肋果茶中的萜类化学成分研究

张兰春，吴兴德，何 隽，彭丽艳，张荣平，赵勤实*

1昆明医科大学药学院，昆明650500;2中国科学院昆明植物研究所植物化学与西部植物资源持续利用国家重点实验室，昆明650204

Introduction

Sladenia celastrifolia Kurz(Sladeniaceae)is a monotypic species widely distributed in Burma，northern Thailand，and the southern China［1］.Terpenoids have been isolated from this plant［2］.To discover more terpenoids，we initiated a phytochemical study on the stems and leaves of S.celastrifolia.As a result，a new seco-iridoid，sladeniafolin A(1)was isolated from this plant，together with fourteen known terpenoids，grasshopper ketone(2)［3］，(3S，5R，6S，7E，9R)-7-megastigmene-3，6，9-triol(3)［4］，hedytriol(4)［5］，(3S，5R，6R，7E，9R)-3，5，6，9-tetrahydroxy-7-megastigmene(5)［6］，1＇S*，4'R*-8-(4＇-hydroxy-2＇，6＇，6＇-trimethylcyclohex-2-enyl)-6-methyloct-3E，5E，7E-trien-2-one(6)［7］，2α，3α，19α，23-tetrahydroxyurs-12-en-28-oic acid(7)［8］，2α，3β，19α，23-tetrahydroxyurs-12-en-28-oicacid(8)［8］，pomolic acid(9)［9］，3-O-acetyl pomolic acid(10)［10］，ursaldehyde(11)［11］，camarolide(12)［12］，3β-hydroxyurs-11-en-13β(28)-ol-ide(13)［13］，3β-hydroxy-11α，12α-epoxy-urs-13β，28-olide(14)［14］，and 28-O-β-D-glucopyranosyl euscaphic acid(15)［15］.Herein，we report the isolations and structure elucidations of these compounds.

Fig.1 Compounds 1-15 from S.celastrifolia

Experimental

General procedures

Optical rotation was measured on a Jasco P-1020 polarimeter.The IR spectrum was obtained with a Bruker Tensor 27 spectrometer KBr disc.NMR spectra were recorded on Bruker AM-400，DRX-500，and Avance III 600 spectrometers(δ in ppm，J in Hz).ESI-MS spectra were carried out on a Bruker HCT/Esquire spectrometer，HR-ESI-MS spectra on an API QSTAR Pulsar spectrometer.Column chromatography(GC)was performed using silica gel(100-200 and 200-300 mesh，Qingdao Haiyang Chemical Co.Ltd，Qingdao，People’s Republic of China)，Lichropre RP-18 gel(40-63 μm，Merck，Darmstadt，Germany)and MCI gel(75-150 μm，Mitsubishi Chemical Corporation，Japan)，Fractions were visualized by heating silica gel plates sprayed with 10%H2SO4in ethanol.

Plant Material

Stems and leaves of S.celastrifolia were collected in Kumming Botanical Gardens of Yannan Province，P.R. China，in July 2010.The plant was indentified by Prof. X.Cheng at Kunming Institute of Botany.A voucher specimen(No.20100715)was deposited at the State Key Laboratory of Photochemistry and Resources in West China，Kunming Institute of Botany，Chinese A-cademy of Sciences，R.P.China.

Extraction and Isolation

The air-dried plant material(28 kg)was percolated with 95%EtOH(3×75 L，48 h)at room temperature.The extract was evaporated to dryness under reduced pressure.The obtained residue was suspended in H2O and partitioned successively with EtOAc to afford an EtOAc extract 1.6 kg.The EtOAc extract was subjected to column silica gel，which eluted gradiently with petroleum ether:Me2CO(1∶0→0∶1)to afford five fractions(1-5).

Fraction 1(10 g)was separated over silical gel column using petroleum ether:Me2CO(9∶1→3∶2)as solvents to give 13(50 mg)and 14(10 mg).Fraction 2(20 g)was divided in to 2 subfractions(2a-2b)over silica gel column with petroleum ether:EtOAc(1∶0→0∶1)as solvents.Subfraction 2a was further purified on silica gel column using petroleum ether:Me2CO (8∶2→7∶3)and combined with sephadax LH-20 eluted with CHCl3-MeOH(1∶1)to afford 11(10 mg)and 12(2 mg).Subfraction 2b with was chromatographed further over MCI(85%MeOH-H2O to 100%MeOH) give fraction 2b1 and 2b2.Subfraction 2b1 was purified on a silica gel column eluted with petroleum ether: Me2CO(8∶2)and than conbined with sephadax LH-20 eluted with MeOH to afford 10(10 mg)，9(9 mg) and 6(5 mg).Subfraction 2b2 was applied to an RP-18 gel eluted with MeOH-H2O(7∶3→1∶0)，followed by chromatographed over repeated silica gel CC and finally purified by sephadax LH-20 eluted with MeOH to 5(30 mg)and 8(10 mg).Fraction 3(10 g)was separated over silica gel column and finally purified by sephadax LH-20 column eluted with CHCl3-MeOH(1∶1)to afforded 7(30 mg)and 1(29 mg).15(16 mg)，4(6 mg)，3(30 mg)and 2(63 mg)were isolated from fraction 4(20 g)by chromatography on MCI gel column(85%MeOH-H2O to 100%MeOH)，and repeated purified over silica gel CC，RP-18 and Sephadex LH-20 columns.

Result and Discussion

Table 1 NMR data of compound 1 in CD3OD(δ in ppm，J in Hz)

Fig.2 Key1H-1H COSY and HMBC correlations

Compound 1 was obtained as colorless oil.Its molecular formula C9H14O4was established by HR-ESI-MS(m/z 209.0789［M+Na］+，calcd 209.0789)，indicating three degrees of unsaturation.Its IR spectrum exhibited absorption bands for hydroxy(3395 cm-1)，ester carbonyl groups(1727 cm-1)，and double band(1646 cm-1).An analysis of the1H NMR spectrum indicated the typical signals of one olefinic protons at δ 5.71 (1H，m)and six oxygenated methylene protons［δH4. 89(1H，d，J=13.2 Hz，H-1a)，4.69(1H，d，J=13. 2 Hz，H-1b)，3.51(1H，m，H-7a)，3.42(1H，m，H-7b)，4.21(1H，m，H-10a)，4.17(1H，m，H-10b)］. The13C NMR(DEPT)spectra of 1 showed two methylenes(δC35.5，C-4;38.9，C-6)，one methane(δC30.7，C-5)，three oxygenated methylenes(δC72.8，C-1;59.6，C-7;58.7，C-10)，one trisubstituted double bond(δC128.9，C-8;136.6，C-9)and an ester carbonyl(δC175.3，C-3).The above evidence implied that compound 1 was a C9seco-iridoid.Its 1D NMR data was similar to those of floribundane B［16］.The obvious differcnce was that the methyl group in floribundane B was substituted by a hydroxymethyl group in 1，which was supported by the 1D NMR data(Table 1). In addition，the ester carbonyl was substituted at C-3 in 1 rather than C-1 in floribundane B，as deduced from the1H-1H COSY correlations of H2-4/H-5/H2-6/H2-7，and confirmed by the HMBC correlations from H2-1，H-4a(δH2.79，dd，J=6.4，15.8 Hz)，and H-4b(2. 64，dd，J=6.0，15.8 Hz)to the ester carbonyl.The ROESY correlation of H-8 with H-1a suggested the E-orientation of the double bond in compound 1.On the basis of the above evidence，compound 1 was determined to be a new C97，8-secoiridoid derivative and named as sladenfolin A.

Sladeniafolin A(1):colorless oil，C9H14O4;［α］-2.18(c 0.67，CH3OH).UV(CH3OH):λmax(log ε):201(3.47).IR(KBr):3395，2935，2883，1727，1384，1318，1296，1268，1087，1086，1055，1023 cm-1.1H and13C NMR:Tables 1，ESI-MS(positive): 209(［M+Na］+).HR-ESI-MS(positive):209. 0787(［M+Na］+，C9H14O4Na;calc.209.0789).

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