- Email: [email protected]
Flavonol triglycosides from Magnolia utilis
Phytochemistry Letters 29 (2019) 57–60
Contents lists available at ScienceDirect
Phytochemistry Letters journal homepage: www.elsevier.com/locate/phytol
Flavonol triglycosides from Magnolia utilis a
a
a
a
Chutima Srinroch , Poolsak Sahakitpichan , Nitirat Chimnoi , Somsak Ruchirawat , ⁎ Tripetch Kanchanapooma,b, a b
T
Chulabhorn Research Institute, Kamphaeng Phet 6, Talat Bang Khen, Lak Si, Bangkok, 10210, Thailand Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
ARTICLE INFO
ABSTRACT
Keywords: Magnolia utilis Magnoliaceae Flavonol triglycoside Champaluangosides A-C
Three undescribed flavonol triglycosides, rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl(1→6)]-β-D-glucopyranoside (champaluangoside A), rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (champaluangoside B) and rhamnocitrin-3-O-α-L-rhamnopyranosyl(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (champaluangoside C), were isolated from Magnolia utilis in addition to eleven known compounds; quercetrin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside, oxytroflavoside G, magnoloside A, magnoloside M, magnoloside D, manglieside A, manglieside B, 1,2-di-O-β-D-glucopyranosyl-4-allylbebzene, syringrin, benzyl β-D-allopyranoside and (+)-syringaresinol-O-β-D-glucopyranoside. The structure elucidation of these compounds was based on analyses of physical and spectroscopic data.
1. Introduction Magnolia utilis V.S. Kumar (syn. Manglietia utilis Dandy; Thai name: Cham-Pa-Luang; Family: Magnoliaceae) is a woody tree up to 30 m high, distributed in northern Thailand and Peninsular Malaysia and Borneo. This species is considered as a member in the section Manglietia of the family Magnoliaceae, (Figlar and Nooteboom, 2004). The phytochemical study has not been carried out on this species. As part of our continuing investigation on Magnoliaceous plants (Sahakitpichan et al., 2017; Kanchanapoom et al., 2018), we investigated the secondary metabolites from this species, growing in Phetchabun Province, Thailand. This present paper deals with the isolation and structure determination of fourteen polar compounds including three new flavonol triglycosides (1–3) (Fig. 1), and eleven known compounds (4-14) from the aqueous soluble fraction of the MeOH extract of the leaves and twigs of this plant. 2. Results and discussion The methanolic extract of the leaves and twigs of M. utilis was partitioned between Et2O and H2O. The aqueous soluble fraction was separated by combination of chromatographic methods to provide three undescribed flavonol triglycosides (1–3) along with eleven known compounds. The known compounds were identified as quercetrin-O-αL-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-
⁎
glucopyranoside (4) (Kazuma et al., 2003), rhamnocitrin-3-O-α-Lrhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (5, oxytroflavoside G) (Wang et al., 2012), magnoloside A (6) (Hasekawa et al., 1988), magnoloside M (7) (Xue et al., 2016), magnoloside D (8) (Yu et al., 2012), manglieside A (9), manglieside B (10) (Kiem et al., 2008), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (11) (Ly et al., 2002), syringrin (12) (Yang et al., 2007), benzyl β-Dallopyranoside (13) (Seigler et al., 2002) and (+)-syringaresinol O-β-Dglucopyranoside (14) (Kobayashi et al., 1985), by comparison of physical data with literature values and from spectroscopic evidence. Champaluangoside A (1) was isolated as a yellow amorphous powder. The molecular formula was determined to be C34H42O20 by high resolution electrospray time-of-flight (HR-ESITOF) mass spectrometric analysis. The 1H NMR spectrum revealed the presence of a pair of meta-coupling aromatic ring at δH 6.32 and 6.57 (each d, J = 2.2 Hz), a set of 1,2,4-trisubstituted aromatic ring system at δH 6.89 (d, J = 9.0 Hz), 7.61 (d, J = 2.0 Hz), and 7.73 (dd, J = 9.0, 2.0 Hz) and a methoxyl singlet signal at δH 3.88 for the aglycone part in addition to three anomeric protons for sugar moieties at δH 5.60 (d, J = 7.7 Hz), 5.22 (d, J = 1.5 Hz) and 4.50 (d, J = 1.6 Hz). Two sugar units could be assigned to be rhamnoses from the characteristic methyl doublet signals at δH 1.01 and 1.07 (both d, J = 6.2 Hz). The chemical shifts were closely related to those of quercetrin-O-α-L-rhamnopyranosyl-(1→2)[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (4), except for the presence of the additional methoxyl signal (δH 3.88 and δC 56.4) in the
Corresponding author at: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand. E-mail address: [email protected] (T. Kanchanapoom).
https://doi.org/10.1016/j.phytol.2018.11.013 Received 16 August 2018; Received in revised form 8 November 2018; Accepted 8 November 2018 1874-3900/ © 2018 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.
Phytochemistry Letters 29 (2019) 57–60
C. Srinroch et al.
2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside. Thus, 2 was determined to be rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-Lrhamnopyranosyl-(1→6)]-β-D-galactopyranoside. Champaluangoside C (3) was isolated as a yellow amorphous powder. The molecular formula was determined as C34H42O19, by its HR-ESITOF mass spectrometric analysis. The chemical shifts indicated that compound 3 (Tables 1 and 2) was an analogue of the flavonol triglycosides, having the same aglycone (rhamnocitrin) as compound 5, as well as the sugar moiety as compounds 1 and 4. Consequently, 3 was established to be rhamnocitrin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-Lrhamnopyranosyl-(1→6)]-β-D-glucopyranoside. Among the compounds isolated, the presence of phenylethanoid and phenylpropanoid glycosides (6-9), having allose as the core sugar unit was related to previous investigations of the same genus (Hasekawa et al., 1988; Kiem et al., 2008; Yu et al., 2012; Xue et al., 2016; Sahakitpichan et al., 2017; Kanchanapoom et al., 2018). The results from this study added the information data of the secondary metabolites to this genus. 3. Experimental 3.1. General procedures NMR spectra were recorded in CD3OD using a Bruker AV-400 (400 MHz for 1H-NMR and 100 MHz for 13C-NMR) spectrometer. The MS data was obtained on a Bruker Micro TOF-LC mass spectrometer. Optical rotations were measured with a Jasco P-1020 digital polarimeter. UV spectra were recorded on a Shimadzu V-1700 spectrophotometer. For column chromatography, Diaion HP-20 (Mitsubishi Chemical Industries Co. Ltd.), silica gel 60 (230–400 mesh, Merck), and RP-18 (50 μm, YMC) were used. HPLC (Shimadzu LC-10AT pump) was carried out on an ODS column (20.0 x 250 mm i.d., Vertisep™UPS) with a Jasco UV-970 detector. The flow rates were 6 ml/min. The spraying reagent used for TLC was 10% H2SO4 in H2O-EtOH (1:1, v/v).
Fig. 1. Structures of compounds 1-5.
3.2. Plant material The leaves and twigs of Magnolia utilis (Dandy) V. S. Kumar were collected from Phetchabun Province, Thailand, in May 2018. Plant specimen was identified by Mr. Thinakorn Komkris. Voucher specimens (TK-PSKKU-0082) are on files in the Herbarium of the Faculty of Pharmaceutical Sciences, Khon Kaen University. 3.3. Extraction and isolation The air dried leaves and twigs of M. utilis (523.0 g) were extracted three times with MeOH, and concentrated to dryness. The greenish residue (47.2 g) was suspended in H2O and partitioned with Et2O. The water soluble part (18.7 g) was subjected to a Diaion HP-20 column, and eluted with H2O, and MeOH, successively. The fraction eluted with MeOH (3.5 g) was applied to a silica gel column using solvent systems EtOAc-MeOH (9:1, 1.0 L), EtOAc-MeOH-H2O (40:10:1, 4.0 L), EtOAcMeOH-H2O (70:30:3, 2.0 L) and EtOAc-MeOH-H2O (6:4:1, 1.0 L), respectively to provide nine fractions (A to I). Fraction B was purified by preparative HPLC-ODS using solvent system H2O-MeCN (80:20, v/v) to provide compounds 6 (15.7 mg), 7 (5.7 mg), 9 (6.8 mg), 10 (25.1 mg) and 13 (6.7 mg). Fraction C was purified by preparative HPLC-ODS using solvent system H2O-MeCN (80:20, v/v) to give compound 14 (12.4 mg). Fraction D was purified by preparative HPLC-ODS using solvent system H2O-MeCN (80:20, v/v) to obtain compounds 8 (2.5 mg) and 12 (7.8 mg). Fraction F (7.8 g) was purified by preparative HPLCODS with solvent system H2O-MeCN (80:20, v/v) to afford compound 11 (0.6 mg). Finally, fraction H was purified by preparative HPLC-ODS with solvent system H2O-MeCN (80:20, v/v) to yield compounds 1 (11.4 mg), 2 (6.5 mg), 3 (10.0 mg), 4 (3.0 mg) and 5 (8.5 mg).
Fig. 2. Significant HMBC correlations of compound 1.
spectra. This methyl group was suggested to be located at C-7 since the chemical shifts of C-6, C-7 and C-8 were changed as compared to compound 4 (Table 2). The assignment was confirmed by the HMBC correlations from H-6 (δH 6.32), H-8 (δH 6.57) and the methoxyl signal (δH 3.88) to C-7 (δC 167.1) as shown in Fig. 2. The aglycone of this compound was rhamnetin (Agrawal and Bansal,1989) therefore, 1 was elucidated as rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside. Champaluangoside B (2) was obtained as a yellow amorphous powder. Its molecular formula was determined as C34H42O19, by its HRESITOF mass spectrometric analysis. The 1H and 13C NMR spectra (Tables 1 and 2) were very similar to those of 1, except for the presence of signals of β-galactopyranosyl unit instead of β-glucopyranosyl unit. The chemical shifts of the sugar moiety were in agreement with those of oxytroflavoside G (5), and identified to be α-L-rhamnopyranosyl-(1→ 58
Phytochemistry Letters 29 (2019) 57–60
C. Srinroch et al.
Table 1 1 H (400 MHz) spectroscopic data of compounds 1–3 (in CD3OD). Position
1
2
3
6.32 (1H, d, J = 2.2 Hz) 6.57 (1H, d, J = 2.2 Hz) 7.61 (1H, dd, J = 2.0 Hz)
6.31 (1H, d, J = 2.2 Hz) 6.57 (1H, d, J = 2.2 Hz) 7.73 (1H, dd, J = 2.1 Hz)
6.88 7.63 3.88 Glc 5.60 3.65 3.54 3.27 3.35 3.81 3.40
(1H, d, J = 9.0 Hz) (1H, d, J = 9.0, 2.0 Hz) (3H, s)
(1H, d, J = 8.5 Hz) (1H, d, J = 8.5, 2.1 Hz) (3H, s)
(1H, (1H, (1H, (1H, (1H, (1H, (3H,
d, d, d, d, d, d, s)
(1H, (1H, (1H, (1H, (1H, (1H, (1H,
d, J = 7.7 Hz) dd, J = 9.2, 7.7 Hz) dd, J = 9.2, 9.1 Hz) dd, J = 9.2, 9.0 Hz) m) dd, J = 10.3, 1.5 Hz) dd, J = 10.3, 6.2 Hz)
6.89 7.60 3.88 Gal 5.69 3.96 3.73 3.81 3.68 3.74 3.49
(1H, (1H, (1H, (1H, (1H, (1H, (1H,
d, J = 7.8 Hz) dd, J = 9.6, 7.8 Hz) dd, J = 9.6, 3.3 Hz) br d, J = 3.3 Hz) m) dd, J = 11.1, 1.8 Hz) dd, J = 11.1, 6.1 Hz)
6.32 6.58 8.06 6.90 6.90 8.06 3.88 Glc 5.60 3.60 3.54 3.23 3.36 3.81 3.38
(1H, (1H, (1H, (1H, (1H, (1H, (1H,
d, J = 7.6 Hz) dd, J = 9.1, 7.6 Hz) dd, J = 9.2, 9.1 Hz) dd, J = 9.2, 8.8 Hz) m) dd, J = 12.2, 1.5 Hz) dd, J = 12.2, 6.1 Hz)
2"-Rha 1'" 2'" 3'" 4'" 5'" 6'"
5.22 4.00 3.79 3.35 4.08 1.01
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.5 Hz) dd, J = 3.2, 1.5 Hz) dd, J = 9.4, 3.2 Hz) dd, J = 9.6, 9.4 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
5.22 4.00 3.78 3.33 4.04 0.95
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.6 Hz) dd, J = 3.2, 1.6 Hz) dd, J = 9.6, 3.2 Hz) dd, J = 9.6, 9.6 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
5.23 4.00 3.79 3.35 4.06 0.99
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.6 Hz) dd, J = 3.2, 1.6 Hz) dd, J = 9.7, 3.2 Hz) dd, J = 9.7, 9.6 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
6"-Rha 1"" 2"" 3"" 4"" 5"" 6""
4.50 3.56 3.47 3.23 3.41 1.07
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.6 Hz) dd, J = 3.4, 1.6 Hz) dd, J = 9.5, 3.4 Hz) dd, J = 9.5, 9.5 Hz) dq, J = 9.5, 6.2 Hz) d, J = 6.2 Hz)
4.54 3.56 3.50 3.26 3.53 1.18
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.7 Hz) dd, J = 3.4, 1.7 Hz) dd, J = 9.5, 3.4 Hz) dd, J = 9.6, 9.5 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
4.49 3.56 3.46 3.22 3.41 1.07
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.5 Hz) dd, J = 3.4, 1.5 Hz) dd, J = 9.5, 3.4 Hz) dd, J = 9.5, 9.5 Hz) dq, J = 9.5, 6.2 Hz) d, J = 6.2 Hz)
Aglycone 6 8 2' 3' 5' 6' 7-OCH3 1" 2" 3" 4" 5" 6"
Table 2 (continued)
Table 2 13 C NMR (100 MHz) spectroscopic data of compounds 1–4 (in CD3OD). Position
1
2
3
4
5
158.8 134.8 179.4 162.9 98.9 167.1 93.0 158.3 106.8 123.2 117.4 145.9 149.8 116.1 123.1 56.4 Gal 101.0 77.4 75.7 70.9 75.3 67.1
159.4 134.5 179.4 162.9 99.0 167.1 93.1 158.4 106.7 123.0 132.2 116.2 161.4 116.2 132.2 56.4 Glc 100.5 79.9 78.9 72.0 77.1 68.4
158.9 134.5 179.3 163.2 99.7 165.6 94.7 158.4 105.9 123.5 117.4 145.9 149.5 116.1 123.6
1" 2" 3" 4" 5" 6"
159.3 134.7 179.4 162.9 98.9 167.1 93.1 158.3 106.7 123.4 117.5 145.9 149.7 116.1 123.5 56.4 Glc 100.5 80.0 78.9 71.9 77.1 68.4
Glc 100.5 80.0 78.9 71.9 77.1 68.3
159.0 134.7 179.5 162.9 99.0 167.1 93.0 158.3 106.7 122.9 132.3 116.2 161.4 116.2 132.3 56.4 Gal 100.9 77.6 75.7 70.7 75.4 67.2
2"-Rha 1"' 2"' 3"' 4"' 5"' 6"'
102.7 72.4 72.3 74.0 70.0 17.5
102.6 72.4 72.3 74.0 69.9 17.4
102.6 72.4 72.3 74.0 69.9 17.6
102.6 72.4 72.3 74.1 70.0 17.5
102.6 72.4 72.3 74.0 69.8 17.9
6"-Rha 1"" 2""
102.3 72.1
101.9 72.1
102.3 72.1
102.3 72.1
101.9 72.1
Aglycone 2 3 4 5 6 7 8 9 10 1' 2' 3' 4' 5' 6' 7-OCH3
J = 2.0 Hz) J = 2.0 Hz) J = 8.9 Hz) J = 8.9 Hz) J = 8.9 Hz) J = 8.9 Hz)
Position
1
2
3
4
5
3"" 4"" 5"" 6""
72.2 73.8 69.7 17.8
72.3 73.9 69.7 18.0
72.3 73.8 69.7 17.8
72.3 73.9 69.7 17.8
72.3 73.9 69.7 17.8
3.4. Champaluangoside A (1) Amorphous powder, [α]D25 −80.6 (MeOH, c 0.48); UV λmaxMeOH (nm): 355.0, 256.5; 1H NMR: Table 1; 13C NMR (CD3OD): Table 2; Positive HRESITOF-MS, m/z: 771.2330 [M+H]+ (C34H43O20 required 771.2342). 3.5. Champaluangoside B (2) Amorphous powder, [α]D25 −85.2 (MeOH, c 0.52); UV λmaxMeOH (nm): 356.0, 256.5; 1H NMR: Table 1; 13C NMR (CD3OD): Table 2; Positive HRESITOF-MS, m/z: 793.2131 [M+Na]+ (C34H42NaO20 required 793.2161). 3.6. Champaluangoside C (3) Amorphous powder, [α]D25 −68.8 (MeOH, c 0.38); UV λmaxMeOH (nm): 347.0, 266; 1H NMR: Table 1; 13C NMR (CD3OD): Table 2; Negative HRESITOF-MS, m/z: 789.2036 [M+Cl]− (C34H42ClO19 required 789.2014). Acknowledgements This research work was supported by the grant from Chulabhorn Research Institute and Khon Kaen University. The authors also thank 59
Phytochemistry Letters 29 (2019) 57–60
C. Srinroch et al.
Mr. Thinakorn Komkris for providing the plant materials from his garden, Khao Kho, Phetchabun Province, Thailand.
Kobayashi, H., Karasawa, H., Miyase, T., Fukushima, S., 1985. Studies on the constituents of Cistanchis herba. V. Isolation and structures of two new phenylpropanoid glycosides, cistanosides E and F. Chem. Pharm. Bull. 33, 1452–1457. Ly, T.N., Yamauchi, R., Shimoyamada, M., Kato, K., 2002. Isolation and structural elucidation of some glycosides from the rhizomes of smaller galangal (Alpinia officinarum Hance). J. Agric. Food Chem. 50, 4919–4924. Sahakitpichan, P., Chimnoi, N., Wongbundit, S., Vorasingha Ruchirawat, S., Kanchanapoom, T., 2017. Phenylethanoid glycosides from the leaves of Magnolia hodgsonii. Phytochem. Lett. 21, 269–272. Seigler, D.S., Pauli, G.F., Nahrstedt, A., Leen, R., 2002. Cyanogenic allosides and glucosides from Passiflora edulis and Carrica papaya. Phytochemistry 60, 873–882. Wang, S.-S., Zhang, X.-J., Que, S., Tu, G.-Z., Wam, D., Cheng, W., 2012. 3-Hydroxy-3Methylglutaryl flavonol glycosides from Oxytropis falcata. J. Nat. Prod. 75, 1359–1364. Xue, Z., Yan, R., Yang, B., 2016. Phenylpropanoid glycosides and phenolic glycosides from stem bark of Magnolia officinalis. Phytochemistry 127, 50–62. Yang, M.C., Lee, K.H., Kim, K.H., Choi, S.U., Lee, K.R., 2007. Lignan and terpene constituents from the aerial parts of Saussurea pulchella. Arch. Pharm. Res. 30, 1067–1074. Yu, S., Yan, R., Liang, R., Wang, W., Yang, B., 2012. Bioactive polar compounds from stem bark of Magnolia officinalis. Fitoterapia 83, 356–361.
References Agrawal, P.K., Bansal, M.C., 1989. Flavonoid glycosides. In: Agrawal, P.K. (Ed.), Carbon13 NMR of Flavonoids. Elsevier, Amsterdam, pp. 283–364. Figlar, R.B., Nooteboom, H.P., 2004. Notes on Magnoliaceae IV. Blumea 49, 87–100. Hasekawa, T., Fukuyama, Y., Yamada, T., Nakagawa, K., 1988. Isolation and structure of magnoloside A, a new phenylpropanoid glycoside from Magnolia obovata Thunb. Chem. Lett. 17, 163–166. Kanchanapoom, T., Sahakitpichan, P., Chimnoi, N., Srinroch, C., Thamniyom, W., Ruchirawat, S., 2018. Monoterpene, benzyl and 3,4-d ihydroxyphenethyl glycosides from Magnolia thailandica. Phytochem. Lett. 25, 28–32. Kazuma, K., Noda, N., Suzuki, M., 2003. Malonylated flavonol glycosides from the petals of Clitoria ternatea. Phytochemistry 62, 229–237. Kiem, P.V., Tri, M.D., Tuong, L.V.D., Tung, N.H., Hanh, N.N., Quang, T.H., Cuong, N.X., Minh, C.V., Choi, E.-M., Kim, Y.H., 2008. Chemical constituents from the leaves of Manglietia phuthoensis and their effects on osteoblastic MC3T3-E1 cells. Chem. Pharm. Bull. 56, 1270–1275.
60
Contents lists available at ScienceDirect
Phytochemistry Letters journal homepage: www.elsevier.com/locate/phytol
Flavonol triglycosides from Magnolia utilis a
a
a
a
Chutima Srinroch , Poolsak Sahakitpichan , Nitirat Chimnoi , Somsak Ruchirawat , ⁎ Tripetch Kanchanapooma,b, a b
T
Chulabhorn Research Institute, Kamphaeng Phet 6, Talat Bang Khen, Lak Si, Bangkok, 10210, Thailand Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand
ARTICLE INFO
ABSTRACT
Keywords: Magnolia utilis Magnoliaceae Flavonol triglycoside Champaluangosides A-C
Three undescribed flavonol triglycosides, rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl(1→6)]-β-D-glucopyranoside (champaluangoside A), rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (champaluangoside B) and rhamnocitrin-3-O-α-L-rhamnopyranosyl(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (champaluangoside C), were isolated from Magnolia utilis in addition to eleven known compounds; quercetrin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside, oxytroflavoside G, magnoloside A, magnoloside M, magnoloside D, manglieside A, manglieside B, 1,2-di-O-β-D-glucopyranosyl-4-allylbebzene, syringrin, benzyl β-D-allopyranoside and (+)-syringaresinol-O-β-D-glucopyranoside. The structure elucidation of these compounds was based on analyses of physical and spectroscopic data.
1. Introduction Magnolia utilis V.S. Kumar (syn. Manglietia utilis Dandy; Thai name: Cham-Pa-Luang; Family: Magnoliaceae) is a woody tree up to 30 m high, distributed in northern Thailand and Peninsular Malaysia and Borneo. This species is considered as a member in the section Manglietia of the family Magnoliaceae, (Figlar and Nooteboom, 2004). The phytochemical study has not been carried out on this species. As part of our continuing investigation on Magnoliaceous plants (Sahakitpichan et al., 2017; Kanchanapoom et al., 2018), we investigated the secondary metabolites from this species, growing in Phetchabun Province, Thailand. This present paper deals with the isolation and structure determination of fourteen polar compounds including three new flavonol triglycosides (1–3) (Fig. 1), and eleven known compounds (4-14) from the aqueous soluble fraction of the MeOH extract of the leaves and twigs of this plant. 2. Results and discussion The methanolic extract of the leaves and twigs of M. utilis was partitioned between Et2O and H2O. The aqueous soluble fraction was separated by combination of chromatographic methods to provide three undescribed flavonol triglycosides (1–3) along with eleven known compounds. The known compounds were identified as quercetrin-O-αL-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-
⁎
glucopyranoside (4) (Kazuma et al., 2003), rhamnocitrin-3-O-α-Lrhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside (5, oxytroflavoside G) (Wang et al., 2012), magnoloside A (6) (Hasekawa et al., 1988), magnoloside M (7) (Xue et al., 2016), magnoloside D (8) (Yu et al., 2012), manglieside A (9), manglieside B (10) (Kiem et al., 2008), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (11) (Ly et al., 2002), syringrin (12) (Yang et al., 2007), benzyl β-Dallopyranoside (13) (Seigler et al., 2002) and (+)-syringaresinol O-β-Dglucopyranoside (14) (Kobayashi et al., 1985), by comparison of physical data with literature values and from spectroscopic evidence. Champaluangoside A (1) was isolated as a yellow amorphous powder. The molecular formula was determined to be C34H42O20 by high resolution electrospray time-of-flight (HR-ESITOF) mass spectrometric analysis. The 1H NMR spectrum revealed the presence of a pair of meta-coupling aromatic ring at δH 6.32 and 6.57 (each d, J = 2.2 Hz), a set of 1,2,4-trisubstituted aromatic ring system at δH 6.89 (d, J = 9.0 Hz), 7.61 (d, J = 2.0 Hz), and 7.73 (dd, J = 9.0, 2.0 Hz) and a methoxyl singlet signal at δH 3.88 for the aglycone part in addition to three anomeric protons for sugar moieties at δH 5.60 (d, J = 7.7 Hz), 5.22 (d, J = 1.5 Hz) and 4.50 (d, J = 1.6 Hz). Two sugar units could be assigned to be rhamnoses from the characteristic methyl doublet signals at δH 1.01 and 1.07 (both d, J = 6.2 Hz). The chemical shifts were closely related to those of quercetrin-O-α-L-rhamnopyranosyl-(1→2)[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside (4), except for the presence of the additional methoxyl signal (δH 3.88 and δC 56.4) in the
Corresponding author at: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen, 40002, Thailand. E-mail address: [email protected] (T. Kanchanapoom).
https://doi.org/10.1016/j.phytol.2018.11.013 Received 16 August 2018; Received in revised form 8 November 2018; Accepted 8 November 2018 1874-3900/ © 2018 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.
Phytochemistry Letters 29 (2019) 57–60
C. Srinroch et al.
2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside. Thus, 2 was determined to be rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-Lrhamnopyranosyl-(1→6)]-β-D-galactopyranoside. Champaluangoside C (3) was isolated as a yellow amorphous powder. The molecular formula was determined as C34H42O19, by its HR-ESITOF mass spectrometric analysis. The chemical shifts indicated that compound 3 (Tables 1 and 2) was an analogue of the flavonol triglycosides, having the same aglycone (rhamnocitrin) as compound 5, as well as the sugar moiety as compounds 1 and 4. Consequently, 3 was established to be rhamnocitrin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-Lrhamnopyranosyl-(1→6)]-β-D-glucopyranoside. Among the compounds isolated, the presence of phenylethanoid and phenylpropanoid glycosides (6-9), having allose as the core sugar unit was related to previous investigations of the same genus (Hasekawa et al., 1988; Kiem et al., 2008; Yu et al., 2012; Xue et al., 2016; Sahakitpichan et al., 2017; Kanchanapoom et al., 2018). The results from this study added the information data of the secondary metabolites to this genus. 3. Experimental 3.1. General procedures NMR spectra were recorded in CD3OD using a Bruker AV-400 (400 MHz for 1H-NMR and 100 MHz for 13C-NMR) spectrometer. The MS data was obtained on a Bruker Micro TOF-LC mass spectrometer. Optical rotations were measured with a Jasco P-1020 digital polarimeter. UV spectra were recorded on a Shimadzu V-1700 spectrophotometer. For column chromatography, Diaion HP-20 (Mitsubishi Chemical Industries Co. Ltd.), silica gel 60 (230–400 mesh, Merck), and RP-18 (50 μm, YMC) were used. HPLC (Shimadzu LC-10AT pump) was carried out on an ODS column (20.0 x 250 mm i.d., Vertisep™UPS) with a Jasco UV-970 detector. The flow rates were 6 ml/min. The spraying reagent used for TLC was 10% H2SO4 in H2O-EtOH (1:1, v/v).
Fig. 1. Structures of compounds 1-5.
3.2. Plant material The leaves and twigs of Magnolia utilis (Dandy) V. S. Kumar were collected from Phetchabun Province, Thailand, in May 2018. Plant specimen was identified by Mr. Thinakorn Komkris. Voucher specimens (TK-PSKKU-0082) are on files in the Herbarium of the Faculty of Pharmaceutical Sciences, Khon Kaen University. 3.3. Extraction and isolation The air dried leaves and twigs of M. utilis (523.0 g) were extracted three times with MeOH, and concentrated to dryness. The greenish residue (47.2 g) was suspended in H2O and partitioned with Et2O. The water soluble part (18.7 g) was subjected to a Diaion HP-20 column, and eluted with H2O, and MeOH, successively. The fraction eluted with MeOH (3.5 g) was applied to a silica gel column using solvent systems EtOAc-MeOH (9:1, 1.0 L), EtOAc-MeOH-H2O (40:10:1, 4.0 L), EtOAcMeOH-H2O (70:30:3, 2.0 L) and EtOAc-MeOH-H2O (6:4:1, 1.0 L), respectively to provide nine fractions (A to I). Fraction B was purified by preparative HPLC-ODS using solvent system H2O-MeCN (80:20, v/v) to provide compounds 6 (15.7 mg), 7 (5.7 mg), 9 (6.8 mg), 10 (25.1 mg) and 13 (6.7 mg). Fraction C was purified by preparative HPLC-ODS using solvent system H2O-MeCN (80:20, v/v) to give compound 14 (12.4 mg). Fraction D was purified by preparative HPLC-ODS using solvent system H2O-MeCN (80:20, v/v) to obtain compounds 8 (2.5 mg) and 12 (7.8 mg). Fraction F (7.8 g) was purified by preparative HPLCODS with solvent system H2O-MeCN (80:20, v/v) to afford compound 11 (0.6 mg). Finally, fraction H was purified by preparative HPLC-ODS with solvent system H2O-MeCN (80:20, v/v) to yield compounds 1 (11.4 mg), 2 (6.5 mg), 3 (10.0 mg), 4 (3.0 mg) and 5 (8.5 mg).
Fig. 2. Significant HMBC correlations of compound 1.
spectra. This methyl group was suggested to be located at C-7 since the chemical shifts of C-6, C-7 and C-8 were changed as compared to compound 4 (Table 2). The assignment was confirmed by the HMBC correlations from H-6 (δH 6.32), H-8 (δH 6.57) and the methoxyl signal (δH 3.88) to C-7 (δC 167.1) as shown in Fig. 2. The aglycone of this compound was rhamnetin (Agrawal and Bansal,1989) therefore, 1 was elucidated as rhamnetin-3-O-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside. Champaluangoside B (2) was obtained as a yellow amorphous powder. Its molecular formula was determined as C34H42O19, by its HRESITOF mass spectrometric analysis. The 1H and 13C NMR spectra (Tables 1 and 2) were very similar to those of 1, except for the presence of signals of β-galactopyranosyl unit instead of β-glucopyranosyl unit. The chemical shifts of the sugar moiety were in agreement with those of oxytroflavoside G (5), and identified to be α-L-rhamnopyranosyl-(1→ 58
Phytochemistry Letters 29 (2019) 57–60
C. Srinroch et al.
Table 1 1 H (400 MHz) spectroscopic data of compounds 1–3 (in CD3OD). Position
1
2
3
6.32 (1H, d, J = 2.2 Hz) 6.57 (1H, d, J = 2.2 Hz) 7.61 (1H, dd, J = 2.0 Hz)
6.31 (1H, d, J = 2.2 Hz) 6.57 (1H, d, J = 2.2 Hz) 7.73 (1H, dd, J = 2.1 Hz)
6.88 7.63 3.88 Glc 5.60 3.65 3.54 3.27 3.35 3.81 3.40
(1H, d, J = 9.0 Hz) (1H, d, J = 9.0, 2.0 Hz) (3H, s)
(1H, d, J = 8.5 Hz) (1H, d, J = 8.5, 2.1 Hz) (3H, s)
(1H, (1H, (1H, (1H, (1H, (1H, (3H,
d, d, d, d, d, d, s)
(1H, (1H, (1H, (1H, (1H, (1H, (1H,
d, J = 7.7 Hz) dd, J = 9.2, 7.7 Hz) dd, J = 9.2, 9.1 Hz) dd, J = 9.2, 9.0 Hz) m) dd, J = 10.3, 1.5 Hz) dd, J = 10.3, 6.2 Hz)
6.89 7.60 3.88 Gal 5.69 3.96 3.73 3.81 3.68 3.74 3.49
(1H, (1H, (1H, (1H, (1H, (1H, (1H,
d, J = 7.8 Hz) dd, J = 9.6, 7.8 Hz) dd, J = 9.6, 3.3 Hz) br d, J = 3.3 Hz) m) dd, J = 11.1, 1.8 Hz) dd, J = 11.1, 6.1 Hz)
6.32 6.58 8.06 6.90 6.90 8.06 3.88 Glc 5.60 3.60 3.54 3.23 3.36 3.81 3.38
(1H, (1H, (1H, (1H, (1H, (1H, (1H,
d, J = 7.6 Hz) dd, J = 9.1, 7.6 Hz) dd, J = 9.2, 9.1 Hz) dd, J = 9.2, 8.8 Hz) m) dd, J = 12.2, 1.5 Hz) dd, J = 12.2, 6.1 Hz)
2"-Rha 1'" 2'" 3'" 4'" 5'" 6'"
5.22 4.00 3.79 3.35 4.08 1.01
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.5 Hz) dd, J = 3.2, 1.5 Hz) dd, J = 9.4, 3.2 Hz) dd, J = 9.6, 9.4 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
5.22 4.00 3.78 3.33 4.04 0.95
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.6 Hz) dd, J = 3.2, 1.6 Hz) dd, J = 9.6, 3.2 Hz) dd, J = 9.6, 9.6 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
5.23 4.00 3.79 3.35 4.06 0.99
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.6 Hz) dd, J = 3.2, 1.6 Hz) dd, J = 9.7, 3.2 Hz) dd, J = 9.7, 9.6 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
6"-Rha 1"" 2"" 3"" 4"" 5"" 6""
4.50 3.56 3.47 3.23 3.41 1.07
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.6 Hz) dd, J = 3.4, 1.6 Hz) dd, J = 9.5, 3.4 Hz) dd, J = 9.5, 9.5 Hz) dq, J = 9.5, 6.2 Hz) d, J = 6.2 Hz)
4.54 3.56 3.50 3.26 3.53 1.18
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.7 Hz) dd, J = 3.4, 1.7 Hz) dd, J = 9.5, 3.4 Hz) dd, J = 9.6, 9.5 Hz) dq, J = 9.6, 6.2 Hz) d, J = 6.2 Hz)
4.49 3.56 3.46 3.22 3.41 1.07
(1H, (1H, (1H, (1H, (1H, (3H,
d, J = 1.5 Hz) dd, J = 3.4, 1.5 Hz) dd, J = 9.5, 3.4 Hz) dd, J = 9.5, 9.5 Hz) dq, J = 9.5, 6.2 Hz) d, J = 6.2 Hz)
Aglycone 6 8 2' 3' 5' 6' 7-OCH3 1" 2" 3" 4" 5" 6"
Table 2 (continued)
Table 2 13 C NMR (100 MHz) spectroscopic data of compounds 1–4 (in CD3OD). Position
1
2
3
4
5
158.8 134.8 179.4 162.9 98.9 167.1 93.0 158.3 106.8 123.2 117.4 145.9 149.8 116.1 123.1 56.4 Gal 101.0 77.4 75.7 70.9 75.3 67.1
159.4 134.5 179.4 162.9 99.0 167.1 93.1 158.4 106.7 123.0 132.2 116.2 161.4 116.2 132.2 56.4 Glc 100.5 79.9 78.9 72.0 77.1 68.4
158.9 134.5 179.3 163.2 99.7 165.6 94.7 158.4 105.9 123.5 117.4 145.9 149.5 116.1 123.6
1" 2" 3" 4" 5" 6"
159.3 134.7 179.4 162.9 98.9 167.1 93.1 158.3 106.7 123.4 117.5 145.9 149.7 116.1 123.5 56.4 Glc 100.5 80.0 78.9 71.9 77.1 68.4
Glc 100.5 80.0 78.9 71.9 77.1 68.3
159.0 134.7 179.5 162.9 99.0 167.1 93.0 158.3 106.7 122.9 132.3 116.2 161.4 116.2 132.3 56.4 Gal 100.9 77.6 75.7 70.7 75.4 67.2
2"-Rha 1"' 2"' 3"' 4"' 5"' 6"'
102.7 72.4 72.3 74.0 70.0 17.5
102.6 72.4 72.3 74.0 69.9 17.4
102.6 72.4 72.3 74.0 69.9 17.6
102.6 72.4 72.3 74.1 70.0 17.5
102.6 72.4 72.3 74.0 69.8 17.9
6"-Rha 1"" 2""
102.3 72.1
101.9 72.1
102.3 72.1
102.3 72.1
101.9 72.1
Aglycone 2 3 4 5 6 7 8 9 10 1' 2' 3' 4' 5' 6' 7-OCH3
J = 2.0 Hz) J = 2.0 Hz) J = 8.9 Hz) J = 8.9 Hz) J = 8.9 Hz) J = 8.9 Hz)
Position
1
2
3
4
5
3"" 4"" 5"" 6""
72.2 73.8 69.7 17.8
72.3 73.9 69.7 18.0
72.3 73.8 69.7 17.8
72.3 73.9 69.7 17.8
72.3 73.9 69.7 17.8
3.4. Champaluangoside A (1) Amorphous powder, [α]D25 −80.6 (MeOH, c 0.48); UV λmaxMeOH (nm): 355.0, 256.5; 1H NMR: Table 1; 13C NMR (CD3OD): Table 2; Positive HRESITOF-MS, m/z: 771.2330 [M+H]+ (C34H43O20 required 771.2342). 3.5. Champaluangoside B (2) Amorphous powder, [α]D25 −85.2 (MeOH, c 0.52); UV λmaxMeOH (nm): 356.0, 256.5; 1H NMR: Table 1; 13C NMR (CD3OD): Table 2; Positive HRESITOF-MS, m/z: 793.2131 [M+Na]+ (C34H42NaO20 required 793.2161). 3.6. Champaluangoside C (3) Amorphous powder, [α]D25 −68.8 (MeOH, c 0.38); UV λmaxMeOH (nm): 347.0, 266; 1H NMR: Table 1; 13C NMR (CD3OD): Table 2; Negative HRESITOF-MS, m/z: 789.2036 [M+Cl]− (C34H42ClO19 required 789.2014). Acknowledgements This research work was supported by the grant from Chulabhorn Research Institute and Khon Kaen University. The authors also thank 59
Phytochemistry Letters 29 (2019) 57–60
C. Srinroch et al.
Mr. Thinakorn Komkris for providing the plant materials from his garden, Khao Kho, Phetchabun Province, Thailand.
Kobayashi, H., Karasawa, H., Miyase, T., Fukushima, S., 1985. Studies on the constituents of Cistanchis herba. V. Isolation and structures of two new phenylpropanoid glycosides, cistanosides E and F. Chem. Pharm. Bull. 33, 1452–1457. Ly, T.N., Yamauchi, R., Shimoyamada, M., Kato, K., 2002. Isolation and structural elucidation of some glycosides from the rhizomes of smaller galangal (Alpinia officinarum Hance). J. Agric. Food Chem. 50, 4919–4924. Sahakitpichan, P., Chimnoi, N., Wongbundit, S., Vorasingha Ruchirawat, S., Kanchanapoom, T., 2017. Phenylethanoid glycosides from the leaves of Magnolia hodgsonii. Phytochem. Lett. 21, 269–272. Seigler, D.S., Pauli, G.F., Nahrstedt, A., Leen, R., 2002. Cyanogenic allosides and glucosides from Passiflora edulis and Carrica papaya. Phytochemistry 60, 873–882. Wang, S.-S., Zhang, X.-J., Que, S., Tu, G.-Z., Wam, D., Cheng, W., 2012. 3-Hydroxy-3Methylglutaryl flavonol glycosides from Oxytropis falcata. J. Nat. Prod. 75, 1359–1364. Xue, Z., Yan, R., Yang, B., 2016. Phenylpropanoid glycosides and phenolic glycosides from stem bark of Magnolia officinalis. Phytochemistry 127, 50–62. Yang, M.C., Lee, K.H., Kim, K.H., Choi, S.U., Lee, K.R., 2007. Lignan and terpene constituents from the aerial parts of Saussurea pulchella. Arch. Pharm. Res. 30, 1067–1074. Yu, S., Yan, R., Liang, R., Wang, W., Yang, B., 2012. Bioactive polar compounds from stem bark of Magnolia officinalis. Fitoterapia 83, 356–361.
References Agrawal, P.K., Bansal, M.C., 1989. Flavonoid glycosides. In: Agrawal, P.K. (Ed.), Carbon13 NMR of Flavonoids. Elsevier, Amsterdam, pp. 283–364. Figlar, R.B., Nooteboom, H.P., 2004. Notes on Magnoliaceae IV. Blumea 49, 87–100. Hasekawa, T., Fukuyama, Y., Yamada, T., Nakagawa, K., 1988. Isolation and structure of magnoloside A, a new phenylpropanoid glycoside from Magnolia obovata Thunb. Chem. Lett. 17, 163–166. Kanchanapoom, T., Sahakitpichan, P., Chimnoi, N., Srinroch, C., Thamniyom, W., Ruchirawat, S., 2018. Monoterpene, benzyl and 3,4-d ihydroxyphenethyl glycosides from Magnolia thailandica. Phytochem. Lett. 25, 28–32. Kazuma, K., Noda, N., Suzuki, M., 2003. Malonylated flavonol glycosides from the petals of Clitoria ternatea. Phytochemistry 62, 229–237. Kiem, P.V., Tri, M.D., Tuong, L.V.D., Tung, N.H., Hanh, N.N., Quang, T.H., Cuong, N.X., Minh, C.V., Choi, E.-M., Kim, Y.H., 2008. Chemical constituents from the leaves of Manglietia phuthoensis and their effects on osteoblastic MC3T3-E1 cells. Chem. Pharm. Bull. 56, 1270–1275.
60