Abstract: 2,3-Dihydrobenzofuran and coumaranone are readily available in numerous naturally occurring compounds. They mostly exist in plenty of food plants and medicinal plants. Such compounds constitute a series of flavor components and bioactive molecules. Their preparation has been an attractive field of research. In the past few decades, great efforts have been made in the preparation of the 2,3-dihydrobenzofuran structure through both metal-catalyzed and organocatalyzed ways. Visible light-promoted reactions sprang up in the early 21st century and represent a green manner of transformations. Under the irradiation of visible light, radicals could be generated under milder conditions. Thus, visible lightpromoted reactions spread widely in the field of chemical synthesis. In recent years, visible light-promoted preparation of 2,3-dihydrobenzofuran and coumaranone has been developed by different groups, including both intramolecular and intermolecular reactions. The benign reaction conditions allow better functional group-tolerance and lead to diverse structures. Several reviews on the synthesis of 2,3- dihydrobenzofuran have been reported. However, visible light-promoted approaches to such structures have not been well reviewed. Our review will cover the literature that has been reported on the discovery of 2,3- dihydrobenzofuran in food and visible light-promoted preparation of 2,3-dihydrobenzofuran, attempting to summarize the existing methods and provide guidance to the chemists on the present challenges.
Geniposide, Geniposide, the main active component in extracts of Gardenia jasminoides ELLIS., is one of the main components of Huanglian-Jiedu-Tang (HJT). This study aimed to validate an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibodies (mAb) against geniposide (anti-geniposide mAb), which was developed by our lab, and apply the assay to study the pharmacokinetics of geniposide in HJT in mice. Blood samples were drawn from mice at predetermined time points after oral administration of HJT in three dosages. A linear correlation was obtained for geniposide concentrations in the range from 1.17 to 37.50 µg/mL. The intra-day and inter-day precision values of the icELISA method were well within the recommended range (≤10%). The recovery rates ranged from 99.74 to 102.40%. Stability studies showed that geniposide sample solutions were intact for 12 h. The Tmax and mean residence time (MRT) of geniposide of the three groups were consistent with previous data. The results suggest that a reliable and effective method was established and could be applied to the study of the pharmacokinetics of geniposide in HJT.
Yaotongning Capsule (YTNC) is a Traditional Chinese Medicinal (TCM) formula that has been demonstrated to be effective for osteoarthritis (OA) treatment in clinical use. Many compounds and 10 component medicinal materials (CMMs for short, i.e., the fundamental elements used in TCM formulas) in YTNC are challenging to study the pharmacological effects and interactions of the CMMs. Besides, it is difficult to know whether the YTNC formula is reasonable, and if YTNC formula could be improved without comparing YTNC with other TCM formulas of treating OA. Based on different combinations of the active fractions from the 10 CMMs of YTNC and eight additional herbs frequently used in the TCM formulas of treating OA, the present study evaluated systematically the in vitro effects of these active fractions and the interactions among the active fractions from YTNC on rat chondrocytes to find possible solutions of the above questions.Based on the formulation of YTNC and the concept of combinatorial chemistry, the active fractions were applied to form the whole YTNC prescription (i.e., the combination of all YTNC active fractions and the extract of YTNC׳s vehicle), five disassembled formulas of YTNC (i.e., the combinations of some active fractions in YTNC) and 21 TCM samples consisted of different kinds of active fractions. The degenerated chondrocytes were induced with interleukin-1β (IL-1β), and then the half-effective concentration (EC50) value of the proliferation activity was analyzed to evaluate the 27 TCM samples. Nine samples were screened for the following evaluation on glycosaminoglycan (GAG) synthesis. Rat articular cartilage was obtained from six Sprague-Dawley rats (seven days of age), and then chondrocytes were isolated through enzymatic digestion with 0.2% Collagenase II. Proliferations of chondrocytes were examined through Cell Counting Kit-8 assay, when the intracellular levels of GAG were detected by 1,9-Dimethylmethylene blue staining. The interactions between the active fractions in YTNC were evaluated by comparing experimental EC50 values of the YTNC formulas with their additive EC50 values. The effects of every active fraction were estimated by comparing the EC50 values of the TCM sample containing the active fraction with that of the initial sample without the active fraction.The whole formula of YTNC was very good at promoting the proliferation and GAG synthesis among all the 27 TCM samples. The vehicle of YTNC (Chinese rice wine) strengthened the two activities of YTNC. Refer to promoting the proliferation in chondrocytes, Davallia mariesii flavonoids (not belong to YTNC) were more potent than Glycyrrhiza uralensis flavonoids in YTNC, while the saponins, volatile oils and polysaccharides of YTNC were more potent than those from the eight additional herbs. Some samples including fewer active fractions were as good as YTNC. The YTNC formula and its disassembled formulas exhibited good activities both in promoting the proliferation and GAG synthesis, and the whole formula was most potent among the six YTNC formulas.The YTNC formula is reasonable and has advantage in promoting the proliferation and GAG synthesis in IL-1β induced chondrocytes. YTNC׳s vehicle Chinese rice wine plays an important role in strengthening the activity of YTNC. YTNC may have the potential activity on treating chondrocytes degeneration caused by OA. However, the formula still can be simplified based on the combination of alkaloids, flavonoids and 50% of saponins from Glycyrrhiza uralensis to improve its quality controllability and safety. The present study can be a quite purposeful work for developing new YTNC-based formulas with maximal therapeutic efficacy and minimal adverse effects.
Abstract Biotransformation of 2‐chlorophenol (2‐cp) and 4‐chlorophenol (4‐cp) in the presence of phenol by Pseudomonas putida (ATCC 49451) was investigated. Strain ATCC 49451 was unable to utilize 2‐cp and 4‐cp as the sole carbon and energy source. In the presence of phenol as a growth substrate, 2‐cp and 4‐cp could be transformed through cometabolism. It was found, however, that cell growth and phenol degradation were strongly inhibited by the presence of 2‐cp and 4‐cp. A much longer lag phase (19 h versus 3 h) occurred with the mere addition of 40 mg/L 2‐cp and 100 mg/L 4‐cp. Further increase in 2‐cp and 4‐cp concentrations resulted in incomplete transformation: only 80% of the initial 100 mg/L 4cp and 50% of the initial 40 mg/L 2‐cp could be degraded in the presence of 200 mg/L phenol. Interactions between substrates affected cell growth and substrates degradation significantly and both 2‐cp and 4‐cp were toxic to the cells. Kinetic models for cell growth as well as substrate transformation were established to simulate the experimental data. The form of the kinetic models and magnitude of the model parameters (K 2 = 5.62 mg/L > K 3 = 3.57 mg/L; k d2 = 17.8 mg/L < k d3 = 51.5 mg/L) indicate that 2‐cp and 4‐cp exhibited different inhibition and toxicity effects on the cells and their degradation capacities. Kinetics also revealed that the toxicity effect of the chlorophenols dominated over the competitive inhibition effect.
The influence of hydrogen bonding on the solubility of carbazole and anthracene in N,N-dimethylformamide (DMF) and isopropanolamine (IPA) is investigated accordingly by 1H nuclear magnetic resonance (NMR) analysis. The chemical shift for the free and hydrogen-bonding proton of the anthracene and carbazole solution in DMF, IPA, and the mixture of the two was collected by a 600 MHz 1H NMR spectrometer. It is proposed that DMF, IPA, and a mixture of the two would be able to efficiently refine carbazole from crude anthracene oil. This phenomenon is shown to be the result of the intermolecular hydrogen bond of N–H···O and N–H···N formed between carbazole and the DMF/IPA mixture solvent, which greatly enhanced the solubility of carbazole in DMF and IPA. The arising steric hindrance effects derived from the intermolecular hydrogen bonding between DMF and IPA result in the significant solubility decline of anthracene and carbazole in the DMF and IPA mixture.
Anthracene and carbazole are both highly value-added products in the anthracene fraction of coal tar, and it is a difficult task to separate and purify anthracene and carbazole from the anthracene fraction/crude anthracene, which consists of many components, differing only slightly in boiling points. To seek a highly efficient solvent to separate carbazole from crude anthracene, the solubilities of anthracene and carbazole in tetrachloroethylene (PCE) and the mixtures of xylene + PCE, N,N-dimethylformamide (DMF) + urea, and DMF + H2O were measured. The separation efficiencies of DMF + 30% H2O, DMF + urea, and DMF + isopropanolamine mixtures with different percentages of urea or isopropanolamine were examined by the cooling crystallization process. Chlorobenzene, PCE, and xylene + 40% PCE mixture were used in the carbazole refining process. The results showed that, with the addition of the third component of urea, isopropanolamine, or water to DMF, the solubility of anthracene and carbazole is inhibited to some extent and the selectivity is increased. The separation efficiency is improved using the mixed solvents, DMF + urea and DMF + isopropanolamine, when the percentage of urea or isopropanolamine in DMF is below 15 or 40%, respectively. The content of carbazole in crude carbazole is higher than 58.14 or 64.80 wt % using DMF + urea or DMF + isopropanolamine, respectively. The yield is greater than 84.43 wt %, and the impurity of anthracene is less than 10.28 wt %. In addition, the content of anthracene in refined anthracene is higher than 92.31 wt % with the yield above 80.23 wt %. During the carbazole refining process when using chlorobenzene as the solvent, the purity of carbazole can reach 98.97 wt % and the total yield was 67.89 wt %.
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