Jaspreet K. Sihraa,
Moses K. Langatab,
Neil R. Crouchbc,
Jean-Marc Nuzillardd,
Bertrand Plainchontd and
Dulcie A. Mulholland*ab
aDepartment of Chemistry, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, Surrey, UK. E-mail: d.mulholland@surrey.ac.uk; Tel: +44 (0)1483686751
bSchool of Chemistry and Physics, University of KwaZulu-Natal, Durban, 4041, South Africa
cBiodiversity Economy Unit, South African National Biodiversity Institute, PO Box 52099, Berea Road 4007, Durban, South Africa
dUniversité de Reims Champagne-Ardenne, Institut de Chimie Moléculaire de Reims, CNRS UMR 7312, SFR CAP-Santé, BP 1039, 51687 Reims Cedex 02, France
First published on 8th March 2017
The bulbs of Eucomis bicolor (Hyacinthoideae) yielded fourteen novel natural compounds, including (17S)-3-oxo-24,25,26,27,28-pentanorlanost-8-en-23,17α-olide, whose structure was determined using the logic for structure determination program, and nine novel lanosterol glycosides. Compounds were screened against the NCI-59 cancer cell panel but showed limited activity.
The HREIMS of compound 1 showed a [M + Na]+ peak at m/z 407.2570 indicating a molecular formula of C25H36O3 and the presence of a pentanortriterpenoid. The IR spectrum showed peaks for lactone and keto group carbonyl stretches respectively at 1767 and 1708 cm−1. The 1H, 13C, 1H–1H COSY, 1H–13C HSQC, and 1H–13C HMBC spectral data were used as input for the automatic structure elucidation software LSD.21,22 The corresponding data file is available as ESI (S.3†). The carbon atoms were numbered in the decreasing order of their 13C NMR chemical shift and the hydrogen atoms were numbered so that a carbon and a hydrogen atom that are bound together have their corresponding resonances bearing the same number, according to the HSQC spectrum. The oxygen atom of the keto group was numbered 26, those from the lactone group were given the numbers 27 (sp2) and 28 (sp3). The assignment of the number of attached hydrogen atoms attached to each carbon atom by means of the J-modulated HSQC spectrum led to an overall number of carbonated hydrogens of 36, thus leaving no possibility for the presence of a hydroxy group. Carbons resonances at 213.1, 177.1, 135.8, and 133.1 we produced by sp2 hybridized carbon atoms, while the one at 98.4 must be sp3 and bound to O-28. The HSQC and HMBC spectra were recorded with a resolution in the 13C domain that was sufficient to avoid any ambiguity on peak positions in this domain. However, peak overlapping in the 1H domain led to the existence of several HMBC correlations for which the interpretation was ambiguous and considered as such by the LSD algorithm. The COSY spectrum identified the two methyl–methine bonds of the molecule and four other carbon–carbon bonds.
The carbons of the singlet methyl groups were also forced to be bonded to quaternary carbons. These constraints and the correlation data produced a single planar structure solution when processed by the LSD software. The NOESY spectrum showed correlations between the 3H-18 and 3H-19, H-20 and 3H-21 resonances, between the 3H-19/H-4 resonances and between the 3H-28/H-5 and 3H-30/H-5 resonances and between the 3H-21/H-12α resonance. Confirming that the C-21 methyl group was in the alpha orientation. Thus compound 1 was identified as (17S)-24,25,26,27,29-pentanor-3-oxo-lanost-8-en-23,17α-olide. This compound would arise from a Michael-type addition of the oxygen of a C-23 hydroxy group oxygen to C-17 of a ring D α,β-unsaturated system (as seen in 4) followed by the oxidative cleavage of the lanostane C-23/C-24 bond, to yield the pentanortriterpenoid structure.
Compound 2 was isolated in very small amounts, but in larger amounts as its tri-acetyl derivative, 2Ac, after acetylation of a complex mixture. The acetate was identified as (17S)-24,25,26,27-tetranor-3β,28,29-triacetoxy-lanost-8-en-23,17α-olide, 2Ac, hence compound 2 was the novel (17S)-24,25,26,27-tetranor-3β,28,29-trihydroxy-lanost-8-en-23,17α-olide. The HREIMS of compound 2Ac, showed a [M + Na]+ peak at m/z 581.3096 for C32H46O8Na, which indicated a molecular formula of C26H40O5 for 2.
Compound 2Ac differed from 1 in the structure of ring A. The 1H NMR spectrum of 2Ac showed that the 3-keto group had been replaced by an acetoxy group with the H-3α resonance occurring at δ 4.89 (dd, J = 11.60, 4.10). The corresponding C-3 resonance (δ 74.0) showed correlations in the HMBC spectrum with two sets of oxymethylene proton resonances (2H-28, δ 4.04, 4.27 ea d, J = 12.00; 2H-29, δ 4.31, 4.40 ea d, J = 12.20). The 13C NMR spectrum displayed three acetyl carbonyl carbon resonances at δC 170.4, δC 170.9 and δC 171.2 and HMBC correlations enabled confirmation that acetylation had taken place at C-3, C-28 and C-29.
The NOESY spectrum showed similar correlations as in 1, and showed additional correlations between the H-5/H-3α/2H-28 resonances, confirming the configuration of the substituent at C-3 as β.
The HREIMS of 3 showed a [M + Na]+ ion at m/z 507.3078 corresponding to the molecular formula C30H44O5 for the compound. The FTIR spectrum showed absorption bands at 1772 and 1701 cm−1 consistent with a γ-lactone and keto group respectively.23 The keto group occurred at C-3 (δC 221.0) and the HMBC spectrum showed correlations between both the C-3 and C-5 (δC 52.1) resonances and two H-29 oxymethylene (δH 3.24, d, J = 11.20 Hz; δH 4.02, d, J = 11.20 Hz), and the 3H-28 (δH 1.28) proton resonances. The eight carbon sidechain was modified into a spiro-γ-lactone as in compounds previously reported from Chionodoxa luciliae Boiss.23 The C-17 resonance (δC 98.7) was seen to correlated with the 3H-18 (δH, H-20 (δH 2.28), 3H-21 (d, δH 1.05) and two H-22 (δH 1.78 and δH 2.72) resonances in the HMBC spectrum, and the C-23 (δC 113.4) resonance showed correlations seen with the H-20, two H-22, two H-24 (δH 2.00, δH 2.47) and H-25 (δH 2.97) resonances. The C-27 lactone carbonyl resonance (δC 179.0) showed correlations with the two H-24, H-25 and 3H-26 (δH 1.26, d, J = 7.40 Hz) resonances. The molecular formula indicated two rings in the sidechain due to the C-17,23 ether and 27,23-lactone. The NOESY spectrum showed correlations between the 3H-19/3H-18 and 3H-19/H-29 (δH 4.02) resonances and H-5/3H-28 resonances as expected. Correlations seen between the 3H-18/H-16β/H-20 resonances confirmed the configuration at C-17 as S and that H-20 was β. Correlations seen between the 3H-26 and two H-22 resonances confirmed the configuration at C-23 as S. Compound 3 was identified as (17S,23S)-17α,23-epoxy-29-hydroxylanosta-8-en-3-on-27,23-olide.
The HREIMS of compound 4 showed a [M + Na]+ peak at m/z 497.3225 which corresponded to a molecular formula of C29H46O5 for the compound. The oxymethine C-3 resonance (δC 80.8), showed correlations in the HMBC spectrum with the H-5 (J = 10.9 Hz 1.18), the 3H-28 (δH 1.26) and the two H-29 (δH 3.35, d, δH 4.23, d, both J = 10.9 Hz) resonances, indicating the presence of an oxymethylene group at C-29 as in 3. Correlations seen in the NOESY spectrum between the H-3 (δH 3.47, dd, J = 9.90, 4.10 Hz), 3H-28 and H-5 resonances, confirmed that H-3 was α, and a correlation was noted between the two H-29 and 3H-19 resonance (δH 0.95). The structure of ring D differed from that of the previous compounds having an α,β-unsaturated ring ketone, showed by resonances at δC 186.6 (C-17), δC 123.0 (C-16) and δC 210.1 (C-15).24 The C-17 resonance showed correlations in the HMBC spectrum with the H-16 (δH 5.61), 3H-18 (δH 0.94), H-20 (δH 2.80), 3H-21 (δH 1.13, d, J = 6.9 Hz), and two H-22 (δH 1.64 and δH 1.73) resonances, and the C-15 resonance showed correlations with the 3H-30 (δH 1.20) and H-16 resonances. The COSY spectrum showed coupling between the two H-22, and the oxymethine H-23 resonance (δH 3.28), between H-23 and the oxymethine H-24 resonance (δH 3.31) and between the H-24/2H-25 (δH 1.43, 1.59) and 2H-25/3H-26 (δH 0.99, t, J = 7.80) resonances.
The configuration at C-23 of the co-isolated 3 and 10 have been determined unequivocally as S, so it was assumed that if compounds like 4 are their precursors, the configuration at C-23 should be the same (S). An attempt was made to determine the configuration at C-24 of the side chain vic-diol employing acyclic 1,2-diol complexation with [Mo2(OAc)4] and subsequent CD measurements.25 However, results were inconclusive. Thus 4 was identified as 3β,23S,24ε,29-tetrahydroxy-27-norlanosta-8-16-diene-15-one.
The HREIMS of compound 5 showed [M + Na]+ at m/z 495.3071 which corresponded to the molecular formula C29H44O5 for the compound. The C-24 hydroxyl group in compound 4 was oxidised to a keto group (δC 212.6) in compound 5. Compound 5 was identified as 3β,23S,29-trihydroxy-27-norlanosta-8-16-diene-15,24-dione, which has been prepared previously as a derivative of eucosterol but incomplete 1H NMR and no13 NMR data was provided.24
The HRMS of compound 6Ac gave an [M + Na]+ ion at m/z 909.4254 indicating the molecular formula of C47H66O16 for this compound. The FTIR spectrum for this compound showed a broad absorption at 1749 cm−1 for the carbonyl groups, 2937 cm−1 and 2868 cm−1 for the aliphatic CH stretches and 1222 cm−1 for a C–O stretch. The 13C NMR spectrum indicated that compound 6Ac was the acetylated form of the C-3β, β-D-glucoside derivative of compound 5. The 1H NMR spectrum showed acetylation had occurred at the C-29 and the C-23 hydroxy groups by downfield shifts of the H-23 and two H-29 proton resonances compared to those of 5 (Tables 1 and 3). The C-3 (δC 90.1) resonance showed a correlation in the HMBC spectrum with an anomeric proton resonance at δH 4.54 and the COSY and HSQC spectra enabled assignment of the sugar resonances. The correlations seen in the NOESY spectrum between H-1′/H-3′ and H-2′/H-4′ resonances, and the coupling constants J1′,2′ (8.0 Hz) and J3′,4′ (9.6 Hz) confirmed that the sugar present was acetylated β-D-glucose.26 Thus, compound 6Ac is 23S,29-diacetoxy-3β-[2′,3′,4′,6′-tetra-O-acetyl-O-β-D-glucopyranoside]-27-norlanosta-8,16-diene-15,24-dione.
No | 1 | 2 | 2Ac | 3 | 4 | 5 |
---|---|---|---|---|---|---|
a Superimposed resonances, J not clear. | ||||||
1α | 1.57 | 1.21 | 1.38 | 1.98 | 1.22 | 1.20 |
1β | 2.07 | 1.74 | 1.82 | 1.76 | 1.75 | 1.76 |
2α | 2.34 | 1.78 | 1.73 | 2.46 | 1.78 | 1.75 |
2β | 2.44 | 1.66 | 1.83 | 2.58 | 1.82 | 1.81 |
3 | — | 3.76a | 4.89, dd, J = 11.60, 4.10 | — | 3.47, dd, J = 9.90, 4.10 | 3.44, dd, J = 12.00, 4.60 |
4 | 2.28 | — | — | — | — | — |
5 | 1.40 | 1.22 | 1.64 | 1.86 | 1.18, m | 1.18, m |
6α | 1.46 | 1.48 | 1.63 | 1.50 | 1.38 | 1.36 |
6β | 1.78 | 1.77 | 1.75 | 1.69 | 1.82 | 1.83 |
7α | 2.04 | 1.98 | 2.03 | 2.05 | 2.48 | 2.47 |
7β | 2.11 | 1.98 | 2.05 | 2.56 | 2.26 | |
11α | 2.13 | 1.99 | 2.17 | 2.07 | 2.13 | 2.13 |
11β | 2.21 | 1.99 | 2.07 | 2.13 | 2.13 | |
12α | 1.54 | 1.49 | 1.52 | 2.20 | 1.70 | 1.72 |
12β | 2.25 | 2.20 | 2.26 | 2.20 | 2.10 | 2.11 |
15α | 1.45 | 1.42 | 1.45 | 1.38 | — | — |
15β | 1.75 | 1.72 | 1.76 | 1.68 | — | — |
16α | 2.12 | 2.07 | 2.14 | 1.84 | 5.48 s | 5.61, s |
16β | 2.72, d, J = 6.40 | 2.76, d, J = 6.40 | 2.73 | 2.50 | — | — |
18 | 1.00, 3H, s | 0.94, 3H, s | 0.96, s | 0.92, s | 0.94, s | 0.94, s |
19 | 1.20, 3H, s | 0.96, 3H, s | 1.06, s | 1.05, s | 0.95, s | 0.95, s |
20 | 2.49 | 2.47 | 2.50 | 2.28 | 2.80 | 2.87 |
21 | 1.13, 3H, d, J = 6.80 | 1.10, d, J = 6.60 | 1.14, d, J = 6.60 | 1.05, d, J = 6.80 | 1.13, d, J = 6.90 | 1.13, d, J = 6.50 |
22α | 2.75, d, J = 6.40 | 2.03 | 2.04 | 2.72, dd, J = 6.70, 13.50 | 1.64 | 1.49 |
22β | 2.03 | 2.72 | 2.77, d, J = 6.20 | 1.78 | 1.73 | 2.04 |
23 | — | — | — | — | 3.28, bta | 3.97, d, J = 11.30 |
24α | — | — | — | 2.47 | 3.31, ma | — |
24β | — | — | 2.00 | — | — | |
25α | — | — | — | 2.97 | 1.43a | 2.44a |
25β | — | — | — | — | 1.59a | 2.53a |
26 | — | — | — | 1.26, d, J = 7.40 | 0.99, t, J = 7.80 | 1.11, t, J = 7.40 |
28A | 1.02, 3H, d, J = 6.7 | 3.74a | 4.04, d, J = 12.00 | 1.26 | 1.26, s | 1.26, s |
28B | — | 4.37, d, J = 11.60 | 4.27, d, J = 12.00 | — | — | — |
29A | — | 3.81a | 4.31, d, J = 12.20 | 3.45, d, J = 11.20 | 3.38, d, J = 10.90 | 3.35, d, J = 10.60 |
29B | — | 4.14, d, J = 11.60 | 4.40, d, J = 12.20 | 4.02, d, J = 11.20 | 4.23, d, J = 10.90 | 4.23, d, J = 10.60 |
30 | 1.10, 3H, s | 1.09, s | 1.11, s | 1.05, s | 1.20, s | 1.21, s |
COCH3 | — | — | 2.2, 2.06 s, 2.08 s | — | — | — |
No | 1 | 2 | 2a | 3 | 4 | 5 |
---|---|---|---|---|---|---|
1 | 37.1 CH2 | 35.3 CH2 | 35.3 CH2 | 35.6 CH2 | 35.2 CH2 | 35.2 CH2 |
2 | 38.0 CH2 | 27.6 CH2 | 23.9 CH2 | 29.0 CH2 | 28.2 CH2 | 28.2 CH2 |
3 | 213.1 C | 77.9 CH | 74.0 CH | 221.0 C | 80.9 CH | 80.8 CH |
4 | 45.2 CH | 46.1 C | 44.1 C | 51.3 C | 43.0 C | 42.9 C |
5 | 49.7 CH | 47.5 CH | 44.5 CH | 52.1 CH | 51.2 CH | 51.2 CH |
6 | 22.1 CH2 | 18.8 CH2 | 19.4 CH2 | 19.1 CH2 | 18.4 CH2 | 18.1 CH2 |
7 | 25.4 CH2 | 26.3 CH2 | 26.8 CH2 | 26.2 CH2 | 27.4 CH2 | 27.7 CH2 |
8 | 135.8 C | 134.8 C | 135.2 C | 132.6 C | 133.6 C | 133.4 C |
9 | 133.1 C | 134.6 C | 134.5 C | 136.3 C | 135.8 C | 136.1 C |
10 | 36.8 C | 36.9 C | 37.1 C | 37.0 C | 37.5 C | 37.6 C |
11 | 21.5 CH2 | 20.8 CH2 | 20.7 CH2 | 21.0 CH2 | 20.6 CH2 | 20.4 CH2 |
12 | 24.7 CH2 | 24.6 CH2 | 24.6 CH2 | 25.0 CH2 | 23.3 CH2 | 23.2 CH2 |
13 | 50.9 C | 50.8 C | 50.9 C | 48.7 C | 51.2 C | 51.2 C |
14 | 49.0 C | 49.0 C | 49.0 C | 50.7 C | 57.3 C | 57.3 C |
15 | 31.5 CH2 | 31.5 CH2 | 31.5 CH2 | 31.9 CH2 | 210.2 C | 210.1 C |
16 | 39.3 CH2 | 39.4 CH2 | 39.3 CH2 | 37.3 CH2 | 123.0 CH | 123.0 CH |
17 | 98.4 C | 98.6 C | 98.4 C | 98.7 C | 186.6 C | 185.8 C |
18 | 18.2 CH3 | 17.9 CH3 | 18.3 CH3 | 18.9 CH3 | 28.8 CH3 | 28.8 CH3 |
19 | 17.7 CH3 | 19.8 CH3 | 19.3 CH3 | 19.9 CH3 | 19.7 CH3 | 19.8 CH3 |
20 | 41.9 CH | 41.9 CH | 41.9 CH | 44.0 CH | 30.1 CH | 30.2 CH |
21 | 17.9 CH3 | 17.9 CH3 | 17.9 CH3 | 18.8 CH3 | 21.7 CH3 | 21.7 CH3 |
22 | 39.2 CH2 | 39.2 CH2 | 39.2 CH2 | 32.0 CH2 | 39.4 CH2 | 39.6 CH2 |
23 | 177.1 C | 177.4 C | 177.4 C | 113.4 C | 71.9 CH | 74.3 CH |
24 | — | — | — | 45.1 CH2 | 76.9 CH | 212.6 C |
25 | — | — | — | 35.8 CH | 26.7 CH2 | 31.4 CH2 |
26 | — | — | — | 15.1 CH3 | 10.2 CH3 | 7.8 CH3 |
27 | — | — | — | 179.0 C | — | — |
28 | 11.7 CH3 | 63.9 CH2 | 62.7 CH2 | 22.1 CH3 | 22.5 CH3 | 22.5 CH3 |
29 | — | 71.4 CH2 | 63.8 CH2 | 66.1 CH2 | 64.5 CH2 | 64.5 CH2 |
30 | 25.9 CH3 | 25.8 CH3 | 25.7 CH3 | 26.2 CH3 | 29.6 CH3 | 29.6 CH3 |
1-OAc | — | — | 21.4 CH3 | — | — | — |
2-OAc | — | — | 21.3 CH3 | — | — | — |
3-OAc | — | — | 21.2 CH3 | — | — | — |
1-OAc | — | — | 170.4 C | — | — | — |
2-OAc | — | — | 170.9 C | — | — | — |
3-OAc | — | — | 171.2 C | — | — | — |
No | 6Ac | 7Ac | 8Ac | 9Ac | 10Ac | 11Ac | 12Ac | 13Ac | 14Ac |
---|---|---|---|---|---|---|---|---|---|
a Overlapped signals. | |||||||||
1α | 1.21 | 1.21 | 1.21 | 1.25 | 1.20 | 1.24 | 1.22 | 1.23 | 1.22 |
1β | 1.82 | 1.87 | 1.79 | 1.86 | 1.79 | 1.85 | 1.75 | 1.81 | 1.82 |
2α | 1.76 | 1.76 | 1.93 | 2.00 | 1.99 | 1.99 | 1.80 | 1.74 | 2.27 |
2β | 1.92 | 1.90 | 2.06 | 2.07 | 1.97 | 1.90 | 2.65 | ||
3 | 3.20, dd, J = 4.00, 11.80 Hz | 3.22, dd, J = 3.20, 12.30 | 3.21, dd, J = 4.10, 11.90 | 3.21, dd, J = 4.00, 12.20 | 3.19, dd, J = 4.00, 11.60 | 3.20 | 3.19, dd, J = 4.00, 11.80 | 3.21, dd, J = 4.30, 12.00 | 3.16, dd, J = 4.30, 12.00 |
4 | — | — | — | — | — | — | — | — | — |
5 | 1.17 | 1.15 | 1.14 | 1.17 | 1.16 | 1.12 | 1.14 | 1.14 | 1.09 |
6α | 1.56 | 1.55 | 1.60 | 1.60 | 1.61 | 1.61 | 1.85 | 1.54 | 1.56 |
6β | 1.88 | 1.88 | 1.78 | 1.83 | 1.80 | 1.81 | 1.98 | 1.84 | 1.83 |
7α | 2.42 | 2.42 | 1.73 | 1.75 | 1.76 | 1.77 | 1.78 | 1.75 | 1.70 |
7β | 2.58 | 2.57 | 1.91 | 1.92 | 1.93 | 1.89 | 1.92 | 1.91 | 1.86 |
11 | 2.15 | 2.16 | 2.07 | 2.07 | 1.98 | 2.10 | 2.04 | 2.11 | 1.92 |
12α | 1.65 | 1.65 | 2.17 | 2.16 | 1.43 | 1.46 | 1.99 | 1.60 | 1.58 |
12β | 2.13 | 2.11 | 2.22 | 2.22 | 2.08 | 2.34 | 2.34 | ||
15α | — | — | 1.32 | 1.37 | 1.35 | 1.38 | — | — | — |
15β | 1.66 | 1.69 | 1.66 | 1.68 | — | — | — | ||
16α | 5.60, s | 5.60, s | 1.79 | 1.81 | 1.63 | 1.70 | 2.22, d, J = 19.2 | 2.22, d, J = 19.20 | 2.20, d, J = 19.20 |
16β | 2.50 | 2.52 | 1.99 | 2.00 | 2.77, d, J = 19.2 | 2.77, d, J = 19.20 | 2.76 d, J = 19.20 | ||
18 | 0.84, s | 0.85, s | 0.90 | 0.90, s | 0.91 | 0.88, s | 0.94, s | 0.94 | 0.93, s |
19 | 1.02, s | 1.02, s | 1.00 | 0.99, s | 1.00 | 0.93, s | 1.02, s | 1.02, s | 1.02, s |
20 | 2.67 | 2.67 | 2.24 | 2.28 | 2.18 | 2.21 | 2.29 | 2.26 | 2.24 |
21 | 1.15, d, J = 7.20 | 1.15, d, J = 6.60 | 1.05, d, J = 6.90 | 1.07, d, J = 6.70 | 1.06, d, J = 7.70 | 1.13, d, J = 6.50 | 1.11, d, J = 6.70 | 1.11, d, J = 6.80 | 1.12, d, J = 6.80 |
22α | 1.84 | 1.85 | 1.76 | 1.79 | 1.81 | 1.84 | 1.89 | 1.92, | 1.86 |
22β | 2.03 | 2.06 | 2.71, dd, J = 6.50, 13.90 | 2.74 | 1.99 | 2.00 | 1.94 | 1.99 | 1.99 |
23 | 4.86, dd, J = 2.70, 10.50 Hz | 4.87, dd, J = 3.00, 10.90 | — | — | 4.56a | 4.54 | 4.69, dd, J = 8.70, 10.40 | 4.68, dd, J = 8.70, 9.90 | 4.67, dd, J = 9.00, 9.40 |
24α | — | — | 1.99 | 2.03 | — | — | — | — | — |
24β | 2.47 | 2.50 | |||||||
25α | 2.45 | 2.41 | |||||||
25β | 2.51 | 2.57 | 2.94 | 2.98 | 2.56, q, J = 7.30 | 2.57, q, J = 7.40 | 2.48, q, J = 7.00 | 2.49, q, J = 7.30 | 2.48, q, J = 7.30 |
26 | 1.07, t, J = 7.30 Hz | 1.07, t, J = 6.50 | 1.25, d, J = 7.10 | 1.28, d, J = 6.70 | 1.08, t, J = 7.30 | 1.11, t, J = 7.40 | 1.07, t, J = 7.20 | 1.07, t, J = 7.30 | 1.07, t, J = 7.30 |
27 | — | — | — | — | — | — | — | — | — |
28 | 1.09, s | 1.09, s | 1.07 | 1.10, s | 1.08 | 1.07, s | 1.08, s | 1.08, s | 1.05, s |
29α | 4.17a | 4.16a | 4.16a | 4.16a | 4.17a | 4.16 | 4.23a | 4.16, d, J = 11.80 | 4.15, d, J = 11.90 |
29β | 4.24a | 4.25a | 4.23a | 4.25a | 4.24a | 4.25 | 4.15a | 4.24, d, J = 11.80 | 4.21, d, J = 11.90 |
30 | 1.19, s | 1.19, s | 1.00 | 1.01, s | 1.26 | 1.21, s | 1.37, s | 1.37, s | 1.35, s |
Glu 1′ | 4.54, d, J = 8.00 Hz | 4.53, d, J = 8.00 | 4.54, d, J = 8.00 | 4.52, d, J = 8.20 | 4.56, d, J = 8.20 | 4.52, d, J = 8.10 | 4.54, d, J = 7.90 | 4.52, d, J = 8.70 | 4.36, d, J = 8.10 |
2′ | 4.98, dd, J = 9.60, 8.00 Hz | 4.95, dd, J = 9.70, 8.00 | 5.00, dd, J = 8.20, 9.40 Hz | 4.95, dd, J = 8.20, 9.70 | 5.00, dd, J = 8.10, 9.50 | 4.90 | 5.00, dd, J = 8.10, 9.80 | 4.94, dd, J = 8.20, 9.40 | 4.94, dd, J = 8.10, 9.60 |
3′ | 5.18, t, J = 9.60 Hz | 5.19, t, J = 9.70 | 5.19, t, J = 9.50 | 5.18, t, J = 9.70 | 5.19, t, J = 9.40 | 5.18 | 5.18, t, J = 9.80 | 5.17, t, J = 9.40 | 3.78, t, J = 9.30 |
4′ | 5.06, t, J = 9.60 Hz | 4.93, t, J = 9.70 | 5.07, t, J = 9.70 Hz | 4.93, t, J = 9.70 | 5.06, t, J = 9.60 | 4.93 | 5.05, t, J = 9.80 | 5.06, t, J = 9.50 | 4.80, t, J = 9.30 |
5′ | 3.68, m | 3.68, m | 3.66, m | 3.69, m | 3.66, m | 3.68 | 3.65, m | 3.66, m | 3.60, m |
6′A | 4.12, m | 3.65, m | 4.23a | 3.65, m | 4.22a | 3.63 | 4.13 | 3.65, m | 3.62, m |
6′B | 4.20, m | 3.84, m | 4.12a | 3.82, m | 4.12a | 3.82 | 4.22 | 3.82, m | 3.79, m |
Arab 1′′ | 4.50, d, J = 6.60 | — | 4.50, d, J = 6.70 | — | 4.49, d, J = 6.10 | — | 4.49, d, J = 6.80 | 4.48, d, J = 6.60 | |
2′′ | 5.16, dd, J = 6.60, 8.80 | — | 5.14, dd, J = 6.70, 9.00 | — | 5.15 | — | 5.14, dd, J = 6.80, 8.90 | 5.13, dd, J = 6.60, 8.80 | |
3′′ | 5.03, dd, J = 3.70, 8.80 | — | 5.03, dd, J = 3.60, 9.07 | — | 5.03 | — | 5.01, dd, J = 3.50, 8.90 | 5.00, dd, J = 3.50, 8.90 | |
4′′ | 5.25, brs | — | 5.25, brs | — | 5.26 | — | 5.28, brs | 5.24, brs | |
5′′α | 4.05 | — | 4.03 | — | 4.03 | — | 4.03, m | 4.01, dd, J = 3.60, 12.90 | |
5′′β | 3.63 | — | 3.62 | — | 3.60 | — | 3.61, dd, J = 3.80, 12.90 | 3.60, m | |
Xyl 1′′′ | — | — | — | — | — | — | 4.53, d, J = 6.20 | ||
2′′′ | 4.75, dd, J = 6.20, 7.80 | ||||||||
3′′′ | — | — | — | — | — | — | 5.03, t, J = 7.80 | ||
4′′′ | — | — | — | — | — | — | 4.85, m | ||
5′′′α | — | — | — | — | — | — | 3.34, dd, J = 7.90, 12.00 | ||
5′′′β | — | — | — | — | — | — | 4.06, dd, J = 4.40, 12.00 | ||
OAc | 2.05, 2.02, 2.12, 2.10, 2.08, 2.02 | 1.98, 2.02, 2.02, 2.04, 2.05, 2.08, 2.12, 2.13 | 2.00, 2.02, 2.02, 2.05, 2.08 | 1.98, 2.02, 2.02, 2.04, 2.04, 2.07, 2.08 | 1.99, 2.02, 2.02, 2.04, 2.08 | 1.98, 2.02, 2.02, 2.04, 2.07, 2.08 | 2.00, 2.02, 2.02, 2.05, 2.08 | 1.98, 2.02, 2.02, 2.04, 2.04, 2.07, 2.08 | 1.98, 2.02, 2.02, 2.04, 2.04, 2.07, 2.08, 2.13, 2.12 |
Compound 7Ac was identified as 23S,29-diacetoxy-3β-[2′,3′,4′-tri-O-acetyl-O-β-D-glucopyranoside-(1′′ → 6′)-2′′,3′′,4′′-tri-O-acetyl-β-D-arabinopyranosyl]-27-norlanosta-8,16-diene-15,24-dione. The HRMS spectrum for compound 7Ac gave a [M + Na]+ ion at m/z 1125.4865 indicating a molecular formula of C56H78O22 for this acetylated compound. The aglycone part of compound was found to be the same as for compounds 5Ac and 6Ac. However, in addition to the acetylated β-D-glucose at C-3β, the molecular formula indicated an additional acetylated pentose sugar and this was confirmed by the 13C NMR spectrum which displayed two characteristic anomeric carbon resonances at δC 102.7 in table (C-1′) and δC 101.1 in table (C-1′′) with corresponding anomeric proton resonances at δH 4.53 (d, J = 8.0 Hz) and δH 4.50 (d, J = 6.6 Hz). The anomeric proton resonance at δH 4.50, assigned as H-1′′, was seen to correlate in the HMBC spectrum to C-6′ of β-D-glucose of C-6′ indicating a 1′′ → 6′ linkage. The COSY and HSQC spectra were again used to assign the pentose sugar resonance sand the NOESY spectrum and coupling constants were used to confirm whether the pentose was xylose or arabinose. The coupling constants of J1′′,2′′ = 6.60 Hz, J,2′′,3′′′ = 8.80 Hz and J3′′,4′′ = 3.70 Hz indicated that H-1′′/H-2′′ and H-2′′′/H-3′′′ are trans–diaxial and that H-3′′ and H-4′′ have an axial–equatorial relationship. Hence, the sugar was identified as β-D-arabinose and this was supported by correlations seen in the NOESY spectrum between the H-1′′/H-3′′, H-3′′/H-4′′, H-4′′/Hβ-5′′ and H-1′′/Hα-5′′ resonances.
Compound 8Ac was identified as (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′,6′-tetra-O-acetyl-O-β-D-glucopyranoside]-lanost-8-en-27,23-olide, the 3β-β-D-glucoside derivative of compound 3. The molecular ion could not be observed in the LCMS spectrum for compound 8Ac, but the structure could be determined from NMR studies. The 13C NMR chemical shifts for the aglycone part were similar to those of compound 3, except that the C-3 keto group carbon was replaced by an oxymethine resonance (δC 90.4) and the C-29 hydroxy group had been acetylated. The HMBC spectrum showed a correlation between the H-3α proton resonances (δH 3.21, d, J = 4.1, 11.9 Hz) and an anomeric carbon resonance (δC 103.2), which corresponded to the proton resonance at δH 4.54 (d, J = 8.0 Hz). The coupling constants and NOESY correlations of the sugar present were the same as those of compound 6Ac, indicating that the sugar present was acetylated β-D-glucose.
Compound 9Ac was identified as (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′-tri-O-acetyl-O-β-D-glucopyranoside-(1′′ → 6′)-2′′,3′′,4′′-tri-O-acetyl-O-β-D-arabinopyranosyl]-lanost-8-en-27,23-olide. The HRMS for compound 9Ac gave a [M + Na]+ ion at m/z 1097.4880, which indicated the molecular formula of C55H78O21 for this compound. The 13C NMR spectrum displayed fifty-five carbon resonances, and showed that the aglycone structure was the same as for 8Ac, but that an extra β-D-arabinose sugar was present and linked as determined for 7Ac.
Compound 10Ac was identified as (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′,6′-tetra-O-acetyl-O-β-D-glucopyranoside]-27-norlanost-8-en-24-one. The LCMS spectrum for compound 10Ac gave a [M]+ ion at m/z 830.4421, which indicated the molecular formula of C45H66O14 for this compound. The aglycone part of the molecule was found to be the 29-acetyl derivative of the co-isolated 15-deoxyeucosterol. The C-17 (δC 97.3) resonance showed correlations in the HMBC spectrum with the 3H-19 (δH 1.00), H-20 (δH 1.26), 3H-21 (δH 1.06, d, J = 7.0 Hz), two H-22 (δH 1.81 and δH 1.99) and H-23 (δH 4.56) resonances. A ketone carbon resonance at δC 213.3 was assigned as C-24 as it showed correlations with the two H-22, H-23, two H-25 (δH 2.56, q, J = 7.3 Hz) and 3H-26 (δH 1.08, t, J = 7.3 Hz) resonances. The H-29 protons occurred as a pair of doublets (δH 4.17, δH 4.24) and H-3 α at δH 3.19 (dd, J = 4.0, 11.6 Hz). The C-3 resonance showed a correlation in the HMBC spectrum with the anomeric proton resonance at δH 4.56. The chemical shifts, coupling constants and correlations seen in the NOESY spectrum of the sugar present were the same as those of the acetylated β-D-glucose in compounds 6Ac and 8Ac. Oxidative cleavage of the C-23/C-24 bond of 10Ac would lead to the γ-lactone structure seen in 1 and 2.
Compound 11Ac was identified as (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′-tri-O-acetyl-O-β-D-glucopyranoside-(1′′ → 6′)-2′′,3′′,4′′-tri-O-acetyl-O-β-D-arabinopyranosyl]-27-norlanost-8-en-24-one. The expected [M + Na]+ peak at m/z 1069.4984 for this compound was not observed in the LCMS spectrum, however, a base peak at m/z 587.1579, which was attributed to the acetylated disaccharide fragment [C23H31O16Na + H]+ was observed. The extra hydrogen is unusual, but was also found in compound 14Ac. It is suggested that this hydrogen comes from the triterpenoid system, solvent or electrospray buffer system. As with compounds 6Ac/7Ac and 8Ac/9Ac, compound 11Ac differed from 10Ac in having an extra acetylated β-D-arabinose group at C-6′. This was confirmed using 2D NMR correlations and 1H NMR coupling constants.
The HRMS spectrum for compound 12Ac, (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′6′-tetra-O-acetyl-O-β-D-glucopyrano-side]-27-norlanost-8-ene-15,24-dione, gave a [M + Na]+ ion at m/z 867.4147, which indicated the molecular formula of C45H64O15 for this compound. 12Ac was the 15-keto derivative of 10Ac. The C-15 (δC 215.6) resonance showed correlations in the HMBC spectrum with the 3H-30 (δH 1.37) and pair of H-16 (2.22, 2.77, ea d, J = 19.2 Hz) proton resonances.
Compound 13Ac was identified as the 15-keto derivative of 11Ac, (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′-tri-O-acetyl-O-β-D-glucopyranoside-(1′′ → 6′)-2′′,3′′,4′′-tri-O-acetyl-O-β-D-arabinopyranosyl]-27-norlanost-8-ene-15,24-dione). The HRMS spectrum gave a [M + Na]+ ion at m/z 1083.4739 which corresponded to the molecular formula of C54H76O21 for this compound. The NMR spectra showed one fewer methylene group but an extra C-15 ketone carbonyl carbon resonance (δC 215.6) which showed correlations in the HMBC spectrum with the 3H-30 (δH 1.37) and two H-16 (δH 2.22 and 2.77, ea d, J = 19.2 Hz) resonances. The identification of the sugars was done as for the previous disaccharides isolated.
Compound 14Ac was identified as the acetylated trisaccharide of eucosterol, (17S,23S)-29-acetoxy-23,17-epoxy-3β-[2′,3′,4′-tri-O-acetyl-O-β-D-glucopyranoside-(1′′ → 6′)-2′′,3′′,4′′-tri-O-acetyl-O-β-D-arabinopyranosyl-(1′′′ → 3′)-2′′′,3′′′,4′′′-tri-O-acetyl-O-β-D-xylopyranosyl]-27-norlanost-8-ene-15,24-dione. The expected [M + Na]+ peak at m/z 1276.5513 for this compound was not observed in the LCMS spectrum. However, a base peak at m/z 803.2235, which was attributed to the acetylated trisaccharide fragment [C32H43O22Na + H]+ was observed, similar to that seen in the MS of compound 11Ac. The 13C NMR spectrum displayed sixty-three carbons resonance and the aglycone part was found to be the same as in compounds 12Ac and 13Ac. The 13C NMR spectrum displayed three anomeric carbon resonances at δC 100.3, δC 101.7 and δC 102.7, which corresponded to the proton resonances at δH 4.48 (d, J = 6.6 Hz), δH 4.53 (d, J = 6.2 Hz) and δH 4.36 (d, J = 8.1 Hz), respectively, confirming that compound 14Ac possessed three sugar groups. The C-3 resonance was seen to correlate in the HMBC spectrum with the resonance at δH 4.36, which was assigned as H-1′. This was used as a starting point to assign the chemical shifts of the first sugar. The COSY and HSQC spectrum enabled all 1H and 13C NMR resonances for the sugar at C-3β to be assigned and the large coupling constants (J1′,2′ = 8.1 Hz, J3′,4′ = 9.30 Hz) confirmed the trans–diaxial relationships between H-1/H-2 and H-3/H-4 indicating the presence of an acetylated β-D-glucose unit. This was supported by correlations seen in the NOESY spectrum between the H-1′ and H-3′, H-1′ and H-5′ and H-2′ and H-4′ resonances.
As in previous compounds, the C-6′ resonance showed a correlation in the HMBC spectrum with the anomeric proton resonance at δH 4.48 (H-1′′) of β-D-arabinose. All resonances for this sugar could be assigned and the coupling constants of J1′′,2′′ = 6.6 Hz and J3′′,4′′ = 3.5 Hz indicated trans–diaxial and axial–equatorial relationships respectively, confirmed by correlations seen in the NOESY spectrum between the H-1′′/H-3′′, H-3′/H-4′′, H-4′′/H-5′′β and between H-1′′/H-5′′α resonances identified the sugar. The C-3′ resonance was seen to correlate with the anomeric proton resonance at δH 4.53 of the pentose sugar in the HMBC spectrum, which was assigned as H-1′′′, indicating the third sugar was linked to β-D-glucose at C-3′. The J1′′′,2′′′ = 6.20 Hz and J3′′′,4′′′ = 7.80 Hz indicated that H-1′′′/H-2′′′ and H-3′′′/H-4′′′ both have trans–diaxial relationships, hence, the sugar was identified as β-D-xylose. This was confirmed by correlations seen in the NOESY spectrum between the H-1′′′/H-3′′′ and H-4′′′/H-2′′′ resonances.
(R)-5,7-Dihydroxy-8-methoxy-3-(4′-methoxybenzyl)-4-chromanone, eucosterol, (17S,23S)-23,17-epoxy-3β,28,29-trihydroxy-27-norlanost-8-en-24-one, 1, 2Ac, 3, 4 and 5 were evaluated against the NCI 60 developmental Therapeutics Program 60 cancer cell line screen at a single dose of 10−5 M. Details of the methodology of NCI-60 Human Tumour Cell Line Screen are described at http://dtp.nci.nih.gov/branches/btb/ivclsp.html. None of the compounds showed sufficient activity to progress to the five-dose assay although 5 showed 72.5% inhibition of the H522 non-small lung cell line. One dose mean graphs for the compounds screened are provided in the ESI (S.5†).
This investigation produced typical Eucomis-type constituents, homoisoflavonoids and lanostane triterpenoid derivatives. The variability of constituents isolated from the Hyacinthaceae has been noted by us previously.4–6 Only two of the compounds isolated in this work had been reported to occur in this species previously, the common homoisoflavonoids 3,5,7-trihydroxy-3-(4′-methoxybenzyl)-4-chromanone7 and 5,7-dihydroxy-3-(4′-methoxybenzyl)-4-chromanone.8 Compounds 3, 8 and 9 had the same spirocyclic triterpenoid skeleton as scillasponin A,10 but instead of being a pentaglycoside, occurred as the free triterpenoid (3) or as the mono- (8) or di-glycosides (9). Compounds 10–14 differed from related compounds isolated previously in that the C-28 methyl group was not oxidised, and the sugars differed. Rhamnopyranosyl sugars found in compounds isolated previously from the Japanese collection9 were not found in this collection from its natural habitat.
The methylene chloride extract yielded (R)-5,7-dihydroxy-8-methoxy-3-(4′-methoxybenzyl)-4-chromanone (6.5 mg), 3,5,7-trihydroxy-3-(4′-methoxybenzyl)-4-chromanone (7.2 mg) and (R)-5,7-dihydroxy-3-(4′-methoxybenzyl)-4-chromanone (7.9 mg), eucosterol (10.2 mg), (17S,23S)-17,23-epoxy-3β,28,29-trihydrox-27-norlanost-8-en-24-one (3.2 mg), 15-deoxoeucosterol (8.2 mg) and 3-dehydro-15-deoxoeucosterol (8.2 mg) and five novel compounds, 1 (8.5 mg), compound 2 which was acetylated to give compound 2Ac (2.8 mg), 3 (3.3 mg), 4 (3.6 mg) and 5 (2.5 mg). The methanol extract yielded (R)-5,7-trihydroxy-3-(4′-hydroxybenzyl)-4-chromanone (8.2 mg) and nine novel lanosterol glycosides which were isolated as their acetate derivatives after acetylation of a complex mixture to yield 6Ac (1.9 mg), 7Ac (1.2 mg), 8Ac (1.8 mg), 9Ac (1.1 mg) 10Ac (2.3 mg), 11Ac (0.8 mg), 12Ac (2.1 mg), 13Ac (1.7 mg) and 14Ac (1.4 mg). A detailed isolation scheme is given in the ESI (S.2†). Full NMR data for compounds 1–5 and acetates of 2, and 6–14 are given in Tables 1–5 and spectra are given in the ESI (S.4†).
No | 6Ac | 7Ac | 10Ac | 11Ac | 12Ac |
---|---|---|---|---|---|
1 | 35.8 CH2 | 35.6 CH2 | 36.0 CH2 | 36.0 CH2 | 35.9 CH2 |
2 | 27.3 CH2 | 27.2 CH2 | 27.2 CH2 | 27.1 CH2 | 27.4 CH2 |
3 | 90.1 CH | 89.9 CH | 90.3 CH | 90.3 CH | 90.3 CH |
4 | 42.3 C | 42.3 C | 42.4 C | 42.4 C | 42.3 C |
5 | 51.4 CH | 51.1 CH | 52.2 CH | 51.9 CH | 51.3 CH |
6 | 19.5 CH2 | 19.4 CH2 | 19.7 CH2 | 19.5 CH2 | 19.6 CH2 |
7 | 26.5 CH2 | 26.3 CH2 | 26.8 CH2 | 26.8 CH2 | 26.5 CH2 |
8 | 133.4 C | 133.3 C | 134.2 C | 134.3 C | 133.5 C |
9 | 136.0 C | 136.0 C | 135.7 C | 135.7 C | 135.9 C |
10 | 37.4 C | 37.4 C | 37.1 C | 37.0 C | 37.4 C |
11 | 20.5 CH2 | 20.5 CH2 | 21.0 CH2 | 21.2 CH2 | 20.5 CH2 |
12 | 23.0 CH2 | 22.9 CH2 | 25.1 CH2 | 25.1 CH2 | 23.1 CH2 |
13 | 47.8 C | 47.6 C | 48.7 C | 48.8 C | 47.6 C |
14 | 57.9 C | 57.9 C | 50.9 C | 50.8 C | 57.9 C |
15 | 215.6 C | 215.7 C | 31.9 CH2 | 31.9 CH2 | 215.6 C |
16 | 51.9 CH2 | 51.7 CH2 | 39.9 CH2 | 39.8 CH2 | 52.1 CH2 |
17 | 91.2 C | 91.2 C | 97.3 C | 97.3 C | 91.3 C |
18 | 20.7 CH3 | 20.4 CH3 | 19.2 CH3 | 19.5 CH3 | 20.7 CH3 |
19 | 19.1 CH3 | 19.6 CH3 | 18.9 CH3 | 19.2 CH3 | 19.0 CH3 |
20 | 43.5 CH | 43.3 CH | 44.0 CH | 43.7 CH | 43.2 CH |
21 | 17.4 CH3 | 17.3 CH3 | 17.4 CH3 | 17.4 CH3 | 17.3 CH3 |
22 | 37.2 CH2 | 36.7 CH2 | 37.1 CH2 | 37.0 CH2 | 37.0 CH2 |
23 | 81.3 CH | 81.8 CH | 81.8 CH | 81.6 CH | 81.6 CH |
24 | 212.2 C | 212.2 C | 213.6 C | 213.6 C | 212.2 C |
25 | 32.7 CH2 | 32.5 CH2 | 32.2 CH2 | 32.4 CH2 | 32.5 CH2 |
26 | 7.6 CH3 | 7.5 CH3 | 7.8 CH3 | 7.6 CH3 | 7.4 CH3 |
28 | 22.6 CH3 | 22.7 CH3 | 22.3 CH3 | 22.5 CH3 | 22.6 CH3 |
29 | 65.7 CH2 | 65.5 CH2 | 65.5 CH2 | 65.5 CH2 | 65.8 CH2 |
30 | 23.9 CH3 | 23.7 CH3 | 25.9 CH3 | 25.8 CH3 | 23.9 CH3 |
Glu 1′ | 102.9 CH | 102.7 CH | 103.1 CH | 102.9 CH | 103.7 CH |
2′ | 71.9 CH | 72.7 CH | 71.9 CH | 71.7 CH | 71.8 CH |
3′ | 73.2 CH | 80.4 CH | 73.1 CH | 73.1 CH | 73.2 CH |
4′ | 69.2 CH | 69.2 CH | 68.8 CH | 69.0 CH | 68.8 CH |
5′ | 73.6 CH | 73.4 CH | 71.8 CH | 73.3 CH | 71.9 CH |
6′ | 67.8 CH2 | 67.6 CH2 | 62.4 CH2 | 67.3 CH2 | 62.3 CH2 |
Arab 1′′ | 100.6 CH | 100.3 CH | — | 100.4 CH | — |
2′′ | 69.2 CH | 69.0 CH | — | 69.0 CH | — |
3′′ | 70.3 CH | 70.0 CH | — | 70.0 CH | — |
4′′ | 67.6 CH | 67.4 CH | — | 67.4 CH | — |
5′′ | 63.1 CH2 | 62.8 CH2 | — | 62.9 CH2 | — |
Xyl 1′′′ | — | 101.1 CH | — | — | — |
2′′′ | — | 70.0 CH | — | — | — |
3′′′ | — | 70.7 CH | — | — | — |
4′′′ | — | 68.6 CH | — | — | — |
5′′′ | — | 61.7 CH | — | — | — |
OAc | 20.6, 21.2, 21.3, 20.9, 20.9, 21.1, 20.9 | 20.6, 21.2, 21.3, 20.9, 21.1, 20.9, 21.2, 21.1 | 20.5, 20.9, 20.9, 21.0, 21.3 | 20.6, 21.2, 21.3, 20.9, 20.9, 21.1, 20.9 | 20.5, 20.7, 20.8, 20.8, 21.0 |
OAc | 170.5, 169.7, 170.3, 170.6, 169.5, 169.4, 171.3 | 170.5, 169.7, 170.3, 170.6, 169.5, 169.4, 171.3, 169.1, 170.1 | 170.6, 169.4, 170.9, 169.6, 170.8 | 170.5, 169.7, 170.3, 170.6, 169.5, 169.4, 171.3 | 170.6, 169.4, 171.2, 169.6, 170.8 |
No | 8Ac | 9Ac | 13Ac | 14Ac |
---|---|---|---|---|
1 | 36.0 CH2 | 36.0 CH2 | 35.7 CH2 | 35.7 CH2 |
2 | 27.1 CH2 | 27.1 CH2 | 26.4 CH2 | 26.3 CH2 |
3 | 90.4 CH | 90.2 CH | 90.1 CH | 90.1 CH |
4 | 42.4 C | 42.4 C | 42.3 C | 42.3 C |
5 | 51.9 CH | 51.9 CH | 51.7 CH | 51.7 CH |
6 | 19.7 CH2 | 19.7 CH2 | 19.6 CH2 | 19.6 CH2 |
7 | 26.5 CH2 | 26.5 CH2 | 28.3 CH2 | 28.3 CH2 |
8 | 134.1 C | 134.2 C | 133.4 C | 133.3 C |
9 | 135.6 C | 135.6 C | 135.7 C | 135.8 C |
10 | 37.0 C | 37.0 C | 37.6 C | 37.6 C |
11 | 20.7 CH2 | 20.7 CH2 | 20.3 CH2 | 20.3 CH2 |
12 | 24.8 CH2 | 24.8 CH2 | 23.5 CH2 | 23.5 CH2 |
13 | 48.6 C | 48.6 C | 51.7 C | 57.2 C |
14 | 50.7 C | 50.6 C | 57.2 C | 51.2 C |
15 | 31.8 CH2 | 31.8 CH2 | 209.4 C | 209.4 C |
16 | 37.4 CH2 | 37.4 CH2 | 123.6 CH | 123.6 CH |
17 | 98.8 C | 98.8 C | 184.3 CH | 184.4 CH |
18 | 18.9 CH3 | 18.9 CH3 | 29.7 CH3 | 29.0 CH3 |
19 | 19.7 CH3 | 19.7 CH3 | 18.7 CH3 | 18.7 CH3 |
20 | 44.0 CH | 44.0 CH | 30.3 CH | 30.4 CH |
21 | 18.9 CH3 | 18.9 CH3 | 21.3 CH3 | 21.1 CH3 |
22 | 45.1 CH2 | 45.1 CH2 | 35.8 CH2 | 35.8 CH2 |
23 | 113.7 C | 113.7 C | 76.6 CH | 76.6 CH |
24 | 45.2 CH2 | 45.2 CH2 | 207.6 C | 207.6 C |
25 | 35.9 CH | 35.9 CH | 32.1 CH2 | 32.1 CH2 |
26 | 15.2 CH3 | 15.2 CH3 | 7.4 CH3 | 7.4 CH3 |
27 | 179.6 C | 179.6 C | — | — |
28 | 22.6 CH3 | 22.6 CH3 | 22.7 CH3 | 22.7 CH3 |
29 | 65.73 CH2 | 65.7 CH2 | 65.8 CH2 | 65.8 CH2 |
30 | 26.0 CH3 | 26.0 CH3 | 29.4 CH3 | 29.4 CH3 |
Glu 1′ | 103.2 CH | 102.9 CH | 103.9 CH | 102.9 CH |
2′ | 71.9 CH | 71.9 CH | 71.8 CH | 71.9 CH |
3′ | 73.3 CH | 73.2 CH | 73.2 CH | 73.1 CH |
4′ | 68.8 CH | 69.2 CH | 68.8 CH | 69.0 CH |
5′ | 71.8 CH | 73.6 CH | 71.9 CH | 73.3 CH |
6′ | 62.3 CH2 | 67.6 CH2 | 62.3 CH2 | 67.7 CH2 |
Arab 1′′ | — | 100.4 CH | — | 100.5 CH |
2′′ | — | 69.2 CH | — | 69.2 CH |
3′′ | — | 70.3 CH | — | 70.3 CH |
4′′ | — | 67.5 CH | — | 67.5 CH |
5′′ | — | 62.9 CH2 | — | 63.0 CH2 |
OAc | 20.8, 20.8, 20.8, 21.3, 21.9 CH3 | 20.6, 21.2, 21.3, 20.9, 20.9, 21.1, 20.9 | 20.8, 21.0, 20.8, 20.8, 20.8, 21.3 | 20.8, 21.2, 21.3, 20.9, 20.9, 21.1, 20.9, 20.4 |
OAc | 170.6, 169.4, 171.2, 169.6, 170.9 C | 170.5, 169.7, 170.3, 170.6, 169.5, 169.4, 171.3 | 169.4, 169.6, 170.4, 170.7, 170.8, 171.2 | 170.5, 169.7, 170.3, 170.6, 169.5, 169.4, 171.3, 170.3 |
Footnote |
† Electronic supplementary information (ESI) available. See DOI: 10.1039/c6ra28584h |
This journal is © The Royal Society of Chemistry 2017 |