Cucumol B, a new triterpene benzoate from Cucumis melo seeds with cytotoxic effect toward ovarian and human breast adenocarcinoma

Article abstract of DOI:10.1080/10286020.2018.1488832

Phytochemical investigation of the methanolic extract of Cucumis melo L. (Cucurbitaceae) seeds furnished a new triterpene benzoate derivative: cucumol B (1) and four known flavonoids: quercetin-3-O-β-D-glucopyranosyl-(1→6)-α-L-rhamnopyranoside (2), quercetin-3-O-β-D-glucopyranoside (3), quercetin (4), and luteolin (5). Their structures were identified by UV, IR, 1D (¹³C and ¹H), 2D (HSQC, ¹H-¹H COSY, HMBC, and NOESY) NMR, and HRESIMS spectral as well as comparing with literature data. Compound 1 has been assessed for the in vitro cytotoxic effect against SKOV-3, MCF-7, and HCT-116 cell lines. It had selective and potent effect toward SKOV-3 and MCF-7 cell lines with IC₅₀s 2.05 and 0.41 μM, respectively, in comparison to doxorubicin (IC₅₀s 0.32 and 0.05 μM). However, it showed moderate activity toward HCT-116 cell line with IC₅₀ 8.27 μM.

Full text of DOI:10.1080/10286020.2018.1488832

Journal of Asian Natural Products Research
ISSN: 1028-6020 (Print) 1477-2213 (Online) Journal homepage: http://www.tandfonline.com/loi/ganp20
Cucumol B, a new triterpene benzoate from
Cucumis melo seeds with cytotoxic effect toward
ovarian and human breast adenocarcinoma
Sabrin Ragab Mohamed Ibrahim, Amgad Ibrahim Mansour Khedr, Gamal
Abdallah Mohamed, Mohamed Fathalla Zayed, Amal Abd-Elmoneim Soliman
El-Kholy & Rwaida Adel Al Haidari
To cite this article: Sabrin Ragab Mohamed Ibrahim, Amgad Ibrahim Mansour Khedr, Gamal
Abdallah Mohamed, Mohamed Fathalla Zayed, Amal Abd-Elmoneim Soliman El-Kholy & Rwaida
Adel Al Haidari (2018): Cucumol B, a new triterpene benzoate from Cucumisꢀmelo seeds with
cytotoxic effect toward ovarian and human breast adenocarcinoma, Journal of Asian Natural
Products Research, DOI: 10.1080/10286020.2018.1488832
To link to this article: https://doi.org/10.1080/10286020.2018.1488832
Published online: 27 Jun 2018.
Submit your article to this journal
Article views: 2
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=ganp20

Journal of asian natural Products research, 2018
ꢁꢁpꢂ://ꢃꢄꢅ.ꢄꢆg/10.1080/10286020.2018.1488832
ꢀ
Cucumol B, a new triterpene benzoate from Cucumis melo
seeds with cytotoxic effect toward ovarian and human breast
adenocarcinoma
a,b
c
Sabrin Ragab Mohamed Ibrahim , Amgad Ibrahim Mansour Khedr ,
d,e
a,f
Gamal Abdallah Mohamed , Mohamed Fathalla Zayed ,
Amal Abd-Elmoneim Soliman El-Kholy and Rwaida Adel Al Haidaria
g,h
ꢇ
dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ Pꢀꢇꢆmꢇꢋꢄgꢉꢄꢂy ꢇꢉꢃ Pꢀꢇꢆmꢇꢋꢈꢌꢁꢅꢋꢇꢍ cꢀꢈmꢅꢂꢁꢆy, cꢄꢍꢍꢈgꢈ ꢄꢊ Pꢀꢇꢆmꢇꢋy, tꢇꢅbꢇꢀ uꢉꢅvꢈꢆꢂꢅꢁy,
b
aꢍ Mꢇꢃꢅꢉꢇꢀ aꢍ Mꢌꢉꢇwwꢇꢆꢇꢀ 30078, sꢇꢌꢃꢅ aꢆꢇbꢅꢇ; fꢇꢋꢌꢍꢁy ꢄꢊ Pꢀꢇꢆmꢇꢋy, dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ Pꢀꢇꢆmꢇꢋꢄgꢉꢄꢂy, aꢂꢂꢅꢌꢁ
uꢉꢅvꢈꢆꢂꢅꢁy, aꢂꢂꢅꢌꢁ 71526, egypꢁ; fꢇꢋꢌꢍꢁy ꢄꢊ Pꢀꢇꢆmꢇꢋy, dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ Pꢀꢇꢆmꢇꢋꢄgꢉꢄꢂy, Pꢄꢆꢁ sꢇꢅꢃ uꢉꢅvꢈꢆꢂꢅꢁy,
Pꢄꢆꢁ sꢇꢅꢃ 42526, egypꢁ; fꢇꢋꢌꢍꢁy ꢄꢊ Pꢀꢇꢆmꢇꢋy, dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ nꢇꢁꢌꢆꢇꢍ Pꢆꢄꢃꢌꢋꢁꢂ ꢇꢉꢃ aꢍꢁꢈꢆꢉꢇꢁꢅvꢈ Mꢈꢃꢅꢋꢅꢉꢈ, Kꢅꢉg
abꢃꢌꢍꢇzꢅz uꢉꢅvꢈꢆꢂꢅꢁy, Jꢈꢃꢃꢇꢀ 21589, sꢇꢌꢃꢅ aꢆꢇbꢅꢇ; fꢇꢋꢌꢍꢁy ꢄꢊ Pꢀꢇꢆmꢇꢋy, dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ Pꢀꢇꢆmꢇꢋꢄgꢉꢄꢂy,
ꢋ
ꢃ
ꢈ
ꢊ
aꢍ-azꢀꢇꢆ uꢉꢅvꢈꢆꢂꢅꢁy, aꢂꢂꢅꢌꢁ 71524, egypꢁ; fꢇꢋꢌꢍꢁy ꢄꢊ Pꢀꢇꢆmꢇꢋy, dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ Pꢀꢇꢆmꢇꢋꢈꢌꢁꢅꢋꢇꢍ cꢀꢈmꢅꢂꢁꢆy,
g
aꢍ-azꢀꢇꢆ uꢉꢅvꢈꢆꢂꢅꢁy, cꢇꢅꢆꢄ 11884, egypꢁ; dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ cꢍꢅꢉꢅꢋꢇꢍ ꢇꢉꢃ hꢄꢂpꢅꢁꢇꢍ Pꢀꢇꢆmꢇꢋy, cꢄꢍꢍꢈgꢈ ꢄꢊ Pꢀꢇꢆmꢇꢋy,
tꢇꢅbꢇꢀ uꢉꢅvꢈꢆꢂꢅꢁy, aꢍ Mꢇꢃꢅꢉꢇꢀ aꢍ Mꢌꢉꢇwwꢇꢆꢇꢀ 30078, sꢇꢌꢃꢅ aꢆꢇbꢅꢇ; ꢀfꢇꢋꢌꢍꢁy ꢄꢊ Pꢀꢇꢆmꢇꢋy, dꢈpꢇꢆꢁmꢈꢉꢁ ꢄꢊ
cꢍꢅꢉꢅꢋꢇꢍ Pꢀꢇꢆmꢇꢋy, aꢅꢉ-sꢀꢇmꢂ uꢉꢅvꢈꢆꢂꢅꢁy, cꢇꢅꢆꢄ 11566, egypꢁ
ABSTRACT
ARTICLE HISTORY
Phytochemical investigation of the methanolic extract of Cucumis
melo L. (Cucurbitaceae) seeds furnished a new triterpene benzoate
derivative: cucumol B (1) and four known flavonoids: quercetin-3-
O-β-D-glucopyranosyl-(1→6)-α-L-rhamnopyranoside (2), quercetin-
rꢈꢋꢈꢅvꢈꢃ 14 fꢈbꢆꢌꢇꢆy 2018
aꢋꢋꢈpꢁꢈꢃ 11 Jꢌꢉꢈ 2018
KEYWORDS
Cucumis melo; cꢌꢋꢌꢆbꢅꢁꢇꢋꢈꢇꢈ;
ꢋꢌꢋꢌmꢄꢍ B; ꢁꢆꢅꢁꢈꢆpꢈꢉꢈ;
ꢋyꢁꢄꢁꢄxꢅꢋ
3
-O-β-D-glucopyranoside (3), quercetin (4), and luteolin (5). Their
13 1 1
structures were identified by UV, IR, 1D ( C and H), 2D (HSQC, H-
1
H COSY, HMBC, and NOESY) NMR, and HRESIMS spectral as well as
comparing with literature data. Compound 1 has been assessed for
the in vitro cytotoxic effect against SKOV-3, MCF-7, and HCT-116 cell
lines. It had selective and potent effect toward SKOV-3 and MCF-7
cell lines with IC s 2.05 and 0.41 μM, respectively, in comparison to
5
0
doxorubicin (IC s 0.32 and 0.05 μM). However, it showed moderate
5
0
activity toward HCT-116 cell line with IC50 8.27 μM.
CONTACT sꢇbꢆꢅꢉ rꢇgꢇb Mꢄꢀꢇmꢈꢃ ibꢆꢇꢀꢅm
ꢂꢆꢅbꢆꢇꢀꢅm@ꢁꢇꢅbꢇꢀꢌ.ꢈꢃꢌ.ꢂꢇ, ꢂꢇbꢆꢅꢉꢂꢀꢇꢌꢆ@gmꢇꢅꢍ.ꢋꢄm
©
2018 iꢉꢊꢄꢆmꢇ uK lꢅmꢅꢁꢈꢃ, ꢁꢆꢇꢃꢅꢉg ꢇꢂ tꢇyꢍꢄꢆ & fꢆꢇꢉꢋꢅꢂ Gꢆꢄꢌp

2
S. R. M. IBRAHIM ET AL.
1
. Introduction
Cucurbitaceae includes musk melons, pumpkins, squash, cucumbers, and watermelons,
which are known as vine crops. ey are wealthy sources of beta-carotene, dietary fib-
ers, minerals, and vitamin C [1,2]. Naturally, they are low in fat, sodium, and cholesterol.
Cucumis melo L. (cantaloupe or netted muskmelon) is one of the most cultivated cucurbits.
It is cultivated worldwide in subtropical, temperate, and tropical regions [1]. Its seeds are
used as febrifuge, digestive, antitussive, vermifuge, and demulcent in Chinese folk medicine
[
3]. e seed kernels are utilized in various ailments such as the inflammation of kidney and
liver, renal disorders, stomach and urinary tract ulcers, burning and painful micturation,
vitiligo, ascites, chronic fevers, and in general debility in the Indian traditional medicine
[
2,4,5]. e fruits are used as a first aid for treating abrasions and burns. C. melo possessed
various bioactivities: analgesic, antioxidant, anti-inflammatory, and antimicrobial [1,2,4,6].
Our former investigation of C. melo revealed the presence of phenylethyl chromones, fla-
vonoids, triterpenoids, triacylglycerides, and sterols [1,2,4,6]. In this work, investigation
of the MeOH extract of C. melo seeds led to the isolation and structural determination of
a new triterpene benzoate derivative: cucumol B (1) and four known metabolites (2–5). In
addition, the in vitro cytotoxic potential of the new compound was assessed toward SKOV-
3
, MCF-7, and HCT-116 cell lines.
2
. Results and discussion
e seeds were defatted with n-hexane and then extracted with MeOH. e MeOH extract

was separated using various chromatographic methods: VLC, silica gel, Sephadex LH-20,
and RP-18 to furnish one new (1) and three known metabolites (2–4) (Figure 1).
Compound 1 was isolated as white amorphous powder. It gave positive Lieberman–
Burchard reaction, indicating its triterpenoidal nature [7,8]. Its molecular formula was
assigned as C H O on the basis of the protonated molecular ion peak at m/z 799.6236
5
3
82
5
+
−1
[
M + H] in HRESIMS. e IR spectrum revealed the existence of hydroxyl (3396 cm ),
−1
−1
−1
ester carbonyl (1727 cm ), double bond (1632 cm ), and C-H aromatic (714 cm ) func-
1
3
tionalities. e DEPT and C NMR spectra of 1 displayed resonances for 53 carbons: 7
Figure 1. cꢀꢈmꢅꢋꢇꢍ ꢂꢁꢆꢌꢋꢁꢌꢆꢈ ꢄꢊ ꢋꢄmpꢄꢌꢉꢃ 1.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
3
1
1
Figure 2. sꢄmꢈ kꢈy h- h cosY ꢇꢉꢃ hMBc ꢋꢄꢆꢆꢈꢍꢇꢁꢅꢄꢉꢂ ꢄꢊ 1.
tertiary methyls, 1 primary methyl, 23 methylenes including an oxymethylene (δ 64.6,
C
C-28), 11 methines, and 11 quaternary carbons, including two ester carbonyls at δ 166.7
C
(
(
C-1′′) and 172.3 (C-1′), and two quaternary olefinic carbons at δ 148.8 (C-9) and 148.0
C
1
C-13). e H NMR spectrum showed seven methyl singlets at δ 1.03 (H-23), 0.84 (H-24),
H
1
.22 (H-25), 1.07 (H-26), 0.98 (H-27), 0.86 (H-29), and 0.91 (H-30), correlated with the
carbon signals at δ 28.0, 15.8, 25.9, 21.7, 20.0, 22.7, and 30.9, respectively, in the HSQC
C
spectrum, indicating that 1 was an oleanane-type triterpene [9,10]. Moreover, signals for
two coupled olefinic protons at δ 5.65 (d, J = 6.1 Hz, H-11) and 5.49 (d, J = 6.1 Hz, H-12)
H
1
1
1
were observed in the H NMR and H- H COSY spectra, indicating the presence of two
tri-substituted olefinic double bonds in 1 (Figure 2). ey had HSQC cross-peaks to the
carbons at δ 116.1 (C-11) and 118.9 (C-12). e placement of the double bonds at C -C
C
9
11
and C -C was proved relying on the HMBC cross-peaks of H-11, H-12, H-25, and H-26
1
2
13
to C-9, H-18 to C-12, and H-11, H-15, H-18, and H-27 to C-13, indicating that 1 had an
1
13
olean-9(11),12-diene framework [11] (Figure 2). e H and C NMR spectra displayed
two oxymethine signals at δ 4.09 (H-1)/δ 71.6 (C-1) and 5.00 (H-3)/74.3 (C-3). eir
H
C
1
1
assignment was established based on the observed H- H COSY of H-2 to H-1 and H-3 as
well as the HMBC cross-peaks of H-1, H-23, and H-24 to C-3 and H-3 and H-25 to C-1. e
coupling constants of H-1 and H-3 revealed that the hydroxyl groups at C-1 and C-3 were
α- and β-oriented, respectively [12]. e signals at δ 4.24 (s, H-28)/δ 64.6 (C-28) revealed
H
C
the presence of an oxymethylene functionality in 1. Its placement at C-17 was established
by the HMBC cross-peaks of H-18 and H-16/C-28. e multiple aliphatic protons at δH
1
.30–1.21 and primary methyl at δ 0.82 indicated the existence of a long-chain aliphatic
H
1
3
moiety. e C NMR signal at δ 172.3 (C-1′) was assignable to an ester carbonyl, which
C
−1
was assured by the IR band at 1727 cm while the signals at δ 0.82 (t, J = 6.8 Hz)/δ 13.1
H
C
were attributed to the terminal CH group of a straight chain fatty acid [7,9,13,14]. Upon
3
alkaline hydrolysis of 1, it gave FAME and benzoic acid. e FAME was identified as methyl
+
ester of palmitic acid by GC and EIMS peak at m/z 270 [M] . Also, benzoic acid was spec-
ified by EIMS and co-TLC with authentic sample and confirmed by the ESIMS fragment
+
peak at m/z 455 [M + H-(palmitoyl + benzoyl moieties)] . e connection of the fatty acyl
moiety at C-3 was established by the HMBC cross-peak of H-3 to C-1′ and confirmed by
the downfield shif of H-3 (δ 5.00). Moreover, signals relevant for benzoyl moiety [δ 7.65
H
H
(
H-3′′, 7′′)/δ 129.9, 7.47 (H-4′′, 6′′)/127.8, 7.20 (H-5′′)/131.3 (C-5′′), 138.4 (C-2′′), and 166.7
C
1
1
(
C-1′′)] were observed [15]. is was assured by the observed H- H COSY and HMBC

4
S. R. M. IBRAHIM ET AL.
Figure 3. sꢄmꢈ kꢈy noesY ꢋꢄꢆꢆꢈꢍꢇꢁꢅꢄꢉꢂ ꢄꢊ 1.
cross-peaks. Its connectivity to C-28 was assured by the cross-peak of H-28/C-1′′ in the
HMBC spectrum. e relative stereochemistry at C-1 and C-3 was assessed by comparing
1
13
the H and C chemical shif s and the J values with those of related triterpenes and it was
secured by NOESY experiment. e NOESY cross-peaks of H-1/H-18 and H-25, as well as
H-18/H-26 and H-30 referred to the presence of these protons on one side of the molecule.
Furthermore, the relations of H-3/H-23, H-27, and H-29 indicated that these protons are on
the other side of the molecule (Figure 3). On the basis of these findings, 1 was assigned as
1
α,3β,28-trihydroxy-28-benzoyl olean-9(11),12-diene-3-palmitate and named cucumol B.
e known metabolites were specified as quercetin-3-O-β-D-glucopyranosyl-(1→6)-α-L-
rhamnopyranoside (2) [16,17], quercetin-3-O-β-D-glucopyranoside (3) [16–18], quercetin

(
4) [18], and luteolin (5) [19] by spectroscopic analysis and comparison of their data with
those in the literature.
Breast and ovarian cancers are one of the leading worldwide causes of death among
women. Various bioactive agents in the last decade have been identified from plants and
human diets and are being developed as therapeutic and chemopreventive agents for diverse
cancers such as breast and ovarian cancers [20]. Phytochemicals are a potential group
of chemicals that are derived from natural resource, especially with plants origin with
health-boosting properties. eir prominent role in maintaining health and protecting from
cancer is raising a significant interest amongst scientists, consumers, and food manufacturers
[
21]. Accordingly, the future’s trend is directed to the functional food with particular health
effects. Various researches referred that terpenoids especially those from cucurbitaceous
plants have shown to exhibit chemoprevention and chemotherapeutic effects toward various
cancers [22]. Hence, the in vitro cytotoxic potential of 1 was estimated toward SKOV-3,
MCF-7, and HCT-116 cell lines. It is noteworthy that 1 had selective and potent effect toward
SKOV-3 and MCF-7 cell lines with IC s 2.05 and 0.41 μM, respectively, in comparison to
5
0
doxorubicin (IC s 0.32 and 0.05 μM, respectively). However, it showed moderate activity
toward HCT-116 cell line with IC 8.27 μM compared to doxorubicin (IC 0.24 μM).
50
5
0
50
e cytotoxic effects exhibited by the isolated triterpene from C. melo reinforce the avail
of it as a cytotoxic agent against ovarian and human breast cancers. Also, these evidences
could provide relevant bases for the scientific rationale of using C. melo in the treatment
of cancer.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
5
3
. Experimental
3
.1. General experimental procedures
Optical rotation was measured on a digital polarimeter (JASCO DIP-370) (Jasco Co., Tokyo,
Japan). UV spectra were recorded in MeOH on a Shimadzu 1601 UV/VIS spectrophotom-
eter (Shimadzu, Kyoto, Japan). e IR spectra were performed on a Shimadzu 400 Infrared
spectrophotometer (Shimadzu, Kyoto, Japan). GCMS analysis was carried out on Clarus
5
00 GCMS (Perkin Elmer, Shelton, CT). Turbo Mass 4.5.0.007 was the sof ware controller/
integrator (Perkin Elmer). A capillary column Elite 5 MS GC (30 × 0.25 mm × 0.5 μm,
Perkin Elmer) was used. Helium was the carrier gas (purity 99.9999%; 2 ml/min) (flow initial
5
5.8 cm/s, 32 p.s.i., split; 1:40). e 100–250 °C was the column’s temperature (5 °C/min).
A LTQ Orbitrap (ermoFinnigan, Bremen, Germany) was used for getting HRESIMS.
BRUKER Unity INOVA 700 was used for NMR spectra measurement (Bruker BioSpin,
Billerica, MA, USA). Sephadex LH-20 (0.25–0.1 mm), SiO 60 (0.04–0.063 mm), and RP-18
2
(
0.04–0.063 mm, Merck, Darmstadt, Germany) were used for chromatographic separations.
TLC analyses were implemented on TLC pre-coated plates (SiO 60 F , 0.2 mm, Merck,
2
254
Darmstadt, Germany).
3
.2. Plant material
Seeds of Cucumis melo L. were obtained from cultivated plants at Mankabad, Assiut, Egypt.
e plant material was identified and authenticated (voucher specimen CM-6-2016) by

Prof. Dr Mohamed A. Farghali, Professor of Horticulture (Vegetable Crops), Faculty of
Agriculture, Assiut University.
3
.3. Extraction and isolation
Fruits were cut and seeds were removed from stringy piths. e seeds were rubbed by
hand and washed quickly with tap water, then transferred to a colander and dried at room
temperature. Dried seeds (305 g) were triturated in a ball mill and sieved through a mesh
of 0.5-mm diameter. e triturated seeds (267 g) were packed in a Soxhlet apparatus and
defatted using n-hexane (3 × 1.5 L), then extracted with MeOH (4 × 1.5 L). e MeOH
extract was concentrated to afford a dark brown residue (14.1 g). e total MeOH extract
was submitted to vacuum liquid chromatography (VLC) using n-hexane, EtOAc, and MeOH
to afford n-hexane (5.4 g), EtOAc (3.1 g), and MeOH (4.5 g) fractions. e EtOAc fraction
(
3.1 g) was separated over a Sephadex LH-20 CC (100 g × 50 × 3 cm, MeOH:CHCl 90:10) to
3
afford seven sub-fractions: CME-1 to CME-7. Sub-fraction CME-3 (71.2 mg) was chromato-
graphed on SiO CC (40 g × 50 × 2 cm) and eluted with CHCl :MeOH (99:1 to 88:12) to give
2
3
1
. Its purification was carried out on RP-18 CC (50 g × 50 × 2 cm, MeOH:H O gradient) to
2
yield 1 (11.2 mg). SiO CC (80 g × 50 × 2 cm, CHCl :MeOH gradient) of sub-fraction CME-4
2
3
(
615 mg) gave 2, which was purified on RP-18 CC eluting with MeOH:H O gradient to get 2
2
(
36.2 mg). Sub-fraction CME-5 (308 mg) was subjected to SiO CC (50 g × 50 × 2 cm) using
2
CHCl :MeOH gradient to get impure 3. Its purification was achieved similar to sub-fraction
3
CME-4 to give 3 (55.4 mg). Sub-fraction CME-6 (629 mg) was SiO CC (80 g × 100 × 3 cm)
using MeOH:H O gradient to obtain compounds 4 (49 mg) and 5 (9.1 mg).
2
2

6
S. R. M. IBRAHIM ET AL.
Table 1. nMr ꢂpꢈꢋꢁꢆꢇꢍ ꢃꢇꢁꢇ ꢄꢊ ꢋꢄmpꢄꢌꢉꢃ 1 (cdcꢍ , 700 ꢇꢉꢃ 175 hz).
3
No.
δH (m, J in Hz)
δC
HMBC
1
2
3
4
5
6
7
8
9
4.09 bꢆꢃ (2.8)
1.61–1.63 m, 1.36–1.39 m
71.6 ch
31.8 ch2
74.3 ch
39.7 c
44.7 ch
16.3 ch2
32.1 ch2
43.9 c
148.8 c
41.0 c
116.1 ch
118.9 ch
148.0 c
2, 3, 5, 10, 25
3, 4, 10
1′, 1, 4, 23, 24
5.00 ꢃꢃ (12.0, 5.0)
–
–
1.54–1.55 m
1.57–1.59 m, 1.40–1.42 m
2.00–2.02 m, 1.81–1.83 m
3, 4, 10, 24, 25
8
–
–
–
–
–
–
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
1
2
3
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
′
–
5.65 ꢃ (6.1)
5.49 ꢃ (6.1)
8, 9, 10, 13
9, 14, 18
–
–
–
–
41.4 c
1.64–1.66 m, 1.21–1.24 m
1.84–1.86 m, 0.97–0.99 m
24.4 ch2
27.7 ch2
32.4 c
45.6 ch
43.4 ch2
31.1 c
13
14, 28
–
–
2.08 ꢃꢃ (12.8, 5.6)
1.63–1.65 m, 1.04–1.06 m
12, 13, 19, 22, 28
17, 21, 29, 30
–
1.34–1.36 m, 1.00–1.02 m
1.42–1.44 m, 1.21–1.24 m
33.5 ch2
37.7 ch2
28.0 ch3
15.8 ch3
25.9 ch3
21.7 ch3
20.0 ch3
64.6 ch2
22.7 ch3
30.9 ch3
172.3 c
33.8 ch2
24.2 ch2
28.8–28.0 ch2
21.6 ch2
13.1 ch3
166.7 c
17, 29, 30
1.03 ꢂ
0.84 ꢂ
1.22 ꢂ
1.07 ꢂ
0.98 ꢂ
4.24 ꢂ
0.86 ꢂ
0.91 ꢂ
–
3, 4, 5, 24
3, 4, 5, 23
1, 5, 9
9, 14
8, 13
17, 18, 22
19, 20, 21, 30
19, 20, 21, 29
–
1′, 3′
1′
–
16′
15′
–
′
′
2.30 ꢁ (7.2)
1.61–1.63 m
1.30–1.21 m
1.14–1.16 m
0.82 ꢁ (6.8)
–
(
ch2)11
5′
6′
′′
1
1
1
2
3
4
5
′′
–
138.4 c
–
′′,7′′
′′, 6′′
′′
7.65 ꢃꢃ (7.4, 1.2)
7.47 ꢃꢁ (7.4, 1.2)
7.19–7.21 m
129.9 ch
127.8 ch
131.3 ch
1′′, 4′′, 6′′, 5′′
2′′, 3′′, 7′′
3′′, 7′′
3
.4. Alkaline hydrolysis of compound 1
Compound 1 (7 mg) in 6-ml KOH/MeOH (3 %) was kept at room temperature for 25 min,
then neutralized with HCl/MeOH (1 N). e solution was extracted with CHCl and evap-
3
orated. e obtained residue was submitted to SiO CC using n-hexane:EtOAc gradient to
2
get benzoic acid and methyl ester of palmitic acid. Benzoic acid was identified by co-TLC
with authentic sample and EIMS. e methyl ester of palmitic acid was identified by GCMS:
+
t 36.6 min and EIMS m/z: 270 [M] [7].
R
3
.4.1. Compound 1
2
5
White amorphous powder; [α] -56.3 (c 0.1, MeOH); UV (MeOH) λ (log ε): 223 (3.02),
D
max
−1
1
13
2
65 (2.19) nm; IR (KBr) νmax: 3396, 1727, 1632, 714 cm ; H and C NMR spectral data
+
see Table 1; HRESIMS: m/z 799.6236 [M + H] (calcd for C H O , 799.6241).
5
3
83
5

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
7
3
.5. Cytotoxic assay

e cytotoxic effect of 1 was evaluated in vitro toward ovarian (SKOV-3), human breast
adenocarcinoma (MCF-7), and colorectal adenocarcinoma (HCT-116) cell lines. e cells
(25,000 cells/well) were incubated for 24 h. Tested sample was added at various concentra-
tions and cells were incubated for 48 h. Neutral Red dye was utilized to determine the cell
viability. Doxorubicin (positive control) and DMSO (negative control) were used [23,24].
Disclosure statement
No potential conflict of interest was reported by the authors.
References
[
[
[
[
[
1] S.R.M. Ibrahim, Nat. Prod. Commun. 5, 403 (2010).
2] S.R.M. Ibrahim, Nat. Prod. Commun. 9, 205 (2014).
3] S. De Marino, C. Festa, F. Zollo, and M. Iorizzi, Phytochem. Lett. 2, 130 (2009).
4] S.R.M. Ibrahim and G.A. Mohamed, Brazilian J. Pharmacog. 25, 462 (2015).
5] N. Ullah, S. Khan, A. Khan, W. Ahmad, Y. Shah, L. Ahmad and I. Ullah, Acta Pol. Pharm-Drug
Res. 72, 651 (2015).
[
[
6] S.R.M. Ibrahim and G.A. Mohamed, Nat. Prod. Res. 29, 1489 (2015).
7] N.M. Al-Musayeib, G.A. Mohamed, S.R.M. Ibrahim and S.A. Ross, Med. Chem. Res. 22, 5297
(
2013).
[8] S.R.M. Ibrahim, G.A. Mohamed, L.A. Shaala, L.M.Y. Banuls, G. Van Goietsenoven, R. Kiss and
D.T.A. Youssef, Phytochem. Lett. 5, 490 (2012).
[9] S.R.M. Ibrahim, R.A. Al Haidari, G.A. Mohamed and M.A.A. Moustafa, Brazilian J. Pharmacog.
2
6, 701 (2016).
[
[
[
[
[
[
[
10] G.A. Mohamed, Nat. Prod. Res. 28, 976 (2014).
11] C.E. Fingolo, T.S. Santos, M.D.M.V. Filho and M.A.C. Kaplan, Molecules. 18, 4247 (2013).
12] S.R.M. Ibrahim, G.A. Mohamed and S.A. Ross, Phytochem. Lett. 15, 125 (2016).
13] M.A. El-Shanawany, H.M. Sayed, S.R.M. Ibrahim and M.A.A. Fayed, Drug Res. 65, 347 (2015).
14] G.A. Mohamed, S.R.M. Ibrahim and S.A. Ross, Phytochem. Lett. 6, 340 (2013).
15] T. Kikuchi, S. Ueda, J. Kanazawa, H. Naoe, T. Yamada and R. Tanaka, Molecules. 19, 4802 (2014).
16] G.A. Mohamed, S.R.M. Ibrahim, M.M.M. Abdel-Latif, S.M. El-Messery, N.M. Al Musayeib and
I.A. Shehata, Starch-Stärke. 67, 976 (2015).
[17] G.A. Mohamed, S.R.M. Ibrahim, E.S. Elkhayat, S.A. Ross, H.M. Sayed, S.A.M. El-Moghazy and
M.A. El-Shanawany, Phytochem. Lett. 11, 177 (2015).
[18] N.M. Al-Musayeib, G.A. Mohamed, S.R.M. Ibrahim and S.A. Ross, Molecules. 19, 2819 (2014).
[19] G.A. Mohamed, S.R.M. Ibrahim, N.M. Al-Musayeib and S.A. Ross, Arch. Pharm. Res. 37, 459
(
2014).
[
[
20] T. Rabi and A. Bishayee, Breast Cancer Res. Treat. 115, 223 (2009).
21] S. Nobili, D. Lippi, E. Witort, M. Donnini, L. Bausi, E. Mini and S. Capaccioli, Pharmacol. Res.
5
9, 365 (2009).
[
[
[
22] A. Petronelli, G. Pannitteri and U. Testa, Anti-Cancer Drugs. 20, 880 (2009).
23] E.S. Elkhayat, S.R.M. Ibrahim, G.A. Mohamed and S.A. Ross, Nat. Prod. Res. 30, 814 (2016).
24] S.R.M. Ibrahim, G.A. Mohamed, R.A. Al Haidari, M.F. Zayed, A.A. El-Kholy and S.A. Ross,
Bioorg. Med. Chem. 26, 786 (2018).