白睿峰 蘇國柱 馮曉 張瑞飛 尹旭 葉云云 陳蘇依勒 屠鵬飛 柴興云
[摘要] 通過色譜方法從羽葉丁香的莖皮中分到11個化學成分,經質譜、核磁共振譜及與文獻數據相比鑒定其結構。其中化合物1為新木脂素,命名為反式羽葉丁香素A (Zpinnatifolin A),10個已知物分別鑒定為pinnatifolin A (2), 乙基松柏苷ethylconiferin(3),甲基松柏苷(4),丁香素(5),β, 3, 4trihydroxyphenethyl alcohol(6), (S)(+)2(3, 4dihydroxyphenyl)2ethoxyleth anol(7), 3, 4dihydroxyβmethoxyphenethyl alcohol(8), 3, 4, 5三羥基苯乙醇(9), 紅景天苷(10), 羥基酪醇(11), 其中3,4,8~11為丁香屬內首次報道,5~7為該種首次報道。化合物1對神經小膠質細胞BV2的NO生成顯示一定的抑制活性。該研究為表征山沉香抗心肌缺血的藥效物質提供了一定的參考。
[關鍵詞] 羽葉丁香; 蒙藥; 反式羽葉丁香素A
A new lignan from stem bark of Syringa pinnatifolia
BAI Ruifeng1, SU Guozhu1, FENG Xiao1, ZHANG Ruifei1, YIN Xu1,
YE Yunyun1,2, CHEN Suyile3, TU Pengfei1, CHAI Xingyun1*
(1. Modern Research Center for Traditional Chinese Medicine, School of Chinese Materia Medica,
Beijing University of Chinese Medicine, Beijing 100029, China;
2. Pharmacy College, Ningxia Medical University, Yinchuan 750004, China;
3. Alashan League Mongolian Medicine Hospital, Alashan League 750300, China)
[Abstract] One new lignan, named Zpinnatifolin A, along with ten known analogues, were isolated from the stem bark of Syringa pinnatifolia by various chromatographic methods. Their structures were extensively determined on basis of MS and NMR spectroscopic data analyses, and comparison with those in literature. Among them, compounds 3,4, and 811 were isolated from this genus for the first time, and 57 were isolated from the specie for the first time. Compound 1 showed a moderate inhibition on NO production in BV2 cells. The present study provides a preliminary data for clarification of bioactive ingredients of S.pinnatifolia with antimyocardial ischemic effect.
[Key words] Syringa pinnatifolia; Mongolian folk medicine; Zpinnatifolin A
羽葉丁香Syringa pinnatifolia Hemsl.是我國丁香屬特有品種,有限集中分布于內蒙古和寧夏交界的賀蘭山地區。羽葉丁香去皮的根、根莖及粗枝,是一種特色蒙藥材——山沉香,具有抑赫依、清熱、止痛等功效,蒙醫用其治療胸悶氣短、心肌缺血等心肺疾病,療效顯著 [12]。
此前本課題組報道了山沉香乙醇提取物的抗心肌缺血作用[3]及莖皮中的木脂素類和環烯醚萜類成分[47]。作為系統研究的一部分,本文進一步報道從莖皮中分離得到的11個化學成分,其中1個新木脂素類命名為反式羽葉丁香素A (Zpinnatifolin A),10個已知物分別鑒定為pinnatifolin A(2),乙基松柏苷ethylconiferin(3),甲基松柏苷(4),丁香素(5),β,3,4trihydroxyphenethyl alcohol(6),(S)(+)2(3,4dihydroxyphenyl)2ethoxylethanol(7),3,4dihydroxyβmethoxyphen ethyl alcohol (8),3,4,5三羥基苯乙醇(9),紅景天苷(10),羥基酪醇(11)。化合物3,4,8~11為丁香屬內首次報道,5~7為本種內首次報道。本研究為闡明山沉香抗心肌缺血的藥效物質提供了一定的參考。
1 材料
1.1 藥材 羽葉丁香于2013年7月采自內蒙古阿拉善賀蘭山地區,經阿拉善盟蒙醫醫院陳蘇依勒鑒定為S. pinnatifolia,異名賀蘭山丁香S.pinnatifolia var. alashanensis Y.C. Ma & S.Q. Zhou[2],剝取莖木部分的皮層,陰涼處干燥,藥材標本存放于北京中醫藥大學中藥現代研究中心(SP201307B)。
1.2 細胞 BV2小膠質細胞系由中國醫學科學院細胞中心提供。
1.3 儀器和試劑 Varian Inova500型核磁共振儀;日本島津高效液相離子阱飛行時間質譜儀;美國魯道夫Autopol IV旋光儀;Sephadex LH20(瑞典Amershan Biosciences);Waters 2535制備液相(美國Waters);半制備色譜柱Shimpack PREPODS (H) C18 (20 mm×250 mm,5 μm)。ODS(40~63 μm,德國Merck);柱色譜用硅膠(200~300目)及薄層色譜用GF254硅膠預制板,均為青島海洋化工廠生產;提取和分離中所用化學試劑均為分析純(北京化工廠);SANYO MCO18AIC細胞培養箱;Motic AE2000倒置熒光顯微鏡;ESCO OptiMair超凈工作臺;瑞士TECAN M1000型多功能酶標儀;DMEM培養基(Hyclone,美國);胎牛血清(Gibco,美國);NO化學法試劑盒(南京建成生物公司);陽性對照為槲皮素和姜黃素(Sigma,美國)。
2 提取與分離
羽葉丁香莖皮(1.3 kg),依次用95%,80%的乙醇回流提取2次,每次2.5 L,提取1.5 h。提取液減壓濃縮得浸膏325 g。采用正相硅膠柱色譜,依次用氯仿甲醇(20∶1~0∶1)洗脫得到9個流分(A~I)。流分C(31.2 g)經正相硅膠柱色譜,依次用二氯甲烷乙酸乙酯(3∶1~0∶1),甲醇洗脫得到10個流分(C1~C10)。C3 (330 mg)經Sephadex LH20 (二氯甲烷甲醇,1∶1)洗脫得3個流分(C3a~C3c)。流分C3c (80 mg)經制備薄層色譜得到化合物7 (20.5 mg)。C4 (980 mg)采用Sephadex LH20 (二氯甲烷甲醇,1∶1) 洗脫得到3個流分(C4a~C4c)。C4b (72 mg) 經制備HPLC (甲醇水,50∶50,7.0 mL·min-1) 純化得到化合物11(tR=9.8 min,4.2 mg),其余部分經制備HPLC(甲醇水,40∶60,7.0 mL·min-1)純化得到化合物2(tR=29.5 min,9.4 mg)和1(tR=43.2 min,8.0 mg)。
流分E(10.6 g)和F (8.2 g)合并,經正相硅膠柱色譜,依次用乙酸乙酯甲醇(10∶1~0∶1),洗脫得到8個流分(EF1~EF8)和結晶化合物5 (2.5 g)。EF1 (1.2 g)采用ODS柱色譜,依次用甲醇水(1∶2~1∶0)洗脫得到8個流分(EF11~EF18)和結晶10 (30.5 mg)。EF15 (310 mg) 經制備HPLC (乙腈水,18∶82,7.0 mL·min-1)純化得到化合物4(tR=26.0 min,7.5 mg)。EF18 (162 mg)經制備HPLC (乙腈水,20∶80,7.0 mL·min-1)純化得到化合物3(tR=35.0 min,7.5 mg)。EF7 (1.6 g)經Sephadex LH20 (甲醇)洗脫得到7個流分(EF7a~7f),其中EF7ce合并為EFX(1.1 g),經正相硅膠柱色譜,依次用乙酸乙酯甲醇(20∶1~0∶1),洗脫得到9個流分(EFX1~X9)。EFX8 (120 mg)經制備HPLC (甲醇水 20∶80,7.0 mL·min-1)純化得到化合物6(tR=9.8 min,10.5 mg),9(tR=18.7 min,6.3 mg)和8(tR=21.8 min,3.5 mg)。
2 結構鑒定
化合物1 白色粉末;HRESIMS給出準分子離子峰359.151 3 [M-H]-,(計算值C20H23O6,359.150 0); [α]25D-34.0° (c 0.1,MeOH); UV (MeOH)λmax (logε) 264 (3.74),208 (4.14) nm; IR (KBr) vmax 3 432,2 922,1 637,1 515,1 273,1 032 cm-1,顯示有羥基和苯環等吸收峰。ECD (MeOH) λmax (Δε) 219 (+1.26),227 (-0.66),251 (-0.52),261 (+0.82),281 (-0.82),290 (-0.73)。1H和13CNMR 見表1,數據顯示2組ABX偶合系統[δH 6.84 (1H,d,J=1.5 Hz,H2),6.70 (2H,overlapped,H5,H5′),6.68 (1H,overlapped,H6)],[δH 6.77 (1H,d,J=1.5 Hz,H2′),6.70 (H5′),6.64 (1H,dd,J=1.5,8.0 Hz,H6′)],1個烯氫單峰δH 6.32 (H7),2個連氧亞甲基δH 4.01,4.21/δC 60.6 (C9)和δH 3.66,3.72/δC 65.8 (C9′),1個亞甲基(C7′)和1個次甲基(C8′)。以上信息并結合HMBC分析可知,1與已知的pinnatifolin A相似,不同之處在H8′ (δH 2.76/3.37)和C8′ (δC 51.3/45.2)[8]數據,見圖1。
NOESY數據顯示1的H7與H7′及H8′有關,說明1的Δ7,8雙鍵為Z構型。通過計算ECD發現,化合物1構象多且計算過程復雜,有待后續更多證據確定其絕對構型,鑒定為Z4,4,9,9四羥基7烯木脂素,為1個新結構,命名為反式羽葉丁香素A (Zpinnatifolin A)。
化合物1 1HNMR (CD3OD, 500 MHz): δ:6.84(1H, d,J=1.5 Hz, H2), 6.70 (2H, overlapped, H5, 5′), 6.68(1H, overlapped,H6), 6.32 (1H, s, H7), 4.21 (1H, d,J=11.5 Hz, H9a), 4.01 (1H, d,J=11.5 Hz, H9b), 6.77 (1H, d,J=1.5 Hz, H2′), 6.64 (1H, dd,J=1.5, 8.0 Hz, H6′), 2.70 (1H, m, H7′a), 2.86 (1H, m, H7′b), 2.76 (1H, m, H8′), 3.72 (1H, m, H9′a), 3.66 (1H, m, H9′b), 3.78 (3H, s, OMe3), 3.82 (3H, s, OMe3′)。13CNMR見表1。
化合物2 白色粉末;[α]25D-14.5° (c 0.01 MeOH); ESIMS m/z 359[M-H]-; 1HNMR (CD3OD,500 MHz) δ: 6.46 (2H,overlapped,H2,6),6.70 (2H,d,J=8.0 Hz,H5,5′),2.75 (1H,dd,J=6.0,14.0 Hz,H7a),2.59 (1H,dd,J=6.0,14.0 Hz,H7b),3.37 (1H,m,H8),3.71 (1H,m,H9a),3.65 (1H,m,H9b),6.55 (3H,overlapped,H2′,6′,7′),4.11 (1H,d,J=13.0 Hz,H9′a),4.28 (1H,d,J=13.0 Hz,H9′b),3.74 (3H,s,OMe3),3.62 (3H,s,OMe3′)。13CNMR數據,見表1;NOESY相關數據顯示H7與H7′及H8′無法觀察到,說明化合物2為E構型,以上NMR數據與文獻[8]對照,鑒定為pinnatifolin A。
化合物3 白色粉末狀;ESIMS m/z 371[M-H]-; 1HNMR (CD3OD,500 MHz) δ:7.07 (1H,d,J=2.0 Hz,H2),7.10 (1H,d,J=8.5 Hz,H5),6.94 (1H,dd,J=2.0,8.5 Hz,H6),6.71 (1H,d,J=16.0 Hz,H7),6.23 (1H,dt,J=4.5,16.0 Hz,H8),4.11 (2H,dd,J=1.0,6.0 Hz,H9),3.86 (3H,s,3OMe),3.60 (2H,m,H1″),1.21 (3H,br t,J=7.0 Hz,H2″),4.89 (1H,J=7.0 Hz,H1′),3.20~3.80 (6H,overlapped,H2′~6′)。13CNMR (CD3OD,125 MHz) δ:133.2 (C1),111.4 (C2),150.9 (C3),147.7 (C4),117.9 (C5),120.8 (C6),133.4 (C7),126.0 (C8),72.3 (C9),56.7 (3OMe),66.6 (C1″),15.9 (C2″),102.7 (C1′),74.9 (C2′),77.9 (C3′),71.3 (C4′),78.2 (C5′),62.5 (C6′)。以上數據與文獻[9]對照,鑒定為乙基松柏苷(ethylconiferin)。
化合物4 白色粉末狀;ESIMS m/z 379[M+Na]+; 1HNMR (CD3OD,500 MHz) δ:6.74 (1H,d,J=1.5 Hz,H2),7.11 (1H,d,J=8.0 Hz,H5),6.95 (1H,dd,J=1.5,8.0 Hz,H6),6.58 (1H,d,J=16.0 Hz,H7),6.23 (1H,dt,J=4.5,16.0 Hz,H8),4.07 (2H,dd,J=1.0,6.0 Hz,H9),3.88 (3H,s,3OMe),3.87 (3H,9OMe),4.89 (1H,J=7.0 Hz,H1′),3.20~3.80 (6H,overlapped,H2′~6′)。13CNMR (CD3OD,125 MHz) δ:133.3 (C1),111.4 (C2),150.9 (C3),147.8 (C4),117.9 (C5),120.9 (C6),133.6 (C7),125.6 (C8),74.2 (C9),56.7 (3OMe),58.1 (9OMe),102.7 (C1′),74.9 (C2′),77.9 (C3′),71.3 (C4′),78.2 (C5′),62.5 (C6′)。以上數據與文獻[10]對照,鑒定為甲基松柏苷(methylconiferin)。
化合物5 白色粉末狀;ESIMS m/z 371[M-H]-;1HNMR (CD3OD,500 MHz) δ:6.74 (2H,s,H2,6),6,53 (1H,d,J=16.0 Hz,H7),6.32 (1H,dt,J=4.5,16.0 Hz,H8),4.21 (2H,d,J=5.5 Hz,H9),3.85 (6H,s,OMe×2),4.85 (1H,overlapped,H1′),3.20~3.80 (6H,overlapped,H2′~6′)。13CNMR (CD3OD,125 MHz) δ:135.3 (C1),105.4 (C2,6),135.9(C4),154.3 (C3,5),130.0 (C7),131.2 (C8),63.6 (C9),57.0 (OMe×2),105.3 (C1′),75.7 (C2′),77.8 (C3′),71.3 (C4′),78.3 (C5′),62.6 (C6′)。以上數據與文獻[11]對照,鑒定為紫丁香素(syringin)。
化合物6 褐色粉末狀;ESIMS m/z 169[M-H]-; 1HNMR (CD3OD,500 MHz)δ:6.80 (1H,br s,H2),6.71 (1H,d,J=8.0 Hz,H5),6.66 (1H,dd,J=1.5,8.0 Hz,H6),3.55 (2H,d,J=6.0 Hz,Hα),4.51 (1H,br t,J=7.0 Hz,Hβ)。13CNMR (CD3OD,125 MHz)δ:134.8 (C1),114.6 (C2),146.2 (C3),145.8 (C4),116.1 (C5),118.9 (C6),68.8 (Cα),75.8 (Cβ)。以上數據與文獻[12]報道一致,鑒定為β,3,4 trihydroxyphenethyl alcohol。
化合物7 白色粉末狀;ESIMS m/z 197[M-H]-; 1HNMR (CD3OD,500 MHz) δ:6.74 (2H,overlapped,H2,6),6.61 (1H,d,J=8.0 Hz,H5),3.58 (1H,m,Hαa),3.46 (1H,overlapped,Hαb),4.20 (1H,d,J=5.0 Hz,Hβ),3.37 (2H,overlapped,H1′),1.15 (3H,br t,J=6.5 Hz,H2′)。13CNMR (CD3OD,125 MHz) δ:132.3 (C1),114.9 (C2),146.3 (C3),146.0 (C4),116.2 (C5),119.6 (C6),67.9 (Cα),84.1 (Cβ),65.1 (C1′),15.5 (C2′)。以上數據與文獻[13]對照,鑒定為(S)(+)2(3,4dihydroxyphenyl)2ethoxylethanol。
化合物8 白色膠狀物;ESIMS m/z 183[M-H]-;1HNMR (CD3OD,500 MHz) δ:6.72 (2H,overlapped,H2,6),6.61 (1H,dd,J=2.0,8.0 Hz,H5),3.58 (1H,dd,J=3.5,13.5 Hz,Hαa),3.48 (1H,dd,J=3.5,13.5 Hz,Hαb),4.08 (1H,dd,J=4.0,8.5 Hz,Hβ),3.22 (3H,s,αOMe)。13CNMR (CD3OD,125 MHz) δ:131.6 (C1),114.9 (C2),146.5 (C3),146.2 (C4),116.2 (C5),119.8 (C6),67.9 (Cα),86.1 (Cβ),56.8 (αOMe)。以上數據與文獻[14]對照,鑒定為3,4dihydroxyβmethoxyphenethyl alcohol。
化合物9 褐色粉末狀;ESIMS m/z 169[M-H]-;1HNMR (CD3OD,500 MHz) δ:6.70 (1H,br s,H2),6.50 (1H,br s,H6),3.48 (2H,m,Hα),2.47 (2H,m,Hβ)。13CNMR (CD3OD,125 MHz) δ:134.1 (C1),117.4 (C2),145.3 (C3),129.1 (C4),144.1 (C5),118.5 (C6),64.0 (Cα),37.0 (Cβ)。以上數據通過分析,鑒定為3,4,5三羥基苯乙醇(3,4,5trihydroxyphenethyl alcohol)。
化合物10 白色晶體;ESIMS m/z 323[M+Na]+; 1HNMR (CD3OD,500 MHz) δ:6.70 (2H,d,J=8.5 Hz,H2,6),7.06 (2H,d,J=8.5 Hz,H3,5),4.04 (1H,dd,J=7.0,13.0 Hz,Hαa),3.69 (1H,overlapped,Hαb),2.83 (2H,m,Hβ),4.30 (1H,d,J=8.0 Hz,H1′),3.20~3.80 (6H,overlapped,H2′~6′)。13CNMR (CD3OD,125 MHz) δ:130.7 (C1),130.9 (C2,6),116.1 (C3,5),156.7 (C4),72.0 (Cα),36.3 (Cβ),104.3 (C1′),75.0 (C2′),77.8 (C3′),71.5 (C4′),78.0 (C5′),62.7 (C6′)。以上數據與文獻[15]對照,鑒定為紅景天苷(salidroside)。
化合物11 褐色粉末狀;ESIMS m/z 153 [M-H]-; 1HNMR (CD3OD,500 MHz)δ:6.64 (1H,d,J=1.0 Hz,H2),6.67 (1H,d,J=8.0 Hz,H5),6.51 (1H,dd,J=1.0,8.0 Hz,H6),3.66 (2H,br t,J=7.0 Hz,Hα),2.65 (2H,br t,J=7.0 Hz,Hβ)。13CNMR (CD3OD,125 MHz)δ:131.8 (C1),116.3 (C2),146.1 (C3),144.6 (C4),117.1 (C5),121.2 (C6),64.6 (Cα),39.6 (Cβ)。以上數據與文獻[16]對照,鑒定為羥基酪醇(hydroxytyrosol)。
4 體外抗炎活性
本研究采用此前報道的相同方法[16]篩選了化合物1和2對BV2細胞的體外抗炎活性。結果顯示,二者對BV2細胞中NO生成有一定的抑制作用,IC50分別為46.4,50.7 μmol·L-1,陽性對照槲皮素的IC50為15.3 μmol·L-1。
5 結果與討論
羽葉丁香去皮的根、根莖及粗枝即為特色蒙藥山沉香,但莖皮并不入藥。本課題組為首次對羽葉丁香莖皮進行化學成分研究,一方面能為羽葉丁香的植物學分類提供化學證據,而羽葉丁香所在屬以下的層級分類一直存在很大的爭議[1],同時莖皮成分研究也有助于后續利用HPLCMS等手段化學表征山沉香藥效部位,因為山沉香和莖皮的成分有一定相似性,主要區別在倍半萜和環烯醚萜類成分[2,7],前者主要來自于去皮莖木,而后者多在皮中,其他如本文所報道的木脂素、苯丙素和苯乙醇等在本植物2個部位中皆有。多酚類具有潛在的抗氧化和神經細胞保護作用[2],與山沉香抗心肌缺血作用有一定的關聯,但類似單體化合物的體外活性和總提取物的體內藥效之間,還需要更多的證據使之相關聯。
上述結構一個顯著特點是部分化合物有甲氧基或乙氧基取代,尤其是乙氧基的存在,很容易與藥材在乙醇提取時的人工產物相關。乙氧基人為引入或天然存在這兩種情況此前都有過報道 [1819],在沒有明確的驗證前,暫不排除化合物4,7,8為人工產物。
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[責任編輯 丁廣治]