·中藥及天然藥物·
銀線草化學成分及生物活性研究
路強強,石新衛*,上官建國,周軍輝,崔新愛
(陜西省西安植物園,陜西省植物研究所,西安710061)
摘要:目的對銀線草的化學成分及海蝦致死活性進行研究。方法利用正、反相柱層析等色譜手段進行分離純化;通過核磁共振譜、質譜等光譜數據鑒定化合物結構;采用96孔板稀釋法進行海蝦致死活性測試。結果從銀線草乙酸乙酯萃取部分分離得到5個化合物,其結構分別鑒定為:銀線草醇B(shizukaol B,1);銀線草內酯G(shizukanolide G,2);銀線草內酯H(shizukanolide H,3);β-谷甾醇(β-sitosterol,4);卡瓦胡椒素A(flavokawain A,5)。結論化合物2,3和5首次從該植物中分離得到;化合物1具有較強的海蝦致死活性(LC50﹤5 mg·L-1)。
關鍵詞:銀線草;化學成分;生物活性
doi:10.3969/j.issn.1004-2407.2015.06.001
中圖分類號:R284文獻標志碼:A
基金項目:國家自然科學
作者簡介:路強強,男,碩士,實習研究員
收稿日期:(2015-04-29)
Study on chemical constituents and bioactivity ofChloranthusjaponicus
LU Qiangqiang,SHI Xinwei*,SHANGGUAN Jianguo,ZHOU Junhui,CUI Xin′ai (Xi′an Botanical Garden of Shaanxi Province,Institute of Botany of Shaanxi Province,Xi′an 710061, China)
Abstract:ObjectiveTo study the chemical constituents of Chloranthus japonicus, which cause brine shrimp (Artemia salina) to death. MethodsThe chemical constituents were isolated and purified by various chromatographic techniques,and their structures were elucidated on the basis of nuclear magnetic resonance and mass spectroscopic analysis. The brine shrimp lethality were tested by 96-well plate dilution method. Results5 compounds were obtained from the ethyl acetate extracts,and their structures were elucidated as: shizukaol B (1),shizukanolide G (2),shizukanolide H (3), β-sitosterol (4),and flavokawain A (5). Conclusion
Compounds 2,3 and 5 were isolated from this plant for the first time, and compound 1 showed significant brine shrimp lethality,with the lethal concentration 50 (LC50) less than 5 mg·L-1.
Key words:Chloranthusjaponicus;chemical constituents;bioactivity
*通信作者:石新衛,男,博士,助理研究員
銀線草 (ChloranthusjaponicusSieb.) 又名白毛七、四塊瓦、四葉細辛、四大天王,屬金粟蘭科金粟蘭屬多年生草本植物,分布于陜西、甘肅等地,全株供藥用,具有祛濕散寒、活血止痛、散瘀解毒等功效,用于治療風寒咳嗽、跌打損傷、癰腫瘡癤、婦女經閉等情況[1-4]。研究表明,銀線草主要含有金粟蘭內酯、銀線草內酯、銀線草醇、銀線草呋喃醇、銀線草螺二烯醇等倍半萜二聚體和單萜類化學成分[5-8]。現代藥理研究表明,銀線草提取物具有抗菌、抗HIV病毒復制和細胞毒活性[9-11]。為了進一步探究銀線草藥理作用的物質基礎,開發利用這一藥用植物資源,本實驗利用正相硅膠、RP-18反相硅膠、MCI樹脂、Sephadex LH-20凝膠等分離材料,采用常壓、減壓等柱色譜技術對銀線草化學成分進行分離純化,從其乙酸乙酯萃取物中獲得了6個化合物,經波譜技術鑒定其結構分別為:銀線草醇B (shizukaol B,1);銀線草內酯G (shizukanolide G,2);銀線草內酯H (shizukanolide H,3);β-谷甾醇 (β-sitosterol,4);卡瓦胡椒素A (flavokawain A,5)。化合物2,3和5首次從銀線草 (Chloranthusjaponicus) 中分離得到,采用96孔板稀釋法對其海蝦致死活性進行測試。化合物1的海蝦致死活性與陽性對照品鬼臼毒素 (podophyllotoxin) 相當,LC50值均小于5 mg·L-1,化合物2~5的LC50值分別為73,48,76和52 mg·L-1。
1儀器與材料
1.1儀器Bruker AM-400和Bruker AV-500核磁共振波譜儀(瑞士布魯克公司);ThermoFisher Q-Exactive質譜儀(美國賽默飛世爾公司);Waters Xevo G2 Q-TOF-MS質譜儀 (美國沃特斯公司);Eyela N-1100旋轉蒸發儀(東京理化公司);X-5顯微熔點測定儀(鞏義予華儀器有限公司)。
1.2材料柱色譜正相硅膠(100~200,200~300目)和薄層色譜硅膠GF254(青島海洋化工廠);RP-18反相硅膠(25~40,40~63 μm,日本YMC公司);Sephadex LH-20凝膠(美國法瑪西亞公司);MCI樹脂(75~150 μm,日本三菱公司);所用試劑均為分析純(天津科密歐化學試劑有限公司);實驗用銀線草于2012年10月采自陜西秦嶺太白山,經陜西省西安植物園周亞福博士鑒定為金粟蘭科金粟蘭屬植物銀線草(Chloranthusjaponicus)。
2提取與分離
將銀線草全草20 kg粉碎,甲醇回流提取3次(150 L×3),每次2 h,濾過,合并濾液,減壓濃縮得到浸膏1.5 kg,以2.5 L水溶解浸膏,依次用2.5 L石油醚、乙酸乙酯、正丁醇各萃取5次,合并萃取液,減壓濃縮得各組分浸膏。其中乙酸乙酯浸膏370 g,經正反相硅膠、MCI樹脂、Sephadex LH-20凝膠等色譜柱層析,以石油醚-乙酸乙酯、石油醚-三氯甲烷-丙酮、三氯甲烷-甲醇體系反復純化,得到化合物1 (44 mg),化合物2 (25 mg),化合物3 (35 mg),化合物4 (2.1 g),化合物5 (20 mg)。
3結構鑒定
化合物1白色無定形粉末(三氯甲烷),易溶于三氯甲烷、甲醇,C40H44O13,mp:117~119 ℃,HR-ESI-MSm/z: 755.267 4 [M+Na]+,756.270 0 [M+Na+H]+。1H-NMR(500 MHz,CDCl3)δppm: 6.63(1H,t,J=6.9 Hz,H-c),5.08(1H,d,J=12.0 Hz,H-13′β),5.07(1H,dd,J=14.9,4.7 Hz,H-dβ),4.64(1H,dd,J=14.7,6.8 Hz,H-dα),4.56(1H,d,J=11.8 Hz,H-15′β),4.54(1H,d,J=12.3 Hz,H-13′α),3.95(1H,s,H-6),3.88(1H,s,H-9),3.70(3H,s,H-OMe),3.65(1H,d,J=11.8 Hz,H-15′α),2.89(1H,dd,J=16.8,10.2 Hz,H-gβ),2.81(1H,d,J=16.2 Hz,H-15α),2.79(1H,d,J=8.0 Hz,H-hβ),2.71(1H,dd,J=18.7,4.9 Hz,H-6′β),2.67(1H,dd,J=16.1,8.1 Hz,H-hα),2.59(1H,d,J=16.1 Hz,H-15β),2.48(1H,dd,J=18.6,4.8 Hz,H-6′α),2.48(1H,dd,J=18.6,4.8 Hz,H-gα),2.05(1H,d,J=8.4 Hz,H-1),1.95(3H,s,H-13),1.92(3H,s,H-e),1.88(1H,m,H-3),1.86(1H,m,H-5′),1.86(1H,d,J=4.1 Hz,H-3′),1.61(1H,d,J=8.6 Hz,H-1′),1.40(1H,t,J=8.1 Hz,H-3′),1.34(1H,d,J=3.5 Hz,H-2′β),1.03(3H,s,H-14),0.96(1H,t,J=7.4 Hz,H-2α),0.83(3H,s,H-14′),0.74(1H,ddd,J=14.5,8.2,3.4 Hz,H-2′α),0.33(1H,d,J=7.4 Hz,H-2β)。3C-NMR(125 MHz,CDCl3)δppm: 200.7(C-8),174.5(C-7′),172.0(C-i),171.7(C-f),171.6(C-12′),170.2(C-12),167.0(C-a),147.5(C-11),142.4(C-4),135.5(C-c),132.2(C-5),131.3(C-7),129.3(C-b),123.4(C-11′),93.3(C-8′),79.9(C-9),77.1(C-4′),72.1(C-15′),61.6(C-d),61.3(C-5′),55.5(C-9′),54.3(C-13′),52.4(C-OMe),51.0(C-10),45.0(C-10′),29.2(C-h),28.7(C-g),27.8(C-3′),26.0(C-1),26.0(C-14′),25.6(C-1′),25.4(C-15),24.8(C-3),23.4(C-6′),20.1(C-13),16.0(C-2),15.3(C-14),13.0(C-e),11.7(C-14)。以上波譜數據與參考文獻[12]數據一致,故確定該化合物為銀線草醇B(shizukaol B)。
化合物2黃色油狀(甲醇),易溶于三氯甲烷、甲醇、丙酮,C17H20O6,HR-EI-MSm/z: 321.133 6 [M+H]+,641.260 2 [2M+H]+。1H-NMR(500 MHz,CDCl3)δppm: 4.43(1H,s,H-9),4.18(2H,m,H-15),4.13(2H,m,H-13),2.77(1H,m,H-6α),2.29(1H,m,H-6β),2.66(1H,m,H-5),2.09(3H,s,H-2′),1.69(1H,m,H-3),1.61(1H,m,H-4),1.31(1H,m,H-1),0.86(1H,m,H-2β),0.84(1H,m,H-2α),0.79(3H,s,H-14)。3C-NMR(125 MHz,CDCl3)δppm: 171.2(C-1′),169.4(C-12),155.5(C-7),130.8(C-11),88.1(C-8),65.9(C-15),64.6(C-9),55.5(C-13),48.6(C-5),42.5(C-4),42.5(C-10),24.6(C-1),22.9(C-6),22.4(C-3),20.9(C-2′),16.7(C-2),16.2(C-14)。以上波譜數據與參考文獻[13]數據一致,故確定該化合物為銀線草內酯G(shizukanolide G)。
化合物3無色油狀(甲醇),易溶于三氯甲烷、甲醇、丙酮,C17H20O5,HR-EI-MSm/z:305.138 6
[M+H]+。1H-NMR(500 MHz,CDCl3)δppm: 6.38(1H,s,H-9),4.44(2H,s,H-13),4.20(2H,dd,J=6.1,1.1 Hz,H-15),2.87(1H,dd,J=16.8,3.4 Hz,H-6α),2.37(1H,m,H-6β),2.26(1H,m,H-5),2.09(3H,s,H-1′),1.75(1H,dtd,J=9.8,6.1,3.8 Hz,H-4),1.56(1H,dt,J=8.1,3.8 Hz,H-1),1.31(1H,ddd,J=11.8,8.1,3.8 Hz,H-3),0.92(3H,s,H-14),0.86(1H,m,H-2β),0.84(1H,m,H-2α)。13C-NMR(125 MHz,CDCl3)δppm: 171.2(C-1′),170.2(C-12),150.3(C-8),149.2(C-7),124.1(C-11),123.1(C-9),65.9(C-15),60.1(C-5),55.1(C-13),42.8(C-4),41.9(C-10),27.2(C-1),22.8(C-6),22.2(C-3),20.9(C-14),20.9(C-2′),16.9(C-2)。以上波譜數據與參考文獻[13]數據一致,故確定該化合物為銀線草內酯H(shizukanolide H)。
化合物4白色無定形粉末(三氯甲烷),易溶于三氯甲烷、甲醇,C29H50O,mp:138~141 ℃,ESI-MSm/z: 438.53 [M+Na+H]+。1H-NMR(500 MHz,CDCl3)δppm: 5.34(1H,br.s,H-6),3.52(1H,m,H-3),2.32~1.03(9H,m),1.02(3H,s,H-19),1.00(3H,s,H-18),0.96(3H,d,J=6.6 Hz,H-21),0.89(3H,d,J=6.7 Hz,H-28),0.85(3H,t,J=6.9 Hz,H-26),0.81(3H,d,J=6.7 Hz,H-29)。13C-NMR(125 MHz,CDCl3)δppm: 140.8(C-5),121.7(C-6),71.8(C-3),56.8(C-14),56.1(C-17),50.2(C-9),45.8(C-24),42.3(C-4),42.1(C-13),39.8(C-12),37.3(C-1),36.5(C-10),36.2(C-20),33.9(C-22),31.9(C-8),31.9(C-7),31.6(C-2),29.2(C-25),28.2(C-16),26.0(C-23),24.3(C-15),23.0(C-28),21.1(C-11),19.8(C-26),19.4(C-19),19.0(C-27),18.8(C-21),12.0(C-29),11.8(C-18)。以上波譜數據與參考文獻[14]數據一致,故確定該化合物為β-谷甾醇(β-sitosterol)。
化合物5無定形黃色粉末(三氯甲烷),易溶于三氯甲烷、甲醇、乙酸乙酯,C18H18O5,mp:114~116 ℃,HR-ESI-MSm/z: 315.121 9 [M+H]+。1H-NMR (500 MHz, CDCl3)δppm: 7.80 (1H,d,J=15.6 Hz,H-β),7.77 (1H,d,J=15.6 Hz,H-α),7.55 (1H, d,J=8.8 Hz,H-2/6),6.92 (1H,d,J=8.7 Hz,H-3/5),6.10 (1H,d,J=2.4 Hz,H-3′), 5.95 (1H,d,J=2.3 Hz,H-5′),3.90 (3H,s,H-6′OMe),3.84 (3H,s,H-4OMe),3.82 (3H,s,H-4′OMe)。13C-NMR (125 MHz,CDCl3)δppm: 192.8 (C=O),168.4 (C-2′),166.0 (C-4′),162.5 (C-6′),161.4 (C-4),142.5 (C-β),130.1 (C-2/6),128.3 (C-1),125.4 (C-α), 114.3 (C-3/5),106.4 (C-1′),93.8 (C-3′),91.2 (C-5′),55.8 (C-6′OMe),55.6 (C-4′OMe),55.4 (C-4OMe)。以上波譜數據與參考文獻[15]數據一致,故確定該化合物為卡瓦胡椒素A (flavokawain A)。
4海蝦致死活性
配制質量濃度為25.0 g·L-1的人工海水(pH 8.0~8.5),取適量豐年蝦卵放入人工海水中,28 ℃孵化48 h,待用。將測試樣品配制成質量濃度為2.0 mg·mL-1的二甲基亞砜 (DMSO) 溶液,用移液槍分別吸取10.0,8.0,6.0,4.0,2.0,1.0和0.5 μL,加入96孔板中,再加入相應的海蝦海水溶液 (約15~20只海蝦) 使孔中液體達到200 μL,鬼臼毒素和DMSO分別為陽性和空白對照,每一處理重復3次。在28 ℃培養24 h,顯微鏡下觀察,記錄海蝦死亡數[16]。根據公式計算不同質量濃度下的校正死亡率,采用SPSS軟件的Probit模型計算半數致死濃度 (LC50)。
校正死亡率=(T-C)/(1-C)×100%
公式中,T為樣品致死率,C為空白對照致死率。
海蝦致死活性測試表明,化合物1的LC50值與陽性對照品相當,均小于5 mg·L-1,化合物3的LC50值(48 mg·L-1) 較強于化合物2 (73 mg·L-1),這可能是由于C-8與C-9間三元氧環還原形成雙鍵,從而導致藥效更強。化合物5也具有中等強度的海蝦致死活性,其LC50值為52 mg·L-1。
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