ABSTRACT
10-Methoxy-2-phenylbenzo[h]quinoline (MPBQ) has been synthesized and characterized by NMR and X-ray single crystal diffraction. Both the ground and the lowest singlet excited-state geometries of MPBQ were optimized by B3LYP and ab initio CIS methods at 6-31G (d,p) level, respectively. The absorption and emission spectra of the compound were experimentally determined in CH(3)CN solution and were simultaneously computed using density functional theory (DFT) and time-dependent density functional theory (TDDFT) in CH(3)CN solution. The calculated absorption and emission wavelengths were in good agreement with the experimental ones. The calculated lowest-lying absorption spectra can be mainly attributed to intramolecular charge transfer (ICT). And the calculated fluorescence spectra can be mainly described as originating from an excited state with intramolecular charge transfer (ICT) character. These results show that MPBQ exhibited excellent thermal stability and could serve as a useful photoluminescence material.
Subject(s)
Models, Theoretical , Quinolines/chemistry , Molecular Structure , Spectrometry, Fluorescence/methodsABSTRACT
Objective To study the correlation of polyphenol oxidase(PPO) activity and baicalin synthesis in callus of Scutellaria baicalensisi.Methods PPO Activity was determined by ultraviolet spectrophotometry and the content of baicalin was detected by HPLC.The effects of various substances(ascorbic acid,sodium chloride,benzoic acid,polyvinylpyrrolidone,and copper sulfate) on PPO activity and the content of baicalin were studied.Results There was no baicalin accumulation in the first 20 d of growth period, while PPO activity was expressed slowly during this period.From 20 d to 35 d,PPO activity increased significantly and the baicalin secondary synthesis was restrained.Conclusion The high-level expression of PPO activity do harm the baicalin secondary synthesis.These chemical substances,such as ascorbic acid, sodium chloride,and benzoic acid could inhibit the PPO activity and improve the content of baicalin;It is obvious for ascorbic acid(0.02%) to improve the content of baicalin with 17.6%(82.3 mg/g) compared with the control.However,polyvinylpyrrolidone and copper sulfate could increase the PPO activity and greatly inhibit the baicalin accumulation.
ABSTRACT
Objective To study the rule of callus culture and baicalin synthesis in Scutellaria baicalensis. Methods Callus was induced by plant cell culture technology and the content of baicalin was determind by HPLC. Results The optimal culture medium on the growth of callus and the synthesis of baicalin in S. baicalensis is: MS culture medium, 60 mmol/L (NH_4+∶NO_3-=1∶1), 0.5—1.5 mmol/L KH_2PO_4, 80 g/L sucrose, 0.3 mg/L IAA, 2 mg/L 6-BA, and 200 mg/L peptone. When it was cultured for 40 d, the total biomass reached 28.7 g/L and the content of baicalin was 167.4 mg/g, which was much higher than that of wild S. baicalensis. Conclusion The growth of S. baicalensis callus and the accumulation of baicalin are not underway simultaneously; the callus grows first and then its secondary metabolic products synthesize. It is obvious for sucrose to regulate the baicalin synthesis. When the concentration of sucrose is less than 3%, it could only promote the callus growth; when between 3% and 8%, it could greatly increase not only the callus growth but also the baicalin synthesis, when 8%, both of them arrive to the maximum content.
