A new xanthone glycoside from the endolichenic fungus Sporormiella irregularis

Article abstract of DOI:10.3390/molecules21060764

A new xanthone glycoside, sporormielloside (1), was isolated from an EtOAc extract of an endolichenic fungal strain Sporormiella irregularis (No. 71-11-4-1), along with two known xanthones (2, 3). Their structures were determined by detailed spectroscopic analysis (IR, MS, and 1D- and 2D-NMR), a chemical method, and a comparison of NMR data with closely related compounds previously reported. According to the structures of isolated compounds, their plausible biosynthetic pathway was deduced.

Full text of DOI:10.3390/molecules21060764

molecules
Article
A New Xanthone Glycoside from the Endolichenic
Fungus Sporormiella irregularis
1
2,
2
2
3
1,
Bin-Jie Yang , Guo-Dong Chen *, Yan-Jun Li , Dan Hu , Liang-Dong Guo , Ping Xiong *
and Hao Gao 2
1
Department of Pharmaceutical Engineering, College of Materials and Energy,
South China Agricultural University, Guangzhou 510640, China; 15920520642@163.com
Institute of Traditional Chinese Medicine & Natural Products, College of Pharmacy, Jinan University,
2
Guangzhou 510632, China; Liyanjun1014@163.com (Y.-J.L.); thudan@jnu.edu.cn (D.H.);
tghao@jnu.edu.cn (H.G.)
State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences,
3
Beijing 100190, China; guold@sun.im.ac.cn
*
Correspondence: chgdtong@163.com (G.-D.C.); xp0000542003@scau.edu.cn (P.X.);
Tel.: +86-20-852-215-59 (G.-D.C.); +86-135-333-857-89 (P.X.)
Academic Editor: Derek J. McPhee
Received: 14 April 2016; Accepted: 4 June 2016; Published: 11 June 2016
Abstract: A new xanthone glycoside, sporormielloside (
endolichenic fungal strain Sporormiella irregularis (No. 71-11-4-1), along with two known xanthones
). Their structures were determined by detailed spectroscopic analysis (IR, MS, and 1D- and
D-NMR), a chemical method, and a comparison of NMR data with closely related compounds
1), was isolated from an EtOAc extract of an
(2, 3
2
previously reported. According to the structures of isolated compounds, their plausible biosynthetic
pathway was deduced.
Keywords: xanthone glycoside; Sporormiella irregularis; endolichenic fungus; biosynthetic pathway
1
. Introduction
Sporormiella is a genus belonging to the family of Sporormiaceae with more than 80 species
distributed across boreal and temperate regions of the world [1–4]. Some species of the genus are
saprobes, and others are endophytic in living plants, fungi, and lichens [5–8]. Previous chemical
investigation of this genus led to isolation of polyketides (such as xanthones (sporormiellins A–C,
sporormiellones A, B, microsphaeropsone A, brocaenol B) [
corymbiferan lactone E, corymbiferone) [ ], macrocyclic lactone (sporostatin) [10], organic acids
including zaragozic acid B, L731-127, L731-128, sporovexins A, B, and sporminarins A, B) [11 13]),
15], and (2aR,2a R,3S,5aR,6bS,9S,10aR,12bS)-9-
5,9], chromones (corymbiferone C,
5
(
–
1
triterpenoids (including FR171456, FR173945 [14
hydroxy-2a ,3,6b,10,10,12b-hexamethyl-1,2,2a,2a ,3,5a,6,6b,7,8,9,10,10a,11,12,12b-hexadecahydro-4H-
cyclopenta[de]naphtho[2,1-g]chromen-4-one [16]), steroids (including 22E-3,7-epoxy-5,10:8,9-
,
1
1
disecoergosta-9(10),22-diene-5,8-dione, 22E-5
epoxyergosta-8(9),22-diene-3 ,7 -diol, 22E-7
2E-3 -hydroxy-5 ,6 -epoxyergosta-22-en-7-one, 22E-ergosta-7,22-diene-3
methoxyergosta-7,22-diene-3 ,5 -diol, 22E-5 ,8 -epidioxyergosta-6,22-dien-3
,6,8(14),22-tetraen-3-one [17]), and the nitrogenous compounds (including terezines A–D [18],
α
,6
α
-epoxyergosta-8(14),22-diene-3
-methoxy-5 ,6 -epoxyergosta-8(14),22-dien-3
,5 ,6 -triol, 22E-6
-ol and 22E-ergosta-
β
,7
α
-diol, 22E-5
α
,6
-ol,
β-
α
-
β
α
α
α
α
β
2
β
α
α
β
α
β
β
α
α
α
β
4
similin B [19], sporovexin C [12], and (2Z,4E,6E)-3-hydroxy-N-(1,11a,11b-trihydroxy-3,6,9-
trioxodecahydro-1H-pyrazino[1,2-a]pyrrolo[2,1-c]pyrazin-10-yl)octadeca-2,4,6-trienamide [20]).
In our previous chemical investigation of this genus Sporormiella, a series of xanthones
(
sporormiellins A–C, sporormiellones A, B, and microsphaeropsone A) were isolated from S. minima
Molecules 2016, 21, 764; doi:10.3390/molecules21060764
www.mdpi.com/journal/molecules

Molecules 2016, 21, 764
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(
No. 66-3-4-2) [9]. Notably, sporormiellin A is the first discovered tetrahydrofuran-fused furochromone
with an unprecedented tetracyclic skeleton. As a part of our continuing search for more xanthones, a
chemical investigation of another species (S. irregularis (No. 71-11-4-1)) from this genus was carried
out, which led to isolation of a new xanthone glycoside, sporormielloside (1), along with two known
biogenetically related compounds, calyxanthone-8-methyl ether ( ) and endocrocin (
2
3). Compound 2
is a known compound; however, there is no reference reporting its NMR data. Therefore, the details of
the isolation and structural elucidation of these isolated compounds are reported herein.
2
. Results and Discussion
Compound
1
was obtained as a yellow amorphous powder. The quasi-molecular ion at
+
m/z 451.1240 [M + H] by HRESIMS indicated the molecular formula of
1 degrees of unsaturation. The H-NMR spectrum (DMSO-d , Figure S1) displayed six exchangeable
1 was C H O with
21 22 11
1
1
6
1
protons (
δ
11.76 (1H, br s), 11.64 (1H, br s), 5.14 (1H, d, J = 4.9 Hz, 2 -O
H
), 5.01 (1H, d, J = 4.8 Hz,
1 1
H), 4.92 (1H, d, J = 5.1 Hz, 4 -OH), and 4.26 (1H, t, J = 5.6 Hz, 6 -OH)), three aromatic protons
H
1
3
(
-O
δ 6.92 (1H, br s, H-3), 6.65 (1H, br s, H-15), and 6.58 (1H, s, H-7)), five sp methine protons (including
H
3
1
δ 4.84 (1H, d, J = 7.6 Hz, H-1 )), one sp methylene group (δ 3.60 (1H, ddd,
H H
3
one anomeric proton
1
1
J = 11.6, 5.6, 1.8 Hz, H-6 a) and 3.39 (1H, ddd, J = 11.6, 5.8, 5.6 Hz, H-6 b)), and two methyl groups
δ 3.92 (3H, s, 8-OCH3), 2.39 (3H, br s, H-1)). The C-NMR and DEPT-135 spectra (Figure S2)
13
(
H
of
1
showed 21 carbon signals including a ketone carbonyl (δC 183.6), twelve aromatic carbons
(
(
δC 160.1, 159.9, 157.6, 155.5, 149.3, 148.5, 125.1, 111.2, 107.9, 104.7, 101.3, and 95.5), two methyl carbons
including one oxygenated (
δ
56.7)), and a set of hexose moiety carbons (
δ
103.6, 77.3, 76.5, 74.2, 69.9,
C
C
3
3
and 61.1). According to the analysis of coupling constants ( J
1
1
= 8.6 Hz, J
1
1
= 8.6 Hz, and
H-2 ,H-3
H-3 ,H-4
3
1
1
J
1
1
= 9.6 Hz), the analysis of H- H COSY (Figure 1), and a comparison with the previously
H-4 ,H-5
13
reported [21
as glucopyranoside (Glu). After acid hydrolysis and derivatization of
the presence of D-glucoses and compared them with derivatives obtained by the same method with
standard monosaccharides [23]. The Glu unit in was attached to the aglycone via a -linkage
on the basis of the coupling constant of the anomeric proton located at 4.84 (1H, d, J = 7.6 Hz,
,22
]
C-NMR data of the glucopyranoside unit, the hexose moiety of
1 was identified
1, the HPLC analysis revealed
1
β
δ
H
1
H-1 ). The connection position of Glu unit to aglycone was established at C-9 on the basis of the
1
HMBC correlation from H-1 to C-9. Combined with the molecular formula and chemical shifts of
1
13
H and C, the structure of aglycone was established based on the key HMBC correlations from
H-1 to C-2/C-3/C-15, from H-3 to C-4/C-12/C-13/C-15, from H-15 to C-3/C-13/C-14, from H-7 to
C-6/C-8/C-9/C-11/C-12, from 8-OCH3 to C-8, and the key ROESY correlations between 8-OCH3 and
1
H-7/H-1 (as shown in Figure 1). Therefore, the structure of 1 was elucidated as shown in Figure 2,
which was a new xanthone glycoside called sporormielloside. The assignments of all proton and
carbon resonances are provided in Table 1.
1
1
Figure 1. Key H- H COSY, HMBC and ROESY correlations of 1 and 2.

Molecules 2016, 21, 764
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Figure 2. Chemical structures of 1–3.
Table 1. The H-NMR (400 MHz) and 13C-NMR (100 MHz) data of compound 1 (in DMSO-d6).
1
1
No.
1
1
δC, Mult
δH, Mult, (J in Hz)
H- H COSY
HMBC
ROESY
1
2
3
4
6
7
8
9
21.9, CH3
149.3, qC
107.9, CH
155.5, qC
157.6, qC
95.5, CH
160.1, qC
125.1, qC
148.5, qC
101.3 qC
183.6, qC
104.7, qC
159.9, qC
111.2, CH
56.7, CH3
2.39, br s
3, 15
1, 15
2, 3, 15
6.92, br s
1, 4, 12, 13, 15
6.58, s
6, 8, 9, 11, 12
8-OCH3
1
0
1
2
3
4
5
1
1
1
1
1
6.65, br s
3.92, s
11.76, br s
11.64, br s
1, 3
1, 3, 13, 14
8
1
8
1
-OCH3
-OH *
7, 1
6
4-OH *
1
1
1
1
1
103.6, CH
74.2, CH
76.5, CH
69.9, CH
77.3, CH
4.84, d, (7.6)
2
9
3 , 5 , 8-OCH3
1
1
1
1
1
1
1
1
2
3.32, overlapped
3.24, td, (8.6, 4.8)
3.16, m
1 , 3 , 2 -OH
1 , 3 , 4
1
1
1
1
1
1
1
1
1
3
2 , 4 , 3 -OH
2 , 4
1 , 5
1
1
1
1
1 1
4
3 , 5 , 4 -OH
3 , 5 , 6
1
1
1
1
1
1
1
5
3.09, ddd, (9.6, 5.8, 1.8)
3.60, ddd, (11.6, 5.6, 1.8), a
4 , 6 a, 6 b
1 , 4
1 , 3
1 1 1
1
5 , 6 b, 6 -OH
6
61.1, CH2
1
1
1
3
.39, ddd, (11.6, 5.8, 5.6), b
5 , 6 a, 6 -OH
1
1
2
-OH
-OH
-OH
-OH
5.14, d, (4.9)
2
1
1
1
1
3
4
6
5.01, d, (4.8)
3
1
4.92, d, (5.1)
4
1
1
4.26, t, (5.6)
6 a, 6 b
*
: The assignment maybe exchanged.
Compound
2
was obtained as a yellowish amorphous powder. The quasi-molecular ion
+
at m/z 323.0527 [M + Na] by HRESIMS indicated the molecular formula of
with 11 degrees of unsaturation. The H-NMR spectrum (DMSO-d , Figure S7) displayed two
2 was C H O
16 12 6
1
6
exchangeable protons (
δ
13.23 (1H, br s), 12.33 (1H, brs)), four aromatic protons ( H
δ
7.20 (1H,
H
d, J = 2.4 Hz, H-9), 6.99 (1H, d, J = 2.4 Hz, H-7), 6.88 (1H, br s, H-3), and 6.67 (1H, br s, H-15)), and
3
13
two sp methyl groups (
δ 3.96 (3H, s, 8-OCH3), 2.41 (3H, s, H-1)). The C-NMR and DEPT-135
H
spectra (Figure S8) showed 16 signals, assigned two carbonyl carbons (a ketone one (
δ 179.2) and a
C
2
carboxylic acid/ester one (
δ
168.8)), twelve sp aromatic carbons, and two methyl carbons (including
C
1
an oxygenated one (
δ 56.6)). Combined with the molecular formula and chemical shifts of H and
C
13
C, the key HMBC correlations from H-1 to C-2/C-3/C-15, from H-3 to C-4/C-13/C-15, from H-15 to
C-3/C-13/C-14, from H-7 to C-5/C-8/C-9/C-11, from H-9 to C-7/C-8/C-10/C-11, from 8-OCH3 to C-8,
and the key ROESY correlations between 8-OCH3 and H-7/H-9 (as shown in Figure 1) established the
planar structure of 2, which was a methyl esterified derivative of calyxanthone [24] at C-8. Therefore,
the structure of
2 was elucidated as the same as that of the known compound (calyxanthone-8-methyl
ether). The assignments of NMR data of 2 are provided in Table 2.

Molecules 2016, 21, 764
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Table 2. The H-NMR (400 MHz) and 13C-NMR (100 MHz) data of 2 (in DMSO-d6).
1
2
No.
1
1
δC, Mult
δH, Mult, (J in Hz)
H- H COSY
HMBC
ROESY
1
2
3
4
5
6
7
8
9
21.9, CH3
148.8, qC
107.2, CH
155.2, qC
168.8, qC
136.5, qC
111.8, CH
164.8, qC
101.2, CH
157.6, qC
109.7, qC
179.2, qC
105.9, qC
160.5, qC
111.2, CH
56.6, CH3
2.41, br s
3, 15
2, 3, 15
6.88, br s
1, 15
1, 4, 13, 15
6.99, d, (2.4)
7.20, d, (2.4)
9
7
5, 8, 9, 11
8-OCH3
8-OCH3
7, 8, 10, 11
1
1
1
1
1
1
0
1
2
3
4
5
6.67, br s
3.96, s
1, 3
1, 3, 13, 14
8
8
5
1
-OCH3
7, 9
-OH *
4-OH *
13.23, br s
12.33, br s
*
: The assignment maybe exchanged.
Compound
at m/z 313.0345 [M
3
was obtained as a yellow amorphous powder. The quasi-molecular ion
´
´
H] by HRESIMS indicated the molecular formula of
3
was C H O
7
16
10
1
13
with 12 degrees of unsaturation. The H-NMR and C-NMR spectrum (DMSO-d ) are the same
6
as that of endocrocin [25].
Based on the structural features of compounds
1–3, the plausible biosynthetic pathway of
them was deduced (Scheme 1). The C -octaketide produced by non-reducing polyketide synthase
16
undergoes cyclization to yield atrochryone carboxylic acid [26], which is either autoxidized to
endocrocin ( ) or undergoes dehydration first followed by decarboxylation and spontaneous
oxidation to give emodin [27 28]. The resulting emodin will be enzymatically transformed into
intermediate by oxidative ring opening between C-4 and C-5 [26 29], and subsequent dehydration
will give intermediate b. Compound may be derived from intermediate b via methylation. After
3
,
a
,
2
decarboxylation and oxidation, intermediate b may transform into intermediate
derived from intermediate c via methylation and glycosylation [26].
c, and 1 may be
Scheme 1. The plausible biosynthetic pathway of 1–3.

Molecules 2016, 21, 764
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3
. Materials and Methods
3
.1. Chemicals
L-cysteine methyl ester hydrochloride, o-tolyl isothiocyanate, D-glucose (D-Glc), L-glucose (L-Glc),
and DMSO-d were purchased from Sigma-Aldrich Chemical Co. Ltd. (Saint Louis, MO, USA).
6
Methanol (MeOH) was purchased from Yuwang Industrial Co. Ltd. (Yucheng, China). Formic acid
(HCOOH) was obtained from Kemiou Chemical Reagent Co. Ltd. (Tianjin, China).
3
.2. General Experimental Procedures
UV data were recorded using a JASCO V-550 UV/vis spectrometer (Jasco International Co. Ltd.,
Tokyo, Japan). IR data were recorded on a JASCO FT/IR-480 plus spectrometer (Jasco International
Co. Ltd.). Optical rotations were measured on a JASCO P1020 digital polarimeter (Jasco International
Co. Ltd.). The ESIMS spectra were performed on a Bruker amaZon SL mass spectrometer (Bruker
Daltonics Int., Boston, MA, USA), and the HRESIMS spectra were obtained on a Waters Synapt G2
mass spectrometer (Waters Corporation, Milford, MA, USA). 1D and 2D NMR spectra were acquired
with Bruker AV 400 spectrometers (Bruker BioSpin Group, Faellanden, Switzerland) using the solvent
signals (DMSO-d6:
δ 2.50/δ 39.5) as internal standards. The analytical HPLC was performed on a
H C
Dionex HPLC system equipped with an Ultimate 3000 pump, an Ultimate 3000 DAD, an Ultimate 3000
Column Compartment, an Ultimate 3000 autosampler (Thermo Fisher Scientific Inc., Sunnyvale, CA,
USA), and an Alltech (Grace) 2000ES evaporative light scattering detector (Alltech International Inc.,
Vienna, VA, USA) using a Phenomenex Gemini C18 column (4.6 mm
Inc., Los Angeles, CA, USA). Semi-preparative HPLC was performed on a Dionex HPLC system, which
was equipped with an Ultimate 3000 pump, and an Ultimate 3000 RS variable wavelength detector
ˆ
250 mm, 5 µm) (Phenomenex
using a Phenomenex Gemini C18 column (10.0 mm
pressure liquid chromatography (MPLC) was performed on ODS (60–80
ˆ
250 mm, 5
µ
m) (Phenomenex Inc.). The medium
µm, YMC Co. Ltd., Tokyo,
Japan) and equipped with a dual pump gradient system, a UV preparative detector, and a Dr Flash II
fraction collector system (Lisui E-Tech Co. Ltd., Shanghai, China). The organic solvent was evaporated
with an EYELA rotary evaporator N-1100 system (Tokyo Rikakikai Co. Ltd., Shanghai, China).
3
.3. Fungus Material
The strain numbered as 71-11-4-1 was isolated from the lichen Usnea mutabilis Stirt, which was
collected in Zixishan Mountain, Yunnan province, China, in November 2006. The strain was identified
as S. irregularis based on the morphological characters by one of our authors (L.-D.G.). The fungal
˝
strain was cultured on slants of potato dextrose agar (PDA) at 25 C for 5 days. Agar plugs were used
to inoculate nine Erlenmeyer flasks (250 mL), each containing 100 mL of potato dextrose broth (PDB).
˝
The nine flasks of the inoculated media were incubated at 25 C on a rotary shaker at 200 rpm for
five days to prepare the seed culture. Fermentation was carried out in 30 Erlenmeyer flasks (500 mL),
each containing 70 g of rice. Distilled H O (105 mL) was added to each flask, and the rice was soaked
2
˝
overnight before autoclaving at 121 C for 30 min. After cooling to room temperature, each flask was
˝
inoculated with 10 mL of the spore inoculum and incubated at 25 C for 40 days.
3
.4. Extraction and Isolation
The culture was extracted four times with EtOAc, and the organic solvent was evaporated in a
vacuum to afford the dry crude extract (29.05 g). The crude extract was dissolved in 90% v/v aqueous
MeOH (500 mL) and partitioned against the same volume of cyclohexane to afford a cyclohexane
fraction (C, 13.42 g) and an aqueous MeOH fraction (W, 12.38 g). The aqueous MeOH fraction
(
W, 12.38 g) was separated by MPLC eluting with MeOH–H O (30:70, 50:50, 70:30, and 100:0, v/v)
2
to afford four fractions (W1 to W4). Fraction W3 (753.4 mg) was further separated by MPLC with
a gradient of MeOH–H O to yield 9 subfractions (W3a–W3i) and (11.7 mg). Fraction W2 (1.14 g)
was further separated by MPLC with a gradient of MeOH–H O to yield 19 subfractions (W2a to
1
2
2

Molecules 2016, 21, 764
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W2s). Subfraction W2m (50.0 mg) was purified by semi-preparative HPLC with MeOH–H O–HCOOH
2
(80:20:0.1, v/v) at a flow rate of 3 mL/min to yield 2 (4.0 mg). Subfraction W2i (66.1 mg) was purified
with semi-preparative HPLC using MeOH–H O–HCOOH (60:40:0.1, v/v) at flow rate of 3 mL/min to
2
yield 3 (9.0 mg).
2
5
Sporormielloside (1) (Figure 2): Yellow amorphous powder; rαs = –46.3 (c = 0.08, CHCl –MeOH = 1:2);
D
3
UV (MeOH) λmax (log ε) 206 (4.66), 232 (4.24), 256 (4.42), 336 (4.13) nm; IR (KBr) υmax 3421, 2906,
´
1
2360, 2339, 1632, 1608, 1515, 1370, 1267, 1209, 1160, 1122, 1071, 1024, 552 cm ; ESIMS (positive):
+
+
+
m/z 473 [M + Na] , 923 [2M + Na] ; HRESIMS (positive): m/z 451.1240 [M + H] (calcd. for C H O ,
2
1
23 11
1
13
4
51.1240); H- and C-NMR data see Table 1.
Calyxanthone-8-methyl ether ( ) (Figure 2): Yellowish amorphous powder; UV (MeOH) λmax (log
02 (4.53), 236 (4.62), 251 (4.51), 302 (4.37) 351 (3.96) nm; IR (KBr) υmax 3446, 3248, 2360, 2335, 1739,
2
ε)
2
´
1
1650, 1600, 1571, 1504, 1455, 1423, 1394, 1273, 1217, 1179, 1154, 1128, 1016, 829, 687 cm ; ESIMS
+
+
´
-
(positive): m/z 301 [M + H] , 323 [M + Na] ; ESIMS (negative) m/z 299 [M
´
H] , 255 [M - COOH] ;
+
1
13
HRESIMS (positive): m/z 323.0527 [M + Na] (calcd. for C H O Na, 323.0532); H- and C-NMR
16
12
6
data see Table 2.
Endocrocin (3) (Figure 2): Yellow amorphous powder; UV (MeOH) λmax (log ε) 203 (4.55), 226
(
7
4.65), 375 (3.50), 440 (4.26) nm; IR (KBr) υmax 3377, 2361, 2339, 1715, 1671, 1622, 1384, 1255, 1206, 1171,
´
1
´
´
H] (calcd.
56 cm ; ESIMS (negative) m/z 313 [M
´
H] ; HRESIMS (negative): m/z 313.0345 [M
´
for C H O , 313.0348).
16
9
7
3
.5. Acid Hydrolysis
Acid hydrolysis was performed according to the method described by Tanaka et al. with standard
˝
1 (1.0 mg) was hydrolyzed with 2 M of HCl for 1 h at 90 C. After it
monosaccharides [23]. Compound
was extracted with EtOAc twice, the H O layer was evaporated in vacuo to furnish a monosaccharide
2
residue using a rotary evaporator. The residue was dissolved in pyridine (1.0 mL) containing L-cysteine
˝
methyl ester hydrochloride (1.0 mg) and heated at 60 C. After 1 h, 10 µL of o-tolyl isothiocyanate was
˝
added to the reaction mixture and further reacted at 60 C for 1 h. Then, the reaction mixture was
directly analyzed by the Dionex HPLC system and detected by an UV detector (at 254 nm). Analytical
HPLC was performed on the Phenomenex Gemini C18 column with isocratic elution of CH CN–H O
3
2
(
40:60, v/v) for 40 min at a flow rate of 0.8 mL/min. The standard monosaccharides of D-Glc and L-Glc
were subjected to the same method.
4
. Conclusions
Xanthones are commonly found in higher plants, fungi, and lichens [30
xanthone aglycones have been isolated from Sporormiella. Xanthone glycosides are mainly isolated
from plants such as Gentianaceae and Guttiferae [32 33] but are rarely reported from fungi, except
for Phomopsis sp. ZH76 [34], Paecilomyces cinnamomeus BCC 9616 [35], and Aschersonia coffeae Henn.
Bcc 28712 [36]. The isolation of sporormielloside ( ), which is the first report for xanthone glycoside
,
31]. However, only eight
,
1
isolated from Sporormiella. Owing to a lack of any references to calyxanthone-8-methyl ether (
2) in the
literature, moreover, the assignments of NMR data of 2 are provided here for the first time.
Supplementary Materials: Supplementary materials can be accessed at: http://www.mdpi.com/1420-3049/21/
/764/s1.
6
Acknowledgments: This work was supported by National Natural Science Foundation of China (81422054
and 81373306), Guangdong Special Support Program (2014TQ01R420), Guangdong Natural Science Funds for
Distinguished Young Scholar (S2013050014287), Guangdong Province Universities and Colleges Pearl River
Scholar Funded Scheme (Hao Gao, 2014), and the Science and Technology Program of Guangzhou (2013J4501037,
2
014A020210018, and 2015A020209134), China.
Author Contributions: Hao Gao and Ping Xiong initiated and coordinated the project. Bin-Jie Yang, Yan-Jun Li,
and Guo-Dong Chen performed the extraction, isolation, and structural identification of the compounds.
Liang-Dong Guo and Dan Hu performed the isolation and identification of the fungal strain (No. 71-11-4-1).
In addition, Guo-Dong Chen wrote this paper.

Molecules 2016, 21, 764
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Conflicts of Interest: The authors declare no conflict of interest.
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Sample Availability: Samples of the compounds are not available from the authors.
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