王嘯洋 吳君 皇甫龍韜 劉紅 李雪梅 湯海峰 張艷華
中圖分類號 R284;R285 文獻標志碼 A 文章編號 1001-0408(2022)05-0602-09
DOI 10.6039/j.issn.1001-0408.2022.05.16
摘 要 目的 研究銀蓮花屬植物小花草玉梅Anemone rivularis var. flore-minore的三萜皂苷類化合物及其抗腫瘤活性。方法 對該植物根莖的70%乙醇提取物正丁醇萃取部位進行分離,采用正相硅膠柱色譜、反相ODS柱色譜、Sephadex LH-20凝膠柱色譜以及半制備高效液相色譜等手段分離純化三萜皂苷類化合物;根據(jù)波譜(核磁共振譜、質譜)數(shù)據(jù)及理化性質鑒定化合物結構;采用MTT法檢測化合物對5種人源腫瘤細胞(HL-60細胞、A549細胞、HepG2細胞、HeLa細胞和U87MG細胞)的增殖抑制活性;通過流式細胞術Annexin V-FITC/PI雙染試驗,評估化合物7對U87MG細胞的誘導凋亡作用。結果 共分離得到16個三萜皂苷類化合物,分別為3β-O-β-D-吡喃木糖-(1→2)-α-L-吡喃阿拉伯糖-齊墩果酸-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷(1)、3β-O-α-L-吡喃阿拉伯糖-齊墩果酸-28-O-β-D-吡喃葡萄糖酯苷(2)、saponin B(3)、齊墩果酸-3β-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖苷(4)、HN-saponin F(5)、clematoside S(6)、prosapogenin CP4(7)、cussonside B(8)、白頭翁皂苷C(9)、clemastanoside D(10)、3β-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖-常春藤皂苷元-28-O-β-D-吡喃葡萄糖酯苷(11)、刺五加皂苷C3(12)、刺五加皂苷A1(13)、huzhangoside D(14)、刺楸皂苷B(15)和hederacolchiside E(16)?;衔?、4、6~9表現(xiàn)出不同程度的抑制腫瘤細胞增殖活性,并以化合物7的活性最強;化合物7能誘導U87MG細胞凋亡從而抑制腫瘤細胞增殖,并呈一定時間依賴趨勢。結論 分離所得的16個化合物均為齊墩果烷型三萜皂苷,其中化合物1為新化合物;苷元C-3位連糖基且C-28位為游離羧基的皂苷抗腫瘤活性較強。
關鍵詞 小花草玉梅;三萜皂苷;鑒定;抗腫瘤活性;齊墩果烷型三萜皂苷
Identification of triterpenoid saponins from Anemone rivularis var. flore-minore and study on their antitumor activities
WANG Xiaoyang1,WU Jun2,HUANGFU Longtao3,LIU Hong1,LI Xuemei1,TANG Haifeng4,ZHANG Yanhua1
[1. Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education), Dept. of Pharmacy, Peking University Cancer Hospital & Institute, Beijing 100142, China; 2. Dept. of VIP Dental Service, Peking University Hospital of Stomatology, Beijing 100081, China; 3. Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education), Division of Gastrointestinal Cancer Translational Research Laboratory, Peking University Cancer Hospital & Institute, Beijing 100142, China; 4. Dept. of Chinese Materia Medica and Natural Medicines/School of Pharmacy, Air Force Medical University, Xi’an 710032, China]
ABSTRACT? ?OBJECTIVE To study the triterpenoid saponins from Anemone rivularis var. flore-minore and their antitumor activities. METHODS The n-butanol extract of 70% ethanol extract from rhizome of the plant was separated. The triterpenoid saponins were separated and purified by normal silica gel column chromatography, reversed phase ODS column chromatography, Sephadex LH-20 gel column chromatography and semi-preparation high performance liquid chromatography. The structures of these saponins were identified by spectral analysis (NMR and MS) and physical and chemical properties. MTT assay was used to test the proliferation inhibitory activity of the compounds against five kinds of human tumor cells(HL-60 cells, A549 cells, HepG2? ? cells, HeLa cells and U87MG cells). The apoptosis inducing effect of compound 7 on U87MG cells was evaluated by flow cytometric Annexin V-FITC/PI staining test. RESULTS Sixteen triterpenoid saponins were obtained and identified as 3β-O-β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-oleanolic acid-28-O-α-L-rhamnopyranosyl-(1→4)-β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside(1), 3β-O-L-arabinopyranosyl oleanolic acid-28-O-β-D-glucopyranoside(2), saponin B(3),oleanolic acid-3β-O-β-D-glucopyranosyl-(1→2)-α-L-arabino- pyranoside (4), HN-saponin F(5), clematoside S(6), prosapogenin CP4(7), cussonside B(8), pulsatilla saponin C(9), clemastanoside D(10), 3β-O-β-D-glucopyranosyl-(1→2)-β-L-arabinopyranosyl-hederagenin-28-O-β-D-glucopyranoside(11), ciwujianoside C3(12), ciwujianoside A1(13), huzhangoside D (14), kalopanaxsaponin B (15) and hederacolchiside E (16). Compounds 3, 4, 6-9 displayed inhibitory activities on the proliferation of tumor cells to different extent, and compound 7 had the strongest activity; compound 7 induced the apoptosis of U87MG cell so as to inhibit the proliferation of cancer cells in a time-dependent manner. CONCLUSIONS The obtained 16 saponins are all identified as oleanolane-type, among which compound 1 is a new compound. The monodesmosidic saponins, the sugar chain of which attached at C-3 and a free carboxyl at C-28, possess stronger antitumor activity than others.
KEYWORDS? ?Anemone rivularis var. flore-minore; triterpenoid saponin; identification; antitumor activities; oleanane-type triterpenoid saponins
毛茛科銀蓮花屬植物在世界范圍內分布廣泛,我國產52種,其中部分品種已作藥用,如兩頭尖(多被銀蓮花的根莖)、蜈蚣三七(林蔭銀蓮花的根莖)、九節(jié)菖蒲(阿爾泰銀蓮花的根莖)等[1-2]。小花草玉梅Anemone rivularis var. flore-minore屬于銀蓮花屬傳統(tǒng)藥用植物,分布于山西、河北、陜西、內蒙古、甘肅、四川等地,據(jù)《全國中草藥匯編》記載,該植物的根或全草藥用名稱為“破牛膝”,用于肝炎、陰疽、癰腫作痛等癥[3]。研究表明,銀蓮花屬植物富含五環(huán)三萜類皂苷成分,是發(fā)揮藥效的主要活性成分[4-5]。本課題組前期已對包括小花草玉梅在內的多種銀蓮花屬植物進行了化學成分的分離鑒定及其活性研究,得到大量三萜皂苷類化合物,其中部分有顯著抗腫瘤藥理活性[6-14]。為進一步探索本屬植物抗腫瘤活性成分,本研究以小花草玉梅的根莖為研究對象,進一步開展系統(tǒng)研究,對其70%乙醇提取物正丁醇萃取部位進行分離、純化,根據(jù)化合物波譜數(shù)據(jù)和理化性質鑒定其化學結構,得到16個三萜皂苷類化合物,其中包含1個新化合物(1);同時,采用MTT法檢測了上述化合物抑制5種人源腫瘤細胞增殖的活性,并采用流式細胞術評價了化合物7對人腦星形膠質母細胞瘤U87MG細胞的促凋亡作用,為進一步闡明本屬植物抗腫瘤活性的物質基礎及后續(xù)相關研究提供依據(jù)。
1 材料
1.1 主要儀器與色譜柱
本研究所用主要儀器包括Perkin-Elmer 341型旋光儀(美國Perkin-Elmer公司),Bruker AVANCE-500型核磁共振(NMR)儀(瑞士Bruker公司),Micromass Quattro型質譜儀(美國Waters公司),F(xiàn)innigan Voyager型氣相色譜儀(美國Finnigan公司),Dionex P680型液相色譜儀(美國Dionex公司),SW-CJ-1D型超凈工作臺(蘇州凈化設備有限公司),M680型酶標儀(美國Bio-Rad公司),Avanti J30型低溫高速離心機(美國Beckman公司),F(xiàn)ACSCalibur型流式細胞儀(美國BD公司)。L-Chirasil- Val氣相色譜柱(25 m×0.32 mm,0.25 μm)購自美國Agilent公司,YMC-Pack R&D ODS-A制備型液相色譜柱(20 mm×250 mm,5 μm)購自日本YMC公司。
1.2 主要藥品與試劑
小花草玉梅藥材采自秦嶺山脈的陜西太白縣太白山區(qū)域,經陜西中醫(yī)藥大學藥學院王繼濤教授鑒定為毛茛科銀蓮花屬植物小花草玉梅A. rivularis var. flore-? ?minore,標本存于陜西中醫(yī)藥大學藥學院中藥標本室。正相柱色譜硅膠(規(guī)格100~140目、200~300目)購自青島海洋化工廠;反相ODS-A硅膠(規(guī)格50 μm)購自日本YMC公司;Sephadex LH-20凝膠(規(guī)格40~70 mm)購自瑞典GE公司;胰蛋白酶(批號1930154)、胎牛血清(批號1814986)均購自美國Gibco公司;DMEM培養(yǎng)基(批號AD21573271)購自美國Hycolne公司;二甲基亞砜(DMSO,批號RNBC1433,純度99.7%)、L-半胱氨酸甲酯鹽酸鹽(批號410209,純度98%)、N-(三甲基硅基)咪唑(批號394847,供氣相色譜衍生用)、MTT試劑(批號M2128,純度98%)、多柔比星(批號D1515,純度98%)、尼莫司?。ㄅ朙5918,純度98%)均購自美國Sigma公司;Annexin V-FITC/PI試劑盒(批號7312394)購自美國BD公司;色譜純甲醇購自天津市科密歐化學試劑有限公司,其他分析純試劑均購自天津市富宇精細化工有限公司,水為純凈水。
1.3 細胞株
本研究所用人急性早幼粒白血病HL-60細胞、人肺癌A549細胞、人肝癌HepG2細胞、人宮頸癌HeLa細胞和人腦星形膠質母細胞瘤U87MG細胞均購自中國科學院上海細胞保存庫。
2 方法與結果
2.1 提取分離
取小花草玉梅干燥根莖5 kg,打成粗粉,加入5倍量(L/kg)70%乙醇回流提取3次(每次2 h),合并提取液,過濾濃縮得1.1 kg醇提物浸膏。醇提物浸膏用10 L水分散后,加入等體積石油醚(10 L)萃取3次;水層再加入等體積正丁醇(10 L)萃取3次,合并正丁醇層,濃縮得正丁醇部位浸膏230 g。取正丁醇浸膏120 g,采用正相硅膠柱色譜進行粗分離,用三氯甲烷-甲醇-水(10 ∶ 1 ∶ 0.04→ 6 ∶ 4 ∶ 0.7)進行梯度洗脫,得8個片段Fr.1~Fr.8。
Fr.1~Fr.5采用正相硅膠柱色譜分離,用三氯甲烷-甲醇-水(8 ∶ 2 ∶ 0.05→6 ∶ 4 ∶ 0.7)進行梯度洗脫,分別得亞片段Fr.1.1~Fr.1.3、Fr.2.1~Fr.2.3、Fr.3.1~Fr.3.6、Fr.4.1~ Fr.4.3和Fr.5.1~Fr.5.6。所有亞片段均經Sephadex LH-20凝膠柱色譜除雜,再采用半制備高效液相色譜純化得到以下化合物:化合物2[24 mg,流動相為甲醇-水(89 ∶ 11,V/V),F(xiàn)r.1.2]、化合物3[22 mg,流動相為甲醇-水(88 ∶ 12,V/V),F(xiàn)r.2.2]、化合物4[22 mg,流動相為甲醇-水(85 ∶ 15,V/V),F(xiàn)r.2.3]、化合物5[24 mg,流動相為甲醇-水(75 ∶ 25,V/V),F(xiàn)r.3.1]、化合物6[31 mg,流動相為甲醇-水(80 ∶ 20,V/V),F(xiàn)r.3.4]、化合物7[33 mg,流動相為甲醇-水(77 ∶ 23,V/V),F(xiàn)r.3.6]、化合物8[33 mg,流動相為甲醇-水(77 ∶ 23,V/V),F(xiàn)r.4.3]、化合物9[25 mg,流動相為甲醇-水(80 ∶ 20,V/V),F(xiàn)r.5.1]、化合物10[20 mg,流動相為甲醇-水(70 ∶ 30,V/V),F(xiàn)r.5.5]、化合物11[17 mg,流動相為甲醇-水(68 ∶ 32,V/V),F(xiàn)r.5.6]。
Fr.6~Fr.8采用反相ODS柱色譜進行分離,用甲醇-水(3 ∶ 7→9 ∶ 1)進行梯度洗脫,分別得亞片段Fr.6.1~Fr.6.5、Fr.7.1~Fr.7.6和Fr.8.1~Fr.8.5。其中Fr.6.1、Fr.7.6、Fr.8.2和Fr.8.3再次經反相ODS柱色譜分離,用甲醇-水(4 ∶ 6→9 ∶ 1)進行梯度洗脫,獲得Fr.6.1.1~Fr.6.1.3、Fr.7.6.1~Fr.7.6.6、Fr.8.2.1~Fr.8.2.3和Fr.8.3.1~Fr.8.3.4,采用半制備高效液相色譜純化得到以下化合物:化合物12[15 mg,流動相為甲醇-水(72 ∶ 28,V/V),F(xiàn)r.6.1.2]、化合物13[56 mg,流動相為甲醇-水(72 ∶ 28,V/V),F(xiàn)r.6.1.2]、化合物1[35 mg,流動相為甲醇-水(75 ∶ 25,V/V),F(xiàn)r.6.2]、化合物14[15 mg,流動相為甲醇-水(70 ∶ 30,V/V),F(xiàn)r.7.6.1]、化合物15[15 mg,流動相為甲醇-水(58 ∶ 42,V/V),F(xiàn)r.8.2.3)]、化合物16[12 mg,流動相為甲醇-水(55 ∶ 45, V/V),F(xiàn)r.8.3.2]。
2.2 酸水解、糖基衍生及氣相色譜分析
取待分析化合物5 mg,加入5 mL三氟醋酸溶液(2 mol/L),置于密閉容器中加熱8 h(110 ℃);反應完畢后放冷至室溫,加入20 mL純凈水,用乙酸乙酯等體積萃取3次;水層濃縮蒸干,向殘留物加1 mL L-半胱氨酸甲酯鹽酸鹽的吡啶溶液(2 mg/L),水浴(60 ℃)反應1 h,氮氣吹干;向殘留物加入0.2 mL N-(三甲基硅基)咪唑和2 mL吡啶,水?。?0 ℃)反應1 h,氮氣吹干;殘留物用水分散,用環(huán)己烷等體積萃取3次,合并萃取液,蒸干即得化合物糖基的三甲基硅醚化衍生物[15-16]。采用L-Chirasil- Val氣相色譜柱進行氣相色譜分析,程序升溫:初始柱溫140 ℃,保持5 min后,以2 ℃/min的速度加溫至180 ℃,保持5 min后,以10 ℃/min的速度加溫至320 ℃,保持10 min;檢測器溫度設定為280 ℃;氣化溫度設定為250 ℃;載氣為氮氣;進樣量為1 μL。標準糖采用同樣方法進行衍生和分析。根據(jù)樣品峰面積以及與標準糖保留時間的比對,可確定化合物的糖基比例和種類。
2.3 結構鑒定
根據(jù)化合物波譜數(shù)據(jù)和理化性質鑒定化合物結構,化合物1~16的化學結構見圖1。
化合物1:白色無定形粉末。高分辨電噴霧離子化質譜(HR-ESI-MS)顯示質荷比m/z實測值為1 213.597 8
[M+Na]+(計算值1 213.598 2,C58H94O25Na),確定化合物1的分子式為C58H94O25。分析1D-NMR,在1H-NMR(500 MHz,C5D5N)中可觀察到7個甲基質子信號:δH 0.91(s,3H),0.92(s,6H,2×CH3),1.09(s,3H),1.12(s,3H),1.26(s,3H)和1.27(s,3H);5個糖端基質子信號:δH 4.89(d,J=6.3 Hz),5.00(d,J=7.8 Hz),5.09(d,J=7.4 Hz),5.86(s)和6.25(d,J=8.1 Hz);1個烯氫信號:δH 5.43(br s)。結合無畸變極化轉移增強碳譜(DEPT,135°)和碳氫近程相關譜(HSQC),在13C-NMR(125 MHz,C5D5N)中可觀察到7個甲基碳信號:δC 15.5,16.3,17.4,23.6,25.9,27.8和33.0;5個糖端基碳信號:δC 95.5,102.6,104.7,105.0和106.6;2個烯碳信號:δC 122.7和144.0;在低場區(qū)存在1個羰基碳信號:δC 176.4。以上均為齊墩果烷型三萜皂苷特征波譜信號,通過對比文獻波譜數(shù)據(jù)[17-18],確定化合物1的苷元為齊墩果酸;綜合分析2D-NMR,包括同核質子相關譜(1H-1H COSY)、碳氫遠程相關譜(HMBC)、HSQC、氫氫空間相關譜(NOESY)和氫氫全相關譜(TOCSY)對苷元碳氫信號進行了全歸屬(表1)。根據(jù)δC 88.8(C-3)和δC 176.4(C-28),可知化合物1為在C-3和C-28位均連有寡糖基單元的雙糖鏈皂苷。
按照“2.2”項下所述方法,對化合物1進行酸水解,并制備糖基的三甲基硅醚化衍生物,進行氣相色譜分析,與標準糖進行對比。結果表明,化合物1中含有4種糖基單元,分別為2種五碳糖:L-吡喃阿拉伯糖(Ara)和D-吡喃木糖(Xyl);1種去氧六碳糖:L-吡喃鼠李糖(Rha);1種六碳糖:D-吡喃葡萄糖(Glc)。4種糖含量比例為? ? 1 ∶ 1 ∶ 1 ∶ 2。綜合分析2D-NMR,進行寡糖基碳氫信號的全歸屬(表1)。寡糖基與苷元的連接位點和各糖基的連接次序,由HMBC譜確定(圖2)。根據(jù)Xyl H-1/Ara C-2和Ara H-1/C-3的HMBC相關信號,可推斷苷元C-3位糖鏈為Xly(1→2)Ara-;根據(jù)Rha H-1/GlcⅡ C-4、GlcⅡ H-1/GlcⅠ C-6和GlcⅠ H-1/C-28的HMBC相關信號,可推斷苷元C-28位糖鏈為Rha(1→4)Glc(1→6)Glc-。通過糖端基氫的耦合常數(shù)Ara(6.3 Hz)、Xyl(7.4 Hz)和Glc(7.8和8.1 Hz),判斷其端基相對構型分別為α、β和β;而Rha端基氫信號為單峰,可通過其C-3、5位的δC值判斷其端基相對構型為α。苷元3位C-O鍵的β構型由NOESY譜圖中H-3、H3-23、H-5的NOESY相關信號推導而來,化合物1的主要HMBC及NOESY相關信號見圖2?;谏鲜龇治龊屯茖?,鑒定化合物1的結構為3β-O-β-D-吡喃木糖-(1→2)-α-L-吡喃阿拉伯糖-齊墩果酸-28-O-α-L-吡喃鼠李糖-(1→4)-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯苷,經查詢SciFinder數(shù)據(jù)庫,該化合物為新化合物。
化合物2:白色無定形粉末。電噴霧離子化質譜(ESI-MS)顯示m/z 749 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C41H66O12。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.86,0.88,0.90,0.94,1.11,1.24,1.25(each 3H,s,CH3);2個糖端基質子信號: δH 4.75(1H,d,J=7.1 Hz,Ara H-1)和6.31(1H,d,J=8.1 Hz,Glc H-1);苷元部分特征質子信號:δH 3.19(1H,dd,J=3.6、13.9 Hz,H-3),3.32(1H,dd,J=4.3、11.8 Hz,H-18),5.42(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.7(C-1),26.0(C-2),88.6(C-3),39.4(C-4),55.8(C-5),18.5(C-6),33.1(C-7),39.8(C-8),48.0(C-9),36.9(C-10),23.7(C-11),122.9(C-12),144.1(C-13),42.1(C-14),28.1(C-15),23.3(C-16),46.9(C-17),41.7(C-18),46.2(C-19),30.7(C-20),33.9(C-21),32.5(C-22),28.1(C-23),16.9(C-24),15.5(C-25),17.4(C-26),26.0(C-27),176.4(C-28),33.3(C-29),23.6(C-30),Ara C-1~C-5(107.5,72.9,74.6,69.5,66.8),Glc C-1~C-6(95.7,74.1,78.9,71.1,79.3,62.1)。對比參考文獻波譜數(shù)據(jù)[19],鑒定該化合物為3β- O-α-L-吡喃阿拉伯糖-齊墩果酸-28-O-β-D-吡喃葡萄糖酯苷。
化合物3:白色無定形粉末。ESI-MS顯示m/z 759 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C40H64O12。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.93,0.95,0.96,1.04,1.07,1.23(each 3H,s,CH3);2個糖端基質子信號:δH 5.09(1H,d,J=7.4 Hz,Xyl H-1)和5.11(1H,d,J=6.3 Hz,Ara H-1);苷元部分特征質子信號:δH 3.30(1H,dd,J=3.3、13.6 Hz,H-18),5.48(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中 δC:39.2(C-1),26.2(C-2),81.3(C-3),43.6(C-4),47.7(C-5),18.5(C-6),32.8(C-7),39.7(C-8),48.1(C-9),36.9(C-10),23.8(C-11),122.6(C-12),144.8(C-13),42.1(C-14),28.3(C-15),23.6(C-16),46.6(C-17),41.9(C-18),46.4(C-19),30.9(C-20),34.2(C-21),33.2(C-22),63.9(C-23),14.0(C-24),16.0(C-25),17.4(C-26),26.1(C-27),180.1(C-28),33.2(C-29),24.1(C-30),Ara C-1~C-5(104.4,82.0,74.0,68.8,65.9),Xyl C-1~C-5(106.8,76.2,78.3,71.0,67.4)。對比參考文獻波譜數(shù)據(jù)[20],鑒定該化合物為saponin B。
化合物4:白色無定形粉末。ESI-MS顯示m/z 773 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C41H66O12。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.81,0.94,0.97,0.99,1.01,1.20,1.26(each 3H,s,CH3);2個糖端基質子信號:δH 4.94(1H,d,J=6.6 Hz,Ara H-1)和5.21(1H,d,J=7.7 Hz,Glc H-1);苷元部分特征質子信號:δH 3.19(1H,dd,J=4.4、11.7 Hz,H-3),3.28(1H,dd,J=4.0、13.7 Hz,H-18),5.45(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.8(C-1),26.6(C-2),88.8(C-3),39.5(C-4),55.8(C-5),18.4(C-6),33.1(C-7),39.7(C-8),48.0(C-9),37.0(C-10),23.7(C-11),122.5(C-12),144.8(C-13),42.1(C-14),28.3(C-15),23.7(C-16),46.7(C-17),42.0(C-18),46.5(C-19),30.9(C-20),34.2(C-21),33.2(C-22),28.2(C-23),16.7(C-24),15.4(C-25),17.4(C-26),26.1(C-27),180.2(C-28),33.3(C-29),23.7(C-30),Ara C-1~C-5(104.8,81.0,73.4,68.3,65.7),Glc C-1~C-6(106.0,76.4,78.1,71.5,78.1,62.5)。對比參考文獻波譜數(shù)據(jù)[21],鑒定該化合物為齊墩果酸-3β-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖苷。
化合物5:白色無定形粉末。ESI-MS顯示m/z 765 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C41H66O13。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.86,0.86,0.91,0.94,1.11,1.16(each 3H,s,CH3);2個糖端基質子信號:δH 4.95(1H,d,J=7.2 Hz,Ara H-1)和6.32(1H,d,J=8.1 Hz,Glc H-1);苷元部分特征質子信號:δH 3.17(1H,dd,J=4.1、13.7 Hz,H-18),5.41(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.8(C-1),26.0(C-2),81.9(C-3),43.5(C-4),47.6(C-5),18.2(C-6),32.8(C-7),39.9(C-8),48.2(C-9),36.9(C-10),23.8(C-11),122.9(C-12),144.1(C-13),42.1(C-14),28.3(C-15),23.3(C-16),47.0(C-17),41.6(C-18),46.1(C-19),30.7(C-20),33.9(C-21),32.5(C-22),64.5(C-23),13.6(C-24),16.2(C-25),17.5(C-26),26.0(C-27),176.4(C-28),33.1(C-29),23.7(C-30),Ara C-1~C-5(106.7,73.1,74.7,69.6,67.0),Glc C-1~C-6(95.7,74.1,78.9,71.1,79.3,62.1)。對比參考文獻波譜數(shù)據(jù)[22],鑒定該化合物為HN-saponin F。
化合物6:白色無定形粉末。ESI-MS顯示m/z 905 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C46H74O16。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.90,0.92,0.97,1.00,1.10,1.23(each 3H,s,CH3);3個糖端基質子信號:δH 6.33(1H,br s,Rha H-1),5.95(1H,d,J=4.4 Hz,Rib H-1)和5.00(1H,d,J=6.8 Hz,Ara H-1);Rha的甲基質子信號:δH 1.61(3H,d,J=6.1 Hz);苷元部分特征質子信號:δH 3.26(1H,dd,J=4.1、13.8 Hz,H-18),5.41(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:39.0(C-1),26.4(C-2),81.3(C-3),43.6(C-4),47.7(C-5),18.1(C-6),32.8(C-7),39.8(C-8),48.2(C-9),36.8(C-10),23.7(C-11),122.6(C-12),144.7(C-13),42.1(C-14),28.3(C-15),23.6(C-16),46.6(C-17),41.9(C-18),46.4(C-19),30.9(C-20),34.2(C-21),33.2(C-22),64.0(C-23),14.1(C-24),16.0(C-25),17.4(C-26),26.1(C-27),180.1(C-28),33.2(C-29),23.7(C-30),Ara C-1~C-5(104.7,75.3,75.0,69.7,66.3),Rha C-1~C-6(101.1,72.2,81.1,72.4,69.7,18.2),Rib C-1~C-5(104.5,72.8,70.3,68.7,65.3)。對比參考文獻波譜數(shù)據(jù)[23],鑒定該化合物為clematoside S。
化合物7:白色無定形粉末。ESI-MS顯示m/z 865 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C46H74O15。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.81,0.90,0.94,0.97,1.02,1.10,1.23(each 3H,s,CH3);3個糖端基質子信號:δH 6.31(1H,br s,Rha H-1),5.92(1H,d,J=4.6 Hz,Rib H-1)和4.94(1H,d,J=6.8 Hz,Ara H-1);Rha的甲基質子信號:δH 1.61(3H,d,J=6.1 Hz);苷元部分特征質子信號:δH 3.22(1H,dd,J=4.1、12.7 Hz,H-3),3.28(1H,dd,J=4.1、13.9 Hz,H-18),5.42(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.8(C-1),26.6(C-2),88.8(C-3),39.5(C-4),55.9(C-5),18.5(C-6),33.2(C-7),39.7(C-8),48.0(C-9),37.0(C-10),23.7(C-11),122.4(C-12),144.8(C-13),42.1(C-14),28.3(C-15),23.7(C-16),46.7(C-17),42.0(C-18),46.5(C-19),30.9(C-20),34.2(C-21),33.2(C-22),28.2(C-23),16.7(C-24),15.4(C-25),17.4(C-26),26.1(C-27),180.3(C-28),33.3(C-29),23.7(C-30),Ara C-1~C-5(105.2,75.4,74.7,69.3,65.7),Rha C-1~C-6(101.3,71.9,81.2,72.5,69.6,18.4),Rib C-1~C-5(104.5,72.8,70.2,68.6,65.2)。對比參考文獻波譜數(shù)據(jù)[24],鑒定該化合物為prosapogenin CP4。
化合物8:白色無定形粉末。ESI-MS顯示m/z 949 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C48H78O17。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.86,0.88,0.91,1.00,1.11(each 3H,s,CH3),1.21(6H,s,2×CH3);3個糖端基質子信號:δH 5.86(1H,br s,Rha H-1),6.24(1H,d,J=8.1 Hz,GlcⅠ H-1)和4.68(1H,d,J=7.9 Hz,GlcⅡ H-1);Rha的甲基質子信號:δH 1.69(3H,d,J=6.2 Hz);苷元部分特征質子信號: δH 3.20(1H,dd,J=3.5、13.6 Hz,H-18),5.42(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:39.0(C-1),28.1(C-2),78.0(C-3),39.4(C-4),55.8(C-5),18.8(C-6),33.1(C-7),39.9(C-8),48.1(C-9),37.4(C-10),23.8(C-11),122.9(C-12),144.1(C-13),42.1(C-14),28.3(C-15),23.4(C-16),47.0(C-17),41.7(C-18),46.2(C-19),30.7(C-20),34.0(C-21),32.5(C-22),28.8(C-23),16.5(C-24),15.6(C-25),17.5(C-26),26.1(C-27),176.5(C-28),33.1(C-29),23.7(C-30),GlcⅠ C-1~C-6(95.7,73.8,78.8,70.8,78.1,69.2),GlcⅡ C-1~C-6(104.9,75.3,76.5,78.2,77.2,61.3),Rha C-1~C-6(102.7,72.6,72.8,74.0,70.3,18.5)。對比參考文獻波譜數(shù)據(jù)[25],鑒定該化合物為cussonside B。
化合物9:白色無定形粉末。ESI-MS顯示m/z 941 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C48H78O18。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.84,0.86,0.99,1.04,1.12,1.15(each 3H,s,CH3);3個糖端基質子信號:δH 5.84(1H,br s,Rha H-1),6.22(1H,d,J=8.1 Hz,GlcⅠH -1)和4.97(1H,d,J=7.8 Hz,GlcⅡH -1);Rha的甲基質子信號:δH 1.67(3H,d,J=6.2 Hz);苷元部分特征質子信號:δH 3.16(1H,dd,J=4.1、13.7 Hz,H-18),5.41(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.8(C-1),27.7(C-2),73.4(C-3),42.9(C-4),48.1(C-5),18.5(C-6),32.5(C-7),39.9(C-8),48.5(C-9),37.2(C-10),23.8(C-11),122.9(C-12),144.1(C-13),42.1(C-14),28.3(C-15),23.3(C-16),47.0(C-17),41.7(C-18),46.2(C-19),30.7(C-20),33.9(C-21),32.5(C-22),67.8(C-23),13.1(C-24),161.0(C-25),17.6(C-26),26.0(C-27),176.5(C-28),33.1(C-29),23.6(C-30),GlcⅠ C-1~C-6(95.6,73.8,78.7,70.8,78.0,69.2),GlcⅡ C-1~C-6(104.9,75.3,76.5,78.2,77.1,61.3),Rha C-1~C-6(102.7,72.6,72.7,74.0,70.3,18.6)。對比參考文獻波譜數(shù)據(jù)[22],鑒定該化合物為白頭翁皂苷C。
化合物10:白色無定形粉末。ESI-MS顯示m/z? ? ? ?1 067 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C52H84O21。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.86,0.87,0.94,1.10,1.12,1.18(each 3H,s,CH3);4個糖端基質子信號:δH 6.32(1H,br s,Rha H-1),6.31(1H,d,J=8.2 Hz,Glc H-1),5.95(1H,d,J=4.5 Hz,Rib H-1)和5.04(1H,d,J=6.8 Hz,AraH-1);Rha的甲基質子信號:δH 1.53(3H,d,J=6.2 Hz);苷元部分特征質子信號:δH 3.17(1H,dd,J=4.1、13.7 Hz,H-18),5.40(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:39.1(C-1),26.2(C-2),81.2(C-3),43.6(C-4),47.7(C-5),18.2(C-6),32.8(C-7),39.8(C-8),48.2(C-9),36.8(C-10),23.7(C-11),122.9(C-12),144.0(C-13),42.1(C-14),28.3(C-15),23.6(C-16),46.6(C-17),41.7(C-18),46.2(C-19),30.8(C-20),34.0(C-21),32.5(C-22),63.9(C-23),14.2(C-24),16.2(C-25),17.5(C-26),26.1(C-27),176.4(C-28),33.2(C-29),23.7(C-30),Ara C-1~C-5(104.7,75.4,75.2,69.9,66.3),Rha C-1~C-6(101.3,72.0,81.1,72.8,69.8,18.2),Rib C-1~C-5(104.7,72.8,70.3,68.9,65.3),Glc C-1~C-6(95.7,74.1,79.3,71.1,78.9,62.2)。對比參考文獻波譜數(shù)據(jù)[26],鑒定該化合物為clemastanoside D。
化合物11:白色無定形粉末。ESI-MS顯示m/z 951 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C47H76O18。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.86,0.87,0.94,1.01,1.15,1.18(each 3H,s,CH3);3個糖端基質子信號:δH 6.31(1H,J=8.1 Hz,28-O-Glc H-1),5.16(1H,d,J=7.6 Hz,3-O-Glc H-1)和5.15(1H,d,J=5.8 Hz,Ara H-1);苷元部分特征質子信號:δH 3.18(1H,dd,J=4.1、13.7 Hz,H-18),5.42(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.8(C-1),26.1(C-2),82.1(C-3),43.5(C-4),47.0(C-5),18.3(C-6),32.6(C-7),40.0(C-8),48.2(C-9),36.9(C-10),23.4(C-11),122.9(C-12),144.2(C-13),42.2(C-14),28.3(C-15),23.4(C-16),47.0(C-17),41.8(C-18),46.2(C-19),30.8(C-20),34.0(C-21),32.5(C-22),64.9(C-23),13.5(C-24),16.2(C-25),17.6(C-26),26.1(C-27),176.5(C-28),33.1(C-29),23.7(C-30),Ara C-1~C-5(104.0,81.4,73.7,68.4,65.1),3-O-Glc C-1~C-6(106.0,76.3,78.4,71.4,78.3,62.6),28-O-Glc C-1~C-6(95.8,74.2,79.0,71.2,79.4,62.3)。對比參考文獻波譜數(shù)據(jù)[27],鑒定該化合物為3β-O-β-D-吡喃葡萄糖-(1→2)-α-L-吡喃阿拉伯糖-常春藤皂苷元-28-O-β-D-吡喃葡萄糖酯苷。
化合物12:白色無定形粉末。ESI-MS顯示m/z? ? ? ?1 081 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C53H86O21。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.85,0.85,0.86,0.92,1.05,1.20,1.22(each 3H,s,CH3);4個糖端基質子信號:δH 4.73(1H,d,J=6.9 Hz,Ara H-1),5.81(1H,br s,Rha H-1),6.19(1H,d,J=8.0 Hz,GlcⅠ H-1)和4.92(1H,d,J=7.8 Hz,GlcⅡ H-1);Rha的甲基質子信號:δH 1.68(3H,d,J=6.1 Hz);苷元部分特征質子信號:δH 3.11(1H,m,H-3),3.30(1H,dd,J=3.1、11.2 Hz,H-18),5.38(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.7(C-1),26.4(C-2),88.6(C-3),39.4(C-4),55.7(C-5),18.4(C-6),33.0(C-7),39.8(C-8),48.0(C-9),36.9(C-10),23.7(C-11),122.8(C-12),144.0(C-13),42.0(C-14),28.1(C-15),23.2(C-16),46.9(C-17),41.5(C-18),46.1(C-19),30.6(C-20),33.9(C-21),32.4(C-22),28.1(C-23),16.8(C-24),15.5(C-25),17.4(C-26),26.0(C-27),176.4(C-28),33.0(C-29),23.6(C-30),Ara C-1~C-5(107.4,72.8,74.5,69.4,66.6),GlcⅠ C-1~C-6(95.5,73.7,78.6,70.7,77.9,69.0),GlcⅡ C-1~C-6(104.7,75.2,76.4,78.1,77.0,61.1),Rha C-1~C-6(102.6,72.4,72.6,73.8,70.2,18.5)。對比參考文獻波譜數(shù)據(jù)[28],鑒定該化合物為刺五加皂苷C3。
化合物13:白色無定形粉末。ESI-MS顯示m/z? ? ? ?1 219 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C59H96O26。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.84,0.85,0.85,1.01,1.06,1.18,1.19(each 3H,s,CH3);5個糖端基質子信號:δH 4.90(1H,d,J=6.2 Hz,Ara H-1),5.15(1H,d,J=7.9 Hz,3-O-Glc H-1),5.82(1H,br s,Rha H-1),6.21(1H,d,J=8.1 Hz,GlcⅠ H-1)和4.92(1H,d,J= 7.8 Hz,GlcⅡ H-1);Rha的甲基質子信號:δH 1.68(3H,d,J=6.2 Hz);苷元部分特征質子信號:δH 3.15(1H,m,H-18),5.38(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.7(C-1),26.4(C-2),88.7(C-3),39.4(C-4),55.7(C-5),18.5(C-6),33.1(C-7),39.8(C-8),48.0(C-9),36.9(C-10),23.7(C-11),122.8(C-12),144.0(C-13),42.0(C-14),28.1(C-15),23.3(C-16),47.0(C-17),41.6(C-18),46.2(C-19),30.7(C-20),33.9(C-21),32.5(C-22),28.1(C-23),16.8(C-24),15.5(C-25),17.4(C-26),26.0(C-27),176.4(C-28),33.1(C-29),23.6(C-30),Ara C-1~C-5(104.7,80.9,73.4,68.2,64.9),3-O-Glc C-1~C-6(105.9,76.3,78.2,71.5,78.0,62.5),GlcⅠ C-1~C-6(95.6,73.8,78.6,70.8,78.0,69.1),GlcⅡ C-1~C-6(104.8,75.3,76.4,78.2,77.1,61.2),Rha C-1~C-6(102.7,72.5,72.7,73.9,70.2,18.5)。對比參考文獻波譜數(shù)據(jù)[29],鑒定該化合物為刺五加皂苷A1。
化合物14:白色無定形粉末。ESI-MS顯示m/z? ? ? ?1 351 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C64H104O30。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.83,0.86,0.97,1.02,1.10,1.13(each 3H,s,CH3);6個糖端基質子信號:δH 4.94(1H,d,J=7.0 Hz,Ara H-1),5.95(1H,d,J=4.6 Hz,Rib H-1),6.31(1H,s,3-O-Rha H-1),5.81(1H,br s,28-O-Rha H-1),6.21(1H,d,J=8.0 Hz,GlcⅠ H-1)和4.97(1H,d,J=7.9 Hz,GlcⅡ H-1);3-O-Rha的甲基質子信號:δH 1.67(3H,d,J=6.2 Hz);28-O-Rha的甲基質子信號:δH 1.68(3H,d,J=6.1 Hz);苷元部分特征質子信號:δH 3.22(1H,dd,J=3.8、13.7 Hz,H-18),5.41(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:39.0(C-1),26.2(C-2),81.0(C-3),43.5(C-4),47.7(C-5),18.1(C-6),32.7(C-7),39.9(C-8),48.1(C-9),36.8(C-10),23.8(C-11),122.8(C-12),144.0(C-13),42.1(C-14),28.3(C-15),23.3(C-16),47.1(C-17),41.6(C-18),46.1(C-19),30.7(C-20),33.9(C-21),32.4(C-22),63.9(C-23),13.9(C-24),16.1(C-25),17.5(C-26),26.1(C-27),176.5(C-28),33.2(C-29),23.7(C-30),Ara C-1~C-5(104.6,75.3,75.0,69.7,66.4),3-O-Rha C-1~C-6(101.2,71.9,81.1,72.8,69.8,18.4),Rib C-1~C-5(104.5,72.4,69.7,69.0,65.1),GlcⅠ C-1~C-6(95.5,73.8,78.7,70.7,77.8,69.1),GlcⅡ C-1~C-6(104.6,75.2,76.5,78.1,77.1,61.2),28-O-Rha C-1~C-6(102.6,72.4,72.5,73.9,70.1,18.3)。對比參考文獻波譜數(shù)據(jù)[24],鑒定該化合物為? ? huzhangoside D。
化合物15:白色無定形粉末。ESI-MS顯示m/z? ? ? ? 1 219 [M-H]-,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C59H96O26。1H-NMR(500 MHz,C5D5N)顯示6個甲基質子信號:δH 0.81,0.85,0.95,1.05,1.12,1.16(each 3H,s,CH3);5個糖端基質子信號:δH 5.09(1H,d,J=6.4 Hz,Ara H-1),6.25(1H,s,3-O-Rha H-1),5.85(1H,br s,28-O-Rha H-1),6.32(1H,d,J=8.2 Hz,GlcⅠ H-1)和4.97(1H,d,J=7.9 Hz,GlcⅡ H-1);3-O-Rha的甲基質子信號:δH 1.62(3H,d,J=6.2 Hz);28-O-Rha的甲基質子信號:δH 1.69(3H,d,J=6.2 Hz);苷元部分特征質子信號: δH 3.12(1H,dd,J=3.6、13.7 Hz,H-18),5.34(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:39.1(C-1),26.2(C-2),81.1(C-3),43.5(C-4),47.8(C-5),18.2(C-6),32.7(C-7),40.0(C-8),48.2(C-9),36.8(C-10),23.8(C-11),122.9(C-12),144.1(C-13),42.2(C-14),28.4(C-15),23.3(C-16),47.1(C-17),41.7(C-18),46.1(C-19),30.7(C-20),33.9(C-21),32.5(C-22),63.9(C-23),13.8(C-24),16.2(C-25),17.4(C-26),26.0(C-27),176.5(C-28),33.1(C-29),23.6(C-30),Ara C-1~C-5(104.3,75.6,74.7,69.3,65.7),3-O-Rha C-1~C-6(101.7,72.3,72.5,74.1,69.7,18.5),GlcⅠ C-1~C-6(95.6,73.9,78.7,70.8,77.9,69.2),GlcⅡ C-1~C-6(104.8,75.3,76.5,78.2,77.1,61.2),28-O-Rha C-1~C-6(102.7,72.5,72.7,74.0,70.3,18.5)。對比參考文獻波譜數(shù)據(jù)[30],鑒定該化合物為刺楸皂苷B。
化合物16:白色無定形粉末。ESI-MS顯示m/z? ? ? ? 1 389 [M+Na]+,綜合其1D-NMR數(shù)據(jù)分析,推測其分子式為C65H106O30。1H-NMR(500 MHz,C5D5N)顯示7個甲基質子信號:δH 0.87,1.08,1.09,1.15,1.22(each 3H,s,CH3),0.86(6H,s,2×CH3);6個糖端基質子信號:δH 4.75(1H,d,J=6.2 Hz,Ara H-1),5.15(1H,d,J=7.9 Hz,3-O-Glc H-1),6.17(1H,s,3-O-Rha H-1),5.85(1H,br s,28-O-Rha H-1),6.28(1H,d,J=8.2 Hz,GlcⅠ H-1),GlcⅡ H-1(overlapped);3-O-Rha的甲基質子信號:δH 1.62(3H,d,J=6.2 Hz);28-O-Rha的甲基質子信號:δH 1.66(3H,d,J=6.1 Hz);苷元部分特征質子信號:δH 3.16(1H,dd,J=4.0、11.5 Hz,H-18),5.39(1H,br s,H-12)。13C-NMR(125 MHz,C5D5N)中δC:38.8(C-1),26.5(C-2),88.6(C-3),39.4(C-4),55.8(C-5),18.5(C-6),33.0(C-7),39.7(C-8),47.9(C-9),36.9(C-10),23.8(C-11),122.8(C-12),144.0(C-13),42.0(C-14),28.1(C-15),23.3(C-16),47.0(C-17),41.5(C-18),46.1(C-19),30.7(C-20),33.9(C-21),32.4(C-22),28.0(C-23),16.9(C-24),15.6(C-25),17.4(C-26),25.9(C-27),176.4(C-28),33.1(C-29),23.6(C-30),Ara C-1~C-5(104.9,76.3,74.0,79.6,64.5),3-O-Rha C-1~C-6(101.7,72.3,72.5,74.0,69.8,18.6),3-O-Glc C-1~C-6(106.4,75.5,78.5,71.2,78.8,62.5),GlcⅠ C-1~C-6(95.6,73.8,78.7,70.8,78.0,69.2),GlcⅡ C-1~C-6(104.9,75.3,76.5,78.2,77.1,61.2),28-O-Rha C-1~C-6(102.7,72.5,72.7,74.0,70.3,18.5)。對比參考文獻波譜數(shù)據(jù)[30],鑒定該化合物為hederacolchiside E。
2.4 抗腫瘤活性研究
2.4.1 抑制腫瘤細胞增殖活性 采用MTT法檢測所得化合物對HL-60細胞、A549細胞、HepG2細胞、HeLa細胞和U87MG細胞增殖的抑制作用。收集對數(shù)生長期的上述細胞,置于96孔板中,調整細胞密度至1×103~1×104個/孔,每孔200 μL,加待測化合物(濃度分別為0、2、4、8、16、32、64 μmol/L),以多柔比星和尼莫司汀為陽性對照,各濃度設3個復孔,在培養(yǎng)箱內培養(yǎng)72 h后,每孔加20 μL MTT試劑染色,繼續(xù)培養(yǎng)4 h;棄上層培養(yǎng)液,每孔加入150 μL DMSO,振蕩10 min,在酶標儀490 nm波長下檢測吸光度,計算半數(shù)抑制濃度(IC50)。結果如表2所示,化合物3、4、6~9均表現(xiàn)出不同程度的抑制腫瘤細胞增殖活性;其中化合物7活性最強,抑制細胞增殖的IC50為8.21~16.82 μmol/L。而其余化合物未顯示對測試細胞株有增殖抑制活性。
2.4.2 流式細胞術檢測細胞凋亡 根據(jù)抑制腫瘤細胞增殖活性實驗結果,選取化合物7作用于U87MG細胞,采用Annexin V-FITC/PI試劑盒檢測其對U87MG細胞凋亡的影響。細胞生長至對數(shù)增殖期,設2個實驗組(24 h組、72 h組)和空白對照組,去除原培養(yǎng)液,實驗組加入藥物濃度為8.6 μmol/L的培養(yǎng)液,空白對照組加入空白培養(yǎng)液,培養(yǎng)一定時間后,用胰酶消化吹打為細胞懸液,調整細胞密度至5×105個/mL,取1 mL離心(2 000 r/min,5 min),PBS洗滌2次,再離心(2 000 r/min,5 min),加入300 μL Binding Buffer重懸;加入5 μL Annexin V-FITC和5 μL PI(碘化丙啶),混勻,室溫避光培養(yǎng)15 min,加入200 μL Binding Buffer,采用流式細胞儀檢測細胞凋亡率。試驗重復3次。結果顯示,24 h組和72 h組中U87MG細胞產生明顯凋亡現(xiàn)象,24 h組的早期和中晚期凋亡細胞分別占8.0%和21.7%,72 h組該占比分別為18.7%和39.6%,呈一定時間依賴趨勢。結果見圖3。
3 討論
本研究采用多種色譜技術,從小花草玉梅根莖中分離純化得到16個化合物,根據(jù)波譜數(shù)據(jù)和理化性質鑒定了它們的化學結構,所得化合物均為齊墩果烷型三萜皂苷,包含2種苷元:齊墩果酸型皂苷元和常春藤型皂苷元。經系統(tǒng)文獻檢索,化合物1為新化合物。通過MTT法檢測所得化合物對5種人源腫瘤細胞(HL-60細胞、A549細胞、HepG2細胞、HeLa細胞和U87MG細胞)的增殖抑制活性,結果顯示所有雙糖鏈皂苷均無活性,且在苷元C-28位連糖基的單糖鏈皂苷(化合物8、9)活性亦較弱,提示這類三萜皂苷結構中苷元C-3位連糖基且C-28位為游離羧基是具備活性的必要條件。苷元C-3位糖鏈存在Rha(1→2)Ara-結構片段的皂苷(化合物6、7)活性較強;糖鏈結構相同的皂苷(化合物6、7),齊墩果酸型皂苷元皂苷活性強于常春藤型皂苷元皂苷,推測苷元C-23位羥基對活性存在削弱作用。以上結論驗證了已報道的有關齊墩果烷型三萜皂苷抗腫瘤的構效關系[31-33]。此外,通過流式細胞術Annexin V-FITC/PI雙染試驗,發(fā)現(xiàn)化合物7能誘導U87MG細胞凋亡,且呈一定時間依賴趨勢,可以推測其通過促進腫瘤細胞的凋亡來抑制腫瘤細胞生長,但細胞凋亡機制較為復雜,需要通過進一步的研究明確該化合物促凋亡的調節(jié)因子及相關信號通路。
綜上所述,本研究豐富了銀蓮花屬植物三萜皂苷類活性成分的物質基礎,并為其抗腫瘤活性的進一步開發(fā)提供了參考和依據(jù)。
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(收稿日期:2021-10-14 修回日期:2022-01-18)
(編輯:曾海蓉)
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