陈 霞,张 楠,刘建华,张援虎*
(1.贵州大学药学院,贵州 贵阳 550001;2.贵州省中国科学院天然产物化学重点实验室,贵州 贵阳 550002)
茜草科钩藤属植物主要分布于东南亚、非洲和南美洲[1];民间用于治疗外伤溃疡、细菌真菌感染等[2]。2010年版《中国药典》(一部)收载的钩藤为多基源中药材,其中茜草科钩藤属植物华钩藤Uncaria sinensis(Oliv.)Havil.是其中的一种,其药用部位是干燥带钩茎枝,秋冬二季采收,去叶,切断,晒干,具有清热平肝息风定惊之功效[3],现代药理学研究表明,其主要具有降压和负性心率等作用[4]。华钩藤在贵州具有丰富的植物资源,目前对贵州产的华钩藤的研究并不多,主要都是针对化学成分进行的研究,刘明川等从华钩藤的乙醇溶液中分离得到7个化合物[5],孙广利等对华钩藤干燥带钩茎枝进行提取,得到五个黄铜类化合物[6],为了进一步寻找和开发利用植物资源,本实验对其中的非生物碱类成分进行了研究,从中分离鉴定了8个化合物,其中化合物 III、V、VI、VIII为首次从该属植物中分离得到。
1.1.1 供试药材 华钩藤样品于2012年12月采于贵州龙里,经贵阳中医学院陈德媛教授鉴定为茜草科钩藤属华钩藤Uncaria sinensis(Oliv.)Havil.干燥带钩茎枝,标本存放于贵州省中国科学院天然产物化学重点实验室。
1.1.2 仪器与试剂 美国HP公司MS5973型质谱仪;VG Auto Spec 3000型质谱仪;美国 Varian INOVA-400型核磁共振波谱仪(TMS内标);美国BRUKER DRX-500MHz超导核磁共振仪(TMS内标,瓦里安有限公司);R-210型旋转蒸发仪(瑞士,瑞士步琦有限公司);干燥箱(101-2A型,天津市泰斯特仪器有限公司);瑞士BUCHI公司R-605型中压泵等。柱色谱硅胶(200-300目 ),硅胶H(10-40 μm)为青岛海洋化工厂产品;反相材料RP-18(40-60 μm)为德国Merck公司产品;微孔吸附树脂CHP 20P(75-150 μm)为日本三菱化学有限公司产品;葡聚糖凝胶Sephadex LH-20(40-70 μm)为 Amersham Pharmacia Biotech AB公司产品。所用试剂为重蒸工业试剂,其他试剂为分析纯。
1.2.1 提取与分离 华钩藤(100 kg)干燥带钩茎枝经粉碎后分批用95% 乙醇加热回流提取4次,时间分别为4,2,2,1 h,减压浓缩后得到浓缩液。浓缩液先用石油醚萃取至石油醚层澄清后再用三氯甲烷萃取至三氯甲烷层澄清,浓缩,得到三氯甲烷萃取部分600 g。通过200~300目硅胶,用三氯甲烷-甲醇(100∶0~0∶100)梯度洗脱,得到6个流分(Fr.1~Fr.6)。Fr.1经三氯甲烷 -甲醇(100∶0~0∶100)梯度洗脱后,分别用三氯甲烷 -甲醇(100∶0~0∶100)、石油醚 -丙酮(100∶0 ~0∶100)梯度洗脱和Sephadex LH-20柱色谱纯化,重结晶,得到 I(184 mg)、II(33 mg)、VI(18 mg);Fr.2经反相Rp-18和正相硅胶柱色谱分离,结合Sephadex LH-20柱色谱纯化,重结晶得到V(6.8 g)、VII(23 mg);Fr.3经三氯甲烷-甲醇(100∶0~0∶100)、石油醚 -乙酸乙酯(100∶0 ~0∶100)、水 -甲醇(100∶0~0∶100),重结晶,得到化合物 VIII(28 mg)、III(54 mg)、IV(56 mg)。得到的8个非生物碱类成分如图1。
图1 华钩藤中非生物碱类成分结构图Fig.1 The structure non-alkaloids constituents of Uncaria sinensis(Oliv.)Havil
白色粉末,5%硫酸乙醇溶液喷洒,加热显紫红色,与乌苏酸标准品进行TLC对照,在多种溶剂系统中展开,Rf值一致,且混合熔点不下降,故I确定为乌苏酸。
白色针状结晶(CHCl3),5%硫酸乙醇溶液喷洒,加热显砖红色,与β-谷甾醇标准品进行TLC对照,在多种溶剂系统中展开,Rf值一致,且混合熔点不下降,故II确定为β-谷甾醇。
白色粉末,C30H46O5,EI-MSm/z:486[M]+,1H-NMR(500MHz,C5D5N)δH:3.34(1H,dd,J=4.6,4.8Hz,H-3),6.04(1H,s,J=2.6Hz,H-12),2.83(1H,d,J=11.3Hz,H-18),0.94(3H,s,H-23),0.86(3H,s,H-24),0.67(3H,s,H-25),0.80(3H,s,H-26),0.86(3H,d,J=4.8Hz,H-29),0.82(3H,d,J=6.5Hz,H-30);13CNMR(125MHz,C5D5N)δc:39.43(C-1),26.44(C-2),78.04(C-3),39.29(C-4),55.82(C-5),19.03(C-6),37.18(C-7),39.35(C-8),47.34(C-9),37.64(C-10),23.42(C-11),129.08(C-12),134.19(C-13),56.88(C-14),28.22(C-15),25.58(C-16),48.82(C-17),55.02(C-18),37.78(C-19),40.11(C-20),30.64(C-21),37.42(C-22),28.66(C-23),16.68(C-24),16.65(C-25),18.32(C-26),178.11(C-27),180.23(C-28),18.94(C-29),21.39(C-30)。以上数据与文献[7]数据一致,因此鉴定为奎洛维酸。
白色无定型粉末,C35H60O6,ESI-MSm/z:599.3[M+Na]+;1H-NMR(500MHz,CDCl3/CD3OD)δH:5.37(1H,d,J=5.1Hz,H-1),3.39-3.61(4H,m,H-2'3'4'5'),5.37(1H,d,J=2.6Hz,H-6),3.85(1H,dd,J=2.7,2.9Hz,H-6a'),3.77(1H,dd,J=13,4.3Hz,H-6b'),1.01(3H,s),0.68(3H,s);13C-NMR(125MHz,CDCl3/CD3OD)δc:37.10(C-1),29.48(C-2),79.09(C-3),38.58(C-4),140.10(C-5),122.08(C-6),31.73(C-7),31.79(C-8),50.02(C-9),36.57(C-10),100.94(C-11),39.60(C-12),42.18(C-13),56.60(C-14),24.14(C-15),28.09(C-16),55.91(C-17),11.69(C-18),19.16(C-19),36.06(C-20),18.61(C-21),33.80(C-22),25.91(C-23),45.70(C-24),29.0(C-25),18.85(C-26),19.64(C-27),22.92(C-28),11.80(C-29),20.92(C-1'),73.38(C-2'),76.18(C-3'),69.86(C-4'),75.53(C-5'),61.71(C-6')。以上数据与文献[8]数据一致,因此鉴定为胡萝卜苷。
白色粉末,C36H40O10,ESI-MSm/z:655.3[M+Na]+,1H-NMR(500MHz,C5D5N)δH:3.34(1H,dd,J=4.6,4.8Hz,H-3),6.04(1H,s,J=2.6Hz,H-12),2.83(1H,d,J=11.3Hz,H-18),0.94(3H,s,H-23),0.86(3H,s,H-24),0.67(3H,s,H-25),0.80(3H,s,H-26),0.86(3H,d,J=4.8Hz,H-29),0.82(3H,d,J=6.5Hz,H-30);13C-NMR(125MHz,C5D5N)δc:39.43(C-1),26.44(C-2),78.04(C-3),39.29(C-4),55.82(C-5),19.03(C-6),37.18(C-7),39.35(C-8),47.34(C-9),37.64(C-10),23.42(C-11),129.08(C-12),134.19(C-13),56.88(C-14),28.22(C-15),25.58(C-16),48.82(C-17),55.02(C-18),37.78(C-19),40.11(C-20),30.64(C-21),37.42(C-22),28.66(C-23),16.68(C-24),16.65(C-25),18.32(C-26),178.11(C-27),180.23(C-28),18.94(C-29),21.39(C-30)。以上数据与文献[9]数据一致,因此鉴定为奎洛维酸-3-O-β-D-海藻糖苷。
白色粉末,C29H52O3,EI-MSm/z:448[M]+;1HNMR(400MHz,CDCl3/CD3OD)δH:1.67(1H,dd,J=2.8,6.8Hz,H-1a),1.58(1H,m,H-2a),4.01(1H,m,H-3a),2.04(1H,dd,J=12.8,11.6Hz,H-4a),5.40(1H,s,H-6),3.55(1H,m,H-6a),1.55(1H,dd,J=4.4,4.8Hz,H-7a),1.74(1H,m,H-8a),1.46(1H,m,H-9a),1.28(1H,m,H-11),1.31(1H,m,H-11a),1.07(1H,m,H-12a),1.05(1H,m,H-14a),1.52(1H,m,H-15a),1.18(1H,m,H-16a),1.07(1H,m,H-17a),0.70(1H,s,H-18),1.18(3H,s,H-19),1.28(1H,m,H-20),0.84(3H,d,J=7.6Hz,H-21),1.31(1H,m,H-22),1.20(1H,m,H-23),0.87(1H,m,H-24),1.15(3H,s,H-25),0.70(3H,s,H-26),0.80(3H,d,J=1.6Hz,H-27),1.61(2H,m,H-28),0.92(3H,d,J=6.4Hz,H-29);13C-NMR(100MHz,CDCl3/CD3OD)δc:33.43(C-1),31.62(C-2),68.28(C-3),41.42(C-4),76.78(C-5),76.45(C-6),35.20(C-7),31.55(C-8),46.51(C-9),39.24(C-10),22.26(C-11),41.34(C-12),43.86(C-13),57.49(C-14),25.19(C-15),29.36(C-16),57.39(C-17),12.61(C-18),17.32(C-19),37.40(C-20),19.30(C-21),35.04(C-22),24.09(C-23),47.19(C-24),27.08(C-25),20.21(C-26),19.41(C-27),30.29(C-28),12.35(C-29)。以上数据与文献[5]数据一致,因此鉴定为3β,5α,6β-三羟基豆甾烷。
白色粉末,C30H48O3,EI-MSm/z:456[M]+;1H-NMR(500MHz,CDCl3/CD3OD)δH:3.43(1H,t,J=14.0Hz,H-3),5.43(1H,d,J=8.1Hz,H-12),0.91(3H,s,CH3-23),1.02(3H,s,CH3-24),0.90(3H,s,CH3-25),0.95(3H,s,CH3-26),1.14(3H,s,CH3-27),0.93(3H,s,CH3-29),0.97(3H,s,CH3-30);13C-NMR(125MHz,CDCl3/CD3OD)δc:38.39(C-1),26.74(C-2),78.75(C-3),38.58(C-4),55.13(C-5),18.17(C-6),32.61(C-7),39.23(C-8),47.50(C-9),36.87(C-10),22.82(C-11),122.50(C-12),143.21(C-13),41.63(C-14),27.47(C-15),23.29(C-16),46.73(C-17),41.09(C-18),45.72(C-19),30.48(C-20),33.69(C-21),31.87(C-22),27.87(C-23),15.40(C-24),15.17(C-25),16.69(C-26),25.62(C-27),176.79(C-28),32.86(C-29),23.34(C-30)。以上数据与文献[11]数据一致,因此鉴定为齐墩果酸。
白色针状结晶(CH3OH);C42H66O15,ESIMSm/z:833.2[M+Na]+,1H-NMR(400MHz,CD3OD)δH:4.30(1H,d,J=7.6Hz,H-1'),5.36(1H,d,J=8.0Hz,H-1″),3.82(2H,dd,J=2.4,2.0Hz,H-3),1.22(3H,s,H-6'),1.35-1.61(2H,m,H-12),2.27(1H,d,J=10.4Hz,H-18),3.12 ~3.38(8H,overlap),0.92(3H,d,J=4.8Hz,CH3),0.89(3H,d,J=1.6Hz,CH3),1.01(3H,s,CH3),0.97(3H,s,CH3),0.88(3H,s,CH3),0.82(3H,s,CH3);13C-NMR(100MHz,CD3OD)δc:39.96(C-1),27.09(C-2),90.72(C-3),40.10(C-4),55.33(C-5),19.28(C-6),37.83(C-7),40.25(C-8),48.07(C-9),38.04(C-10),23.88(C-11),130.92(C-12),133.26(C-13),57.30(C-14),25.83(C-15),26.43(C-16),49.81(C-17),56.92(C-18),38.25(C-19),40.82(C-20),31.13(C-21),37.01(C-22),28.49(C-23),19.23(C-24),17.96(C-25),18.12(C-26),179.16(C-27),177.98(C-28),17.07(C-29),21.48(C-30),106.68(C-1'),75.64(C-2'),78.61(C-3'),72.62(C-4'),77.66(C-5'),62.77(C-6'),95.60(C-1″),73.89(C-2″),78.23(C-3″),71.18(C-4″),78.23(C-5″),62.51(C-6″)。以上数据与文献[12]数据一致,因此鉴定为奎洛维酸-3-O-β-D-吡喃葡萄糖苷(28→1)-β-D-吡喃葡萄糖苷。
华钩藤在贵州具有丰富的植物资源,目前对它的研究并不多,本实验对未经过酸碱处理的华钩藤的非生物碱进行研究,在没有破坏化合物原型的基础上希望得到一些新颖结构的化合物。利用多种色谱技术从华钩藤中分离得到的8个化合物中,4个成分为首次从钩藤属植物中分离得到,丰富了中草药华钩藤的非生物碱类成分的研究。
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