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  热带亚热带植物学报  2020, Vol. 28 Issue (2): 203-208  DOI: 10.11926/jtsb.4135
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引用本文  

王国凯, 刘海涛, 刘丛彬, 等. 宁前胡内生真菌Fusarium tricinctum固体发酵代谢产物研究[J]. 热带亚热带植物学报, 2020, 28(2): 203-208. DOI: 10.11926/jtsb.4135.
WANG Guo-kai, LIU Hai-tao, LIU Cong-bin, et al. Metabolites of Fusarium tricinctum, An Endophytic Fungus Isolated from Ningguo Peucedanum praeruptorum on Solid Fermentation[J]. Journal of Tropical and Subtropical Botany, 2020, 28(2): 203-208. DOI: 10.11926/jtsb.4135.

基金项目

安徽省高校优秀青年人才支持计划重点项目(gxyqZD2019035);安徽高校自然科学研究重点项目(KJ2019A0477)资助

通信作者

王国凯.E-mail:wanggk@ahtcm.edu.cn 刘劲松.E-mail:jinsongliu@ahtcm.edu.cn

作者简介

王国凯(1981~), 男, 博士, 副教授, 研究方向为天然药物化学

文章历史

收稿日期:2019-08-19
接受日期:2019-09-24
宁前胡内生真菌Fusarium tricinctum固体发酵代谢产物研究
王国凯 1, 刘海涛 1, 刘丛彬 1, 杨家欣 2, 王刚 1, 刘劲松 1     
1. 安徽中医药大学药学院, 现代中药安徽省工程技术中心, 合肥 230012;
2. 中国医药大学附设医院医学研究部, 中国台湾, 台中 40447
摘要:为了解宁前胡内生真菌Fusarium tricinctum固体发酵代谢产物的化学成分,采用硅胶色谱、中压以及制备液相等方法对其进行分离鉴定和抗肿瘤活性研究。结果表明,从其中分离得到14个化合物,结构鉴定分别为fungerin(1)、fusagerins F(2)、6-[(3R)-3-hydroxybutan-2-yl]-5-(hydroxymethyl)-4-methoxy-2H-pyran-2-one(3)、6-[(3S)-3-hydroxybutan-2-yl]-5-(hydroxymethyl)-4-methoxy-2H-pyran-2-one(4)、6α-chlamydosporol(5)、6β-chlamydosporol(6)、(3R,4R)-(-)-4-hydroxymellein(7)、(3R)-(-)-8-hydroxymellein(8)、enniatin B(9)、enniatin B1(10)、enniatin A1(11)、enniatin A(12)、enniatin B3(13)和enniatin B2(14)。所有化合物均为首次从宁前胡内生真菌中分离得到。体外抗肿瘤活性试验表明化合物均无显著的细胞毒活性。
关键词宁前胡    内生真菌    代谢产物    抗肿瘤活性    
Metabolites of Fusarium tricinctum, An Endophytic Fungus Isolated from Ningguo Peucedanum praeruptorum on Solid Fermentation
WANG Guo-kai 1, LIU Hai-tao 1, LIU Cong-bin 1, YANG Jia-sing 2, WANG Gang 1, LIU Jin-song 1     
1. School of Pharmacy, Anhui University of Chinese Medicine&Anhui Engineering Research Center of Modernized Chinese Material, Hefei 230012, China;
2. Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40441, Taiwang, China
Foundation item: This work was supported by the Project for College Excellent Young Talents in Anhui (Grant No. gxyqZD2019035), and the Key Project in Natural Science Research of Colleges in Anhui (Grant No. KJ2019A0477)
Abstract: To investigate the chemical metabolites from Fusarium tricinctum, an endophytic fungus isolated from Ningguo Peucedanum praeruptorum, 14 compounds were isolated from solid fermentation and purified by silica gel column chromatography, MPLC, and preparative liquid chromatography. Based on data of MS and NMR, their structures were identified as fungerin (1), fusagerins F (2), 6-[(3R)-3-hydroxybutan-2-yl]-5-(hydroxymethyl)-4-methoxy-2H-pyran-2-one (3), 6-[(3S)-3-hydroxybutan-2-yl]-5-(hydroxymethyl)-4-methoxy-2H-pyran-2-one (4), 6α-chlamydosporol (5), 6β-chlamydosporol (6), (3R, 4R)-(-)-4-hydroxymellein (7), (3R)-(-)-8-hydroxymellein (8), enniatin B (9), enniatin B1 (10), enniatin A1 (11), enniatin A (12), enniatin B3 (13), enniatin B2 (14). All these compounds are isolated from this endophytic fungus for the first time. The cytotoxicity assay of all compounds did not show anti-tumor activities.
Key words: Ningguo Peucedanum praeruptorum    Endophytic fungus    Metabolite    Anti-tumor activity    

植物内生真菌是指其全部或部分的生长发育过程在健康植物的茎干或叶片等组织中,而不引起明显病害症状的一类真菌[1]。研究表明植物内生真菌的次生代谢产物在抗肿瘤、促进宿主植物生长等多方面具有良好的作用[2-3],内生真菌次生代谢产物会表现出与宿主植物相同或者相似的生物活性。内生真菌和寄主植物之间的相互作用类型,受其共生体基因和外在环境调节的控制,其相互作用往往具有生长快速、抗逆境、抗病害等益处,比未感染植株更具生存竞争力[4]。在内生真菌-植物宿主-食草动物生态系统中,植物内生真菌扮演着前所未有的重要生态学作用。发挥这些作用的物质基础是内生真菌产生的丰富多样的次生代谢产物,它们具有多种生物活性。这些植物内生真菌与宿主之间特殊的共生关系及其自身独特的生物学特性为阐释药材道地性的形成带来了新的启发,同时也为从植物内生真菌次生代谢产物的研究中寻找新型的天然活性先导物质带来了新的方向。

前胡为伞形科(Umbelliferae)白花前胡(Peuce- danum praeruptorum)的干燥根,具有降气化痰、散风清热之功效。安徽宁国市是前胡道地产区之一, 所产前胡称为宁前胡[5]。前期从宁前胡中分离鉴定了一系列内生真菌[6],其中Fusarium tricinctum为宁前胡内生真菌中的优势菌株。不同发酵方式对内生真菌次级代谢产物产量、成分类别具有显著影响[7]。为探讨不同发酵方式对内生真菌优势菌株代谢产物的影响,分别对F. tricinctum采用固体和液体发酵法进行发酵,从液体发酵液中分离了13个单体化合物[8],本研究继续对其固体发酵的次生代谢产物进行研究。

1 材料和方法 1.1 材料

AM-400、DRX 500和AVANCE III-600核磁共振(Bruker公司);Auto Premier P776质谱仪(Waters公司);制备液相(Agilent公司);中压制备(BÜCHI公司);柱色谱硅胶及薄层色谱硅胶板(青岛海洋化工厂);葡聚糖凝胶Sephadex LH-20 (GE公司)。

宁前胡采自安徽宁国(标本编号QHX34)。菌株从白花前胡(Peucedanum praeruptorum)新鲜根中分离得到,经形态及ITS rDNA鉴定为镰刀属Fusa- rium tricinctum (菌株编号LH10),菌株保存于安徽中医药大学药学院。

1.2 内生真菌的固体发酵培养

500 mL锥形瓶中加入80 g蒸馏水清洗晾干大米,20 mL无机盐水溶液,100 mL蒸馏水。其中无机盐水溶液为:0.5% (NH4)2SO4、0.25% KH2PO4、0.1% MgSO4、0.1% NaCl。锥形瓶扎口,121℃灭菌30 min,按照10%的接种量接种于灭菌后的大米培养基中,28℃静置培养30 d。乙酸乙酯萃取,合并浓缩至蒸干得到固体发酵产物。

1.3 提取和分离

乙酸乙酯物浸膏55 g经硅胶柱层析,以石油醚-丙酮系统梯度洗脱(1:0~0:1, V/V)得7个组分A~ G。组分C经中压色谱以甲醇-水(10:100~100:0)梯度洗脱得到6个组分,组分C-5经Sephadex LH-20 (氯仿-甲醇)洗脱得到3个组分,C-5-1再经制备液相(乙腈/水, 70:30→100:0)制备得化合物11 (14.2 mg, 36.3 min)和10 (15.4 mg, 37.5 min)。组分C-5-3经制备液相(乙腈/水, 70:30→100:0)制备得化合物9 (34 mg, 38.2 min)和12 (6.2 mg, 39.6 min)。将C-6经Sephadex LH-20 (氯仿/甲醇)柱洗脱得到组分C-6-1, 将C-6-1再经制备液相(乙腈/水, 70:30→100:0)制备得化合物14 (9.5 mg, 33.2 min)和13 (10.3 mg, 32.0 min)。组分D经硅胶柱层析,以石油醚-丙酮(15:1~5:1)洗脱得到3个组分,组分D-2经中压色谱以甲醇-水(10:100~100:0)梯度洗脱得到5个组分,组分D-2-2经Sephadex LH-20用纯甲醇洗脱,再经制备液相(乙腈/水, 10%~25%)得到化合物1 (19.5 mg, 28.5 min)和2 (7.5 mg, 26.4 min)。部位E经中压色谱以甲醇-水(10:100~100:0)梯度洗脱得到6个组分,组分E-1经Sephadex LH-20 (甲醇)柱洗脱,组分E-1-3再经制备液相(乙腈/水, 10:90→25:75)制备得化合物5 (6.5 mg, 26.6 min)和6 (4.4 mg, 27.5 min)。组分E-2经Sephadex LH-20用纯甲醇洗脱,E-2-2再经制备液相(乙腈/水, 10:90→25:75))制备得化合物3 (8.5 mg, 25.6 min)和4 (7.4 mg, 23.3 min)。组分F经中压色谱以甲醇-水(10:100~100:0)梯度洗脱得到4个组分,组分F-2经Sephadex LH-20 (甲醇)柱洗脱,再将组分F-2-2经制备液相(乙腈/水, 10%~25%)得化合物7 (4.3 mg, 33.4 min)和8 (3.5 mg, 27.2 min)。

1.4 结构鉴定

化合物1   针状结晶。ES I-MS m/z: 235 [M + H]+,易溶于甲醇。1H NMR (CD3OD, 400 MHz): δ 7.40 (1H, s, H-6), 7.38 (1H, d, J = 15.6 Hz, H-3), 6.18 (1H, d, J = 15.2 Hz, H-2), 4.88 (1H, t, J = 7.0 Hz, H- 10), 3.53 (3H, s, H-15), 3.39 (3H, s, H-14), 3.27 (2H, dd, J = 6.8, 13.6 Hz, H-9), 1.58 (3H, s, H-12), 1.52 (3H, s, H-13); 13C NMR (CD3OD, 125 MHz): δ 169.9 (C-1), 140.4 (C-6), 136.4 (C-3), 135.6 (C-8), 134.2 (C-4), 120.3 (C-10), 114.6 (C-2), 51.9 (C-15), 32.1 (C-14), 25.7 (C-12), 23.0 (C-9), 18.0 (C-13)。根据文献[9-10]报道,确定化合物1为fungerin。

图 1 化合物1~14的结构 Fig. 1 Structures of compounds 1-14

化合物2   针状结晶。ES I-MS m/z: 273 [M + Na]+,易溶于甲醇。1H NMR (CD3OD, 400 MHz): δ 7.70 (1H, d, J = 15.3 Hz, H-3), 7.66 (1H, s, H-6), 6.60 (1H, d, J = 16.0 Hz, H-9), 6.51 (1H, d, J = 15.6 Hz, H-2), 6.27 (1H, d, J = 16.4 Hz, H-10), 3.77 (3H, s, H- 15), 3.70 (3H, s, H-14), 1.43 (3H, s, H-12), 1.41 (3H, s, H-13); 13C NMR (CD3OD, 125 MHz): δ 169.8 (C- 1), 147.3 (C-10), 141.0 (C-6), 136.6 (C-3), 135.2 (C-4), 134.4 (C-8), 115.8 (C-2), 112.5 (C-9), 71.9 (C-11), 52.0 (C-15), 32.8 (C-14), 29.8 (C-12), 29.8 (C-13)。根据文献[9-10]报道,确定化合物2为fusagerins F。

化合物3   白色粉末。ES I-MS m/z: 251 [M + Na]+,易溶于甲醇。1H NMR (CD3OD, 400 MHz): δ 5.58 (1H, s, H-3), 4.45 (2H, s, H-5a), 3.92 (3H, s, OCH3), 3.65 (1H, m, H-8), 3.02 (1H, m, H-7), 1.27 (3H, d, J = 6.4 Hz, H-8a), 1.19 (3H, d, J = 7.2 Hz, H- 7a); 13C NMR (CD3OD, 125 MHz): δ 172.6 (C-4), 167.6 (C-2), 166.9 (C-6), 113.7 (C-5), 88.4 (C-3), 70.2 (C-8), 57.2 (OCH3), 54.0 (C-5a), 44.0 (C-7), 21.5 (C- 8a), 15.2 (C-7a)。根据文献[11]报道,确定化合物3为6-[(3R)-3-hydroxybutan-2-yl]-5-(hydroxymethyl)-4- methoxy-2H-pyran-2-one

化合物4   白色粉末。ESI-MS m/z: 251 [M + Na]+,易溶于甲醇。1H NMR (CD3OD, 400 MHz): δ 5.58 (1H, s, H-3), 4.45 (2H, s, H-5a), 3.92 (3H, s, OCH3), 3.53 (1H, m, H-8), 3.02 (1H, m, H-7), 1.27 (3H, d, J = 6.4 Hz, H-8a), 1.19 (3H, d, J = 7.2 Hz, H- 7a); 13C NMR (CD3OD, 125 MHz): δ 172.6 (C-4), 167.6 (C-2), 166.9 (C-6), 113.7 (C-5), 88.4 (C-3), 68.7 (C-8), 57.2 (OCH3), 54.1 (C-5a), 43.5 (C-7), 21.2 (C- 8a), 15.6 (C-7a)。根据文献[11]报道,确定化合物4为6-[(3S)-3-hydroxybutan-2-yl]-5-(hydroxymethyl)-4- methoxy-2H-pyran-2-one。

化合物5   白色粉末。ES I-MS m/z: 249 [M + Na]+,易溶于甲醇。1H NMR (CD3OD, 400 MHz): δ 5.59 (1H, s, H-3), 4.51 (1H, dd, J = 3.2, 11.6 Hz, H- 7a), 4.40 (1H, dd, J = 5.2, 8.0 Hz, H-7b), 3.89 (3H, s, OCH3), 2.80 (1H, m, H-6), 1.46 (3H, d, J = 7.4 Hz, H- 8), 1.26 (3H, s, H-9); 13C NMR (CD3OD, 125 MHz): δ 170.8 (C-2), 167.2 (C-5), 160.9 (C-4), 107.3 (C-4a), 97.8 (C-8a), 88.1 (C-3), 56.9 (C-7), 56.5 (OCH3), 41.7 (C-6), 26.5 (C-8), 15.9 (C-9)。根据文献[12]报道,确定化合物5为6α-chlamydosporol。

化合物6   白色粉末。ES I-MS m/z: 249 [M + Na]+,易溶于甲醇。1H NMR (400 MHz, CD3OD): δ 5.59 (1H, s, H-3), 4.51 (1H, dd, J = 3.2, 11.6 Hz, H- 7a), 4.40 (1H, dd, J = 5.2, 8.0 Hz, H-7b), 3.89 (3H, s, OCH3), 2.80 (1H, m, H-6), 1.46 (3H, d, J = 7.4 Hz, H- 8), 1.26 (3H, s, H-9); 13C NMR (125 MHz, CD3OD): δ 170.8 (C-2), 166.8 (C-5), 159.5 (C-4), 108.1 (C-4a), 98.2 (C-8a), 88.4 (C-3), 57.1 (C-7), 56.5 (OCH3), 41.5 (C-6), 25.6 (C-8), 11.4 (C-9)。根据文献[12]报道,确定化合物6为6β-chlamydosporol。

化合物7   白色粉末。ES I-MS m/z: 217 [M + Na]+,易溶于甲醇氯仿。1H NMR (400 MHz, CDCl3): δ 11.0 (1H, s, H-9a), 7.54 (1H, t, J = 7.6 Hz, H-7), 7.03 (1H, d, J = 8.4 Hz, H-6), 6.93 (1H, d, J = 7.2 Hz, H-8), 4.84 (1H, d, J = 5.6 Hz, H-4), 4.7 (1H, m, H-3), 1.59 (3H, d, J = 6.8 Hz, H-3a); 13C NMR (125 MHz, CDCl3): δ 169.2 (C-1), 162.0 (C-9), 140.5 (C-5), 136.7 (C-7), 118.5 (C-6), 118.4 (C-8), 118.3 (C-10), 78.2 (C-3), 67.2 (C-4), 16.0 (C-3a)。根据文献[13]报道,确定化合物7为(3R, 4R)-(-)-4-hydroxymellein。

化合物8   白色粉末。ESI-MS m/z: 217 [M + Na]+,易溶于甲醇、氯仿。1H NMR (400 MHz, CDCl3): δ 10.58 (1H, s, H-8), 7.01 (1H, d, J = 8.8 Hz, H-7), 6.78 (1H, d, J = 8.8 Hz, H-6), 5.12 (1H, m, H-3), 3.17~3.12 (1H, dd, J = 3.2, 13.6 Hz, H-4a), 2.71~2.64 (1H, m, H- 4b), 1.38 (3H, d, J = 7.2 Hz, H-11); 13C NMR (150 MHz, CDCl3): δ 170.1 (C-1), 156.4 (C-9), 143.9 (C-8), 124.6 (C-5), 124.2 (C-6), 116.2 (C-7), 108.5 (C-10), 76.2 (C- 3), 28.7 (C-4), 21.1 (C-11)。根据文献[14]报道,确定化合物8为(3R)-(-)-8-hydroxymellein。

化合物9   白色粉末。ES I-MS m/z: 662 [M + Na]+,易溶于氯仿。1H NMR (400 MHz, CDCl3): δ 5.21 (1H, d, J = 8.0 Hz, H-6), 4.72 (1H, t, J = 8.8 Hz, H-3), 3.26 (3H, s, H-4a), 2.35~2.29 (1H, m, H-10), 2.23~2.16 (1H, m, H-7), 1.11 (3H, d, J = 6.8 Hz, H-11, H-12), 1.05 (3H, d, J = 6.4 Hz, H-8, H-9); 13C NMR (125 MHz, CDCl3): δ 172.8 (C-3), 172.2 (C-5), 76.9 (C-6), 63.7 (C-3), 33.1 (C-4a), 31.6 (C-7), 29.5 (C-10), 20.8 (C-11), 20.7 (C-12), 19.1 (C-8), 18.7 (C-9)。根据文献[15]报道,确定化合物9为enniatin B。

化合物10   白色结晶。ES I-MS m/z: 676 [M + Na]+,易溶于氯仿。1H NMR (400 MHz, CDCl3): δ 5.28 (1H, t, J = 7.2 Hz, H-5, H-11), 4.70 (1H, t, J = 8.4 Hz, H-2, H-8), 3.23 (3H, s, H-1a, H-7a), 3.10~ 3.06 (1H, m, H-23), 2.35~2.27 (1H, m, H-16), 2.21~ 2.10 (1H, m, H-13, H-20), 1.60~1.48 (2H, m, H-18), 1.12 (3H, d, J = 6.8 Hz, H-17), 1.05 (3H, d, J = 6.4 Hz, H-19), 0.96 (3H, d, J = 6.4 Hz, H-24, H-25), 0.90 (3H, d, J = 6.4 Hz, H-21, H-22), 0.88 (3H, d, J = 6.4 Hz, H- 14, H-15); 13C NMR (125 MHz, CDCl3): δ 172.8 (C- 3), 172.7 (C-9), 172.2 (C-6), 172.1 (C-12), 76.9 (C-5), 76.7 (C-11), 63.7 (C-2), 61.8 (C-8), 35.6 (C-16), 33.0 (C-1a, 7a), 31.6 (C-13, 20), 29.5 (C-23), 27.4 (C-18), 20.8 (C-24, 25), 19.0 (C-21, 22), 18.7 (C-14, 15), 16.8 (C-17), 11.3 (C-19)。根据文献[15]报道,确定化合物10为enniatin B1。

化合物11   白色结晶。ES I-MS m/z: 690 [M + Na]+,易溶于氯仿。1H NMR (400 MHz, CDCl3): δ 5.22 (1H, t, J = 7.2 Hz, H-5, H-11), 4.70 (1H, t, J = 8.8 Hz, H-2, H-8), 3.23 (3H, s, H-1a, H-7a), 3.11~ 3.06 (1H, m, H-23), 2.35~2.27 (1H, m, H-16), 2.22~ 2.10 (1H, m, H-13, H-20), 1.60-1.48 (2H, m, H-18), 1.12 (3H, d, J = 6.8 Hz, H-17), 1.05 (3H, d, J = 6.4 Hz, H-19), 0.96 (3H, d, J = 6.4 Hz, H-24, H-25), 0.90 (3H, d, J = 6.4 Hz, H-21, H-22), 0.88 (3H, d, J = 6.4 Hz, H- 14, H-15); 13C NMR (125 MHz, CDCl3): δ 172.8 (C- 3), 172.7 (C-9), 172.2 (C-6), 172.1 (C-12), 76.9 (C-5), 76.7 (C-11), 63.7 (C-2), 61.8 (C-8), 35.6 (C-16), 33.0 (C-1a, 7a), 31.6 (C-13, 20), 29.5 (C-23), 27.4 (C-18), 20.8 (C-24, 25), 19.0 (C-21, 22), 18.7 (C-14, 15), 16.8 (C-17), 11.3 (C-19)。根据文献[15]报道,确定化合物11为enniatin A1。

化合物12   白色粉末。ESI-MS m/z: 704 [M + Na]+,易溶于氯仿。1H NMR (400 MHz, CDCl3): δ 5.23 (1H, d, J = 8.0 Hz, H-6), 4.74 (1H, d, J = 8.8 Hz, H-3), 3.23 (3H, s, H-4a), 2.34~2.30 (1H, m, H-10), 2.26~2.19 (1H, m, H-7), 1.10 (3H, d, J = 6.4 Hz, H-11), 1.04 (3H, t, J = 6.4 Hz, H-13), 0.94 (3H, t, J = 6.4 Hz, H-8, H-9); 13C NMR (125 MHz, CDCl3): δ 172.0 (C- 2), 171.7 (C-5), 76.5 (C-6), 61.9 (C-3), 33.2 (C-4a), 31.4 (C-10), 29.4 (C-7), 27.0 (C-12), 20.6 (C-8, 9), 16.6 (C-11), 11.0 (C-13)。根据文献[16]报道,确定化合物12为enniatin A。

化合物13   白色结晶。ES I-MS m/z: 634 [M + Na]+,易溶于氯仿。1H NMR (400 MHz, CDCl3): δ 8.10 (1H, s, H-1), 5.14 (1H, d, J = 5.6 Hz, H-5), 4.62 (1H, d, J = 8.4 Hz, H-2), 4.43 (1H, d, J = 10.0 Hz, H- 8), 3.16 (3H, s, H-7a), 2.98 (1H, m, H-9), 2.58~2.47 (1H, m, H-12), 2.22~2.04 (1H, m, H-15), 1.03 (3H, d, J = 6.8 Hz, H-16, H-17), 0.88 (3H, d, J = 6.4 Hz, H-10, H-11), 0.85 (3H, d, J = 6.4 Hz, H-13, H-14); 13C NMR (125 MHz, CDCl3): δ 173.5 (C-3), 172.2 (C-6), 77.0 (C-5), 76.6 (C-8), 64.2 (C-2), 32.5 (C-7a), 31.6 (C-15), 29.4 (C-12), 29.0 (C-9), 21.5 (C-10, 11), 20.6 (C-16, 17), 18.8 (C-13, 14)。根据文献[17]报道,确定化合物13为enniatin B3。

化合物14   白色结晶。ESI-MS m/z: 648 [M + Na]+,易溶于氯仿。1H NMR (400 MHz, CDCl3): δ 8.21 (1H, s, H-1), 5.18 (1H, d, J = 5.6 Hz, H-5), 4.56 (1H, d, J = 8.4 Hz, H-2), 4.39 (1H, d, J = 10.0 Hz, H- 8), 3.18 (3H, s, H-7a), 3.02 (1H, m, H-9), 2.61~2.52 (1H, m, H-12), 2.22~2.04 (1H, m, H-15), 1.01 (3H, d, J = 6.8 Hz, H-16, H-17), 0.94 (3H, d, J = 6.4 Hz, H-10, H-11), 0.88 (3H, d, J = 6.4 Hz, H-13, H-14); 13C NMR (125 MHz, CDCl3): δ 173.7 (C-3), 172.1 (C-6), 76.9 (C-5), 76.3 (C-8), 63.9 (C-2), 32.3 (C-7a), 29.6 (C-15), 29.4 (C-12), 29.0 (C-9), 21.5 (C-10, 11), 20.4 (C-16, 17), 18.6 (C-13, 14)。根据文献[17]报道,确定化合物14为enniatin B2。

1.5 抗肿瘤活性结果

将化合物对5种口腔癌细胞株CAR、CAL27、SCC-4、SCC-9、HSC-3进行抗肿瘤活性筛选,结果表明,化合物均无显著活性。

2 结果和讨论

前期研究从宁前胡中分离鉴定了一系列内生真菌,Fusarium tricinctum为宁前胡内生真菌中的优势菌株,其隶属于瘤座孢科(Discellaceae)镰刀属[18], 是一类全世界广泛分布的真菌,Fusarium tricinctum作为一类重要的真菌资源,表现出多样的价值,越来越受到重视。其次生代谢产物往往具有良好的生理活性。Zhang等从F. tricinctum中分离得到了1个独特骨架的新的倍半萜类化合物fusartricin, 对Enterobacter aerogenesMicrococcus tetragenuCandida albicans具有显著的抗菌活性[19]。Sun等从F. tricinctum SYPF 7082中分离得到2个新的生物碱, 其中[-(α-oxyisohexanoyl-N-methyl-leucyl)2-]对小鼠巨噬细胞产生一氧化氮有显著的抑制作用[20]

前期从宁前胡内生菌F. tricinctum液体发酵液中分离鉴定了13个化合物,分别为cyclo-(L-pro-L-pro)、cyclo-(S-pro-S-leu)、cyclo-(L-phe-L-phe)、cyclo-(D-pro- L-phe)、cyclo-(L-pro-L-phe)、cyclo-(D-pro-L-leu)、cyclo- (S-pro-S-leu)、cyclo-[D-(4-hydroxyprolinyl)]-(L)-leucine、cyclo-[L-(4-hydroxyprolinyl)]-(L)-leucine、cyclo-(trans- 4-hydroxy-L-prolyl-L-phenylalanine)、cyclo-(D-cis-hyp- L-phe)、苯甲酸苄酯和苯乙酸。体外抗肿瘤活性试验表明3个化合物对CAR、CAL27、SCC-4、SCC-9和HSC-3等5种口腔癌肿瘤细胞有一定的细胞毒活性。为比较不同发酵方式对内生真菌优势菌株代谢产物的影响,分别对宁前胡内生真菌F. tricinctum进行固体和液体发酵法比较研究,结果表明不同发酵方式的宁前胡优势菌株发酵产物完全不同。本研究在该菌株液体发酵次生代谢产物研究基础上,从F. tricinctum固体发酵液中分离并鉴定了14个单体化合物。所有化合物均为首次从宁前胡内生真菌中分离得到,且同菌株不同发酵方式的发酵液中没有结构相同的次生代谢产物,尤其在固体发酵代谢产物中分离的环肽类化合物在液体发酵中并未分离到,说明发酵方式对代谢产物结构有重要影响。已有报道的化合物Enniatins A1、B和B1能够产生抗癌活性[21],但本研究的所有化合物对5种口腔癌肿瘤细胞均无显著的细胞毒活性。目前国内外对宁前胡内生菌的次生代谢产物研究无相关报道,本研究进一步丰富了宁前胡内生真菌F. tricinctum次生代谢产物结构多样性。

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