New cerebroside and nucleoside derivatives from a red sea strain of the marine cyanobacterium moorea producens

Article abstract of DOI:10.3390/molecules21030324

In the course of our ongoing efforts to identify marine-derived bioactive compounds, the marine cyanobacterium Moorea producens was investigated. The organic extract of the Red Sea cyanobacterium afforded one new cerebroside, mooreaside A (1), two new nucleoside derivatives, 3-acetyl-2′-deoxyuridine (2) and 3-phenylethyl-2′-deoxyuridine (3), along with the previously reported compounds thymidine (4) and 2,3-dihydroxypropyl heptacosanoate (5). The structures of the compounds were determined by different spectroscopic studies (UV, IR, 1D, 2D NMR, and HRESIMS), as well as comparison with the literature data. Compounds 1-5 showed variable cytotoxic activity against three cancer cell lines.

Full text of DOI:10.3390/molecules21030324

molecules
Article
New Cerebroside and Nucleoside Derivatives from a
Red Sea Strain of the Marine Cyanobacterium
Moorea producens
Diaa T.A. Youssef 1,*, Sabrin R.M. Ibrahim 2,3, Lamiaa A. Shaala 4,5, Gamal A. Mohamed 1,6 and
Zainy M. Banjar 7
1
Department of Natural Products, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589,
Saudi Arabia; gamals2001@yahoo.com
Department of Pharmacognosy and Pharmaceutical Chemistry, College of Pharmacy, Taibah University,
2
Al Madinah Al Munawwarah 30078, Saudi Arabia; sribrahim@taibahu.edu.sa
Department of Pharmacognosy, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
Natural Products Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589,
3
4
Saudi Arabia; lshalla@kau.edu.sa
Suez Canal University Hospital, Suez Canal University, Ismailia 41522, Egypt
Department of Pharmacognosy, Faculty of Pharmacy, Al-Azhar University, Assiut Branch,
5
6
Assiut 71524, Egypt
7
Department of Clinical Biochemistry, Faculty of Medicine, King Abdulaziz University, Jeddah 21589,
Saudi Arabia; zmbanjar@yahoo.com
*
Correspondence: dyoussef@kau.edu.sa; Tel.: +966-548-535-344
Academic Editor: Isabel C. F. R. Ferreira
Received: 16 January 2016 ; Accepted: 1 March 2016 ; Published: 9 March 2016
Abstract: In the course of our ongoing efforts to identify marine-derived bioactive compounds,
the marine cyanobacterium Moorea producens was investigated. The organic extract of the Red Sea
cyanobacterium afforded one new cerebroside, mooreaside A (
3-acetyl-21-deoxyuridine ( ) and 3-phenylethyl-21-deoxyuridine (
reported compounds thymidine ( ) and 2,3-dihydroxypropyl heptacosanoate (
of the compounds were determined by different spectroscopic studies (UV, IR, 1D, 2D NMR, and
1
), two new nucleoside derivatives,
), along with the previously
). The structures
2
3
4
5
HRESIMS), as well as comparison with the literature data. Compounds
activity against three cancer cell lines.
1–5 showed variable cytotoxic
Keywords: marine cyanobacterium; Moorea producens; cerebroside; nucleosides; cytotoxic activity
1. Introduction
Nucleosides and cerebrosides are found in both terrestrial and marine organisms. Cerebrosides
are composed of a hydrophobic part named ceramide, which is linked to one sugar moiety [1].
Cerebrosides play an important role in major cellular processes including growth, morphogenesis and
cell differentiation. They also affect cell signaling by controlling the assembly and specific activities of
plasma membrane proteins [
2,
3]. Nucleosides are derivatives of glycosylamines, which are central
metabolites in all life forms [4]. Nucleotides, the building block of DNA and RNA are composed
mainly of nucleosides with at least one phosphate group. Nucleoside-derived compounds are used
effectively in treatment of tumors, viral infections and malignant neoplasms [5,6].
Marine cyanobacteria are vital producers of diverse chemical entities with significant
bioactivities [
for novel bioactive compounds of different classes [11
display a wide range of biological activities including those that are antimicrobial, antiproliferative,
7
–
10]. The genus Moorea (formerly Lygnbya) [11] has been proven to be a rich source
,
12]. Cyanobacteria derived compounds
Molecules 2016, 21, 324; doi:10.3390/molecules21030324
www.mdpi.com/journal/molecules

Molecules 2016, 21, 324
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anticancer, antifeedant, antifungal, and anti-inflammatory [13
–
17]. Previous work on the Red
Sea cyanobactrium Moorea producens revealed the presence of nitrogen-containing compounds,
polyketides and peptides [16 17]. In continuation of our ongoing interest to allocate new bioactive
compounds from Red Sea marine cyanobacteria [16 19], we here focus on the Red Sea strain of the
cyanobacterium Moorea producens. In this paper, we reported the isolation and structure determination
of a new cerebroside, mooreaside A (
), two new nucleoside derivatives, 3-acetyl-21-deoxyuridine
) and 3-phenylethyl-21-deoxyuridine (
), along with the known compounds thymidine ( ) and
2,3-dihydroxypropyl heptacosanoate ( ) from the organic extract of the marine cyanobacterium
,
–
1
(2
3
4
5
Moorea producens. The structures of the compounds were determined using different spectroscopic
techniques. The cytotoxic activity of the compounds against three cancer cell lines will be discussed.
2. Results and Discussion
2.1. Purification of Compounds 1–5
Samples of M. producens were extracted with a mixture of MeOH/CH2Cl2 (2:1). The organic
extract was subjected to chromatographic separation on normal SiO2, Sephadex LH-20, and RP-18
columns to provide three new compounds 1–3 and two known compounds 4 and 5 (Figure 1). The
isolated compounds were evaluated for their cytotoxic activity.
Figure 1. Structures of compounds 1–5.
2.2. Structure Elucidation of Compound 1
Compound 1 (Figure 1) was obtained as a colorless amorphous powder. Its molecular formula
was suggested as C48H93NO8 on the basis of the HRESIMS quasi-molecular ion peak at m/z 812.6982
[M + H]+ and 1H- (Figures S1–S3) and 13C-NMR (Figures S4 and S5) spectral analyses, requiring three
degrees of unsaturation. Its IR spectrum showed characteristic absorption bands at 3435 (hydroxyl),
3320 and 1635 (amide), 3005 and 960 (olefinic), and 1150 (C–O) cm´1, suggesting the cerebroside nature
of
1
[
20
–
23]. The 1H-NMR spectrum of
1
showed two signals at δH 5.35 (dt, J = 15.3, 7.6 Hz, H-5) and 5.37
1
(dt, J = 15.3, 7.1 Hz, H-6) in H-NMR spectrum characteristic for the presence of a di-substituted

Molecules 2016, 21, 324
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olefinic moiety (Table 1) which was supported y COSY correlation (Figure S6). These protons
correlated to the carbon signals at δC 129.9 and 128.8, respectively, in the HSQC spectrum (Figure S7)
The trans (E) configuration of the double bond was proven by the large vicinal coupling constant
value (J5,6 = 15.3 Hz) and the chemical shifts of the carbons next to the double bond at δH 32.2
.
(C-4) and 32.0 (C-7) [24–26]. The location of the olefinic moiety at C-6/C-7 was established
based on the HMBC cross peaks from H-5 to C-3, C-4, and C-7 and from H-6 to C-4, C-5, and
1
C-7 (Figure S8). In the H, 13C, and multiplicity-edited HSQC spectra, the signals at δH 4.28
(d, J = 7.7 Hz, H-111)/δC 104.0 (C-111) revealed the presence of a
β-glucopyranoside moiety. This was
also confirmed by the ESIMS fragment ion peak at m/z 633 [MH
´
Glc]+. The attachment of the glucose
moiety at C-1 was established by the downfield shift of C-1 (δC 68.5) and HMBC correlation of H-111
1
(
δH 4.28) with C-1. Moreover, the H-NMR spectrum of
1
showed signals at δH 3.61 (m, H-3),
3.97 (m, H-2), 3.91 and 3.74 (each m, H-1) attributable to oxymethine, NH-bonded methine, and
oxymethylene groups, respectively. They correlated with the carbon signals at 73.4 (C-3), 59.3 (C-2),
and 68.5 (C-1) in the HSQC spectrum. 1H-1H COSY cross peaks were observed between the NH
proton (δH 7.51) and H-2, which coupled to H-1 and H-3, suggesting the presence of hydroxyl group in
the long chain base. This was further confirmed by the HMBC correlations of H-1 to C-2 and C-3, H-2
to C-1, C-3, and C-4, H-3 to C-1 and C-2, and 2-NH to C-2 and C-3 (Figure 2). Comparing 13C-NMR
spectrum of
1
with those of glucosyl-erythro-ceramide and glucosyl-threo-ceramide, proved the erythro
27 32]. The length of the fatty acid chain
configuration at C-2 and C-3 in the sphingosine part of
1
[ –
(C-11
Ñ
C-251) and base chain (C-1
C-17) was determined by the ESIMS. The EIMS spectrum of 1
Ñ
showed characteristic fragment ion peaks at m/z 380 [CH3(CH2)23CONH]+, 365 [CH3(CH2)23CO]+,
337 [CH3(CH2)23]+, 225 [CH3(CH2)10-CH=CH-CH2(CHOH)]+, 181 [CH3(CH2)10-CH=CH]+, and 155
[CH3(CH2)10]+ (Figure 3), supporting the chain lengths of
1. Methanolysis of 1 gave long chain base
(LCB) and fatty methyl ester (FAME). The FAME in the n-hexane layer was identified as pentacosanoic
acid methyl ester based on the GCMS molecular ion peak at m/z 396 [M]+. The LCB showed an EIMS
molecular ion peak at m/z 285 [M]+, corresponding to (2S,3R,E)-2-aminoheptadec-5-ene-1,3-diol.
Based on the above evidence and discussion, compound
hydroxy-1-O-(( -D-glucopyranosyl)heptadec-5-en-2-yl)pentacosanamide. Compound
generically named mooreaside A.
1
was assigned as N-((2S,3R,5E)-3-
β
1
was
Figure 2. Key 1H-1H COSY and HMBC correlations of compounds 1–3.
m/z 337
m/z 365
O
m/z 380
C
OH
O
NH
HO
HO
O
OH
m/z 155
m/z 181
m/z 225
m/z 633
OH
Figure 3. Key MS fragments of 1.

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Table 1. NMR spectral data of compound 1 (CDCl3, 850 and 213 MHz).
No.
δ
H
[mult., J (Hz)]
δC (mult.)
HMBC
1
2
3
3.91 m, 3.74 m
3.97 m
68.5 CH2
59.3 CH
73.4 CH
2, 3, 111
1, 3, 4, 11
1, 2
3.61 m
4
5
6
7
2.08 m
32.2 CH2
129.9 CH
128.8 CH
32.0 CH2
30.3–29.0 CH2
22.6 CH2
14.1 CH3
173.8 C
34.4 CH2
24.8 CH2
28.7 CH2
30.3–29.0 CH2
22.7 CH2
14.1 CH3
104.0 CH
70.2 CH
2, 5, 6
3, 4, 7
4, 5, 7
5, 6
5.35 dt (15.3, 7.6)
5.37 dt (15.3, 7.1)
2.01 m
8–15
16
17
11
1.27–1.23
1.29 m
0.87 t (6.7)
-
2.33 t (7.6)
1.61 m
1.28 m
1.27–1.23 m
1.30 m
0.89 t (6.8)
4.28 d (7.7)
3.65 m
-
15, 17
14, 16
-
21
11, 41
31
11, 21, 41
-
41
51–171
181
191
111
211
311
411
511
611
2-NH
-
1711, 1911
16 , 18
1, 211, 311
311, 411
111, 211, 411
511, 611
411, 611
111, 511
2, 3, 11
3.63 m
4.02 m
3.56 m
71.7 CH
69.5 CH
74.6 CH
62.7 CH2
-
4.38 m, 4.22 m
7.52 d (8.5)
2.3. Structure Elucidation of Compound 2
Compound (Figure 1) was obtained as a white powder. Its HRESIMS gave a quasi-molecular
ion peak at m/z 271.0927 [M + H]+, consistent with a molecular formula C11H14N2O6, requiring six
degrees of unsaturation. The IR spectrum of showed absorption bands at 3394 (hydroxyl) and 1693
(amide carbonyl) cm´1. These data in conjunction with characteristic UV absorption bands at
253
2
2
λ
max
and 268 nm along with 1H NMR spectrum (Figures S9–S11) suggested the presence of uracil moiety in
. The 13C (Figure S12) and multiplicity-edited HSQC (Figure S13) spectra of
showed signals for 11
2
2
carbons including one methyls, two methylenes, five methines, and three quaternary carbonyls at δC
151.7 (C-2), 162.8 (C-4), and 183.4 (C-8). The 1H-1H COSY spectrum (Table 2) showed two ortho-coupled
protons at δH 5.69 (d, J = 8.5 Hz, H-5) and 7.98 (d, J = 8.5 Hz, H-6). These protons correlated to the
carbon signals at δC 102.6 and 142.5, respectively in the HSQC, indicating the presence of uracil moiety
in 2. This was confirmed by the HMBC (Figure S14) cross peaks from H-5 to C-4 and C-6 and from
H-6 to C-2 and C-4. Moreover, the 1H- and 13C-NMR signals at δH 6.27 (t, J = 6.8 Hz, H-11)/δC 86.6
(C-11), 2.28 (m, H2-21)/41.4 (C-11), 4.38 (m, H-31)/72.2 (C-31), 3.891(m, H-41)/89.0 (C-41), and 3.75 (m,
1
1
1
H-5 a) and 3.71 (m, H-5 b)/62.8 (C-5 ) supported the presence of 2 -deoxyribose moiety [33] in 2. The
connectivity of this moiety at N-1 of the uracil moiety was established by the HMBC cross peaks from
H-6 to C-11 and from H-11 to C-2 and C-6. Furthermore, signals for an acetyl group at δH 1.95 (3H,
s, H-211)/δC 23.5 (C-211) and 183.4 (qC, C-111) were observed [34]. This was confirmed by the ESIMS
fragment ion peak at m/z 228 [MH – COCH3]+. Based on the 13C chemical shifts, the acetyl group
was assigned at N-3 of the uracil moiety, completing the molecular formula of
2
and the degrees of
1
unsaturation. Consequently,
natural product.
2 was assigned as 3-acetyl-2 -deoxyuridine and is reported here as a new

Molecules 2016, 21, 324
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Table 2. NMR spectral data of compounds 2 and 3 (CD3OD, 850 and 213 MHz).
2
3
δH [mult.,
J Hz)]
δH [mult.,
J (Hz)]
No.
δC (mult.)
HMBC
No.
δC (mult.)
HMBC
2
4
5
-
-
151.7 C
162.8 C
2
4
5
-
-
151.7 C
162.8 C
-
-
6
5.69 d (8.5)
7.98 d (8.5)
6.27 t (6.8)
2.28 m
4.38 m
3.89 m
102.6 CH
142.5 CH
86.6 CH
41.4 CH2
72.2 CH
89.0 CH
62.8 CH2
183.4 C
4, 6
2, 4, 5, 11
2, 6, 21
11, 31
5.69 d (8.5)
7.98 d (8.5)
6.26 t (6.8)
2.21 m
4.36 m
3.91 m
3.75 m, 3.71 m
3.16 t (7.6)
2.95 t (7.6)
-
7.27 brd (6.8)
7.35 m
102.6 CH
142.5 CH
86.2 CH
41.2 CH2
72.3 CH
88.8 CH
62.8 CH2
42.0 CH2
34.7 CH2
137.9 C
6
6
2, 4, 5
21, 31
11, 31
11
21
31
41
51
111
211
11
21
31
41
3.75 m, 3.71 m
-
51
111
211
311
411, 811
511, 711
611
2, 4, 211, 311
311, 411, 811
-
1.95 s
23.5 CH3
111
129.8 CH
130.0 CH
128.3 CH
211, 611
311, 411, 811
7.27 m
2.4. Structure Elucidation of Compound 3
Compound
3 (Figure 1) was obtained as white amorphous powder with a molecular formula
C17H20N2O5 as determined from its HRESIMS quasi-molecular ion peak at m/z 333.1446 [M + H]+,
requiring nine degrees of unsaturation. The 1D and 2D-NMR (Figures S15–S20) spectral data (Table 2)
of
3 were quite similar to those of 2 except the absence of the signals associated with acetyl group at
N-3. Instead, new signals at δH
J = 8.5 Hz, H-4 ,8 )/129.8 (C-4 ,8 ), 7.25 (1H, t, J = 8.5 Hz, H-6 )/128.3 (C-6 ), 2.95 (2H, t, J = 7.6 Hz,
/
δC 7.35 (2H, d, J = 8.5 Hz, H-15111,711)/130.0 1(1C-511,711), 7.27 (2H, brd,
11 11
11
11 11
11
11
11
H-2 )/34.7 (C-2 ), and 3.16 (2H, t, J = 7.6 Hz, H-1 )/34.7 (C-1 ) were observed. The signals suggested
the presence of a N-bonded phenylethyl moiety. This was established by 1H-1H COSY cross peaks,
11
11
11
11
and further confirmed by HMBC correlations (Figure 2) from H-2 to C-4 /C-8 and C-1 , and from
11
11
11
11
11
H-1 to C-2 and C-3 . The HMBC cross peaks of H-1 /C-2 and H-1 /C-4 supported the placement
of phenylethyl moiety at N-3. Moreover, the ESIMS of gave a characteristic fragment ion peak at
m/z 228 [MH
CH2CH2C6H5]+, indicating the loss of a phenylethyl moiety [35]. Thus, compound
was assigned as 3-phenylethyl-2 -deoxyuridine and is considered a new natural product.
The known compounds were identified as thymidine ( ) [36] and 2,3-dihydroxypropyl
38] by analysis of their spectroscopic data and comparison with those in
2
´
3
1
4
heptacosanoate (
the literature.
5) [37,
The compounds were evaluated for their cytotoxic activities against three cancer cell lines,
including colorectal carcinoma (HCT-116, ATCC CCL-247), hepatocellular carcinoma (HepG2, ATCC
HB-8065), and breast cancer (MCF-7, ATCC HTB-22). Compounds 1–3 showed moderate activity
towards MCF-7 cancer cell line. Meanwhile, they were inactive towards HCT-116 and HepG2 cancer
cell lines (Table 3).
Table 3. Cytotoxic activities of compounds 1–5.
IC50 (µg/mL)
Compound
Colorectal Carcinoma
(HCT-116)
Hepatocellular Carcinoma
(HepG2)
Breast Cancer (MCF-7)
1
2
3
4
>50
>50
>50
NT
>50
>50
>50
NT
20.5
18.2
22.8
NT
5
NT
0.789
NT
0.621
NT
0.415
Doxorubicin
NT = Not tested.

Molecules 2016, 21, 324
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3. Experimental Section
3.1. General Experimental Procedures
Optical rotations were measured on a JASCO DIP-370 digital polarimeter (Jasco Co., Tokyo, Japan)
˝
at 25 C at the sodium D line (589 nm). UV spectra were recorded on a Hitachi 300 spectrometer
(Hitachi High-Technologies Corporation, Kyoto, Japan). The IR spectra were acquired with a Shimadzu
Infrared-400 spectrophotometer (Shimadzu, Kyoto, Japan). EIMS was recorded on a JEOL the mass
route JMS.600H mass spectrometer (JEOL USA, Inc., Peabody, MA, USA). HRESIMS spectra were
performed on a Micromass Qtof 2 mass spectrometer (Bruker, Rheinstetten, Germany). GCMS
analysis was performed on GCMS Hewlett-Packard 5890 GC (Hewlett-Packard, Wilmington, DE,
USA) equipped with a mass-selective detector MSD 5970 MS, a split injector and a fused-silica
˝
HP-5 column (25 m
30 mL/min. NMR spectra were determined on Bruker Ascend
Billerica, MA, USA) using CD3OD and CDCl3 as solvent. The HPLC separation was performed on a
RP-18, 250 10 mm, 5 m Phenomenex Luna column using H2O/ACN as mobile phase, detected at
ˆ
0.2 mm; i.d. 0.33 mm film); column temp. 230 C, carrier N2, flow rate
™
850 (850 MHz) (Bruker BioSpin,
ˆ
µ
220 nm with a flow rate of 2.0 mL/min. Column chromatographic separations were performed on SiO2
60 (0.04–0.063 mm, Merck, Darmstadt, Germany), Sephadex LH-20 (0.25–0.1 mm, Merck), and RP-18
(0.04–0.063 mm, Merck). Pre-coated SiO2 60 F254 plates (Merck) were used for TLC. Compounds were
detected by UV absorption at
reagent and heating at 110 C for 1–2 min.
λ
255 and 366 nm followed by spraying with p-anisaldehyde/H SO
max
2 4
˝
3.2. Biological Materials
The marine cyanobacterium Moorea producens was collected from the Red Sea by hand at 1 m
depth near Jeddah, Saudi Arabia. The cyanobacterium was identified by Dr. Ali Gab-Alla, Faculty of
Science of Suez Canal University. A voucher sample was kept at Department of Natural Products and
Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University under the registration code
No. 2013-LM5.
3.3. Extraction and Purifications of Compounds 1–5
The freeze-dried cyanobacterium M. producens (35 g) was extracted at room temperature with
a mixture of MeOH/CH2Cl2 (2:1, 1 L
pressure to give a greenish organic extract. The extract (980 mg) was subjected to flash SiO2 column
ˆ
4). The combined extracts were evaporated under reduced
using n-hexane/EtOAc/MeOH gradients to give 7 fractions (F1–F7). Fraction F2 (n-hexane/EtOAc
8:2, 65 mg) was chromatographed over SiO2 column (35 g
(97:3 to 90:10) to give impure , which was purified by C18 semi-preparative HPLC column using
30% ACN to give (5.3 mg). Fraction F4 (55 mg, EtOAc) was chromatographed over SiO2 column
(30 g 50 cm 2 cm) using CHCl3/MeOH (95:5 to 85:15) elution afforded impure , which further
purified on C18 HPLC semi-preparative column using 55% ACN to give pure (9.6 mg). Sephadex
LH-20 column chromatography (50 g 50 cm 3 cm) of fraction F6 (68 mg) using MeOH as solvent
system gave impure and . Final purification of the two compounds was achieved on RP-18 column
(60 g 50 cm 3 cm) using MeOH/H2O (50:50 to 90:10) elution to give (4.3 mg) and (3.2 mg). HPLC
purification of F7 (35 mg) on C18 HPLC semi-preparative column using 60% ACN gave 4 (3.5 mg).
ˆ
50 cm
ˆ
2 cm) using n-hexane/EtOAc
5
5
ˆ
ˆ
1
1
ˆ
ˆ
2
3
ˆ
ˆ
2
3
Mooreaside A (
1
): Colorless amorphous powder; rαs2D5 + 4.8 (c 0.2, MeOH); IR (film)
νmax 3435, 3320,
3005, 1635, 1150, 960 cm´1; HRESIMS m/z 728.6031 (calcd for C42H82NO8, 728.6040 [M + H]+); NMR
spectral data, see Table 1.
3-Acetyl-21-deoxyuridine (
(2.36), 268 (2.89) nm; IR (film)
2
): White powder; rαs2D5 + 18.6 (c 1.0, MeOH); UV (MeOH)
λmax (log ε) 253
ν
3294, 2956, 1693 cm´1; HRESIMS m/z 271.0927 [M + H]+ (calcd for
max
C11H15N2O6, 271.0930 [M + H]+); NMR spectral data, see Table 2.

Molecules 2016, 21, 324
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25
1
3-Phenylethyl-2 -deoxyuridine (
3
): White amorphous powder; rαsD + 14.1 (c 0.2, MeOH); UV (MeOH)
λ
max
(log
ε
) 257 (2.42), 269 (2.87) nm; IR (film)
ν
3289, 2959, 1694, 970, 746 cm´1; HRESIMS m/z
max
333.1446 [M + H]+ (calcd C17H21N2O5, 333.1450); NMR spectral data, see Table 2.
3.4. Evaluation of the Cytotoxicity of the Compounds
The isolated compounds (1–5) were evaluated for their cytotoxic activity against colorectal
carcinoma (HCT-116), hepatocellular carcinoma (HepG2), and breast cancer (MCF-7). The cells were
obtained commercially from ATCC. The cytotoxicity was evaluated by the sulforhodamine B (SRB)
assay, as described previously [39]. Doxorubicin was used as positive control drug (Table 3).
3.5. Methanolysis
Compound
ampoule. The reaction mixture was diluted by adding 20 mL of distilled water, then extracted with
n-hexane (3 15 mL) to give a corresponding FAME, which was identified by GCMS. The aqueous
1
(4.5 mg) was treated with 6 mL of 1N HCl in MeOH at 90 ˝C for 15 h in a sealed
ˆ
layer was evaporated to dryness and subjected to Sephadex LH-20 using CHCl3:MeOH (10:90) to give
LCB and sugar. The base was analyzed by EIMS [22].
4. Conclusions
In conclusion, the investigation of the Red Sea strain of the marine cyanobacterium Moorea
producens led to the isolation of a new cerebroside (
and ), along with two known compounds ( and ). Their structures were determined using
showed moderate cytotoxic activity against breast
1) and two new nucleoside derivatives
(2
3
4
5
extensive spectroscopic studies. Compounds
cancer cell lines.
1–3
Supplementary Materials: The following are available online at http://www.mdpi.com/1420-3049/21/3/324/s1,
Figure S1: 1D and 2D NMR spectra of compounds 1–3.
Acknowledgments: This project was funded by the National Plan for Science, Technology and Innovation
(MAARIFAH)—King Abdulaziz City for Science and Technology—the Kingdom of Saudi Arabia–award number
(11-BIO1555-03). The authors also, acknowledge with thanks Science and Technology Unit, King Abdulaziz
University for technical support.
Author Contributions: Diaa T.A. Youssef and Lamiaa A. Shaala conceived and designed the experiments; Lamiaa
A. Shaala, Gamal A. Mohamed and Sabrin R.M. Ibrahim performed the experiments; Zainy M. Banjar performed
the anticancer evaluation of the compounds; Diaa T.A. Youssef, Sabrin R.M. Ibrahim, Gamal A. Mohamed and
Lamiaa A. Shaala analyzed the data; Diaa T.A. Youssef and Sabrin R.M. Ibrahim. wrote the paper; Diaa T.A.
Youssef edited the paper.
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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