Synthesis and Cytotoxicity Assessment against Human Colorectal Cancer Cell Lines of Quaternary 8-Dichloromethyl Protoberberine Alkaloids.

Twenty-two quaternary 8-dichloromethylprotoberberine alkaloids were synthesized from unmodified quaternary protoberberine alkaloids (QPAs) to improve their physical and chemical properties and to obtain selectively anticancer derivatives. The synthesized derivatives showed more appropriate octanol/water partition coefficients by up to values 3-4 compared to unmodified QPA substrates. In addition, these compounds exhibited significant antiproliferative activity against colorectal cancer cells and lower toxicity on normal cells, resulting in more significant selectivity indices than unmodified QPA compounds in vitro. The IC50 values of antiproliferative activity of quaternary 8-dichloromethyl-pseudoberberine 4-chlorobenzenesulfonate and quaternary 8-dichloromethyl-pseudopalmatine methanesulfonate against colorectal cancer cells are 0.31 µM and 0.41 µM, respectively, significantly stronger than those of other compounds and positive control 5-fluorouracil. These findings suggest that 8-dichloromethylation can be used as one of the modification strategies to guide the structural modification and subsequent investigation of anticancer drugs for CRC based on QPAs.

Chemoproteomics Reveals That Quaternary Protoberberine Alkaloids Inhibit Telomerase Activity Oncologically by Binding to PES1.

Natural QPAs have anti-cancer property. The prodrugs of QPAs synthesized in our work with significantly improved solubility showed significantly stronger activity in animal experiments. Nevertheless, the mechanism of action of QPAs for treating cancers remains poorly understood. Here, a chemoproteomic study reveals that QPAs non-covalently and multivalently bind to PES1 in CRC cells, which impinges on the direct interaction between hTERT and hTR in the assembly of the telomerase complex, downregulates telomerase activity, and so promotes the aging process of CRC cells. This study is beneficial for us to conduct extensively the pharmaceutical chemistry research of QPAs.

A unified total synthesis of benzo[d][1,3]dioxole-type benzylisoquinoline alkaloids of aporphines, coptisines, and dibenzopyrrocolines.

The first total synthesis of (S)-(+)-ovigerine, (S)-(+)-N-formylovigerine, and (6aS,6a'S)-(+)-ovigeridimerine of aporphine alkaloids with a benzo[d][1,3]dioxole structure feature was established. The strategy was based upon the well-known Pd-catalyzed arylation to set the aporphine framework, and Noyori asymmetric hydrogenation followed by diastereoselective resolution to achieve excellent enantioselectivity. By slightly modifying the total synthetic route and strategically combining it with a aza-Michael addition, Bischler-Napieralski reaction and N-arylation, this methodology was also applied to the total syntheses of benzo[d][1,3]dioxole-type benzylisoquinoline alkaloids of coptisines and dibenzopyrrocolines, including two impatiens, tetrahydrocoptisine, and quaternary coptisine bromide of coptisines and two dibenzopyrrocoline analogues, with the syntheses of all of these target compounds being efficient. Among the nine synthesized compounds, the total syntheses of the three aporphines and the two impatiens, all with ee values of greater than 99%, were reported for the first time. This work also represents the first unification of synthetic routes for the total synthesis of benzo[d][1,3]dioxole-type aporphines, coptisines, and dibenzopyrrocolines.

Trifluoromethylation of dihydrocoptisines and the effect on structural stability and XBP1-activating activity.

In order to obtain new dihydrocoptisine-type compounds with stable structure and activating XBP1 transcriptional activity, (±)-8-trifluoromethyldihydrocoptisine derivatives as target compounds were synthesized from quaternary ammonium chlorides of coptisine alkaloids as starting materials by a one-step reaction. The structures of the synthesized compounds were confirmed by 1H-, 13C-, and 19F-NMR as well as HRESIMS methods. These compounds showed more significant structural stability and activating XBP1 transcription activity in vitro than dihydrocoptisine as positive control. No obvious cytotoxicity on normal cell in vitro was observed with (±)-8-trifluoromethyldihydrocoptisines. Trifluoromethylation can be used as one of the fluorine modification strategies for dihydrocoptisines to guide follow-up studies on structural modification of coptisine-type alkaloids and on anti-Ulcerative colitis drugs with coptisines.

Syntheses and Structure-Activity Relationships in Antibacterial Activity against Clostridium difficile and XBP1 Activation Property of 13-[(N-Alkylamino)methyl]-8-oxodihydrocoptisines.

13-[(N-Alkylamino)methyl]-8-oxodihydrocoptisines were synthesized to evaluate antibacterial activity against Clostridium difficile and activating x-box-binding protein 1 (XBP1) activity, biological properties both associated with ulcerative colitis. Improving structural stability and ameliorating biological activity were major concerns. Different substituents on the structural modification site were involved to explore the influence of diverse structures on the bioactivities. The target compounds exhibited the desired activities with definite structure-activity relationship. In the series of 13-[(N-n-alkylamino)methyl]-8-oxodihydrocoptisines, the length of n-alkyl groups has a definite effect on the bioactivity, elongation of the length increasing the antibacterial activity. The synthesized compounds were determined to display strong or weak XBP1-activating activity in vitro. The preliminary results of this study warrant further medicinal chemistry studies on these synthesized compounds.

Syntheses and Structure-Activity Relationships in Growth Inhibition Activity against Human Cancer Cell Lines of 12 Substituted Berberine Derivatives.

In this study, quaternary berberine chloride is used as a lead compound to design and synthesize a series of berberine-12-amine derivatives to evaluate the growth inhibition activity against human cancer cell lines. Forty-two compounds of several series were obtained. The quaternary berberine-12-N,N-di-n-alkylamine chlorides showed the targeted activities with the IC50 values of most active compounds being dozens of times those of the positive control. A significant structure-activity relationship (SAR) was observed. The activities of quaternary berberine-12-N,N-di-n-alkylamine chlorides are significantly stronger than those of the reduced counterparts. In the range of about 6-8 carbon atoms, the activities increase with the elongation of n-alkyl carbon chain of 12-N,N-di-n-alkylamino, and when the carbon atom numbers are more than 6-8, the activities decrease with the elongation of n-alkyl carbon chain. The activities of the tertiary amine structure are significantly higher than that of the secondary amine structure.

Syntheses and structure-activity relationships on antibacterial and anti-ulcerative colitis properties of quaternary 13-substituted palmatines and 8-oxo-13-substituted dihydropalmatines.

In this study, quaternary palmatine is used as a lead compound to design and synthesize derivatives to evaluate bioactivities, with twenty-seven compounds of four series being obtained. Antibacterial activity was examined by determining the minimal inhibitory concentration (MIC) values on Staphylococcus aureus, Escherichia coli, and Candida albicans, three series of derivatives being found to exhibit activity in vitro with significant structure-activity relationship (SAR). Elongating the carbon chain led to the antibacterial activity increased, with quaternary 13-hexanoylpalmatine chloride, quaternary 13-(ω-ethoxycarbonyl)heptylpalmatine chloride, and 8-oxo-13-(N-n-nonyl)aminomethyldihydropalmatine, all of which possess the longest aliphatic carbon chain in the corresponding series of derivatives, showing the MIC values of 62.5, 7.81, and 15.63 µg/ml against S. aureus, respectively. The property of anti-ulcerative colitis (anti-UC) was assessed at the levels of both in vitro and in vivo, with X-box-binding protein 1 (XBP1) being targeted in vitro. Seven compounds were found not only to be hypocytotoxic toward intestinal epithelial cells, but also to exhibit activity of activating the transcription of XBP1 in vitro. Five compounds were found to possess significant dose-effect relationship with EC50 values at a level of 10-7 µM in vitro. 8-Oxo-13-formyldihydropalmatine as an intermediate was found to display significant curative effect on UC in vivo based on the biomarkers of body weight change, colon length change, and calculated values of disease activity index and colon macroscopic damage index of the experimental animals, as well as the examination into the pathological changes of the colon tissue of the modeled animals.

Re-engineering and synthesis of cytotoxic 2,3:7,8-di(alkylenedioxy)-extended analogs of quaternary sanguinarine chloride.

A method was developed to synthesize 2,3:7,8-di(alkylenedioxy)-extended analogs of quaternary sanguinarine chloride. 1-Bromo-2-bromomethyl-3,4-alkylenedioxy benzenes and 6,7-alkylenedioxynaphthalen-1-amines were synthesized first. Reactions to construct the target compounds with these two series of synthons involved alterations on a published method for synthesizing 2,3,7,8-tetraoxygenated derivatives of benzo[c]phenanthridinium, substituting benzyl bromides for benzoic aldehydes, prolonging the radical annulation time, and conducting N-methylation with formic acid and NaBH4. All the target compounds showed the same or better in vitro growth inhibitory activities against cancer cell lines compared with the positive compound. The structure activity relationship relevant to cytotoxicity and lipophilicity of the target compounds was produced.

Azacyclo-indoles and Phenolics from the Flowers of Juglans regia.

Seven new azacyclo-indoles and phenolics and four known alkaloids were isolated from the flowers of Juglans regia. Spectroscopic and chromatographic data revealed that the structures of the new compounds are 5,6,11,12-tetrahydropyrrolo[1',2':1,2]azepino[4,5-b]indole-3-carbaldehyde (1), (±)-5,6,7,11c-tetrahydro-1H-indolizino[7,8-b]indol-3(2H)-one (2), (±)-9-hydroxy-5-oxo-2,3,4,5-tetrahydro-1H-benzo[b]azepine-2-carboxamide (3), 5-(ethoxymethyl)-1-(4-hydroxyphenethyl)-1H-pyrrole-2-carbaldehyde (4), (±)-5,8-dihydroxy-4-(1H-indol-3-yl)-3,4-dihydronaphthalen-1(2H)-one (5), (±)-4-(6-amino-9H-purin-9-yl)-5,8-dihydroxy-3,4-dihydronaphthalen-1(2H)-one (6), and (±)-4-(6-amino-9H-purin-9-yl)-5-hydroxy-3,4-dihydronaphthalen-1(2H)-one (7). The five pairs of enantiomers were resolved, and the absolute configurations of the enantiomers were assigned via electronic circular dichroism data. Compound 1 exhibited significant in vitro growth inhibition against the HCT-116, HepG2, BGC-823, NCI-H1650, and A2780 cancer cell lines, with IC50 values of 2.87, 1.87, 2.28, 2.86, and 0.96 µM, respectively, and low cytotoxicity toward normal IEC-6 cells, with a 79.6% survival rate at a 10 µM concentration.

Sugar-free pregnane-type steroids from the roots of Cynanchum stauntonii.

Two new sugar-free 14,15-secopregnane-type steroids, 14-O-methyl-3-epi-hirundigenin (1) and 2-deoxyamplexicogenin A (2), along with two known sugar-free pregnane-type steroids, were isolated from the 95% ethanol extract of the roots of Cynanchum stauntonii. The structures of the new compounds were characterized on the basis of extensive spectroscopic analyses, mainly 1D and 2D NMR methods, albeit the MS experiments did not display the molecular ion peaks. Compound 2 was the aglycones of stauntosides J and K, etc., previously isolated from C. stauntonii. The isolation and identification of the new compounds graced the structural diversity of pregnane-type steroids from C. stauntonii.

14,15-Secopregnane-Type Glycosides with 5α:9α-Peroxy and Δ6,8(14)-diene Linkages from the Roots of Cynanchum stauntonii.

Three new 14,15-secopregnane-type glycosides, stauntosides UA, UA1, and UA2, were isolated from the roots of Cynanchum stauntonii. The three compounds share the first reported and same basic structural features of 3ß-hydroxy-14:16,15:20,18:20-triepoxy-5α:9α-peroxy-14,15-secopregnane-6,8(14)-diene named as stauntogenin G as the aglycones. The structures of the new compounds were characterized on the basis of extensive spectroscopic analyses, mainly 1D and 2D NMR and MS methods and chemical analysis. The isolation and identification of the new compounds graced the structural diversity of pregnane-type steroids from C. stauntonii.

Synthesis and Structure-Activity Relationships of N-Dihydrocoptisine-8-ylidene Aromatic Amines and N-Dihydrocoptisine-8-ylidene Aliphatic Amides as Antiulcerative Colitis Agents Targeting XBP1.

In this study, natural quaternary coptisine was used as a lead compound to design and synthesize structurally stable and actively potent coptisine analogues. Of the synthesized library, 13 N-dihydrocoptisine-8-ylidene amines/amides were found not only to be noncytotoxic toward intestinal epithelial cells (IECs), but they were also able to activate the transcription of X-box-binding protein 1 (XBP1) targets to varying extents in vitro. Antiulcerative colitis (UC) activity levels were assessed at the in vitro molecular level as well as in vivo in animals using multiple biomarkers as indices. In an in vitro XBP1 transcriptional activity assay, four compounds demonstrated good dose-effect relationships with EC50 values of 0.0708-0.0132 µM. Moreover, two compounds were confirmed to be more potent in vivo than a positive control, demonstrating a curative effect for UC in experimental animals. Thus, the findings of this study suggest that these coptisine analogues are promising candidates for the development of anti-UC drugs.

Versatile methods for synthesizing organic acid salts of quaternary berberine-type alkaloids as anti-ulcerative colitis agents.

Two versatile methods to synthesize kinds of organic acid salts of quaternary berberine-type alkaloids were investigated in order to determine which is more efficient to improve the liposolubility of the target compounds and to explore the efficacy of the target compounds as anti-ulcerative colitis (UC) agents. Overall evaluation according to the reaction results and yields of the final products indicated that the synthetic method using tertiary (±)-8-acylmethyldihydroberberine-type alkaloids as key intermediates is superior to that of using tertiary dihydroberberine-type alkaloids as intermediates. Ten target compounds were synthesized using quaternary berberine chloride and quaternary coptisine chloride as starting materials, respectively, and the anti-UC activity of some target compounds was evaluated in an in vitro x-box-binding protein 1 (XBP1) transcriptional activity assay using dual luciferase reporter detection. At 10 µM, the tested compounds were found to activate the transcription of XBP1 target at almost the same level as that of quaternary coptisine chloride. The synthesized target compounds were also found to share higher liposolubility than the inorganic acid salts of quaternary berberine-type alkaloid.

Phenylpropanoids from the stems of Ephedra sinica.

Two new compounds of phenylpropanoids, (S)-N-((1R,2S)-1-hydroxy-1-phenylpropan-2-yl)-5-oxopyrrolidine-2-carboxamide (1) and (3R)-3-O-ß-d-glucopyranosyl-3-phenylpropanoic acid (2), were isolated from the stems of Ephedra sinica. Their structures were elucidated by in-depth examination of spectroscopic data, mainly including those from the 1D and 2D NMR and HRESIMS techniques, and chemical method. The absolute configurations of the two compounds were also corroborated through CD procedure.

[Lignans from cultivated Gynura nepalensis].

Taking application of some isolation and purification technologies, including solvent extraction, rude solvent isolation, column chromatographies on silica gel and Sephadex LH-20 , and preparative HPLC , 4 compounds were obtained from Gynura nepalensis cultivated in a suburban area of Beijing. Their structures were identified by spectroscopic methods in conjunction with comparison of the NMR data with literature values as 7S,8R-9'-O-ethyl-dehydrodiconiferyl-9-acetate (1), 9'-O-ethyl-dehydrodiconiferyl alcohol (2), dehydrodiconiferyl-9,9'-diacetate(3), and (+)-medioresinol(4), respectively. 1 is a new 2,3-dihydrobenzofuran-8,3'-neolignane type compound, and 2-4 were isolated from G.nepalensis for the first time. The complete assignment of the 1H- and 13C-NMR spectroscopic data of the four compounds recorded in DMSO-d6 was achieved.

[Research on certified reference material of emodin in rhubarb and its alcohol extract, water extract].

The certified reference materials (CRMs) of emodin in rhubarb and its alcohol extract, water extract were developed by using quantity transfer technology from single chemical composition to the complex systems. The CRM of emodin was used for quantity transfer, and high performance liquid chromatography (HPLC) method was used to determine the contents of emodin in different matrix composition. By establishing mathematical model and calculating the parts of uncertainty, the uncertainty values were finally gotten. CRMs of emodin in rhubarb, alcohol extract and water extract were accomplished. The content values of emodin were 0.40% ±0.03%, 1.15%±0.18%, 0.16%±0.08% (k=2,P=0.95), respectively. The established method for quantity transfer has successfully solved the technical problems that the value of active ingredient of traditional Chinese medicine can't be traced to SI units. The series of CRMs are assigned as grade primary reference materials, which are useful for quality control of the emodin content, also provide the accurate and reliable CRM, materials standard and standard methods.

Cembranoids from the Gum Resin of Boswellia carterii as Potential Antiulcerative Colitis Agents.

Eight new cembranoids, boscartins A-H (1, 2, and 4-9), and the known incensole oxide were isolated from the gum resin of Boswellia carterii. The absolute configurations of 1, 2, 4, and incensole oxide were unequivocally resolved using single-crystal X-ray diffraction analysis with Cu Kα radiation, and the absolute configuration of 5 was resolved via electronic circular dichroism data. The antiulcerative colitis activities of the compounds were evaluated in an in vitro x-box-binding protein 1 (XBP 1) transcriptional activity assay using dual luciferase reporter detection. At 10 µM, compounds 1, 5, 6, and 7 significantly activated XBP 1 transcription with EC50 values of 0.34, 1.14, 0.88, and 0.42 µM, respectively, compared with the pGL3-basic vector control.

Two new flavonoids from the roots of Scutellaria baicalensis.

One new flavone, 5,7-dihydroxy-8,2',3',6'-tetramethoxyflavone (1), and one new flavonol, 5,7,6'-trihydroxy-2'-methoxyflavonol (2), were isolated from the roots of Scutellaria baicalensis, and their structures were elucidated on the basis of extensive spectroscopic evidences, especially 1D and 2D NMR and HR-ESI-MS experiments. The structure features of these new compounds lie in the substitution at both C-2' and C-6' positions of B-ring by hydroxyl or methoxyl groups.

[Chemical constituents of the roots of Macleaya microcarpa and activation efficacy of benzophenanthridine alkaloids for the transcription of xbp1 gene].

Ongoing study on the chemical constituents of the roots of Macleaya microcarpa led to the isolation of eight compounds of derivatives of triterpenes and organic acids in addition to some previously identified benzophenanthridines. The eight compounds were identified by spectroscopic methods as well as comparison with literature values as 1-oxo-2, 22 (30)-hopandien-29-oic acid (1), 3-oxo-12-oleanen-30-oic acid (2), 3α-hydroxy-12-oleanen-30-oic acid (3), 3ß-hydroxy-12-oleanen-30-oic acid (4), ferulic acid (5), ferulic acid 4-O-ß-D-glucoside (6), 3-O-feruloylquinic acid (7), and methyl 3-O-feruloylquinate (8). Of which, 1 is a new triterpenoid of hopanes and 2-8 are isolated from M microcarpa for the first time. In order to discover natural active compounds as potential agents of anti-ulcerative colitis (UC), an in vitro drug high-throughput screening model targeted x-box-binding protein 1 (xbp1) was employed to evaluate the activity of the major chemical constituents of M microcarpa. The result confirmed that two dihydrobenzophenanthridines, dihydrosanguinarine (9) and dihydrochelerythrine (10), showed a certain activity on activating the transcription of xbpl, a transcription factor (TF) associated with the occurrence, development, and potential treatment of UC, with their relative activating ratios being 1.76 and 1.77 times, respectively, as compared with control group.

[Constituents with anti-oxidative activity from seeds of Jufeng grape].

Taking application of some isolation and purification technologies, including crushing, solvent extraction, preliminary solvent isolation, column chromatographies over silica gel and Sephadex LH-20 gel and preparative HPLC, 8 compounds were obtained from the seeds of Jufeng grape sourced from market. Their structures were identified by spectroscopic methods and comparison with literature values as Catechin (1), Epicatechin (2), quercetin (3), ethylgallate (4), rel-(2S, 3R) -2-(4-hydroxy-3-methoxyphenyl) -3- (hydroxymethyl)-5-(3-hydroxypropyl)-2,3-dihydrobenzofuran-7-ol (5), rel-(2α, 3ß)-7-O-methylcedrusin (6), rel-(1R,2S)-1-(4-hydroxy-3-methoxyphenyl) -2-(4-(3-hydroxypropyl) -2-methoxyphenoxy) propane-1,3-diol (7), and (+) -isolariciresinol (8), respectively. Compounds 5-8 were serial lignans isolated from the seeds of grape for the first time. Structurally, 5 and 6 belong in benzofuran-8,3'-neolignans, 7 in 8,4'-oxyneolignan, and 8 in 8,8' :2,7'-cyclolignan. According to in vitro activity evaluation conducted in cell model, compound 6 showed significant anti-oxidative ability, with the activity of RAW264. 7 cell superoxide dismutase being raised evidently in the test as compared with the positive anti-oxidative agents, compounds 1 and 2.