Three new metabolites from the endophytic fungus Climacocystis montana isolated from the root bark of Paeonia ostia

Article abstract of DOI:10.1016/j.phytol.2018.05.019

Two new pyridine derivatives climacomontaninates A–B (1–2), and a new sesquiterpenoid derivative climacomontanetate (3), together with twelve known compounds (4–15) were isolated from the culture extract of the fungal strain Climacocystis montana from the root bark of Paeonia ostii. The structures of these compounds were determined through spectroscopic methods such as NMR and HRMS. Moreover, we expound the absolute configuration of 1 using the organic synthesis method. The cytotoxicity against five human cancer cell lines of new compounds were evaluated by SRB assay.

Full text of DOI:10.1016/j.phytol.2018.05.019

PhytochemistryLetters26(2018)50–54
Contents lists available at ScienceDirect
Phytochemistry Letters
journal homepage: www.elsevier.com/locate/phytol
Three new metabolites from the endophytic fungus Climacocystis montana
isolated from the root bark of Paeonia ostia
Pei-liang Zhanga, Gang Wanga,b, Jin-song Liua,b, Feng-qing Xua,b, Zhen-zhu Zhaoc,
⁎
⁎
Wen-xiang Wangd, Ju-tao Wanga,b, Guo-kai Wanga,b, , Pei-yun Wua,b,
a
School of Pharmacy, Anhui University of Chinese Medicine, Anhui Key Laboratory of Modern Chinese Materia Medica, Hefei 230012, China
Synergetic Innovation Center of Anhui Authentic Chinese Medicine Quality Improvement, Hefei 230012, China
State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
Yunnan Agricultural University, College of Agronomy and Biotechnology, Kunming 650201, China
b
c
d
A R T I C L E I N F O
A B S T R A C T
Keywords:
Two new pyridine derivatives climacomontaninates A–B (1–2), and a new sesquiterpenoid derivative climaco-
montanetate (3), together with twelve known compounds (4–15) were isolated from the culture extract of the
fungal strain Climacocystis montana from the root bark of Paeonia ostii. The structures of these compounds were
determined through spectroscopic methods such as NMR and HRMS. Moreover, we expound the absolute con-
figuration of 1 using the organic synthesis method. The cytotoxicity against five human cancer cell lines of new
compounds were evaluated by SRB assay.
Pyridine derivatives
Sesquiterpenoid derivative
Fungal strain
Climacocystis montana
Cytotoxicity
1. Introduction
(c = 0.55, MeOH). Its molecular formula C14H20N2O3 was determined
on the basis of HR-ESI–MS (m/z 287.1366, [M+Na]+, calcd for
The endophytes are considered as a promising source for novel and
bioactive metabolites (Aly et al., 2010). It has been proved that the
fungal strain could produce new bioactive molecules with great phar-
maceutical potential including anticancer, antioxidant, antidiabetic,
antibiotics, antiviral and immunosupressive agents (Itamar et al., 2014;
Strobel et al., 2004). In addition, endophytic fungi are easy to be cul-
tured and have the advantage of rapid growth (Jenzsch et al., 2006). So
the target compounds can be quickly obtained in short term through
microbial fermentation when the molecules were found from the fungal
strain, which will breakthrough the bottleneck of slow growth, low
yield and limited resources of plant.
In the course of our ongoing search for novel secondary metabolites,
a chemical investigation of cultures of Climacocystis montana, led to
isolation of two new pyridine derivatives, climacomontaninate A (1)
and climacomontaninate B (2), and a new sesquiterpenoid derivative
climacomontanetate (3), together with twelve known compounds.
Herein, the structures of new compounds were elucidated by means of
spectroscopic methods, while the known compounds were identified by
comparison with data reported in the literature.
287.1366), indicating six degrees of unsaturation. The IR spectrum
showed the absorption bands for carbonyl groups (1744 cm−1). The UV
spectrum showed maximum absorptions at 200, 229, 268 nm. The 13C
NMR and DEPT spectra (Table 1) exhibited the presence of three me-
thyls (δC 13.9, 18.6 and 52.5), three methylenes (δC 32.8, 33.2 and
22.3), four methines (δC 122.1, 137.1, 148.5 and 48.1) and four qua-
ternary carbon atoms (δC 164.3, 147.2, 141.5 and 173.4). Comparing
the 1H and 13C NMR data of 1 with those of fusaric acid (4) (Xu et al.,
2010) pointed out that their structures were similar, the only difference
is that hydroxyl group on the carboxyl group δC 167.4 (C-2) in 4 were
replaced by an alanine with methyl esterification (C-12 to C-15) in 1.
The presence of the unit from C-12 to C-15 was confirmed by analysis of
2D NMR spectra. According to the 1H-1H COSY spectrum, one cross-
peak H-12/H-13 was established as shown in Fig. 2, the HMBC corre-
lations from H-12, H-13 to C-14 indicated the methane (C-12) was
linked to carbonyl (C-14), and the correlation from H-15 to C-14
showed the fragment eCOOCH3 group. These correlations of 1H-1H
COSY and HMBC spectrum confirmed the presence of alanine methyl
ester group. On the basis of molecular formula C14H20N2O3 and the
HMBC correlation from H-12 (δH 3.77) to C-2 revealed the alanine
methyl ester group was connected with C-2 through nitrogen atom.
Thus, the planar structure of compound 1 was established by the in-
formation above.
2. Results and discussion
Compound
1
was obtained as yellow oil with [α]2D3.6 +1.2
⁎
Corresponding authors at: School of Pharmacy, Anhui University of Chinese Medicine, Anhui Key Laboratory of Modern Chinese Materia Medica, Hefei 230012, China.
E-mail addresses: wanggk@ahtcm.edu.cn (G.-k. Wang), peiyunwu@sina.com (P.-y. Wu).
https://doi.org/10.1016/j.phytol.2018.05.019
Received 4 January 2018; Received in revised form 14 April 2018; Accepted 4 May 2018
1874-3900/©2018PhytochemicalSocietyofEurope.PublishedbyElsevierLtd.Allrightsreserved.

P.-l. Zhang et al.
PhytochemistryLetters26(2018)50–54
13H18N2O3 as deduced on the basis of HR-ESI–MS analysis (m/z
Table 1
C
1H NMR (400 MHz) and 13C NMR (100 MHz) data for compounds 1, 1c and 2 in
273.1193, [M+Na]+, calcd for 273.1210), indicating six degrees of
unsaturation. The presence of carbonyl groups showed by IR spectrum
at 1753 cm−1 and UV spectrum exhibited maximum absorptions at 200,
229, 268 nm. The 13C NMR and DEPT spectra (Table 1) revealed the
presence of two methyls (δC 13.9, and 52.5), four methylenes (δC 32.8,
33.2, 22.3, and 41.4), three methines (δC 122.2, 137.1 and, 148.6) and
four quaternary carbon atoms (δC 165.0, 147.1, 141.6, and 170.4). The
1H NMR and 13C NMR data of 2 were similar to those of 1, except that
the methyl group at C-12 being missing in 1, it was exposed by the
molecular formula C13H18N2O3 and the hydrogen signal at δH 4.26 (2H,
d, J = 5.7, H-12). The 1H-1H COSY spectrum exhibited crosspeaks of H-
8/H-9/H-10/H-11. HMBC spectrum showed correlations from H-12 and
H-14 to ester carbonyl at C-13; H-4 and H-12 to amide at C-2; H-5 to C-
3; H-7 to C-3, C-5, C-6. These correlations of 2D NMR spectra supported
the presence of butyl group and it was located at position C-6. There-
fore, the structure of 2 was determined as methyl (3-butylpicolinoyl)-
glycinate and named as climacomontaninate B.
CDCl3.
Position
1
1c
2
δH
δC
δH
δC
δH
δC
1
8.42 (d,
8.1, NH)
–
–
8.42 (d,
8.4, NH)
–
–
–
8.43 (t,
8.0, NH)
–
–
–
2
3
4
164.3 (C)
147.2 (C)
164.3 (C)
147.3 (C)
165.0 (C)
147.1 (C)
122.2 (CH)
–
8.07 (d,
8.0)
122.1 (CH) 8.07 (d,
122.1 (CH) 8.09 (d,
7.8)
137.1 (CH) 7.62 (d,
7.8)
7.9)
137.1 (CH) 7.64 (d,
7.9)
5
7.63 (d,
8.0)
137.1 (CH)
6
7
8
–
141.5 (C)
–
141.5 (C)
–
141.6 (C)
148.6 (CH)
32.8 (CH2)
8.38 (s)
2.67 (t,
7.7)
148.5 (CH) 8.38 (s)
32.8 (CH2) 2.66 (t,
7.8)
148.5 (CH) 8.39 (s)
32.8 (CH2) 2.67 (t,
7.7)
9
1.60 (m) 33.2 (CH2) 1.60 (m) 33.2 (CH2) 1.62
33.2 (CH2)
22.3 (CH2)
13.9 (CH3)
41.4 (CH2)
170.4 (C)
(m)
1.35 (m) 22.3 (CH2) 1.35 (m) 22.3 (CH2) 1.36
(m)
0.93 (t,
7.3)
Compound 3 isolated as colorless oil with [α]2D3.5 +17.8 (c = 0.4,
MeOH). Its molecular formula was established as C23H42O10 by HR-
ESI–MS (m/z 501.2668, [M+Na]+, calcd for 501.2670), indicating
three degrees of unsaturation. Its UV spectrum showed the maximum
absorption at 202 nm. The signals 3420, 1724 cm−1 of IR showed the
presence of hydroxyl and carbonyl groups. The 1H NMR and 13C NMR
data (Table 2) for 3 displayed five methyls (δC/H 17.7/1.63, 25.9/1.68,
21.8/1.11, 21.1/2.01 and 13.0/1.70), six methylenes (δC/H 69.2/4.27,
36.1/1.98, 1.56, 39.7/1.49, 23.0/2.10, 65.4/3.82 and 64.5/3.77), two
olefinic methines (δC/H 124.4/5.67 and 125.8/5.13), five oxygenated
methines (δC/H 74.3/3.39, 78.6/3.70, 72.9/3.80, 72.4/3.64 and 71.9/
3.73), two quaternary carbons (δC 139.0 and 132.1), one oxygenated
quaternary carbon (δC 75.1) and one carbonyl (δC 172.4). According to
the 1H-1H COSY spectrum, the cross-peaks H-1/H-2, H-4/H-5/H-6, H-8/
H-9/H-10 and H-5′/H-6′/H-7′/H-8′ were established. In the HMBC
spectrum, the correlations from H-12 to C-10, C-11 and C-13, and H-13
to C-10 and C-11 showed the unit (CH3)2C = CHCH2CH2-; H-6 to C-4,
C-8 and C-14, H-14 to C-8, and H-8 to C-7 indicated the connection
between C-4, C-5, C-6, C-7, C-8 and C-14; H-1 to C-3, and H-4 to C-2, C-
7 showed the connection between C-1, C-2, C-3, C-4, and C-15. These
messages along with the correlations from H-4′ to C-3′, C-5′ and C-6′
showed the similar skeleton with fusartricin reported in literature
(Zhang et al., 2015) and illustrated that 3 possessed a sesquiterpene
unit with a ring-opening pyranose moiety. Besides, the HMBC spectrum
revealed the presence of acetyl group by correlation of H-2′ to C-1′.
Finally, the planar structure of 3 was completed by the HMBC corre-
lation from H-1 to C-4′ via an ether bridge accounting for the molecular
formula and the chemical shift of C-1 and C-4′. Therefore, the structure
of 3 was determined as 6,7-dihydroxy-3,7,11-trimethyl-1-((3′,5′,6′,7′,6-
pentahydroxyhexan-2-yl) oxy) dodeca-2,10-dien-4-yl acetate and
named climacomontanetate.
10
11
12
13
13.9 (CH3) 0.93 (t,
7.3)
13.9 (CH3) 0.94 (t,
7.4)
4.79 (m) 48.1 (CH)
4.79 (m) 48.1 (CH)
4.26 (d,
5.7)
–
1.54 (d,
7.2)
18.6 (CH3) 1.53 (d,
18.6 (CH3)
7.2)
–
14
15
–
173.4 (C)
173.4 (C)
52.6 (CH3)
3.79 (s)
52.5 (CH3)
3.77 (s)
52.5 (CH3) 3.77 (s)
Furthermore, the organic synthesis method was used to verify the
planar structure of 1 and determine its absolute configuration. By the
above analysis, hydroxyl group on the carboxyl group in 4 were re-
placed by an alanine with methyl esterification in 1. Therefore, the
routines that alanine which was methyl esterification and then sub-
stituted the hydroxyl group on the carboxyl group in fusaric acid (4)
were designed to confirm the structure of 1 (Scheme 1). The product 1c
was generated by this way and the structure of 1c was determined as
methyl (3-butylpicolinoyl)-L-alaninate.
The spectrum data of 1 and 1c revealed the planar structure of them
were completely identical. However, the optically signal +1.2 of 1 and
+12.6 of 1c indicated there is a difference in their absolute config-
uration, and it was confirmed by comparing their retention time in
chiral analysis. The chirality of 1 and 1c was analyzed by the chiral
column CHIRALPAK (85% n-hexane/isopropanol, 18 min) respectively,
which with the injection volume of 5 μL and the sample concentration
was in 1 mg/ml. On account of there are only two possibilities of the
absolute configuration of 1, the structure of 1 was determined as me-
thyl (3-butylpicolinoyl)-D-alaninate and named as climacomontaninate
A.
The optically inactive compound 2, isolated as a yellow oil with
[α]2D3.8 −2.9 (c = 0.45, MeOH), had the molecular formula of
Furthermore, twelve known compounds including fusaric acid (4),
Scheme 1. Synthesis of 1c.
51

P.-l. Zhang et al.
PhytochemistryLetters26(2018)50–54
Table 2
3.2. Reagents
1H NMR (500 MHz) and 13C NMR (125 MHz) data for compound 3 in CD3OD.
Sodium bicarbonate was purchased from Sinopharm Chemical
ReagentCo., Ltd (Shanghai, China). Dicyclohexylcarbodiimide and 4-
dimethylaminopyridine were purchased from Energy Chemical
(Shanghai, China). L-alanine was purchased from J&K Chemical Ltd
(Beijing, China). Thionyl chloride was purchased from Macklin
(Shanghai, China). All of the chemicals were of analytical grade.
Position
δH
δC
1
2
3
4
5
4.27 (d, 6.6)
5.67 (t, 6.5)
–
5.33 (dd, 10.7, 2.3)
1.98 (m)
1.56 (m)
3.39 (dd, 10.8, 1.6)
–
69.2 (CH2)
124.4 (CH)
139.0 (C)
77.2 (CH)
36.1 (CH2)
6
7
74.3 (CH)
75.1 (C)
3.3. Fungal strain
8
9
1.49 (m)
2.10 (m)
5.13 (t, 7.2)
–
1.63 (s)
1.68 (s)
1.11 (s)
1.70 (s)
–
39.7 (CH2)
23.0 (CH2)
125.8 (CH)
132.1 (C)
17.7 (CH3)
25.9 (CH3)
21.8 (CH3)
13.0 (CH3)
172.4 (C)
21.1 (CH3)
65.4 (CH2)
78.6 (CH)
72.9 (CH)
72.4 (CH)
71.9 (CH)
64.5 (CH2)
The endophytic fungus C. Montana was isolated from the fresh root
bark of P. ostii collected in March 2016 in Anhui Province, China by Dr.
C.W. Fang, and a voucher specimen (No. F04013) was deposited in the
Anhui University of Chinese Medicine. The fungus was identified by
analysis of its ITS region of the rDNA. (Kjer et al., 2010). After ampli-
fication and sequencing of the rDNA, the sequence data was submitted
to GenBank, and a BLAST search result showed the most similar (99%)
to the sequence of C. montana (GenBank accession NO. KJ566628).
10
11
12
13
14
15
1′
2′
3′
4′
5′
6′
7′
8′
2.01 (s)
3.82 (m)
3.70 (m)
3.80 (m)
3.64 (m)
3.73 (m)
3.77 (m)
3.4. Fermentation, extraction and isolation
The fungal strain was cultured on PDA and maintained at 28 °C until
discrete fungal colonies appeared. Then the fresh mycelium of strain C.
montana was inoculated in liquid PDB medium. Fermentation was
carried out in 1000 mL flasks each contain 500 mL medium on a rotary
shaker at 150 r/min, 28 °C for 15 days. The cultures (55 L) were filtered
through gauze to separate into mycelium and broth medium. The
former was dried at 45 °C and ultrasonic extraction for 30 min with 95%
ethanol, the extract was concentrated until no smell of alcohol and
poured into the culture filtrate. Then the mixture was concentrated
under reduced pressure to about 5 L and extracted for three times
successively with ethyl acetate to generated crude residue (20 g). The
residue was fractionated by MPLC with a MeOH/H2O gradient system
(0:100–100:0, v/v) to give fractions A-M. Fraction L was subjected to
Sephadex LH-20 column chromatography with MeOH to give subfrac-
tions L1, L2, L3, L4. Subfractions L3, L4 were purified by preparative
HPLC (22–42% CH3CN/H2O, 25 min) to afford compounds 1 (7.0 mg),
2 (7.0 mg) and 5 (1.3 mg) respectively. Fraction M was purified by
preparative HPLC (8–28% CH3CN/H2O, 30 min) to afford compound 7
(4.5 mg). Fraction H was chromatographed over Sephadex LH-20
(MeOH) to give subfractions H1, H2, H3, H4 and H5. Subfraction H4
was chromatographed on a silica gel CC, eluted with a gradient system
of petroleum ether/acetone (10:1–0:1) to afford compounds 8 (1.2 mg)
and 15 (6.8 mg). Subfraction H5 was purified by preparative HPLC
(8–28% CH3CN/H2O, 30 min) to give compound 13 (8.6 mg). Fraction
K was first fractionated by Sephadex LH-20 (MeOH), and then purified
9,10-dehydrofusaric acid (5), methylester of 9, 10-dehydrofusaric acid
(6), −[Me-Phe-D-Hiv-Me-Phe-D-Hiv]- (7), cyclo(S-Pro-S-Leu) (8), cyclo-
(D-Pro-L-Leu) (9), cyclo(Ala-Ile) (10), cyclo(Ala-Leu) (11), cyclo-(trans-
4-hydroxy-L-prolyl-L-phenylalanine) (12), cyclo(R-Pro-S-Phe) (13),
cyclo-(trans-4-hydroxy-L-prolyl-L-leucine) (14), cyclo(L-Pro-L-Phe) (15)
were also isolated from this genus. (Fig. 1) (Xu et al., 2010; Morooka
et al., 2009; Lücke et al., 2016; Pedras et al., 2005; Kumar et al., 2013;
Liu et al., 2011; De et al., 2003; Wang et al., 2010; Li et al., 2013).
3. Materials and methods
3.1. General experimental procedure
Optical rotation was measured on a SEPA 300 polarimeter (Horiba,
Japan). UV spectra were recorded on a Shimadzu 2401A spectro-
photometer (Shimadzu, Japan) equipped with a 1 cm path-length cell.
IR spectra were obtained with BRUKER TENSOR 27 FT-IR (Bruker
Corporation, Germany) with KBr pellets. The NMR spectra were re-
corded by Bruker DRX-500 and AM-400 spectrometer (Karlsruhe,
Germany), using tetramethylsilane as an internal standard. Chemical
shifts were expressed in ppm with reference to the solvent signals. HR-
ESI–MS spectra were measured on Agilent 6200 Q-TOF MS system
(Agilent Technologies, Santa Clara, CA, USA) and Shimadzu IT-TOF
spectrometer. HPLC analyses were performed on an Agilent 1100 series
and the ODS column used was a 150 × 4.9 mm i.d., 5 μm, Agilent
Zorbax SB C18 column (America). The chiral column used was a
4.6 × 250 mm i.d., 5 μm, CHIRALPAK AS-H column (Daicel Chiral
Technologies Co., Ltd, Shanghai, China). Preparative HPLC were per-
formed on an Agilent 1260 with the ODS column was an Agilent Zorbax
SB C18 column (5 μm, 9.4 × 150 mm, America). MPLC was performed
on a BÜCHI Sepacore system, the column was packed with chromatorex
C-18 (40–75 mm, Fuji Silysia Chemical Ltd., Japan). Column chroma-
tography (CC) was carried out on silica gel (200–300 mesh, Qingdao
Marine Chemical Co. Ltd., Qingdao, China) and Sephadex LH-20
(Amersham Biosciences, Sweden). A silica gel GF254 (Qingdao Haiyang
Chemical Co. Ltd., Qingdao, China) was used to monitor fractions from
column chromatography.
by silica gel (petroleum ether/acetone) to produce compound
3
(4.5 mg). Fractions D and F were severally subjected to Sephadex LH-20
(MeOH) and further purified by preparative HPLC (15–35% CH3CN/
H2O, 30 min) to give compounds 4 (38.6 mg), 5 (22.9 mg) and 14
(10.8 mg). Fraction
E was chromatographed on Sephadex LH-20
(MeOH) to give five subfractions E1-E5. The subfractions E3, E4 and E5
were repeatedly subjected to silica column (petroleum ether/acetone)
and preparative HPLC (5–25% CH3CN/H2O, 35 min) respectively to
yield compounds 9 (4.8 mg), 10 (3.9 mg), 11 (2.0 mg) and 12 (5.6 mg).
3.4.1. Synthesis of 1c (Scheme 1)
The L-alanine was used as substrate to produce (S)-2-alanine methyl
ester hydrochloride (1a) according to the literature. (Xing et al., 2012).
Add 15 mL of absolute ethanol to the round bottom flask, Slow-drop
2.16 mL of SOCl2 (0.03 mol) into absolute ethanol at −15 °C and
maintained at 0 °C for an hour. Take 14 mL of absolute ethanol and
1.4 mL (0.019 mol) of SOCl2 to another round bottom flask with the
above steps. Then, 1.118 g of L-alanine were put into the solution and
heating reflux for 1.5 h. After concentrated the solution under reduced
52

P.-l. Zhang et al.
PhytochemistryLetters26(2018)50–54
Fig. 1. Structure of compounds 1–15.
pressure, the initial preparation of the SOCl2 solution was poured into
the round bottom flask and continued reflux for 1.5 h to give 1a (yield
100%). Since the hydrochloric acid produced in this step was not
conducive to the next reaction, put NaHCO3 into the round bottom flask
when reflux was ended to destroy its acidity until no more bubbles are
generated. Finally, the solution was concentrated to afford 1b (yield
100%).
The fusaric acid (4) and 1b together with 15 mL of dichloromethane
were put into a round bottom flask and stirred uniformly, then an ex-
cess of catalyst dicyclohexylcarbodiimide (DCC) and 4-dimethylami-
nopyridine (DMAP) were added and reflux for 24 h. Concentrated the
solution under reduced pressure and the product was purified by using
preparative HPLC (25–45% CH3CN/H2O, 20 min) to obtain 1c (yield
52%).
3.4.2. Climacomontaninate A [methyl (3-butylpicolinoyl)-D-alaninate (1)]
Yellow oil; [α]2D3.6 +1.2 (c = 0.55, MeOH); UV (MeOH) λmax (log
ε): 268 (3.4), 229 (3.8), 200 (3.7); IR (KBr) υmax cm−1: 3388, 2957,
2932, 1744, 1677, 1518; 1H and 13C NMR data see Table 1; HR-ESI–MS
m/z: 287.1366 [M+Na]+ (calcd for [(C14H20N2O3) +Na], 287.1366);
Fig. 2. Key HMBCs and COSY correlations of compounds 1, 2 and 3.
53

P.-l. Zhang et al.
PhytochemistryLetters26(2018)50–54
3.4.3. Methyl (3-butylpicolinoyl)-L-alaninate (1c)
Program of Anhui Province University (KJ2017A294 and KJ2016A853)
and Public Welfare Technology Application Research Linkage Plan of
Anhui Province (1501ld04001).
Yellow oil; [α]2D4 +12.6 (c = 0.2, CDCl3); UV (MeOH) λmax (log ε):
269 (3.5), 230 (3.8), 199 (3.6); IR (KBr) υmax cm−1: 3389, 2957, 2933,
1744, 1677, 1518; 1H and 13C NMR data see Table 1; HR-ESI–MS m/z:
287.1366 [M+Na]+ (calcd for [(C14H20N2O3) +Na], 287.1366);
Appendix A. Supplementary data
3.4.4. Climacomontaninate B [methyl (3-butylpicolinoyl) glycinate (2)]
Yellow oil; [α]2D3.8 −2.9 (c = 0.45, MeOH); UV (MeOH) λmax (log
ε): 268 (3.4), 229 (3.8), 200 (3.6); IR (KBr) υmax cm−1: 3392, 2957,
2932, 1753, 1677, 1523; 1H and 13C NMR data see Table 1; HR-EI-MS
m/z: 273.1193 [M+Na]+ (calcd for [(C14H20N2O3) +Na], 273.1210);
Supplementary data associated with this article can be found, in the
online version, at https://doi.org/10.1016/j.phytol.2018.05.019.
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3.4.5. Climacomontanetate [6,7-dihydroxy-3,7,11-trimethyl-1-((3′,5′,6′,
7′,6-pentahydroxyhexan-2-yl)oxy) dodeca-2,10-dien-4-yl acetate (3)]
Colorless oil; [α]D23.5 +17.8 (c = 0.4, MeOH); UV (MeOH) λmax (log
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Acknowledgements
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This study was supported by Key research and development project
of Anhui Province (1704a0802145); Natural Science Key Research
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