大葉紫珠中得到的一個新苯丙素類衍生物

孟令杰，劉百聯，張 英，周光雄

暨南大學藥學院 廣東省普通高校中藥及天然藥物藥效物質基礎重點實驗室 中藥及天然藥物研究所，廣州 510632

Introduction

Callicarpa macrophyllaVahl (Verbenaceae)is mainly distributed in Guangdong，Guangxi，Yunnan，Guizhou，and other southern provinces of China［1］.It has been used to treat various diseases or symptoms，such as dispelling wind and eliminating dampness，and hemostatic in the folk.The chemical investigation carried in the past years had revealed that it contained triterpenes，diterpens，flavonoids and phenylpropanoid derivatives［2-12］.In this study，we reported the isolation and structural determination of a new phenylpropanoid derivative(1)from the titled plant.The structure of the new compound was elucidated by spectroscopic analyses including 2D NMR spectra (1H-1H COSY，HSQC and HMBC) and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS).

Materials and Methods

General experimental procedures

Optical rotations were carried out using a JASCO P-1020 automatic digital polarimeter (JASCO Corporation，Tokyo，Japan).UV spectra were recorded on a JASCO V-550 UV/VIS spectrometer (JASCO Corporation，Tokyo，Japan).The IR spectra were recorded on a Nicolet Impact 410-FTIR instrument (Thermo，San Jose，CA，USA)in KBr pellets.HR-ESI-MS was acquired using Agilent 6210 LC/MSD TOF mass spectrometer(Agilent Technologies，Santa Clara，CA，USA).1D and 2D NMR spectra were recorded in CD3OD using Bruker AV-300 spectrometer (Bruker Instrument，Inc.，German)with tetramethylsilane (TMS)as the internal standard，and the chemical shifts were expressed in δ values (ppm).Open column chromatography was performed by silica gel (300-400 mesh，Haiyang Chemical Group Corporation，Qingdao，China)，and ODS (50 μm，YMC，Tokyo，Japan).Sephadex LH-20 (25-100 μm)was obtained from Pharmacia (Uppsala，Sweden).HSGF254silica gel thin-layer chromatography(TLC)plates (0.2 mm thickness，200 × 200 mm，Qingdao Marine Chemical，China)were used for analysis.

Plant material

The experimental material was collected from Liuxihe natural forest reservation district，Conghua city，Guangdong province，China.The original plant was authenticated asCallicarpa macrophyllaVahl (Verbenaceae)by Prof.Guangxiong Zhou at Pharmacognosy Department，college of pharmacy，Jinan University.A specimen(2011CM001)was deposited in the Pharmacognosy Department of the college.

Extraction and isolation

The dried root ofCallicarpa macrophyllaVahl (12 kg)were extracted with 70% alcohol under reflux for three times.The extracts were combined and concentrated under reduced pressure to about 700 g.Then，the extract was suspended in distilled water and partitioned successively with petroleum ether，ethyl acetate，and nbutanol to afford 45 g，80 g，and 200 g of extracts，respectively as well as 300 g water-soluble residue.The ethyl acetate extract (80 g)was subjected to silica gel chromatography eluting with gradient CHCl3-MeOH systems (100∶0→100∶2→100∶3→20∶1→9∶1→8∶2→7∶3 →6∶4→1∶1→0∶100)to afford 20 fractions (Fr 1～20)after combination of fractions by TLC pattern.Fr 12 was subjected to ODS column chromatography eluting with MeOH-H2O (30%→40%→60%→80%→100%)to afford 2 subfractions (Fr 12-1～2).Fr 12-1 was purified on sephadex LH-20 column eluting with MeOH to obtain compound 1 (11 mg).

Results and Discussion

Structural elucidation

Yellow powder;MP:280～285℃;［α］25D:-5.8° (c 0.33，MeOH);UV (MeOH)λmax:209，287，313 nm;IR (KBr)υmax:3418，2925，1737，1618 cm-1;1H NMR(300 MHz，CD3OD)and13C NMR (75 MHz，CD3OD)data，see table 1;HR-ESI-MS:m/z619.16407 ［M +Na］+(calcd.for C27H32O15，619.16334，△+1.18 ppm).Compound 1 was obtained as a yellow powder.Its molecular formula was deduced to be C27H32O15from the HR-ESI-MS spectrum atm/z619.16407［M+Na］+.The1H NMR signals belonged to olefinic and aromatic protons at δH7.47 (1H，d，J=15.9 Hz)，6.15 (1H，d，J=15.9 Hz)，7.0 (1H，br s)，6.89 (1H，d，J=7.8 Hz)and 6.77 (1H，d，J=7.8 Hz)，combining with the signal of one ester carbonyl carbon at δC169.0 in13C NMR spectrum.Furthermore，the correlations of protons at δH6.89 (H-6''')，7.0 (H-2''')with a carbon at δC149.8 (C-4''')and the proton at δH6.77(H-5''')with a carbon at δC146.9 (C-3''')in the HMBC spectrum suggested the presence of onetrans-pcaffeoyl moiety［13］.The1H and13C NMR spectra (See Table 1)also revealed the presence of glucopyranosyl and apiofuranosyl moieties.The β-anomeric configuration for the glucopyranosyl was determined from the coupling constant value of the anomeric proton at δH4.82 (1H，d，J=7.0 Hz).The β-anomeric configuration for the apiofuranosyl was indicated from the anomeric signals at δC/δH110.6/5.5 (1H，br s).The apiosyl-(1→2)-glucosyl linkage of the disaccharride was assigned on the basis of the correlation between apiosyl proton at δH5.50 (H-1'')and glucosyl carbon at δC78.9 (C-2')in the HMBC spectrum (Fig.1).Furthermore，the HMBC correlation between proton at δH4.25 (H-5'')and carbon at δC169.0 (α-C)suggested that the caffeoyl unit was attached to C-5 of apiosyl.The1H NMR spectrum also indicated a methoxy group at δH3.78 and three aromatic protons at δH6.71 (1H，d，J=2.6 Hz)，6.64 (1H，d，J=8.6 Hz)and 6.49 (1H，dd，J=8.6，2.6 Hz)from a AMX spin-coupling system.The correlations of protons at δH6.71 (H-5)，6.64 (H-3)and 3.78 (2-OCH3)with a carbon at δC149.4 (C-2)in the HMBC spectrum showed that the methoxy group was linked to C-2.The HMBC correlation between proton at δH4.82 (H-1')and carbon at δC152.7 (C-4)revealed that the disaccharride chain was connected to C-4 of benzene moiety.Based on the above elucidation，the structure of 1 was established as methoxyquinol 4-O-［(5-O-trans-p-coffeeacyl)-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside］.

Table 1 1D and 2D NMR data of compound 1 in CD3OD

Fig.1 Key HMBC(H→C)correlations of compound 1

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