Determination of Total Lignanoids in Tangjiangshenkang Granules by Two-Wavelength Ultraviolet Spectrophotometry

[Objectives] To establish a determination method for the content of total lignanoids in Tangjiangshenkang granules. [Methods] Two-wavelength ultraviolet spectrophotometry (TWBS) was used to scan arctiin control solution, chlorogenic acid control solution and Tangjiangshenkang granule test solution in the range of 200-400 nm. In the ultraviolet scanning diagram of arctiin reference solution, the maximum absorption wavelength of 280 nm was determined as the determination wavelength λ 1, the detection wavelength in the ultraviolet scanning diagram of chlorogenic acid reference solution ( λ 1=280 nm) was determined, and 350 nm was the reference wavelength λ 2;the content of total lignosides in Tangjiangshenkang granules was determined with arctiin as the reference substance. [Results] The precision, accuracy, and durability of this method were fine. The concentration of arctiin was linearly correlated with the absorbance difference in the range of 0.007 95-0.071 55 mg/mL ( r =0. 999 9). The average recovery of arctiin was 100.8%, and the RSD value was 1.04% ( n =6). Calculated as arctiin, three batches of Tangjiangshenkang granules contain no less than 20% of total lignosides. [Conclusions] The method has the advantages of simple operation, good accuracy, precision and reliable stability. It can be used as the content determination and quality control method of total lignosides in Tangjiangshenkang granules.

ULTRAVIOLET SPECTROPHOTOMETRY OF MULTI-COMPONENT MIXTURES USING ARTIFICIAL NEURAL NETWORKS

Three—layer back—propagation neural networks were used for processing the information provided by the ultraviolet spectra of five—component mixtures, affecting the simultaneous determination of the components with satisfactory results.

Optimization of Extraction Process of Chlorogenic Acid from Sambucus chinensis Lindl

[Objectives] The chlorogenic acid in Sambucus chinensis Lindl is a kind of biologically active substance with multiple pharmacological effects, but the content is relatively small. It is of great significance to find the best extraction process. Therefore, we designed single factor experiments and orthogonal experiments to screen the best conditions for extracting chlorogenic acid from S. chinensis. [Methods] With ethanol concentration, ultrasonic power, and extraction time as three single factors, single factor experiments were performed on S. chinensis, and its chlorogenic acid content was calculated from a standard curve. The contents of chlorogenic acid obtained under various conditions were compared, and then, orthogonal experiments were designed according to the orthogonal table to analyze the optimal extraction conditions of chlorogenic acid. [Results] The optimal extraction conditions of chlorogenic acid for S. chinensis were: the ethanol concentration 60%, the ultrasonic power 36 W, and the extraction time 40 min.[Conclusions] The factor that had the greatest effect on the extraction rate of chlorogenic acid in S. chinensis was ethanol concentration, followed by extraction time, and the least influencing factor was ultrasonic power. With 60% ethanol solution serving as the extractant, the ultrasonic power of 36 W, and the extraction time of 40 min, a better extraction rate was obtained. These conditions can be used as the best extraction conditions for chlorogenic acid.

Study on the Extraction Process of Total Flavonoids from Morinda citrifolia L.

[Objectives]This study was conducted to explore the best extraction technology of total flavonoids from Morinda citrifolia L.[Methods]An orthogonal test was carried out to select the best extraction process with the yield of total flavonoids in the extract as the investigation index.[Results]Among the four factors of experimental design,the extraction time had a very significant impact on the results,the ethanol concentration had a significant impact on the results,and the extraction temperature and ethanol dosage had no significant impacts on the results.The optimal extraction process conditions for the total flavonoids of M.citrifolia were as follows:extraction time 1.5 h,ethanol concentration 90%,extraction temperature 60-65℃,and ethanol dosage 1∶20(g/ml).The total flavonoids in M.citrifolia fruit were extracted according to the optimal extraction process conditions,and the yield was 2.936%.[Conclusions]This study provides a theoretical basis for obtaining the optimal extraction process conditions for total flavonoids of M.citrifolia.

Establishment of the Determination Methods of Total Anthraquinone Content in Different Processed Products of Rhubarb

[Objectives]Ultraviolet spectrophotometry was established for the determination of total content of anthraquinone in different processed products of rhubarb.[Methods]Emodin was used as the control substance,and its color was developed by magnesium acetate methanol solution with the concentration of 1%,the absorbance was determined at the wavelength of 516 nm,the content of total anthraquinone in different processed products of rhubarb was determined to compare the content differences.[Results]The regression equation was y=0.0452 x+0.0015,R 2=0.9991.Emodin had a good linear range in the concentration of 0.98-23.52μg/mL,with high accuracy,good repeatability and stable detection results.This method revealed the content changes of total anthraquinone in rhubarb before and after processing.[Conclusions]This method could be used as the quality control method of different processed products of rhubarb,and provided reference for the comprehensive development and utilization of rhubarb resources in the future.

Amplified ultraviolet detection of natural DNA based on Mo_6S_(9-x)I_x nanowires

We demonstrate that Mo6S9-xIx nanowires （MoSI NWs） can serve as an excellent signal-intensifying nanomaterial for highly sensitive and label-free detection of DNA by ultraviolet （UV） spectrophotometry. The DNA extinction at 260 nm was greatly enhanced after addition of MoSI NWs solute, and the extinction value was linear with DNA concentration in the range of 0.0289-11.68 μg/mL with the real determination limit of 28.9 ng/mL. The association of DNA with the nanowires was characterized by transmission electronmicroscopy and circular dichroic spectroscopy. The results illustrate that the UV response amplification of DNA in the presence of MoSI NWs is attributed to the greater DNA coverage on the MoSI NW surface and the conformational transformation of DNA due to interaction of DNA with MoSI NWs. MoSI NWs are a promising nano-structured material for developing ultrasensitive sensors for detection of DNA.