P450-Modified Ribosomally Synthesized Peptides with Aromatic Cross-Links.

Cyclization of linear peptides is an effective strategy to convert flexible molecules into rigid compounds, which is of great significance for enhancing the peptide stability and bioactivity. Despite significant advances in the past few decades, Nature and chemists' ability to macrocyclize linear peptides is still quite limited. P450 enzymes have been reported to catalyze macrocyclization of peptides through cross-linkers between aromatic amino acids with only three examples. Herein, we developed an efficient workflow for the identification of P450-modified RiPPs in bacterial genomes, resulting in the discovery of a large number of P450-modified RiPP gene clusters. Combined with subsequent expression and structural characterization of the products, we have identified 11 novel P450-modified RiPPs with different cross-linking patterns from four distinct classes. Our results greatly expand the structural diversity of P450-modified RiPPs and provide new insights and enzymatic tools for the production of cyclic peptides.

Building Streptomyces albus as a chassis for synthesis of bacterial terpenoids.

Terpenoids comprise the most chemically and structurally diverse family of natural products. In contrast to the huge numbers of terpenoids discovered from plants and fungi, only a relatively small number of terpenoids were reported from bacteria. Recent genomic data in bacteria suggest that a large number of biosynthetic gene clusters encoding terpenoids remain uncharacterized. In order to enable the functional characterization of terpene synthase and relevant tailoring enzymes, we selected and optimized an expression system based on a Streptomyces chassis. Through genome mining, 16 distinct bacterial terpene biosynthetic gene clusters were selected and 13 of them were successfully expressed in the Streptomyces chassis, leading to characterization of 11 terpene skeletons including three new ones, representing an ∼80% success rate. In addition, after functional expression of tailoring genes, 18 novel distinct terpenoids were isolated and characterized. This work demonstrates the advantages of a Streptomyces chassis which not only enabled the successful production of bacterial terpene synthases, but also enabled functional expression of tailoring genes, especially P450, for terpenoid modification.

[Rapid quality evaluation of Glycyrrhizae Radix et Rhizoma and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle based on color digitization and multi-component determination].

To explore the color value changes after processing and further explore the correlations between color values and internal components, we established a rapid evaluation method for the quality of Glycyrrhizae Radix et Rhizoma and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle. In this study, the color values of Glycyrrhizae Radix et Rhizoma and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle were digitized by a spectrophotometer, and the standard ranges of color values of the two herbal medicines were established. Further, a discriminant analysis model was established to quickly and accurately distinguish the two herbal medicines. The content of 9 flavonoids and 1 triterpene in Glycyrrhizae Radix et Rhizoma and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle were determined by HPLC, and Pearson correlation analysis was adopted to analyze the correlations between the color values and the content of 10 components. The standard ranges of L~*, a~*, and b~* values were 65.539 6-68.305 8, 7.296 3-8.467 3, and 29.998 8-32.212 8 for Glycyrrhizae Radix et Rhizoma, and 43.654 3-47.166 4, 14.050 0-15.133 8, and 16.424 6-20.984 8 for Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle, respectively. Glycyrrhizae Radix et Rhizoma had higher L~* and b~* values and lower a~* value than Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle, which indicated that processing with honey decreased the white and yellow values and increased the red value. The original and cross validation of the established discriminant analysis model met the requirements, and the external validation of the model showed the prediction accuracy of 100%. Pearson correlation analysis showed that the a~* value was positively correlated with the content of liquiritin apioside and isoliquiritin apioside(P<0.05), while the L~* and b~* values were negatively correlated with the content of the above two components(P<0.05). After processing with honey, L~* and b~* decreased while a~* increased, and the content of liquiritin apioside and isoliquiritin apioside increased, which was consistent with the content determination results. This study reveals the regularity of the color values of Glycyrrhizae Radix et Rhizoma after processing with honey roasting, as well as the correlations between color values and component content, which provides a basis for the rapid quality evaluation of Glycyrrhizae Radix et Rhizoma and Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle.

[Study on quality identification of Curcumae Rhizoma from different origins based on quantitative analysis of appearance color and content of main components].

L~*, a~* and b~* values of prepared slices of Curcumae Rhizoma were measured by spectrophotometer. SPSS 21.0 was used for discriminant analysis to establish the color range and mathematical prediction model of prepared slices of Curcumae Rhizoma. The values of L~*, a~* and b~* of kwangsiensis ranged from 58.09-62.40, 4.53-5.66 and 23.61-24.29, while the values of L~*, a~* and b~* of phaeocaulis were between 64.02-70.71,-0.89-4.13 and 44.59-54.52, respectively. The values of L~*, a~* and b~* of wenyujin were 68.55-70.99,-0.11-1.47 and 28.26-32.19, respectively. The mathematical prediction model was proved to be able to realize 100% identification of Curcumae Rhizome of different origins through original and cross validation and external samples validation. A dual wavelength HPLC was established; the contents of 9 sesquiterpenoids and 3 Curcumae Rhizomes were determined simultaneously; and the contents of Curcumae Rhizome of different origins were determined. The results showed that kwangsiensis had higher contents of neocurdione, ß-elemene and isocurcumaenol, phaeocaulis curcumin, furadienone, demethoxycurcumin and curcumin; and wenyujin mainly contained curdione, furadienes and guimarone. Pearson correlation analysis on L~*, a~*, b~* value and content of 12 components showed that curcumin, furadienone, demethoxycurcumin and curcumin had a significant positive correlation with b~* value(P<0.01). There was a significant negative correlation between neocurdione, ß-elemene and isocurcumaenol and L~* value(P<0.01). Curdione, furadienes and guimarone were significantly correlated with L~* value(P<0.01),indicating that the appearance co-lor of Curcumae Rhizoma could reflect the change of the content of the internal components. This study provided reference for the rapid recognition of Curcumae Rhizoma and the establishment of quality evaluation system.

Lagerindicine, a New Pyrrole Alkaloid Isolated from the Flowers of Lagerstroemia indica Linnaeus.

A phytochemical investigation of the EtOH extract of the flowers of Lagerstroemia indica L. led to the isolation and characterization of a new pyrrole alkaloid, named lagerindicine (1), along with four known compounds (2-5). Their structures were elucidated by the detailed spectroscopic analysis and comparison with literature data, whereas the structure, in particularly, the absolute configuration (AC) of 1, was firmly determined by total synthesis. All the isolates were evaluated for their cytotoxic effects against human colon cancer cell (HCT-116), and compound 3 exhibited weak cytotoxicity with IC50 value of 28.4 µM.

Two new hydroperoxy steroids from the South China Sea gorgonian Rumphella sp.

Two new hydroperoxy steroids, namely, xidaosteroids A and B (1 and 2), along with five known related compounds 3-7, were isolated from the South China Sea gorgonian Rumphella sp.. Their structures were established by extensive spectroscopic analyses and comparison of the spectral data with those reported in the literature. In bioassay, compound 3 showed weak cytotoxicities against SNU-398 and Capan-1 cells.

[Problems and solutions in modern research of traditional Chinese herbal pieces processing technology].

Chinese medicine processing is the main feature that distinguishes traditional Chinese medicine from natural medicine and plant medicine, and is the main feature in clinical medication of traditional Chinese medicine. The research of Chinese medicine processing technology is an important link to realize standardization and standardization of Chinese herbal pieces, with urgent need to attract high attention. At present, there are still many problems in the research of processing technology of Chinese herbal pieces, mainly including inconsistent processing technology, large differences in process technology parameters, and unstable production technology of Chinese herbal pieces, resulting in uncontrollable quality of Chinese herbal pieces and affecting the clinical efficacy of Chinese medicine. This paper focused on the establishment of a unified standard processing technology, and put forward the countermeasures for the processing technology of Chinese medicine based on a comprehensive analysis of the current situations of the processing technology of Chinese herbal pieces, with significance for guiding the establishment of a standardized processing technology of Chinese medicine.

Positive skeletal effect of two ingredients of Psoralea corylifolia L. on estrogen deficiency-induced osteoporosis and the possible mechanisms of action.

Estrogen replacement therapy (ERT) is utilized as a major regime for treatment of postmenopausal osteoporosis at present. However, long-term supplement of estrogen may cause uterine hyperplasia and hypertension leading to a high risk of endometrial cancer and breast cancer. Psoralea corylifolia L. has long been used as tonic and food additives in many countries. Previous studies had found two ingredients in P. corylifolia L.: bavachin and bakuchiol exhibited osteoblastic activity. The present study was designed to investigate the protective effect of bakuchiol and bavachin on ovariectomy-induced bone loss and explore the possible mechanism. In vivo, bakuchiol and bavachin could prevented estrogen deficiency-induced bone loss in ovariectomized rats without uterotrophic activity. In vitro studies suggested that bakuchiol and bavachin induced primary human osteoblast differentiation by up-regulating the Wnt signalling pathway. This study suggests that such a bone-protective role makes them a promising and safe estrogen supplement for the ERT.

[Fingerprint of Vinegar Processed Genkwa Flos Based on Improving Euclidean Distance].

OBJECTIVE: To improve the traditional fingerprint method to distinguish vinegar processed Genkwa Flos from raw Genkwa Flos. METHODS: Ten batches of Genkwa Flos were collected, processed with vinegar through a standard method, and then analyzed under the optimum HPLC condition. Based on the chromatographic data obtained, a common model of vinegar processed Genkwa Flos fingerprints, including 11 common peaks and the components genkwanin, hydroxygenkwanin, luteolin, apigenin and yuanhuacin were identified, was established. The peak of baicalein, an exogenous component added quantitatively to the samples as an internal standard, was served as the reference peak. The similarity between the test samples and the common model was computed using the improved Euclidean distance method developed in this paper. RESULTS: The similarities between vinegar processed Genkwa Flos samples and the common model were higher than 0.9, whereas those between raw Genkwa Flos and the common model were lower than 0.9. CONCLUSION: The proposed method thus effectively provides a clear distinction between vinegar processed and raw Genkwa Flos samples. The result is helpful to ensure the safe clinical use of the plant and expand the application field of fingerprinting technology.

[Progress of sulfur fumigation and modern processing technology of Chinese traditional medicines].

Infestation, moldy and other phenomenon in the processing and storage of Chinese herbal medicines is a problem that faced in the production of Chinese traditional medicine. The low productivity of traditional processing methods can not guarantee the quality of Chinese herbal medicines. Sulfur fumigation is the first choice of grassroots to process the Chinese herbal medicine with its low cost and easy operation. Sulfur fumigation can solve some problems in the processing and storage of Chinese herbal medicines, but modern pharmacological studies show that long-term use of Chinese traditional medicine which is fumigated by sulfur can cause some serious harm to human liver, kidney and other organs. This paper conducts a review about the application history of sulfur fumigation, its influence to the quality of Chinese herbal medicines as well as domestic and foreign limits to sulfur quantity, and a brief introduction of the status of modern processing technologies in the processing of food and some Chinese herbal medicines, the problems ex- isting in the Chinese herbal medicines processing, which can provide a reference basis for the further research, development and application of investigating alternative technologies of sulfur fumigation.

[Research situation of effects of sulfur fumigation on quality of traditional Chinese medicine].

Sulfur fumigation (SF) is a universal phenomenon in primary processing of Traditional Chinese Medicine (TCM) in modern times. In the process, fumigation, sulfur or both of them act on the TCMs. Some active components of TCMs change quantitatively or qualitatively during the processing. At the same time, the sulfur dioxide and heavy metal would remain and cause a serious influence on quality and future development of TCM. This article reviews the chemical compositions change after SF to study the change law and their influence on quality. This article provide references for SF in TCMs' processing for a better and safer quality.

[Application of traditional Chinese medicine reference standards in quality control of Chinese herbal pieces].

Traditional Chinese medicine (TCM) reference standards plays an important role in the quality control of Chinese herbal pieces. This paper overviewed the development of TCM reference standards. By analyzing the 2010 edition of Chinese pharmacopoeia, the application of TCM reference standards in the quality control of Chinese herbal pieces was summarized, and the problems exiting in the system were put forward. In the process of improving the quality control level of Chinese herbal pieces, various kinds of advanced methods and technology should be used to research the characteristic reference standards of Chinese herbal pieces, more and more reasonable reference standards should be introduced in the quality control system of Chinese herbal pieces. This article discussed the solutions in the aspect of TCM reference standards, and future development of quality control on Chinese herbal pieces is prospected.

[Research on chemical reactions during ginseng processing].

As a kind of commonly used traditional Chinese medicine, ginseng has a high reputation at home and abroad. The research of ginseng has been expanded to medicine, pharmacy, biology, food science and other fields, with great achievements in recent years. Ginseng contains ginsenosides, volatile oil, carbohydrates, amino acids, polypeptides, inorganic elements and othser chemical constituents. Each component has extensive physiological activity, and is the base of ginseng's effect. After processing, the complicated changes are taken place in the constituents of ginseng, and some new substances produced. This paper aims to review the studies on chemical constituents and their mechanisms during ginseng processing, and the ideas, methods and the direction of the development of traditional Chinese medicine processing in the future.

[Study progress of spectral color science and its prospect of application in the field of Chinese medicine].

The paper reviewed the research progress in the spectral color science, including the common model, color measurement instrument in recent years, application of color measurement technology in agriculture, food, industry, medicine and other fields. The possibility to achieve the color quantization of Chinese medicine was explored by color measurement technology, and analyzed its application prospect in the field of Chinese medicine, provided a model for the study on quality control for Chinese medicine non-destructive online

[Optimization of preparation of salt-processed psoraleae fructus medicines with multi-index orthogonal method].

OBJECTIVE: To optimize the preparation of salt-processed Psoraleae Fructus by the orthogonal test method. METHOD: With the 12 components such as coumarin, flavone and phenolics as study indexes, a L9 (3(4)) orthogonal test was adopted to compare the effect of different factors on salt-processed Psoraleae Fructus. RESULT: According to the finalized optimal process, 100 g Psoraleae Fructus was added with 2 g salt, moistened for 2 hours, and then fried for 10 min at 150 degrees. CONCLUSION: The orthogonal test is so reasonable and reliable that it can provide basis for the preparation of salt-processed Psoraleae Fructus.

[Study on the chemical constituents of vinegar Schisandra chinensis].

OBJECTIVE: To study the chemical constituents of vinegar Schisandra chinensis. METHODS: Column chromatography was used in the isolation procedure. The structures of isolated compounds were elucidated by spectral data. RESULTS: Five compounds were isolated and their structures were identified as kadsuranin (I), beta-sitosterol (II), schizandrin (III), 5,5'-[oxybis (methylene)] bis-2-furancarboxaldehyde (IV) and (NH)-form-2-Hydroxyquinoline4-carboxylic acid (V). CONCLUSION: Compound 5 is isolated from this genus for the first time.

Requirement of hydrogen peroxide and Sp1 in the stimulation of Na,K-ATPase by low potassium in MDCK epithelial cells.

We have previously implicated reactive oxygen species oxygen (ROS) as a critical signal transducer in the upregulation of Na,K-ATPase by low K+ in MDCK cells, but how ROS mediate this process has not been well defined. We reported here that both of hydrogen peroxide (H2O2) and superoxide anion (O2*(-)) were rapidly produced at the early stage of low K+-treated MDCK cells. Further analysis revealed that NADP/NADPH oxidase-derived H2O2 was specifically involved in low K+-induced Na,K-ATPase alpha1 gene transcription as well as alpha1 and beta1 subunits expressions. Exogenous H2O2 even mimicked the stimulatory effect of low K+ on Na,K-ATPase alpha1 gene transcription. Low K+ triggered a H2O2-dependent ERK1/2 phosphorylation in MDCK cells, nonetheless, this ERK1/2 activation did not finally lead to the upregulation of Na,K-ATPase. Similar to previous findings that Na,K-ATPase beta1 gene transcription was mediated by Sp1, Na,K-ATPase alpha1 gene transcription in low K+-treated MDCK cells was also closely relevant to Sp1 participation, as confirmed by siRNA as well as PCR mutagenesis technologies. Furthermore, Sp1 activation was dependent on H2O2 generation triggered by low K+. Taken together, the data described in this study outlines an essential role of H2O2 and Sp1 in mediating the upregulation of Na,K-ATPase in MDCK cells by low external K+.

The cytotoxicity induced by brucine from the seed of Strychnos nux-vomica proceeds via apoptosis and is mediated by cyclooxygenase 2 and caspase 3 in SMMC 7221 cells.

To study the cytotoxicity of four alkaloids: brucine, strychnine, brucine N-oxide and isostrychnine from nux vomica on SMMC 7721 cells and their possible mechanisms, MET assay was used to examine the growth inhibitory effects of these alkaloids. Brucine revealed the strongest growth inhibitory effect on SMMC-7721 cells. Furthermore, as directly observed under an inverted microscope, fluorescent microscope and transmission electronic microscope, brucine caused SMMC-7721 cell shrinkage, membrane blobbing, formation of apoptotic body as well as nucleus condensation, all of which are typical characteristics of apoptotic programmed cell death. In addition, brucine dose-dependently caused SMMC-7721 cells apoptosis via formation of subdipolid DNA and phosphatidylserine externalization, as evidenced by flow cytometry analysis. The brucine-induced apoptosis was partially attributed to the activation of caspase 3 as well as cyclooxygenase 2 inhibition, since neither caspase 3 specific inhibitor, z-DEVD-fmk nor was exogenous addition of prostaglandin E(2) able to completely abrogate the brucine-induced SMMC 7721 cell apoptosis. In sum, this paper indicate that the major alkaloids present in the seed of Strychnos nux-vomica are effective against SMMC-7721 cells proliferation, among which brucine proceeds SMMC-7721 cells death via apoptosis, probably through the participation of caspase 3 and cyclooxygenase 2.

The anti-tumor effects of alkaloids from the seeds of Strychnos nux-vomica on HepG2 cells and its possible mechanism.

To screen the anti-tumor effects of the four alkaloids: brucine, strychnine, brucine N-oxide and isostrychnine from the seed of Strychnos nux-vomica, MTT assay was used to examine the growth inhibitory effects of these alkaloids on human hepatoma cell line (HepG2). Brucine, strychnine and isostrychnine revealed significant inhibitory effects against HepG2 cell proliferation, whereas brucine N-oxide didn't have such an effect. In addition, brucine caused HepG2 cell shrinkage, membrane blebbing, apoptotic body formation, all of which are typical characteristics of apoptotic programmed cell death. The results of flow cytometric analysis demonstrated that brucine caused dose-dependent apoptosis of HepG2 cells through cell cycle arrest at G0/G1 phase, thus preventing cells entering S or G2/M phase. Immunoblot results revealed that brucine significantly decreased the protein expression level of cyclooxygenase-2, whereas increased the expression caspase-3 as well as the caspase-3-like protease activity in HepG2 cells, suggesting the involvement of cyclooxygenase-2 and caspase-3 in the pro-apoptotic effects exerted by brucine. Therefore, this paper indicate that the major alkaloids present in the seed of Strychnos nux-vomica are effective against HepG2 cells proliferation, among which brucine proceed HepG2 cells death via apoptosis, probably through the participation of caspase-3 and cyclooxygenase-2.

Analgesic and anti-inflammatory properties of brucine and brucine N-oxide extracted from seeds of Strychnos nux-vomica.

To further understand the purpose of the traditional processing method of the seeds of Strychnos nux-vomica L. (Loganiaceae) as well as analgesic and anti-inflammatory activities of brucine and brucine N-oxide extracted from this medicinal plant, various pain and inflammatory models were employed in the present study to investigate their pharmacological profiles. Both brucine and brucine N-oxide revealed significant protective effects against thermic and chemical stimuli in hot-plate test and writhing test. However, on different phases they exerted analgesic activities in formalin test. Brucine N-oxide showed stronger inhibitory effect than brucine in carrageenan-induced rat paw edema, both of them significantly inhibited the release of prostaglandin E2 in inflammatory tissue, reduced acetic acid-induced vascular permeability and the content of 6-keto-PGF1a in Freund's complete adjuvant (FCA) induced arthritis rat's blood plasma. In addition, brucine and brucine N-oxide were shown to reduce the content of 5-hydroxytryptamine (5-HT) in FCA-induced arthritis rat's blood plasma, while increase the content of 5-hydroxytryindole-3-acetic acid (5-HIAA) accordingly. These results suggest that central and peripheral mechanism are involved in the pain modulation and anti-inflammation effects of brucine and brucine N-oxide, biochemical mechanisms of brucine and brucine N-oxide are different even though they are similar in chemical structure.