A.; Park, J.J.; Islam, M.N.; Jin, S.E.; Min, B.S.; Lee, J.H.; Sohn, H.S.; Choi, J.S. Inhibitory activity of
coumarins from Artemisia capillaris against advanced glycation endproduct formation. Arch. Pharm. Res.
2012,35, 1021–1035. [CrossRef] [PubMed]
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... Compounds 1-6 were identified as syringaldehyde (1), benzoic acid (2), phthalic acid (3), hippuric acid (4), urolithin B (5), and (+)-usnic acid (6) using 1 H and 13 C -NMR spectroscopy, UHPLC-ESI/LTQ-Orbitrap-HRMS and by comparison with results of previous studies. [14][15][16][17][18][19][20][21][22][23] After identification of compounds 1-6, HPLC-UV analysis was performed to determine the major compounds of Mongolian Shilajit extract ( Figure 1). However, compounds 5 and 6 were not detected at any of the UV wavelengths. ...
... The IC 50 values of the positive control in inhibiting AChE, BChE, and BACE1 activity and AGE formation were similar to previously reported values. 18,19,31,32 The Shilajit extract and n-BuOH fraction inhibited AChE activity (IC 50 422.83 ± 6.11 and 240.28 ± 8.58 µg/ mL, respectively, whereas the n-BuOH fraction and extract showed greater inhibition of BChE activity (IC 50 55.85 ± 1.01, 59.36 ± 0.76 µg/mL, respectively) than the other fractions. ...
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Shilajit has a longstanding use as an anti-aging and memory enhancing drug. It is known to have excellent anti-bacterial effects and is believed to be effective for cognitive enhancement, but is difficult to standardize because of the lack of quality control standards. This study, for the first time, proposes a quality control standard using a simultaneous analytical method for the drug’s multi-compound content using high-performance liquid chromatography-ultraviolet detection (HPLC-UV) as an aid for the internationalization of Mongolian Shilajit. Phenolic compounds 1-6 were isolated from Mongolian Shilajit extract using bioassay-guided isolation, and the isolated compounds were evaluated for cognitive-related anti-Alzheimer’s disease (AD) activities using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging, acetylcholinesterase (AChE), butyrylcholinesterase (BChE), β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), and advanced glycation end-product (AGE) formation assays. The isolated compounds showed good effects for each activity. In addition, the isolated compounds were successfully quantified using a validated quantitative HPLC analysis method. As a result, the isolated compounds were suggested as standard marker compounds for Mongolian Shilajit. Also, we proved that the original material of Mongolian Shilajit is a lichen named Xanthoparmelia somloensis (Gyel.) Hale using HPLC-UV, ultra-high-performance liquid chromatography-electrospray ionization/hybrid linear trap-quadruple-orbitrap-high-resolution mass spectrometry (UHPLC-ESI/LTQ-HRMS).
... Therefore, the above mentioned drugs possess constricted efficacy, toxicity, and have unfavorable side effects such as diarrhea, vomiting, dizziness, hepatotoxicity, and nausea (39), so there is a need for more potent and highly efficient cholinesterase inhibitors for the treatment of AD. According to literature surveying, there are a few studies about anticholinesterase activity studies on anthraquinone compounds (40)(41)(42)(43) but there is not any study about thioanthraquinone compounds except for the study of Tonelli et al. (44), in which only one thioanthraquinone compound was investigated for anticholinesterase activity. This study is important to examine the properties of anti-acetyl and butyrylcholinesterase inhibitory activities for thioanthraquinone compounds. ...
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In this study, the enzyme activity of anthraquinone compounds which were synthesized beforehand by our research group was investigated. Molecular docking studies were performed for compounds 1-(4-aminophenylthio)anthracene-9,10-dione (3) and 1-(4-chlorophenylthio)anthracene-9,10-dione (5). Compound 3 was synthesized from the reaction of 1-chloroanthraquinone (1) and 4-aminothiophenol (2). Compound 5 was synthesized (1) from the reaction of 1-chloroanthraquinone (1) and 4-chlorothiophenol (4). Anthraquinone analogs (3, 5) were synthesized with a new reaction method made by our research group (2). Inhibitory effects of compounds 3 and 5 were investigated against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes which are related to Alzheimer's Disease (AD). Compounds 3 and 5 exhibited strong anti-acetyl-and butyryl-cholinesterase inhibition activities than galanthamine used as standard compound (92.11±1.08 and 80.95±1.77 %, respectively). The EHOMO-ELUMO values, molecular descriptors, and the calculated UV-Vis spectra of anthraquinone derivatives were computed by B3LYP/6-31+G(d,p) levels in the CHCl3 phase. Based on the fluorescence property of the anthraquinone skeleton, the fluorescence activity of the bioactive anthraquinone analogue (5) was investigated. MTT test was performed to determine the cytotoxic effects of thioanthraquinone molecules 3 and 5. In MTT analyses, 3 compounds showed the highest effect against Ishikawa cells at a dose of 10 µg/mL, while compound 5 showed the highest effect at a dose of 50 µg/mL. The cell viability for compound 3 was 84.18% for 10 µg/mL and the cell viability for compound 5 was 75.02% for 50 µg/mL.
... Cassia tora and Morinda officinalis are mature medicinal plants. Recent studies have shown that the extracts of both Cassia tora and Morinda officinalis can effectively inhibit the activity of cholinesterase [81,82]. Through ITC analysis, Budryn et al. found that active substances in coffee, ferulic acid and dihydrocaffeic acid, could interact strongly with BChE, indicating the potential therapeutic effects of coffee [83]. ...
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Alzheimer's disease (AD) is a chronic neurodegenerative disease that 4 widespread in the elderly. The etiology of AD is complicated, and its pathogenesis is still unclear. Although there are many researches on anti-AD drugs, they are limited to reverse relief symptoms and cannot treat diseases. Therefore, the development of high-efficiency anti-AD drugs with no side effects has become an urgent need. Based on the published literature, this paper summarizes the main targets of AD and their drugs, and focuses on the research and development progress of these drugs in recent years. Keywords Amyloid beta (Aβ), Acetylcholinesterase (AChE), Amyloid-beta binding alcohol dehydrogenase (ABAD), Butyryl-cholinesterase (BChE), B-site APP cleaving enzyme 1 (BACE1), Cyclin-dependent kinase-5 (CDK-5), Glycogen synthase kinase-3β (GSK-3β), Monoamine oxidase (MAO), Tau protein.
... Morinda officinalis is a commonly used traditional Chinese medicines (TCMs) [1], which has been used in China for many years. People use it as a tonic or tonifying kidney product to protect against and cure depression, rheumatoid arthritis, osteoporosis, and kidney-yang deficiency syndrome [2][3][4][5][6]. Its main active components include oligosaccharides, polysaccharides, iridoid glycosides, and anthraquinones [7][8][9]. ...
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... Lee et al isolated 8 anthraquinones from Morinda officinalis using a bioassay-guided approach. 18 Among the compounds isolated, alizarin-1-methyl ether, 1,2-dimethoxy-3-hydroxy anthraquinone, 2-methoxy anthraquinone, rubiadin-1-methyl ether, 1-hydroxy-3-hydroxymethyl anthraquinone, and rubiadin showed potent inhibitory activities against β-secretase with IC 50 values of 192.4, 114.6, 9.3, 25.9, 178.4, and 19.8 µM, respectively ( Figure 17). ...
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Reports on β-secretase inhibitors of natural origin are listed in order to reveal their chemical diversity. Various types of compounds were found to inhibit β-secretase, and natural resources included a wide spectrum of biological species. Among them, some triterpenes and moracin derivatives, which are nonpeptidic compounds, were determined to be competitive inhibitors. In addition, no peptide compounds were reported from natural resources. These points will be clarified in future studies.
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Morinda officinalis How was widely applied to alleviate symptom like impotence, menstrual disorders, osteoporosis, and rheumatoid arthritis. To expand resources usage, phytochemistry of the aerial parts was studied and the structures of compounds were elucidated based on NMR, HRESIMS, IR and UV. Moreover, the anti-inflammatory effect and possible mechanism were investigated by Griess kit, RT-qPCR, ELISA, western blot and molecular docking on LPS-induced inflammation in RAW 264.7 cells. Herein, we isolated and identified 16 iridoid derivatives, including seven new iridoids officinaloside A-G (1–7) and nine known iridoids. All the compounds were safe to RAW 264.7 cells. Luckily, compounds 5 and 6 showed inhibitory effect on production of NO, and decreased the expression of inflammatory cytokines at mRNA and protein levels in a dose-dependent way. The possible mechanism of their anti-inflammation may be the affinity interaction between 5 with COX-2 protein, and 6 with iNOS protein. Overall, compounds 5 and 6 exert promising effects in inhibiting inflammatory cytokines, indicating that they could be used as lead compounds for developing health products or clinical practice for inflammation, which provides a scientific basis for further sustainable development and usage of the aerial parts of Morinda officinalis How.
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Morinda (Morinda officinalis) is widely consumed as a health-care herb in Asia and reported to possess various biological activities. In this study, anti-inflammatory phytochemicals were investigated and two pairs of new methyl-2-naphthoate enantiomers (1a/1b, 2a/2b), one new anthraquinone (3), three new natural unknown anthraquinones (5-6, 23), and eighteen known anthraquinones were isolated and elucidated from the roots of morinda. Anti-inflammatory activities of the isolated compounds were assessed in lipopolysaccharide-stimulated RAW 264.7 macrophages. Compounds 2b and 19 significantly inhibited the production of NO with IC50 values of 34.32±4.87 and 17.17±4.13 μM (indomethacin, IC50 26.71±6.32 μM), and they were further corroborated via immunoblotting, quantitative real-time PCR and immunofluorescence staining assays. They could dose-dependent suppress lipopolysaccharide-stimulated pro-inflammatory factors (COX-2 and iNOS) production and block nuclear translocation of NF-κB. The results implied that reasonable consumption of morinda may be beneficial for preventing and reducing the occurrence of inflammatory-associated diseases.
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Alzheimer’s disease (AD) is a progressive neurodegenerative disease that is characterized by memory loss, cognitive impairment, and functional decline leading to dementia and death. AD imposes neuronal death by the intricate interplay of different neurochemical factors, which continue to inspire the medicinal chemist as molecular targets for the development of new agents for the treatment of AD with diverse mechanisms of action, but also depict a more complex AD scenario. Within the wide variety of reported molecules, this review summarizes and offers a global overview of recent advancements on naphthoquinone (NQ) and anthraquinone (AQ) derivatives whose more relevant chemical features and structure-activity relationship studies will be discussed with a view to providing the perspective for the design of viable drugs for the treatment of AD. In particular, cholinesterases (ChEs), β-amyloid (Aβ) and tau proteins have been identified as key targets of these classes of compounds, where the NQ or AQ scaffold may contribute to the biological effect against AD as main unit or significant substructure. The multitarget directed ligand (MTDL) strategy will be described, as a chance for these molecules to exhibit significant potential on the road to therapeutics for AD.
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Morinda citrifolia is a small tree in appearance with elliptical leaves. The fruit juice is used as alternative medicine for treatment of arthritis, diabetes, high blood pressure, muscle aches and pains, menstrual problems, headaches, heart disease, gastric ulcers, sprains, mental depression, constipation, atherosclerosis, and blood vessel problems. The ethanolic extracts demonstrated anti‐inflammatory, trypanocidal, antidiabetic, gastrointestinal, analgesic, cardiovascular, anticancer, antioxidant, immunomodulatory, and antibacterial activities. The production of anthraquinones is correlated with the activity of isochorismate synthase under diverse conditions and circumstances. The addition of pectic acid to culture medium as elicitor increased the synthesis of anthraquinones by 5‐fold higher than control cell cultures in Morinda citrifolia. In methyl jasmonate with various concentrations in addition to culture medium, after three to six days, the maximum production was reported in cell cultures of Morinda elliptica.
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The inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) plays important roles in prevention and treatment of Alzheimer’s disease (AD). Among the individual parts of Morus alba L. including root bark, branches, leaves, and fruits, the root bark showed the most potent enzyme inhibitory activities. Therefore, the aim of this study was to evaluate the anti-AD activity of the M. alba root bark and its isolate compounds, including mulberrofuran G (1), albanol B (2), and kuwanon G (3) via inhibition of AChE, BChE, and BACE1. Compounds 1 and 2 showed strong AChE- and BChE-inhibitory activities; 1–3 showed significant BACE1 inhibitory activity. Based on the kinetic study with AChE and BChE, 2 and 3 showed noncompetitive-type inhibition; 1 showed mixed-type inhibition. Moreover, 1–3 showed mixed-type inhibition against BACE1. The molecular docking simulations of 1–3 demonstrated negative binding energies, indicating a high affinity to AChE and BACE1. The hydroxyl group of 1–3 formed hydrogen bond with the amino acid residues located at AChE and BACE1. Consequently, these results indicate that the root bark of M. alba and its active compounds might be promising candidates for preventive and therapeutic agents for AD.
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Since glycation can lead to the onset of diabetic complications due to chronic hyperglycemia, several indigenous Artemisia species were evaluated as potential inhibitors of advanced glycation endproducts (AGE). Among them, the Artemisia capillaris plant demonstrated the highest AGE inhibitory activity. Repeated column chromatography was performed to isolate a new acylated flavonoid glycoside, acacetin-7-O-(6″-O-acetyl)-β-D-glucopyranosyl-(1→2)[α-L-rhamnopyranosyl]-(1→6)-β-D-glucopyranoside, along with 11 known flavonoids (acacetin-7-O-β-D-glucopyranosyl-(1→2)[α-L-rhamnopyranosyl]-(1→6)-β-D-glucopyranoside, linarin, quercetin, hyperoside, isorhamnetin, isorhamnetin 3-galactoside, isorhamnetin 3-glucoside, isorhamnetin 3-arabinoside, isorhamnetin 3-robinobioside, arcapillin, and cirsilineol), six coumarins (umbelliferone, esculetin, scopoletin, scopolin, isoscopolin, and scoparone), and two phenolic derivatives (4,5-di-O-caffeoylquinic acid and chlorogenic acid). In determining the structure-activity relationship (SAR), it was found that the presence and position of hydroxyl group of test coumarins (coumarin, esculin, isoscopoletin, daphnetin, 4-methylcoumarin, and six isolated coumarins) may play a crucial role in AGE inhibition. A free hydroxyl group at C-7 and a glucosyl group instead of a methoxyl group at C-6 are two important parameters for the inhibitory potential of coumarins on AGE formation. A. capillaris and five key AGE inhibitors, including 4,5-di-Ocaffeoylquinic acid, umbelliferone, esculetin, esculin, and scopoletin, were identified as potential candidates for use as therapeutic or preventive agents for diabetic complications and oxidative stress-related diseases. We understand this to be the first detailed study on the SAR of coumarins in AGE inhibition.
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ETHNOPHARMACOLOGICAL RELEVANCE: Semen Cassiae has been traditionally used as an herbal remedy for liver, eye, and acute inflammatory diseases. Recent pharmacological reports have indicated that Cassiae semen has neuroprotective effects, attributable to its anti-inflammatory actions, in ischemic stroke and Alzheimer's disease (AD) models. AIM OF THE STUDY: The basic goal of this study was to evaluate the anti-AD activities of C. obtusifolia and its major constituents. Previously, the extract of C. obtusifolia seeds, was reported to have memory enhancing properties and anti-AD activity to ameliorate amyloid β-induced synaptic dysfunction. However, the responsible components of C. obtusifolia seeds in an AD are currently still unknown. In this study, we investigated the inhibitory effects of C. obtusifolia and its constituents against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) enzyme activity. MATERIALS AND METHODS: In vitro cholinesterase enzyme assays by using AChE, BChE, and BACE1 were performed. We also scrutinized the potentials of Cassiae semen active component as BACE1 inhibitors via enzyme kinetics and molecular docking simulation. RESULTS: In vitro enzyme assays demonstrated that C. obtusifolia and its major constituents have promising inhibitory potential against AChE, BChE, and BACE1. All Cassiae semen constituents exhibited potent inhibitory activities against AChE and BACE1 with IC50 values of 6.29-109µg/mL and 0.94-190µg/mL, whereas alaternin, questin, and toralactone gentiobioside exhibited significant inhibitory activities against BChE with IC50 values of 113.10-137.74µg/mL. Kinetic study revealed that alaternin noncompetitively inhibited, whereas cassiaside and emodin showed mixed-type inhibition against BACE1. Furthermore, molecular docking simulation results demonstrated that hydroxyl group of alaternin and emodin tightly interacted with the active site residues of BACE1 and their relevant binding energies (-6.62 and -6.89kcal/mol), indicating a higher affinity and tighter binding capacity of these compounds for the active site of BACE1. CONCLUSION: The findings of the present study suggest the potential of C. obtusifolia and its major constituents for use in the development of therapeutic or preventive agents for AD, especially through inhibition of AChE, BChE and BACE1 activities.
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Morinda officinalis How. (Rubiaceae) has been used as tonic, warming, sex impulse and anti-inflammatory agents. Two known anthraquinones, rubiadin-l-methyl ether (I) and rubiadin (II) were isolated from root of M. officinalis. Their structures were identified using NMR and literature comparisons. The contents of I in eighteen M. officinalis were evaluated by HPLC-PDA. Chromatography was performed using a reversed-phase system with Luna Clg (2) column and acetonitrile-water (50:50, v/v) with a flow rate of 1.0 mL/min under UV 280 nm. Under these conditions, the content of rubiadin-l-methyl ether was 0.013%.
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In the current study, we examined the effect of Morinda officinalis polysaccharides (MOP) on bone quality in aged rats. Rats were given orally by daily gavage at 200 and 400 mg/kg/day for 3 months, respectively. The results showed that there was a significant decrease in serum alkaline phosphatase (ALP), Interleukin 6 (IL-6) content and a significant increase in density and strength of femur and lumbar vertebrae in aged rats 3 months after Morinda officinalis polysaccharides treatment. In conclusion, these data suggest that Morinda officinalis polysaccharides can protect the age-induced bone degeneration.
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In this study, the optimization of the main variables involved in the extraction process has been done by response surface methodology (RSM) using, as responses, the extraction yield. The maximum amount of Morinda officinalis polysaccharides (7.32%) was obtained when M. officinalis were extracted with 4 times volume (v/v) of water above 100°C for more than 160min. A second-order polynomial response surface equation was developed indicating the effect of variables on extraction yield. The models were found to agree with the data at the probability level of 99%. The results indicated that the models explained 94% of the variability for M. officinalis polysaccharides extraction. Analysis of variance also showed that the regression models for M. officinalis polysaccharides extraction were statistically good with a significance level of P
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Four known hydroxyanthraquinones (1-4) together with four new derivatives having a tetralone moiety, namely coniothyrinones A-D (5-8), were isolated from the culture of Coniothyrium sp., an endophytic fungus isolated from Salsola oppostifolia from Gomera in the Canary Islands. The structures of the new compounds were elucidated by detailed spectroscopic analysis and comparison with reported data. The absolute configurations of coniothyrinones A (5), B (6), and D (8) were determined by TDDFT calculations of CD spectra, allowing the determination of the absolute configuration of coniothyrinone C (7) as well. Coniothyrinones A (5), B (6), and D (8) could be used as ECD reference compounds in the determination of absolute configuration for related tetralone derivatives. This is the first report of anthraquinones and derivatives from an isolate of the genus Coniothyrium sp. These compounds showed inhibitory effects against the fungus Microbotryum violaceum, the alga Chlorella fusca, and the bacteria Escherichia coli and Bacillus megaterium. Chirality, 2012. © 2012 Wiley Periodicals, Inc.