One-pot domino syntheses of 3-alkyl-3-N-substituted aminobenzofuran-2(3H)-ones based on alkali-promoted Michael addition and lactonization.

In this paper, a novel cascade reaction of caesium carbonate-promoted Michael addition and lactonization for the one-pot synthesis of 3-alkyl-3-N-substituted aminobenzofuran-2(3H)-one derivatives has been established based on the screening of the alkaline reagents and optimization of reaction conditions, in which the N-substituted (ortho-hydroxy)aryl glycine esters were used as the Michael donors to react with different α, ß-unsaturated carbonyl compounds. In the case of using the asymmetric starting material, the epimers could be successfully separated by conventional chromatography. In addition, plausible mechanisms were suggested and the absolute configuration of the epimer was analysed. All the chemical structures of unreported benzofuran-2(3H)-one derivatives were characterized by 1H nuclear magnetic resonance (NMR), 13C NMR, IR and high-resolution mass spectrometry (HRMS).

Aging affects artemisinin synthesis in Artemisia annua.

Artemisinin (ART) is the most effective component in malaria treatment, however, the extremely low content restricts its clinical application. Therefore, it is urgent to increase the yield of ART. ART gradually accumulates with aging, small RNA (sRNA) and transcriptome analysis were applied on the leaves of 2-week-old (2 w) and 3-month-old (3 m) A. annua respectively. Among all the annotated sRNAs, 125 were upregulated and 128 downregulated in the 3 m sample compared to the 2 w one. Whereas 2183 genes were upregulated and 2156 downregulated. Notably, the level of miR156 and several annotated miRNAs gradually decreased while SPLs increased. In addition, the genes on ART biosynthesis pathway were significantly upregulated including ADS, CYP71AV1, ADH1, DBR2 and ALDH1, and so were the positive transcription factors like AaERF1, AaORA and AaWRKY1 indicating that age influences the ART biosynthesis by activating the expression of the synthesizing genes as well as positive transcription factors. This study contributes to reveal the regulatory effects of age on ART biosynthesis both in sRNA and transcription levels.

Colorimetric grading scale can promote the standardization of experiential and sensory evaluation in quality control of traditional Chinese medicines.

Experiential and sensory evaluation is an ancient method that remains important in the current quality control system of Traditional Chinese Medicines (TCMs). The process is rapid and convenient when evaluating the quality of crude materials in TCM markets. However, sensory evaluation has been met with skepticism because it is mainly based on experience and lacks a scientific basis. In this study, rhubarb was selected to demonstrate how color-based sensory evaluation could differentiate the quality of herbal medicines objectively. The colors of the rhubarb samples, expressed as RGB values, were obtained from different parts and forms of the plant, including the plant's surface, fracture surface color, and a powdered form with or without treatment with a color-developing reagent. We first divided the rhubarb samples into three grades based on the total content of five hydroxyanthraquinone derivatives, the major pharmacological components in rhubarb. Then, a three-layer back-propagation artificial neural network (BP-ANN), calibrated with selected training samples, was used to correlate the quality of the rhubarb with its color. The color of the rhubarb powder after coloration attained the highest accuracy (92.3%) in predicting the quality grade of the test samples with the established artificial neural networks. Finally, a standardized colorimetric grading scale was created based on the spatial distribution of the rhubarb samples in a two-dimensional chromaticity diagram according to the colors of the powdered rhubarb after color enhancement. By comparing the color between the scale and the tested samples, similar to performing a pH test with indicator paper, subjects without sensory evaluation experience could quickly determine the quality grade of rhubarb. This work illustrates the technical feasibility of the color-based grading of rhubarb quality and offers references for quantifying and standardizing the sensory evaluation of TCMs, foods and other products.

[Antimicrobial activity and chemical differences between the two chemotypes of rhubarbs].

Through our pre-investigation and literature analysis, it was found that rhubarb could be categorized into two types, chrysophanol-type and rhein-type, based on the proportion of the two constituents in the total content of anthraquinones after acid hydrolysis. In this paper, the antimicrobial activities of chrysophanol-type and rhein-type rhubarbs against Staphylococcus aureus were compared with microcalorimetric analysis, in order to illustrate the bioactive differentiability between the two chemotypes. For the aim to display the distinction of chrysophanol and rhein percentage in total anthraquinones, the sampling volume was regulated to make the total anthraquinones equivalent, thus, the antimicrobial difference was only attributed to the difference of chemotypes. The results indicated that the antimicrobial difference between the two chemotypes was confirmable labeled at the biothermokinetic parameters of S. aureus growth affected by the rhubarb samples. The growth rate constant (k1) of the first exponential phase for the growth of S. aureus affected by the rhein-type rhubarb was significantly lower than that of chrysophanol-type (P<0.01), which suggested stronger antimicrobial activity of rhein-type rhubarb than that of chrysophanol-type. However, the antimicrobial activities of rhein-type rhubarbs were not positively correlated to the contents of rhein. It suggested that the antimicrobial activity of rhubarb might be related to some unknown components which were of same accumulating pattern of rhein. The findings in present study provided some experimental evidence on categorizing rhubarb into two chemotypes through the difference of antimicrobial activity on S. aureus by microcalorimetric analysis and, further, offered references to revision of the commercial specification of rhubarb from chemical view.