Isolation, purification, and cytotoxicity of 5-methoxypodophyllotoxin, a lignan from a root culture of Linum flavum.

A method has been developed for the large scale isolation of 5-methoxypodophyllotoxin [1] from a high-producing root culture derived from Linum flavum. A closely related lignan, 5'-demethoxy-5-methoxypodophyllotoxin [2], was also present in the root culture and was the cause of the main isolation difficulties. Essential steps in the isolation procedure are CH2Cl2 and XAD-4 extraction and XAD-8 cc followed by Si gel chromatography, using two different mobile phases. The isolated 5-methoxypodophyllotoxin [1] was very pure (greater than 99%) and possessed the desired stereochemical configuration, namely (-)-5-methoxypodophyllotoxin [1]. The in vitro cytotoxicity of 5-methoxypodophyllotoxin [1] against EAT and HeLa cells was determined and compared with those of podophyllotoxin [3], etoposide (VP-16-213) [4], teniposide (VM-26) [5], and 5-methoxypodophyllotoxin-4-beta-D-glucoside [6]. It appeared that 5-methoxypodophyllotoxin [1] has about the same cytotoxic potency as podophyllotoxin [3].     

Absolute configuration of verticillane diterpenoids by vibrational circular dichroism

Good agreement between theoretical and experimental vibrational circular dichroism curves of (1S,11S,12S)-(+)-verticilla-3E,7E-dien-12-ol (1) established the absolute configuration of this natural diterpene isolated from Bursera suntui. Molecular modeling of 1 was carried out using the Monte Carlo protocol followed by geometry optimization at the B3LYP 6-31G(d,p) level of theory. The 12-membered ring of 1 was found in a single preferred chair-chair-chair-chair conformation. In the six-membered ring a chair prevails over a distorted boat, and the C-OH bond rotation generates three predominant rotamers. Validation of the minimum energy conformation for 1 was achieved by comparison of theoretical and experimental infrared frequencies, vicinal 1H NMR coupling constants, and X-ray diffraction data. This study confirms that (+)-verticillol 1 isolated from Bursera species has the 1S,11S,12S absolute configuration that corresponds to the same enantiomeric series as verticillanes from Sciadopitys and Taxus, while verticillanes from Jackiella and Jungermannia have antipodal structures.     

Lignans from Dysosma versipellis with inhibitory effects on prostate cancer cell lines

A new monoepoxylignan, dysosmarol (1), along with eight known compounds, podophyllotoxin (2), 4'-demethylpodophyllotoxin (3), deoxypodophyllotoxin (4), 4'-demethyldeoxypodophyllotoxin (5), diphyllin (6), kaempferol, quercetin, and beta-sitosterol, were isolated from the roots of Dysosma versipellis. The structure of 1 was elucidated by spectroscopic methods. Aryltetralin lignans 2-4 showed the most potent inhibitory activities against the growth of androgen-sensitive (LNCaP) and androgen-independent (PC-3) human prostate cancer cell lines, with IC50 values in the ranges 0.030-0.056 and 0.032-0.082 microM, respectively. A quantitative HPLC analysis showed that compound 2 occurred at the highest concentration in the plant (37.21 mg/g) followed by compound 4 (5.01 mg/g) and compound 3 (2.75 mg/g). Furthermore, D. versipellis roots contain a similar content of compound 2 as compared with the rhizomes and roots of Podophyllum hexandrum, a commercial source of the lignan. Thus, cultivation of D. versipellis in suitable locations may serve as an alternative source for podophyllotoxin (2) production.     

Synthesis and cytotoxicity of racemic isodeoxypodophyllotoxin analogues with isoprene-derived side chains

A series of isodeoxypodophyllotoxin (5) analogues, 26-38, with various isoprene-derived side chains at the E-ring were designed and synthesized. For comparison, compound 39, with a benzyloxy group on the E-ring, and six D-ring opened analogues, 40-45, were also prepared. All the synthetic compounds were evaluated for their cytotoxic activities in vitro against seven cultured human tumor cell lines. Compounds 27, 43, and 44 were more cytotoxic than etoposide on BEL-7404, A549, and HL-60 cell lines, respectively. However, none of the synthetic isodeoxypodophyllotoxins were more cytotoxic than podophyllotoxin (1).     

A comparison of inverse-detected heteronuclear NMR performance: conventional vs cryogenic microprobe performance

We report a comparison of the results obtained at 500 MHz for heteronuclear shift correlation (HSQC) experiments with very small natural product samples using conventional and cryogenically cooled 3 mm NMR probes. The cryo probe affords a 12- to 16-fold reduction in data acquisition time for a comparable signal-to-noise ratio.     

高效液相色谱法测定疣克酊中鬼臼毒素的含量

 目的：建立疣克酊中鬼臼毒素含量的高效液相色谱测定方法。方法：以Discovery C₁₈(4.6 mm × 250 mm,5μm)为分析柱，以甲醇-水(50:50)为流动相，检测波长285 nm，流速为0.8 mL·min^-1。结果：当鬼臼毒素的浓度在24.8?99.2 mg·L^-1范围内时，面积与浓度间呈良好的线性关系（r =0.9999，n =6),方法的平均回收率为98.5%，日内和日间精密度分别为3.8% 和4.1%。3批疣克酊剂中鬼臼毒素的百分含量分别为102.00% ,101.46%, 100.39%。结论：本方法具有准确，简便，灵敏且 重现性好的特点，可适用于复方制剂中鬼臼毒素含量的测定。     

桃儿七茎部产鬼臼毒素类成分的内生真菌筛选及鉴定

目的:筛选和鉴定濒危藏族药桃儿七茎部产鬼臼毒素类成分的内生真菌,为保护桃儿七植物资源和发现新的天然活性菌株提供参考。方法:采用组织块法对桃儿七茎部的内生真菌进行分离,利用TLC和HPLC检测其代谢产物中的鬼臼毒素类成分,检测波长254 nm,流动相乙腈-水(40∶60)。采用形态学和分子生物学相结合的方法对产鬼臼毒素类成分的内生真菌进行鉴定。结果:共分离得到9株内生真菌,其中菌株J-1,J-2,J-3的发酵液中含有鬼臼毒素类成分,分别鉴定为Chaetomium globosum strain MF564,C.sp.4RF3和Pseudallescheria sp.T55。结论:从桃儿七茎中分离到3株产鬼臼毒素类成分的内生真菌,分别来源于2个新属的不同种菌株,为开发新绿色生物能源和实现内生真菌工业发酵生产鬼臼毒素类成分奠定了理论基础。     

Structural reassignment of a marine metabolite from a binaphthalenetetrol to a tetrabrominated diphenyl ether

The structure of a reported natural product isolate has been revised from (S)-2,2'-dimethoxy-[1,1'-binaphthalene]-5,5',6,6'-tetraol to a known tetrabrominated diphenyl ether. After total synthesis of the reported binaphthalenetetrol was accomplished via a key reduction of a binaphtho-ortho-quinone, comparison of the physical properties and NMR spectroscopic data of the synthetic material indicated that the structure of the natural product isolate was incorrect. Evaluation of the authentic natural product suggested the structure is a tetrabrominated diphenyl ether, likely 3,5-dibromo-2-(3,5-dibromo-2-methoxyphenoxy)phenol.     

Absolute configuration and antimicrobial activity of acylhomoserine lactones

(S)-N-Heptanoylhomoserine lactone is an uncommon acyl odd-chain natural product employed by many Gram-negative bacteria as a signaling substance in chemical communication mechanisms known as quorum sensing. The absolute configuration determination of the metabolite produced by the phytopathogen Pantoea ananatis Serrano is reported herein. As with all other substances of this class, the lactone moiety possesses S configuration, corroborating the hypothesis that it shares the same biosynthetic pathway as the (S)-N-hexanoylhomoserine lactone and also that some LuxI homologues can accept both hexanoyl- and heptanoyl-ACP as precursors. Evaluation of the antimicrobial activity of enantiomeric acylhomoserine lactones against three Gram-positive bacteria (Bacillus cereus, B. subtilis, and Staphylococcus aureus) revealed important features between absolute configuration and antimicrobial activity. The N-heptanoylhomoserine lactone was considerably less active than the 3-oxo derivatives. Surprisingly, non-natural (R)-N-(3-oxo-octanoyl)homoserine lactone was as active as the S enantiomer against B. cereus, while the synthetic racemic product was less active than either enantiomer.     

鬼臼毒素纳米脂质体抗肿瘤作用的研究

目的:比较鬼臼毒素纳米脂质体和鬼臼毒素混悬液抗肿瘤作用。方法:以每只0.2 mL肿瘤细胞悬液,接种于小鼠右前肢腋部皮下,24 h后将小鼠随机分组,各组分别给不同浓度的鬼臼毒素纳米脂质体、鬼臼毒素混悬液、环磷酰胺(CX)、生理盐水。环磷酰胺1次性腹腔注射,其他组每4天腹腔注射1次,共3次,停药后第12天将小鼠拉颈处死,剥取瘤块称重,计算抑瘤率。结果:鬼臼毒素纳米脂质体和鬼臼毒素混悬液在5.0 mg.kg^-1剂量时对小鼠肝癌H₂₂瘤体生长有抑制作用,抑瘤率分别为52.37%和38.25%。结论:鬼臼毒素纳米脂质体和鬼臼毒素混悬液有抗肝癌作用,且相同剂量下,鬼臼毒素纳米脂质体比鬼臼毒素混悬液抑瘤效果显著。     

seco-Cycloartane triterpenes from Gardenia aubryi

Three new 3,4-seco-cycloartanes, secaubryenol (1), secaubrytriol (2), and secaubryolide (3), were isolated from an exudate collected on the aerial parts of Gardenia aubryi, in addition to the known (24S)-cycloartane-24,25-diol-3-one, coccinetane A, herbacetin 3,8-dimethyl ether, hibiscetin 3,8,3',4'-tetramethyl ether, and conyzatin. The structures of 1 and 2 were established by mass spectrometry and NMR experiments, while the relative configuration of 2 was defined unequivocally using X-ray crystallography. The in vitro cytotoxic activity of compounds 1-3 was evaluated against four human solid tumor cell lines.     

0.5%鬼臼毒素涂膜剂治疗尖锐湿疣的临床研究

 目的 评价0.5%鬼臼毒素涂膜剂治疗尖锐湿疣的临床疗效和安全性。方法 50例尖锐湿疣患者随机分为两组,治疗组用0.5%鬼臼毒素涂膜剂,对照组用0.5%鬼臼毒素酊剂。用药方法为外用给药,疗程7～28 d。结果 两组疗效相当（P＞0.05),但治疗组不良反应低于对照组 (P＜0.01)。结论 0.5%鬼臼毒素涂膜剂治疗尖锐湿疣较酊剂具有同样疗效,而不良反应较轻。     

Configurational assignment of cyclic peroxy metabolites provides an insight into their biosynthesis: isolation of plakortolides, seco-plakortolides, and plakortones from the Australian marine sponge Plakinastrella clathrata

Sixteen new compounds, comprising nine new plakortolides K-S (1-9), four seco-plakortolides (10-13), and three plakortones (14-16), were isolated from the Australian sponge Plakinastrella clathrata. Structural elucidation, including relative configurational assignment, was based on extensive spectroscopic analysis, while the absolute configurations of 1-4 were deduced from (1)H NMR analyses on MPA esters derived from Zn/AcOH reduction products. Diastereomeric sets of plakortolides, e.g., K and L, or M and N, differed in configuration at C-3/C-4 rather than at C-6, a stereochemical result that compromises a biosynthetic pathway involving Diels-Alder cycloaddition of molecular oxygen to a Δ(3,5)-diunsaturated fatty acid precursor. The biosynthesis may plausibly involve cyclization of a 6-hydroperoxydienoic acid intermediate following stereospecific introduction of the hydroperoxy group into a polyketide-derived precursor. Isolated seco-plakortolides converted under mild conditions into plakortones with full retention of configuration, suggesting C-6 hydroxy attack on an α,β-unsaturated lactone intermediate. The NMR data reported for the compound named plakortolide E are inconsistent with the current literature structure and are those of the corresponding seco-plakortolide (19). The reported conversion of the metabolite into a plakortone ether on storage is consistent with this structural revision.     

High-field 1H-NMR spectral analysis of some cucurbitacins

1H-nmr spectra of the natural products cucurbitacins A, B, C, D, E, F, I, L, 23, 24-dihydrocucurbitacin F, and hexanorcucurbitacin F, as well as three acetylated derivatives, were measured at 360 MHz in pyridine-d5. Chemical shifts and coupling constants were tabulated. In addition to all of the ring and side-chain protons, it was possible to assign several of the hydroxy group signals of these compounds. These compiled data should be useful for the structure determination of new compounds in this series.     

高效液相色谱法测定窝儿七中槲皮素、鬼臼毒素、山柰素

目的 建立HPLC测定窝儿七中槲皮素、鬼臼毒素、山柰素的方法。方法 采用HPLC,Diamonsil(钻石)C₁₈(4.6 mm×250 mm,5 μm)色谱柱,甲醇-0.4％的冰醋酸水溶液为流动相,梯度洗脱;检测波长：290 nm,流速：1.0 mL·min,柱温30 ℃。结果 槲皮素、鬼臼毒素、山柰素的线性范围分别为0.023~0.287 μg（r=0.999 9）、0.208~2.6 μg（r= 0.999 9）、0.036 1~0.451 μg（r=0.999 9）,平均回收率分别为99.64%（RSD=0.83%）、100.04%（RSD=0.61%）、99.88%（RSD=1.19%）。结论 本实验所建立的方法灵敏、准确、重复性好,可用于窝儿七中槲皮素、鬼臼毒素、山柰素的测定。     

天然来源的鬼臼毒素研究进展（英文）

芳基萘满木脂素鬼臼毒素,是从不同鬼臼属植物根茎中提取的树脂中的主要成分,具有显著的抗肿瘤和抗病毒活性,自古以来被多个国家广泛用于相关疾病的治疗。目前,鬼臼毒素主要作为细胞毒类药物合成的母体结构而受到广泛关注。例如依托泊苷和替尼泊苷,这些药物常与其他药物合并使用治疗一系列肿瘤疾病。本文对鬼臼毒素予以综述,对其结构特征、药用来源、生物活性、衍生物和应用方面进行了总结。     

Structures and absolute configurations of sulfate-conjugated triterpenoids including an antifungal chemical defense of the green macroalga Tydemania expeditionis

Cytotoxicity-guided fractionation of the green macroalga Tydemania expeditionis led to isolation of four sulfate-conjugated triterpenoids including one new lanostane-type triterpenoid disulfate, lanosta-8-en-3,29-diol-23-oxo-3,29-disodium sulfate (1), and three known cycloartane-type triterpenoid disulfates, cycloartan-3,29-diol-23-one 3,29-disodium sulfate (2), cycloart-24-en-3,29-diol-23-one 3,29-disodium sulfate (3), and cycloartan-3,23,29-triol 3,29-disodium sulfate (4). Extensive 1D and 2D NMR analyses in combination with X-ray crystallography established the structure and absolute configuration of 1 and allowed determination of the absolute configurations of 2-4 with a revision of previously assigned configuration at C-5. Each natural product was moderately cytotoxic in tumor cell and invertebrate toxicity assays. Of the natural products, only 4 exhibited significant antifungal activity at whole-tissue natural concentrations against the marine pathogen Lindra thalassiae. Comparison of the biological activities of natural products with their desulfated derivatives indicated that sulfation does not appear to confer cytotoxicity or antifungal activity.     

An approach to furolabdanes and their photooxidation derivatives from R-(+)-sclareolide

A synthetic route to furolabdanes from commercially available R-(+)-sclareolide is reported, with the specific aim of preparing (12R and 12S,15xi)-12,15-dihydroxylabda-7,13-dien-16,15-olides (3 and 5) and (12R and 12S,16xi)-12,16-dihydroxylabda-7,13-dien-15,16-olides (4 and 6). The key points of our approach are the use of Weinreb's amide 11 to join the furan ring to the terpenic unit. Photooxidation of the furan moiety of compounds 15 and 16, and of their acetates 19 and 20, has been used to built the hydroxybutenolide fragment. In this way the four possible isomers at the butenolide moiety, compounds 3-6, and their C-12 acetyl derivatives 21-24 have been obtained. On the basis of comparison of the spectral data ((1)H NMR) of the synthetic peracetates 25-28 (derived from 21-24) with the reported data for the peracetate 2 (derived from the natural product 1), the relative configuration at carbon C-12 of the natural product has been corrected. Furthermore, the absolute configuration of the natural product 1, considered to belong to the enantio-series, has to be changed to the normal-series on the basis of the optical rotation obtained for the synthetic derivative.     

Antineoplastic agents, 120. Pancratium littorale

The bulbs of Pancratium littorale collected in Hawaii were found to contain a new phenanthridone biosynthetic product designated pancratistatin (4a) that proved to be effective (38-106% life extension at 0.75-12.5 mg/kg dose levels) against the murine P-388 lymphocytic leukemia. Pancratistatin also markedly inhibited (ED50, 0.01 microgram/ml) growth of the P-388 in vitro cell line and in vivo murine M-5076 ovary sarcoma (53-84% life extension at 0.38-3.0 mg/kg). An X-ray crystal structure determination of pancratistatin monomethyl ether (4c) and a detailed high resolution (400 MHz) nmr study of pancratistatin and its pentaacetate (4b) completed assignment of structure 4a. Companion antineoplastic constituents of P. littorale were found to be narciclasine (2c) and its 7-deoxy derivative (2a). The structure of 7-deoxynarciclasine (2c) was also confirmed by an X-ray crystallographic analysis.     

Efficient total synthesis of (+)-dihydropinidine, (-)-epidihydropinidine, and (-)-pinidinone

The 2,6-disubstituted piperidine alkaloids (+)-dihydropinidine (1), (-)-epidihydropinidine (2) (as HCl salts), and (-)-pinidinone (3) were efficiently synthesized from (S)-epichlorohydrin (7) as common substrate using regioselective Wacker-Tsuji oxidation of alkenylazides 10 and 14 as well as a highly diastereoselective reduction of cyclic imine 11 as key steps. The protecting group free total syntheses represent the up to date shortest routes with highest overall yields for all three naturally occurring alkaloids (1-3). The first single-crystal X-ray analysis of (-)-epidihydropinidine hydrochloride (2·HCl) confirmed its proposed absolute configuration to be (2S,6S), corresponding to that of the isolated natural product.