Jianguo Zeng

Integration of Transcriptome, Proteome and Metabolism Data Reveals the Alkaloids Biosynthesis in Macleaya cordata and Macleaya microcarpa

Background The Macleaya spp., including Macleaya cordata and Macleaya microcarpa, are traditional anti-virus, inflammation eliminating, and insecticide herb medicines for their isoquinoline alkaloids. They are also known as the basis of the popular natural animal food addictive in Europe. However, few studies especially at genomics level were conducted on them. Hence, we performed the Macleaya spp. transcriptome and integrated it with iTRAQ proteome analysis in order to identify potential genes involved in alkaloids biosynthesis. Methodology and Principal Findings We elaborately designed the transcriptome, proteome and metabolism profiling for 10 samples of both species to explore their alkaloids biosynthesis. From the transcriptome data, we obtained 69367 and 78255 unigenes for M. cordata and M. microcarpa, in which about two thirds of them were similar to sequences in public databases. By metabolism profiling, reverse patterns for alkaloids sanguinarine, chelerythrine, protopine, and allocryptopine were observed in different organs of two species. We characterized the expressions of enzymes in alkaloid biosynthesis pathways. We also identified more than 1000 proteins from iTRAQ proteome data. Our results strongly suggest that the root maybe the organ for major alkaloids biosynthesis of Macleaya spp. Except for biosynthesis, the alkaloids storage and transport were also important for their accumulation. The ultrastructure of laticifers by SEM helps us to prove the alkaloids maybe accumulated in the mature roots. Conclusions/Significance To our knowledge this is the first study to elucidate the genetic makeup of Macleaya spp. This work provides clues to the identification of the potential modulate genes involved in alkaloids biosynthesis in Macleaya spp., and sheds light on researches for non-model medicinal plants by integrating different high-throughput technologies.

Facile synthesis of tetrahydroprotoberberine and protoberberine alkaloids from protopines and study on their antibacterial activities

A series of isoquinoline alkaloids including tetrahydroprotoberberines, N-methyl tetrahydroprotoberberines and protoberberines were facile synthesised with protopines as the starting material. All compounds were evaluated for their antibacterial activities against four pathogenic bacteria Escherichia coli, Staphyloccocus aureus, Staphylococcus gallinarum and Salmonella choleraesuis. Experimental results indicated that protoberberines were the most active compounds to the target bacteria among the tested alkaloids. It was suggested that planar molecule with high aromatisation level (e.g. coptisine 5 and berberine 6) or a positive charge of the molecules (e.g. N-methyl tetrahydroprotoberberines 11 and 12) had a positive influence on the antibacterial effects.

Simultaneous quantitative determination of sanguinarine, chelerythrine, dihydrosanguinarine and dihydrochelerythrine in chicken by HPLC-MS/MS method and its applications to drug residue and pharmacokinetic study.

A specific and reliable HPLC-MS/MS method was developed and validated for simultaneously determination of sanguinarine, chelerythrine and their metabolites (dihydrosanguinarine and dihydrochelerythrine) in chicken tissue for the first time. This is important because these compounds are related to the use of a naturally occurring and novel feed additive with many benefits, but the levels of these compounds must be strictly controlled. The compounds were extracted by acetonitrile and 1% HCl-methanol solution successively and then separated on a C18 column. A triple-quadrupole mass spectrometer equipped with an electrospray ionization (ESI) source was used for detection. Quantification was performed using multiple reaction monitoring with positive mode. The method was validated in terms of specificity, linearity, precision, accuracy and stability. The calibration curves were linear over the concentration range of 0.5-100.0ng/g for sanguinarine, 0.5-100.0ng/g for chelerythrine, 0.2-100.0ng/g for dihydrosanguinarine and 0.1-100ng/g for dihydrochelerythrine, respectively. All of the recovery rates of the four analytes were over 85%. The RSD of intra-day and inter-day precision was less than 5.0%, and the relative error was all within 12.0%. This validated method has been successfully applied to assess the drug residue and metabolite residue characteristics of sanguinarine and chelerythrine in chicken tissue after oral administration of the extracts of Macleaya cordata (Willd.) R. Br, and to investigate the pharmacokinetic parameters of sanguinarine and dihydrosanguinarine in chicken plasma.

N-(Acyloxy)phthalimides as tertiary alkyl radical precursors in the visible light photocatalyzed tandem radical cyclization of N-arylacrylamides to 3,3-dialkyl substituted oxindoles

A visible light promoted tandem radical cyclization of N-arylacrylamides with N-(acyloxy)phthalimides to 3,3-dialkyl substituted oxindoles was developed. In the presence of a photocatalyst Ru(bpy)3Cl2·6H2O, an organic base i-Pr2NEt and the irradiation of a 25 W compact fluorescence bulb at room temperature, N-(acyloxy)phthalimides may be used as a masking group for tertiary alkyl radicals. This tandem radical reaction proceeded smoothly to afford the 3,3-dialkyl substituted oxindoles at room temperature and avoided the use of peroxide.

Metal-Free Photoredox Catalyzed Cyclization of O-(2,4-Dinitrophenyl)oximes to Phenanthridines

A metal-free visible-light photoredox-catalyzed intermolecular cyclization reaction of O-2,4-dinitrophenyl oximes to phenanthridines was developed. In this study, the organic dye eosin Y and i-Pr2NEt were used as photocatalyst and terminal reductant, respectively. The oxime substrates were transformed into iminyl radical intermediates by single-electron reduction, which then underwent intermolecular homolytic aromatic substitution (HAS) reactions to give phenanthridine derivatives.

A novel C–C radical–radical coupling reaction promoted by visible light: facile synthesis of 6-substituted N-methyl 5,6-dihydrobenzophenanthridine alkaloids

A novel photoredox-mediated direct intermolecular C–H functionalization of N-methyl 5,6-dihydrobenzophenanthridine is developed utilizing the visible light-induced reductive quenching pathway of photocatalyst Ir(ppy)3. In the proposed coupling mechanism, an α-amino C-radical is generated at the 6-position of N-methyl 5,6-dihydrobenzophenanthridine which is capable of coupling with α-EWG (electron withdrawing group) substituted C-radicals. The utility of this methodology has been demonstrated via rapid access to the analogue of natural 6-substituted N-methyl 5,6-dihydrobenzophenanthridine alkaloids.

Medicinal plants of the genus Macleaya (Macleaya cordata, Macleaya microcarpa): A review of their phytochemistry, pharmacology, and toxicology.

In the genus Macleaya, Macleaya cordata and Macleaya microcarpa have been recognized as traditional herbs that are primarily distributed in China, North America, and Europe and have a long history of medicinal usage. These herbs have been long valued and studied for detumescence, detoxification, and insecticidal effect. This review aims to provide comprehensive information on botanical, phytochemical, pharmacological, and toxicological studies on plants in the genus Macleaya. Plants from the genus of Macleaya provide a source of bioactive compounds, primarily alkaloids, with remarkable diversity and complex architectures, thereby having attracted attention from researchers. To date, 291 constituents have been identified and/or isolated from this group. These purified compounds and/or crude extract possess antitumor, anti‐inflammatory, insecticidal, and antibacterial activities in addition to certain potential toxicities. Macleaya species hold potential for medicinal applications. However, despite the pharmacological studies on these plants, the mechanisms underlying the biological activities of active ingredients derived from Macleaya have not been thoroughly elucidated to date. Additionally, there is a need for research focusing on in vivo medical effects of Macleaya compounds and, eventually, for clinical trials.

Mass spectrometry-guided isolation of two new benzoquinoline alkaloids from Macleaya cordata

Abstract Two new alkaloids, named 2,3-methylenedioxy-7,10-dimethyl-7,8,9,10-tetrahydro-benzoquinoline (1) and 2,3-methylenedioxy-7,10-dimethyl-8-carboxyl-benzoquinoline (2), were detected primarily from the fruits of Macleaya cordata by their different fragmentation pathways. And then isolation of the two compounds was performed by column chromatography and preparative HPLC under the guiding of mass spectrometry. Finally, their structures were determined by spectroscopic analysis. Graphical abstract

TBHP mediated oxidation of N-2-alkynylphenyl α-amino carbonyl compounds to oxalic amides using visible light photoredox catalysis and their application in the synthesis of 2-aryl indoles

A visible light promoted and TBHP mediated oxidative reaction of N-2-alkynylphenyl α-amino carbonyl compounds to N-2-alkynylphenyl oxalic amides was developed. In the presence of CuBr and photocatalyst Ru(bpy)3Cl2·6H2O, the reaction proceeded smoothly to afford the corresponding oxalic amides under the irradiation of a 26 W compact fluorescence bulb at room temperature. Furthermore, N-2-alkynylphenyl oxalic amides could be subsequently transferred to 2-aryl indoles without an additional deacylation step through a favored 5-endo-dig N-cyclization process using AgNO3 as catalyst.

Tissue-specific metabolite profiling of benzylisoquinoline alkaloids in the root ofMacleaya cordataby combining laser microdissection with ultra-high-performance liquid chromatography/tandem mass spectrometry: Tissue-specific metabolite profiling

RATIONALE Tissue-specific metabolite profiling helps to find trace alkaloids masked during organ analysis, which contributes to understanding the alkaloid biosynthetic pathways in vivo and evaluating the quality of medical plants by morphology. As Macleaya cordata contains diverse types of benzylisoquinoline alkaloids (BIAs), the alkaloid metabolite profiling was carried out on various tissues of the root. METHODS Laser microdissection with fluorescence detection was used to recognize and dissect different tissues from the root of M. cordata. Ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry was applied to analyze the trace alkaloids in tissues. These detected alkaloids were elucidated using their accurate molecular weights, MS/MS data, MS fragmentation patterns and the known biosynthetic pathways of BIAs. Finally, the distribution of alkaloids in dissected tissues and whole sections was mapped. RESULTS Forty-nine alkaloids were identified from five microdissected tissues, and 24 of them were detected for the first time in M. cordata. Some types of alkaloids occurred specifically in dissected tissues. More alkaloids were detected in the cork and xylem vascular bundles which emit strong fluorescence under fluorescence microscopy. Some of the screened alkaloids were intermediates in sanguinarine and chelerythrine biosynthetic pathways, and others were speculated to be involved in the new branches of biosynthetic pathways. CONCLUSIONS The integrated method is sensitive, specific and reliable for determining trace alkaloids, which is also a powerful tool for metabolite profiling of tissue-specific BIAs in situ. The present findings should contribute to a better understanding of the biosynthesis of BIAs in M. cordata root and provide scientific evidence for its quality evaluation based on morphological characteristics. Copyright