New lupane-type and ursane-type triterpene saponins from the leaves of Trevesia palmata

Article abstract of DOI:10.1080/14786419.2019.1696797

Three new triterpene saponins including two lupane-types and an ursane-type were isolated from the leaves of Trevesia palmata. Their structures were determined as 2α,3β,23-trihydroxylup-20(29)-en-28-oic acid 3-O-α-L-arabinopyranoside (1), 2α,3β,23-trihydroxylup-20(29)-en-28-oic acid 3-O-[α-L-arabinopyranoside]-28-O-[β-D-glucopyranosyl] ester (2), and 2α,3β,23-trihydroxyurs-12-en-28-oic acid 3-O-[α-L-arabinopyranoside]-28-O-[β-D-glucopyranosyl(1→2)-β-D-glucopyranosyl] ester (3) by analysis of their HR-ESI-MS, 1D and 2D NMR spectra. The 2α,3β,23-trioxygenated pentacyclic triterpenes were uncommonly found in the nature. At concentration of 100 μM, compounds 1–3 inhibited NO production in LPS activated BV2 cells with inhibitory rates of 17.4 ± 1.8%, 33.1 ± 1.2%, and 11.7 ± 2.2%, respectively. But, they did not significantly inhibit yeast α-glucosidase activity.

Full text of DOI:10.1080/14786419.2019.1696797

Natural Product Research
Formerly Natural Product Letters
ISSN: 1478-6419 (Print) 1478-6427 (Online) Journal homepage: https://www.tandfonline.com/loi/gnpl20
New lupane-type and ursane-type triterpene
saponins from the leaves of Trevesia palmata
Pham Hai Yen, Vu Van Doan, Giang Thi Kim Lien, Nguyen Thị Hong Chuong,
Nguyen Thi Viet Thanh, Do Thi Trang, Duong Thi Dung, Nguyen Xuan Nhiem,
Bui Huu Tai, Chau Van Minh & Phan Van Kiem
To cite this article: Pham Hai Yen, Vu Van Doan, Giang Thi Kim Lien, Nguyen Thị Hong Chuong,
Nguyen Thi Viet Thanh, Do Thi Trang, Duong Thi Dung, Nguyen Xuan Nhiem, Bui Huu Tai, Chau
Van Minh & Phan Van Kiem (2019): New lupane-type and ursane-type triterpene saponins from the
leaves of Trevesiaꢀpalmata, Natural Product Research, DOI: 10.1080/14786419.2019.1696797
To link to this article: https://doi.org/10.1080/14786419.2019.1696797
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NATURAL PRODUCT RESEARCH
https://doi.org/10.1080/14786419.2019.1696797
New lupane-type and ursane-type triterpene saponins
from the leaves of Trevesia palmata
Pham Hai Yena,b, Vu Van Doana, Giang Thi Kim Lienc, Nguyen Thị Hong
Chuongd, Nguyen Thi Viet Thanhe, Do Thi Tranga, Duong Thi Dunga,
Nguyen Xuan Nhiema,b, Bui Huu Taia,b, Chau Van Minha and Phan Van Kiema,b
aInstitute of Marine Biochemistry, Vietnam Academy of Science and Technology (VAST), Hanoi
b
c
Vietnam; Graduate University of Science and Technology, VAST, Hanoi, Vietnam; The University of
d
Danang, Danang, Vietnam; University of Education, The University of Danang, Danang, Vietnam;
eSchool of Chemical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
ABSTRACT
ARTICLE HISTORY
Received 23 October 2019
Accepted 14 November 2019
Three new triterpene saponins including two lupane-types and an
ursane-type were isolated from the leaves of Trevesia palmata. Their
structures were determined as 2a,3b,23-trihydroxylup-20(29)-en-28-
oic acid 3-O-a-L-arabinopyranoside (1), 2a,3b,23-trihydroxylup-20(29)-
en-28-oic acid 3-O-[a-L-arabinopyranoside]-28-O-[b-D-glucopyranosyl]
ester (2), and 2a,3b,23-trihydroxyurs-12-en-28-oic acid 3-O-[a-L-arabi-
nopyranoside]-28-O-[b-D-glucopyranosyl(1!2)-b-D-glucopyranosyl]
ester (3) by analysis of their HR-ESI-MS, 1D and 2D NMR spectra. The
2a,3b,23-trioxygenated pentacyclic triterpenes were uncommonly
found in the nature. At concentration of 100 mM, compounds 1–3
inhibited NO production in LPS activated BV2 cells with inhibitory
rates of 17.4 1.8%, 33.1 1.2%, and 11.7 2.2%, respectively. But,
they did not significantly inhibit yeast a-glucosidase activity.
KEYWORDS
Trevesia palmata;
trevepaloside A;
trevepaloside B;
trevepaloside C;
NO production
1. Introduction
Trevesia palmata (known as snowflake aralia) is an evergreen tree belonging Araliaceae
family. It is found in serval Asia countries such as India, Cambodia, Thailand, and
Vietnam. In traditional medicine, the leaves, stems, and roots of T. palmata have been
CONTACT Phan Van Kiem
phankiem@yahoo.com
Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1696797.
ß 2019 Informa UK Limited, trading as Taylor & Francis Group

2
P. H. YEN ET AL.
used as a tonic drug, perineal healing, postpartum recovery, reducing inflammation
and pain (Tommasi et al. 2000; Lamxay et al. 2011). Phytochemical studies on T. pal-
mata suggests that this plant is rich of triterpene saponins showing anti-inflammation,
antimicrobial and antiproliferative activities (Tommasi et al. 2000; Kim et al. 2018). Our
previous study also identified two new acetylated saponins, acetyltrevesiasaponins A
and B, from T. palmata leaves. The acetyltrevesiasaponin B was revealed inhibiting NO
production in LPS activated BV2 cells with IC50 of 40.7 mM (Thao et al. 2018).
Continuing course study to find new natural saponins from medicinal plants, herein,
we describe the isolation and structural elucidation of three new triterpene saponins
from the leaves of T. palmata. Their inhibitory effects on a-glucosidase activity and NO
production in activated BV2 cells were also investigated.
2. Results and discussion
Compound 1 was obtained as a white amorphous powder. Its molecular formula was
deduced to be C35H56O9 by a pair of quasi-molecular ion peaks at m/z 655.3617
[M þ Cl]ꢀ (calcd. for C35H56O935Cl, 655.3613) and m/z 665.3913 [M þ HCOO]ꢀ (calcd.
for C36H57O11, 665.3901) in the negative mode HR-ESI-MS, indicating 8 degrees of
unsaturation. The 1H NMR spectrum of 1 appeared signals of 5 methyl groups [dH
1.72, 1.04, 0.99, 0.97 and 0.74 (each 3H, s)], an anomeric proton [dH 4.30 (1H, d,
J ¼ 7.5 Hz)], and two olefinic protons [dH 4.74 and 4.62 (each 1H, s)]. The 13C NMR,
DEPT and HSQC spectra of 1 revealed signals of 35 carbons including 7 non-proto-
nated carbons, 11 methines, 12 methylenes, and 5 methyl groups. Among them, a
signal at dC 180.3 was assigned for a carboxylic carbon. A pair of olefinic carbons at
dC 152.0 (C) and 110.2 (CH2) indicated the presence of a terminal double bond. An
anomeric carbinol group was deduced at dC 106.2 and dH 4.30. The remaining carbon
signals at dC 14.1 ꢁ 88.2 were characterized for sp3 hybridized carbons.
Aforementioned evidence suggested that compound 1 may be a lupane-type penta-
cyclic triterpene saponin and in close similarity with hovenic acid (Yoshikawa et al.
1998). Location of double bond at C-20/C-29 was confirmed by HMBC correlations
between H3-30 (dH 1.72) and C-20 (dC 152.0)/C-29 (dC 110.2)/C-19 (dC 48.5). The HMBC
correlations between H-18 (dH 1.64) and C-20/C-28 (dC 180.3) indicated the presence
of carboxylic group C-28 (Supporting data, Figure S1). Assignments of three methyl
group (C-25, C-26, and C-27) were demonstrated by HMBC correlations between H3-
25 (dH 0.97) and C-1 (dC 47.4)/C-5 (dC 48.0)/C-9 (dC 51.9)/C-10 (dC 38.8), between H3-26
(dH 0.99) and C-9/C-7 (dC 34.9)/C-8 (dC 41.9)/C-14 (dC 43.7), and between H3-27 (dH
1.04) and C-8/C-13 (dC 39.6)/C-14/C-15 (dC 30.8). The COSY cross peaks of H2-1 (dH
2.08 and 0.81)/H-2 (dH 3.80)/H-3 (dH 3.46) and the chemical shifts of C-2 (dC 68.2) and
C-3 (dC 88.2) indicated the presence of oxygenated groups at C-2 and C-3.
Additionally, the chemical shift of C-23 (dC 63.9) as well as the HMBC correlations
between H3-24 (dH 0.74) and C-23/C-3 (dC 88.2)/C-4 (dC 45.2)/C-5 (dC 48.0) indicated
another oxygenated group at C-23 and assignment of C-24 methyl group. The HMBC
correlation from anomeric proton (H-10, dH 4.30) to C-3 (dC 88.2) indicated the O-
glycosidic linkage at C-3. According to the lupane-type triterpenes, methyl group (C-
27) and protons (H-5, H-9, H-18) were all located as a-orientations meanwhile methyl

NATURAL PRODUCT RESEARCH
3
Figure 1. Chemical structures of compounds 1–3 isolated from the leaves of T. palmata.
groups (C-25, C-26), carboxylic group (C-28), and protons (H-13, H-19) were located as
b-orientations. This deduction was re-confirmed by NOESY experiment such as the NOESY
correlations of H-5 (dH 1.28)/H-9 (dH 1.43), H-9/H3-27 (dH 1.04), H3-27/H-18 (dH 1.64), H3-26
(dH 0.99)/H-13 (dH 2.34) (Supporting data, Figure S2). Continuously, the NOESY correlation
between H-5 (dH 1.28) and H-3 (dH 3.46) suggested a-orientation of H-3. The NOESY corre-
lations of H3-25 (dH 0.97)/H3-24 (dH 0.74), H3-24/H-2 (dH 3.80), and H-2/H3-25 (dH 0.97)
demonstrated b-orientations of both H-2 and methyl group C-24. Beside 30 carbon signals
belonging to lupane triterpene backbone, five carbinol carbons [dC 106.2 (C-10), 72.9 (C-20),
74.6 (C-30), 70.1 (C-40), 67.8 (C-50)] together with a broad singlet multiplicity of H-40 (dH
3.84) were assigned for an arabinopyranosyl group. Acid hydrolysis of 1, sugar residue
was transformed to thiocarbamoylthiazolidine derivative and subjected to HPLC analysis
(Tanaka et al. 2007), confirming the presence of L-arabinose in the sugar moiety of com-
pound 1 (Supporting data). Consequently, structure of compound 1 was determined to
be 2a,3b,23-trihydroxylup-20(29)-en-28-oic acid 3-O-a-L-arabinopyranoside, a new com-
pound and named as trevepaloside A (Figure 1).
Compound 2 was isolated as a white amorphous powder. The HR-ESI-MS of com-
pound 2 displayed quasi-molecular ion peaks at m/z 817.4132 [M þ Cl]ꢀ (calcd. for
C41H66O1435Cl, 817.4141) and m/z 827.4421 [M þ HCOO]ꢀ (calcd. for C42H67O16,
1
827.4429), indicating molecular formula of C41H66O16. The H and 13C NMR spectral
data of compound 2 observed close similarity with those of 1 except for the add-
itional signals of a glucopyranosyl group (Supporting data, Table S1). Attachment of
O-glucopyranosyl group at C-28 was deduced by HMBC correlation of Glc H-1ʺ (dH
5.52)/C-28 (dC 176.1) and by the slight upfield shifted of both carbonyl (C-28, dC
176.1) and anomeric carbon (Glc C-1, dC 95.2). Relative configurations at C-2, C-3,
and C-4 of compound 2 were also recognized similar with those of 1 by NOESY cor-
relations between H-5 (dH 1.28) and H-3 (dH 3.46), H3-25 (dH 0.97) and H3-24 (dH
0.74), H3-24 and H-2 (dH 3.80), H-2 and H3-25 (dH 0.97). Finally, alkaline hydrolysis of
compound 2 revealed compound 1 (compared by TLC analysis) and sugar residue.
The presence of D-glucose in the sugar moiety was confirmed by HPLC analysis its
thiocarbamoylthiazolidine derivative in comparison with the derivatives of authentic
D-glucose (Tanaka et al. 2007). Thus, structure of compound 2 was determined

4
P. H. YEN ET AL.
as 2a,3b,23-trihydroxylup-20(29)-en-28-oic acid 3-O-[a-L-arabinopyranoside]-28-
O-[b-D-glucopyranosyl] ester, a new compound and named as trevepaloside B
(Figure 1).
Compound 3 was obtained as while amorphous powder. Its molecular formula,
C46H74O18, was determined by quasi-molecular ion peaks at m/z 949.4556 [M þ Cl]-
(calcd. for C46H74O1835Cl, 949.4564), m/z 959.4859 [M þ HCOO]- (calcd. for C47H75O20,
959.4852) in the HR-ESI-MS and in conjunction with its 13C NMR spectral data. The
1H NMR spectrum of 3 contained signals for six methyl groups [dH 1.15, 1.08, 0.85,
0.78 (each 3H, s) and dH 0.99, 0.92 (each 3H, d, J ¼ 6.0 Hz)], an olefinic proton [dH
5.27 (1H, br s)], and three anomeric protons [dH 5.42, 4.61 (each 1H, d, J ¼ 8.0 Hz)
and dH 4.28 (1H, d, J ¼ 7.5 Hz)]. The 13C NMR spectrum of 3 contained signals for 46
carbons which were divided by DEPT into 7 non-protonated carbons, 21 methines,
12 methylenes, and 6 methyl groups. Of these, a carbon signal at dC 177.9 was
assigned for a carbonyl group. Two olefinic carbon signals at dC 139.3 (C) and 126.8
(CH) suggested for the presence of a trisubstituted double bond. Three anomeric
1
carbons were observed at dC 106.2, 105.6, and 93.8. Unlike compounds 1 and 2, H
and 13C NMR spectral data of compound 3 suggested it to be an ursane-type triter-
pene saponin, similar with those of ilekudinoside C (Nishimura et al. 1999). The
ursane-type triterpene backbone was further confirmed by HMBC correlations
between H3-25 (dH 1.08) and C-1 (dC 47.3)/C-5 (dC 47.7)/C-9 (dC 48.8)/C-10 (dC 38.5),
H3-26 (dH 0.85) and C-7 (dC 33.6)/C-8 (dC 41.0)/C-9 (dC 48.8)/C-11 (dC 24.5), H3-27 (dH
1.15) and C-8 (dC 41.0)/C-13 (dC 139.3)/C-14 (dC 43.2)/C-15 (dC 29.6), H3-29 (dH 0.92)
and C-18 (dC 54.0)/C-19 (dC 40.3)/C-20 (dC 40.2), H3-30 (dH 0.99) and C-19/C-20/C-21
(dC 31.7). The COSY cross peaks of H2-1 (dH 2.06 and 0.87)/H-2 (dH 3.82)/H-3 (dH
3.48) and chemical shift of C-2 (dC 68.0), C-3 (dC 88.3) indicated the presence of oxy-
genated groups at C-2 and C-3. Chemical shift value of C-23 (64.0) together with
HMBC correlations between H3-24 (dH 0.78) and C-23/C-3 (dC 88.3)/C-4 (dC 45.1)/C-5
(dC 47.7) indicated another oxygenated group at C-23. The HMBC correlations
between H-18 (dH 2.26) and C-12 (dC 126.8)/C-13 (dC 139.3)/C-28 (dC 177.9) indicated
position of double bond at C-12/C-13 and assignment of carbonyl carbon C-28. In a
similar manner with compounds 1 and 2, the NOESY correlation between H-5 (dH
1.33) and H-3 (dH 3.48), H3-25 (dH 1.08) and H3-24 (dH 0.78), H3-24 and H-2 (dH 3.82),
H-2 and H3-25 (dH 1.08) demonstrated the b-orientations of H-2/methyl group C-24
and the a-orientation of H-3. Five carbinol carbon [dC 106.2 (C-10), 72.9 (C-20), 74.5
(C-30), 70.0 (C-40), 67.8 (C-50)], broad singlet of Ara H-40 (dH 3.85), and the HMBC cor-
relation of anomeric proton Ara H-10 (dH 4.28)/C-3 (dC 88.3) indicated the presence
of O-arabinopyranosyl group at C-3. The HMBC correlation between another anome-
ric proton Glc H-1ʺ (dH 5.42) and C-28 confirmed glucopyranosyl moiety at C-28 as
showed in compound 2. The last sugar group was deduced to be xylopyranosyl
group by its proton splitting in the 1H NMR spectrum and as well as trans-axial
coupled (J ¼ 8.0 ꢁ 9.0 Hz) of Xyl H-1000 (dH 4.61)/Xyl H-2000 (dH 3.22)/Xyl H-3000 (dH 3.34)/
Xyl H-4000 (dH 3.44). The COSY cross peak of Glc H-1ʺ (dH 5.42)/Glc H-2ʺ (dH 3.60),
HSQC correlation of Glc H-2ʺ/Glc C-2ʺ (dC 80.6), and HMBC correlation of Xyl H-1000
(dH 4.61)/Glc 2ʺ indicated location of O-xylopyranosyl group at Glc C-2ʺ (Supporting
data, Figure S1). Additionally, acid hydrolysis of 3 revealed D-glucose, L-arabinose,

NATURAL PRODUCT RESEARCH
5
and D-xylose which were confirmed by HPLC analysis of their thiocarbamoylthiazoli-
dine derivatives in comparison with those of authentic sugars (Tanaka et al. 2007).
Thus, the structure of compound 3 was completely established as 2a,3b,23-trihy-
droxyurs-12-en-28-oic
acid
3-O-[a-L-arabinopyranoside]-28-O-[b-D-glucopyrano-
syl(1!2)-b-D-glucopyranosyl] ester, a new compound and named as trevepaloside C
(Figure 1).
Compounds 1–3 were screened their anti-inflammatory activity through inhibiting NO
production in the LPS activated BV2 cells (Trang et al. 2016). Unfortunately, all of compounds
1–3 exhibited modest inhibitory activity on the NO production. At concentration of 100 lM,
compounds 1–3 inhibited NO production in LPS activated BV2 cells with inhibitory rates of
17.4 1.8%, 33.1 1.2%, and 11.7 2.2%, respectively. L-NMMA (20 mM) was used as a posi-
tive control, showing inhibitory rates of 58.8 1.5%. Compounds 1–3 (100 mM) were also
evaluated their inhibitory activity on the yeast a-glucosidase (Trang et al. 2019). However,
none of them showed a-glucosidase inhibitory activity.
3. Experimental
3.1. General
Optical rotation was recorded on a Jasco P2000 digital polarimeter. HR-ESI-MS was
acquired on an Agilent 6530 Accurate Mass Q-TOF LC/MS. NMR spectra were meas-
ured on a Bruker 500 MHz spectrometer. Column chromatography was performed
using silica gel, reverse phase C-18, and diaion HP-20 resins as stationary phase. Thin
layer chromatography was carried out using pre-coated silica gel 60 F254 and RP-18
F254S plates. The spots were visualized by spraying with aqueous solution of H2SO4 5%
followed by heating with a heat gun.
3.2. Plant material
The leaves of Trevesia palmata were collected at Ha Giang, Vietnam in December 2017
and taxonomically identified by botanist Nguyen The Cuong, Institute of Ecology and
Biological Resources, VAST. A voucher specimen (number NCCT-P117) was deposited
at the Institute of Marine Biochemistry, VAST.
3.3. Extraction and isolation
The dried powdered leaves of T. palmata (5.0 kg) was macerated with MeOH in ultra-
sonic bath (three times, each 10 L of MeOH in 30 min at room temperature). After
removal of the solvent in vacuo, methanol extract (450 g) was suspended in 2 L of
water and then successively separated with n-hexane, dichloromethane, and ethyl
acetate to give corresponding organic solvent soluble fractions and water layer. The
water layer was loaded on a diaion (HP-20) column chromatography, washed with
water, and eluted with methanol/water (1/4, 1/1, 3/4, 1/0, v/v) to give four fractions
TP1-TP4. Fraction TP3 (65.0 g) was chromatographed on a silica gel column, eluting
with gradient of dichloromethane/methanol (0–100% methanol) to give eight fractions
TP3A-TP3H. Fraction TP3B (4.1 g) was separated on a silica gel CC eluting with

6
P. H. YEN ET AL.
acetone/dichloromethane (4/1, v/v) to give six fractions TP3B1-TP3B6. Fraction TP3B1
was subjected on a reverse phase C18 column and eluted with acetone/water (1/1, v/
v) to obtain compound 1 (34 mg). Fraction TP3B3 was purified on a reverse phase C18
column chromatography, eluting with acetone/water (2/3, v/v) to give compound 2
(27 mg). Fraction TP3C (6.7 g) was fractionated on a silica gel column chromatography,
eluting with dichloromethane/methanol/water (4/1/0.1, v/v/v) to give three fractions
TP3C1-TP3C3. Compound 3 (22 mg) was isolated from the fraction TP3C2 using reverse
phase C18 column and methanol/water (1/1, v/v) as an eluent.
3.3.1. Trevepaloside A (1)
ꢃ
25
White amorphous powder, ½aꢂD : þ12.8 (c 0.1, MeOH); HR-ESI-MS m/z 655.3617
[M þ Cl]- (calcd. for C35H56O935Cl, 655.3613), m/z 665.3913 [M þ HCOO]- (calcd. for
C36H57O11, 665.3901); 1H NMR (CD3OD, 500 MHz) dH: 4.74 (s, Ha-29), 4.62 (s, Hb-29),
4.30 (d, J ¼ 7.5 Hz, H-10), 3.93 (dd, J ¼ 2.0, 12.5 Hz, Ha-50), 3.84 (br s, H-40), 3.80 (ddd,
J ¼ 5.0, 9.5, 12.5 Hz, H-2), 3.71 (d, J ¼ 11.5 Hz, Ha-23), 3.64 (br d, J ¼ 12.5 Hz, Hb-50), 3.60
(dd, J ¼ 7.5, 9.5 Hz, H-20), 3.53 (dd, J ¼ 3.5, 9.5 Hz, H-30), 3.46 (d, J ¼ 9.5 Hz, H-3), 3.28 (d,
J ¼ 11.5 Hz, Hb-23), 3.05 (m, H-19), 2.34 (m, H-13), 2.26 (m, Ha-16), 2.08 (dd, J ¼ 5.0,
12.5 Hz, Ha-1), 1.97 (m, Ha-21), 1.92 (m, Ha-22), 1.75 (m, Ha-12), 1.72 (s, H3-30), 1.64 (dd,
J ¼ 11.5, 11.5 Hz, H-18), 1.58 (m, Ha-7, Ha-15), 1.50 (m, Ha-11), 1.48 (m, Ha-6), 1.45 (m,
Hb-22), 1.43 (m, H-9), 1.42 (m, Hb-16), 1.41 (m, Hb-6), 1.40 (m, Hb-21), 1.38 (m, Hb-7),
1.32 (m, Hb-11), 1.28 (m, H-5), 1.19 (m, Hb-15), 1.10 (m, Hb-12), 1.04 (s, H3-27), 0.99 (s,
H3-26), 0.97 (s, H3-25), 0.81 (dd, J ¼ 12.5, 12.5 Hz, Hb-1), 0.74 (s, H3-24); 13C NMR
(CD3OD, 125 MHz) dC: 180.3 (C-28), 152.0 (C-20), 110.2 (C-29), 106.2 (C-10), 88.2 (C-3),
74.6 (C-30), 72.9 (C-20), 70.1 (C-40), 68.2 (C-2), 67.8 (C-50), 63.9 (C-23), 57.6 (C-17), 51.9 (C-
9), 50.5 (C-18), 48.5 (C-19), 48.0 (C-5), 47.4 (C-1), 45.2 (C-4), 43.7 (C-14), 41.9 (C-8), 39.6
(C-13), 38.8 (C-10), 38.2 (C-22), 34.9 (C-7), 33.4 (C-16), 31.8 (C-21), 30.8 (C-15), 26.8 (C-
12), 22.3 (C-11), 19.6 (C-30), 18.6 (C-6), 18.4 (C-25), 16.7 (C-26), 15.1 (C-27), 14.1 (C-24).
3.3.2. Trevepaloside B (2)
ꢃ
25
White amorphous powder, ½aꢂD : þ32.3 (c 0.1, MeOH); HR-ESI-MS: m/z 817.4132
[M þ Cl]- (calcd. for C41H66O1435Cl, 817.4141), m/z 827.4421 [M þ HCOO]- (calcd. for
1
C42H67O16, 827.4429); H NMR (CD3OD, 500 MHz) dH: 5.52 (d, J ¼ 8.5 Hz, H-1ʺ), 4.75 (s,
Ha-29), 4.63 (s, Hb-29), 4.30 (d, J ¼ 7.5 Hz, H-10), 3.93 (dd, J ¼ 2.0, 12.5 Hz, Ha-50), 3.85 (br
d, J ¼ 12.0 Hz, Ha-6ʺ), 3.84 (br s, H-40), 3.80 (ddd, J ¼ 4.5, 9.5 Hz, 12.0, H-2), 3.72 (dd,
J ¼ 4.0, 12.0 Hz, Hb-6ʺ), 3.70 (d, J ¼ 11.5 Hz, Ha-23), 3.64 (br d, J ¼ 12.5 Hz, Hb-50), 3.60
(dd, J ¼ 7.5, 9.5 Hz, H-20), 3.53 (dd, J ¼ 3.5, 9.5 Hz, H-30), 3.47 (m, H-5ʺ ), 3.46 (d,
J ¼ 9.5 Hz, H-3), 3.41 (t, J ¼ 9.0 Hz, H-4ʺ ), 3.40 (t, J ¼ 9.0 Hz, H-3ʺ ), 3.34 (dd, J ¼ 8.5,
9.0 Hz, H-2ʺ), 3.28 (d, J ¼ 11.5 Hz, Hb-23), 3.02 (m, H-19), 2.37 (m, Ha-20), 2.34 (m, H-13),
2.08 (dd, J ¼ 4.5, 12.0 Hz, Ha-1), 2.00 (m, Ha-22), 1.94 (m, Ha-16), 1.76 (m, Ha-12), 1.72 (s,
H3-30), 1.68 (dd, J ¼ 11.0, 11.0 Hz, H-18), 1.61 (m, Ha-15), 1.56 (m, Ha-7), 1.50 (m, Ha-11),
1.49 (m, Ha-6, Hb-22), 1.47 (m, Hb-20), 1.42 (m, Ha-9), 1.40 (m, Hb-6), 1.39 (m, Hb-16),
1.37 (m, Hb-7), 1.33 (m, Hb-11), 1.28 (m, H-5), 1.19 (m, Hb-15), 1.10 (m, Hb-12), 1.04 (s,
H3-27), 0.98 (s, H3-26), 0.97 (s, H3-25), 0.82 (dd, J ¼ 12.0, 12.0 Hz, Hb-1), 0.74 (s, H3-24);
13C NMR (CD3OD, 125 MHz) dC: 176.1 (C-28), 151.7 (C-20), 110.3 (C-29), 106.2 (C-10),
95.2 (C-1ʺ), 88.2 (C-3), 78.7 (C-3ʺ), 78.3 (C-5ʺ), 74.6 (C-30), 74.0 (C-2ʺ), 72.9 (C-20), 71.1 (C-

NATURAL PRODUCT RESEARCH
7
4ʺ), 70.0 (C-40), 68.2 (C-2), 67.8 (C-50), 63.9 (C-23), 62.4 (C-6ʺ), 57.9 (C-17), 51.9 (C-9),
50.6 (C-18), 48.3 (C-19), 48.0 (C-5), 47.4 (C-1), 45.2 (C-4), 43.6 (C-14), 42.0 (C-8), 39.3 (C-
13), 38.8 (C-10), 37.5 (C-22), 34.8 (C-7), 32.8 (C-21), 31.4 (C-16), 30.7 (C-15), 26.7 (C-12),
22.2 (C-11), 19.5 (C-30), 18.7 (C-6), 18.4 (C-25), 16.7 (C-26), 15.1 (C-27), 14.1 (C-24).
3.3.3. Trevepaloside C (3)
ꢃ
25
White amorphous powder; ½aꢂD : þ18.4 (c 0.1, MeOH); HR-ESI-MS: m/z 949.4556
[M þ Cl]- (calcd. for C46H74O1835Cl, 949.4564); m/z 959.4859 [M þ HCOO]- (calcd. for
1
C47H75O20, 959.4852); H NMR (CD3OD, 500 MHz) dH: 5.42 (d, J ¼ 8.0 Hz, H-1ʺ), 5.27 (br
s, H-12), 4.61 (d, J ¼ 8.0 Hz, H-1000), 4.28 (d, J ¼ 7.5 Hz, H-10), 3.85 (br s, H-40), 3.83 (br d,
J ¼ 11.5 Hz, Ha-5000), 3.82 (ddd, J ¼ 4.0, 10.0, 12.0 Hz, H-2), 3.81 (br d, J ¼ 12.0 Hz, Ha-6ʺ),
3.72 (d, J ¼ 11.5 Hz, Ha-23), 3.69 (dd, J ¼ 4.5, 12.0 Hz, Hb-6ʺ), 3.66 (t, J ¼ 9.5 Hz, H-3ʺ),
3.61 (dd, J ¼ 2.0, 12.0 Hz, Ha-50), 3.60 (dd, J ¼ 8.0, 9.5 Hz, H-2ʺ), 3.57 (dd, J ¼ 7.5, 9.5 Hz,
H-20), 3.51 (dd, J ¼ 3.0, 9.5 Hz, H-30), 3.50 (br d, J ¼ 12.0, Hb-50), 3.48 (d, J ¼ 10.0, H-3),
3.44 (m, H-4000), 3.42 (t, J ¼ 9.5, H-4ʺ), 3.38 (m, H-5ʺ), 3.34 (dd, J ¼ 9.0, 9.0 Hz, H-3000), 3.29
(d, J ¼ 11.5 Hz, Hb-23), 3.22 (dd, J ¼ 8.0, 9.0 Hz, H-2000), 3.19 (dd, J ¼ 11.5, 11.5 Hz, Hb-5000),
2.26 (d, J ¼ 11.5 Hz, H-18), 2.07 (m, Ha-16), 2.06 (dd, J ¼ 4.0, 12.0 Hz, Ha-1), 2.03 (m, Ha-
11), 2.00 (m, Ha-15), 1.98 (m, Hb-11), 1.80 (m, Hb-16), 1.72 (m, Ha-22), 1.69 (m, Hb-22),
1.68 (m, Ha-6), 1.62 (m, Ha-7), 1.65 (m, H-9), 1.53 (m, Ha-21), 1.40 (m, H-19), 1.38 (m, Hb-
21), 1.36 (m, Hb-6), 1.33 (m, H-5), 1.30 (m, Hb-7), 1.15 (s, H3-27), 1.08 (s, H3-25), 1.04 (m,
Hb-15), 1.00 (m, H-20), 0.99 (d, 6.0, H3-30), 0.92 (d, J ¼ 6.0 Hz, H3-29), 0.87 (dd, J ¼ 12.0,
12.0Hz, Hb-1), 0.85 (s, H3-26), 0.78 (s, H3-24); 13C NMR (CD3OD, 125MHz) dC: 177.9 (C-28),
139.3 (C-13), 126.8 (C-12), 106.2 (C-10), 105.6 (C-1000), 93.8 (C-1ʺ), 88.3 (C-3), 80.6 (C-2ʺ),
78.4 (C-3ʺ), 78.4 (C-5ʺ), 77.9 (C-3000), 75.8 (C-2000), 74.5 (C-30), 72.9 (C-20), 71.1 (C-4000), 70.8
(C-4ʺ), 70.0 (C-40), 68.0 (C-2), 67.8 (C-50), 67.0 (C-5000), 64.0 (C-23), 62.4 (C-6ʺ), 54.0 (C-18),
49.4 (C-17), 48.8 (C-9), 47.7 (C-5), 47.3 (C-1), 45.1 (C-4), 43.2 (C-14), 41.0 (C-8), 40.3 (C-19),
40.2 (C-20), 38.5 (C-10), 37.3 (C-22), 33.6 (C-7), 31.7 (C-21), 29.6 (C-15), 24.9 (C-16), 24.5
(C-11), 24.2 (C-27), 21.6 (C-30), 18.7 (C-6), 17.9 (C-25), 17.9 (C-26), 17.7 (C-29), 14.5 (C-24).
4. Conclusions
Three new triterpene saponins belonging lupane-type (compounds 1 and 2) and
ursane-type (compound 3) were obtained from the leaves of Trevesia palmata. Their
structures were elucidated by analysis of HR-ESI-MS, 1D, and 2D NMR spectra.
Pentacyclic triterpenes 1–3 contained 2,3,23-trioxygenated groups which were
uncommonly found in the nature. Therefore, compounds 1–3 would be useful as
chemical markers for identification or quality control of T. palmata medicinal mater-
ial. On the other hand, compounds 1–3 weakly inhibited NO production in LPS
stimulated BV2 cells with their inhibitory rates of 17.4 1.8%, 33.1 1.2%, and
11.7 2.2%, respectively.
Disclosure statement
The authors declare no conflict of interest.

8
P. H. YEN ET AL.
Funding
This research is funded by Vietnam National Foundation for Science and Technology
Development (NAFOSTED) under grant number 104.01-2017.08.
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