The Effect of Bacterial AHL on the Cyclic Adenosine Monophosphate Content in Plants According to High-Performance Liquid Chromatography

Cyclic adenosine monophosphate (cAMP) is an important second messenger in cells, mediating various stimulation signals such as the growth and development of organisms and stress and participating in regulating various biological processes of cells. This article explores the quantitative determination of cAMP in plants using High-Performance Liquid Chromatography (HPLC) and applies this method to analyzing the changes in cAMP content during the process of plant response to the bacterial quorum sensing signal N-acyl homoserine lactone (AHL). Research has shown that the optimal detection conditions for HPLC are as follows: the chromatographic column is Venusil MP C18 (2), the mobile phase is methanol-water (0.1% trifluoroacetic acid) (v:v, 10:90), the detection wavelength is 259 nm, the column temperature is 35 °C, and the flow rate is 0.8 mL/min. The precision of the standard sample of this method is 98.21%, the precision of the sample is 98.87%, and the recovery rate is 101.067%. The optimal extraction conditions for cAMP in Arabidopsis are to use 15% methanol ultrasonic extraction for 10 min, followed by a 40 °C water bath for 4 h. Bacterial AHL signal processing can significantly stimulate an increase in cAMP levels in Arabidopsis leaves and roots. The establishment of HPLC detection methods for the cAMP content in plants is of great significance for in-depth research on the signal transduction mechanisms of plant-bacterial interactions.

[Comparison of HPLC fingerprints and determination of main components of Viticis Fructus from different species]

In order to comprehensively evaluate the quality of Viticis Fructus, this study established HPLC fingerprints and evaluated the quality of 24 batches of Viticis Fructus samples from different species by similarity evaluation and multivariate statistical analysis(PCA, HCA, PLS-DA). On this basis, an HPLC method was established to compare the content differences of the main components, including casticin, agnuside, homoorientin, and p-hydroxybenzoic acid. The analysis was performed on the chromatographic column(Waters Symmetry C_(18)) with a gradient mobile phase of acetonitrile(A)-0.05% phosphoric acid solution(B) at the flow rate of 1 mL·min~(-1) and detection wavelength of 258 nm. The column temperature was 30 ℃ and the injection volume was 10 μL. The HPLC fingerprint of 24 batches of Viticis Fructus samples was established with 21 common peaks, and nine peaks were identified. Similarity analysis was carried out based on chromatographic data of 24 batches of chromatographic data of Viticis Fructus, and the results showed that except for DYMJ-16, the similarity of Vitex trifolia var. simplicifolia was ≥0.900, while that of V. trifolia was ≤0.864. In addition, the similarity analysis of two different species showed that the similarity of 16 batches of V. trifolia var. simplicifolia was 0.894-0.997 and that of the eight batches of V. trifolia was between 0.990 and 0.997. The results showed that the similarity of fingerprints of these two species was different, but the similarity between the same species was good. The results of the three multivariate statistical analyses were consistent, which could distinguish the two different species. The VIP analysis results of PLS-DA showed that casticin and agnuside contributed the most to the distinction. The content determination results showed that there was no significant difference in the content of homoorientin and p-hydroxybenzoic acid in Viticis Fructus from different species, but the content of casticin and agnuside was significantly different in different species(P<0.01). The content of casticin was higher in V. trifolia var. simplicifolia, while agnuside was higher in V. trifolia. The findings of this study show that there are differences in fingerprint similarity and component content of Viticis Fructus from different species, which can provide references for the in-depth study of the quality and clinical application of Viticis Fructus.

[Separation, characterization and anti-psoriasis effect of self-assembled nanoparticles from Shaoyao Gancao Decoction]

This study aims to separate and characterize self-assembled nanoparticles(SAN) from Shaoyao Gancao Decoction(SGD) and determine the content of active compounds. Further, we aimed to observe the therapeutic effect of SGD-SAN on imiquimod-induced psoriasis in mice. The separation of SGD was performed by dialysis, and the separation process was optimized by single factor experiment. The SGD-SAN isolated under the optimal process was characterized, and the content of gallic acid, albiflorin, paeoniflorin, liquiritin, isoliquiritin apioside, isoliquiritin, and glycyrrhizic acid in each part of SGD was determined by HPLC. In the animal experiment, mice were assigned into a normal group, a model group, a methotrexate group(0.001 g·kg~(-1)), and SGD, SGD sediment, SGD dialysate, and SGD-SAN groups of different doses(1, 2, and 4 g·kg~(-1)) respectively. The psoriasis grade of mice was evaluated based on the pathological changes of skin lesions, the content of inflammatory cytokines, organ index and other indicators. The results showed that SAN obtained by centrifugation at 13 000 r·min~(-1) for 30 min was stable after dialysis for 4 times, which were uniform spherical nanoparticles with the particle size of(164.43±1.34) nm, the polydispersity index of(0.28±0.05), and the Zeta potential of(-12.35±0.80) mV. The active compound content accounted for more than 70% of SGD. Compared with the model group, SAN and SGD decreased the skin lesion score, spleen index, and inflammatory cytokine levels(P<0.05 or P<0.01) and alleviated the skin thickening and infiltration of inflammatory cells. However, the sediment group and the dialysate group had no obvious effect. SGD showed a good therapeutic effect on imiquimod-induced psoriasis in mice, and SAN demonstrated the effect equivalent to SGD in a dose-dependent manner. Therefore, we conclude that the SAN formed during decocting is the main active form of SGD, which can lower the levels of inflammatory cytokines, promote the normal differentiation of keratinocytes, and reduce the infiltration of inflammatory cells in the treatment of psoriasis lesions in mice.

Colour and content of some biologically active substances in natural products and products of natural origin

The paper draws attention to the correlations between the results of instrumental colour measurements and the content of some biologically active organic substances (carotenoids, chlorophyll, anthocyanins, curcuminoids, etc.) in natural products and products of natural origin. After supplementation by regression analysis and calibration, sufficiently close correlations can lead to the development of procedures for rapid determination of the content of these substances and their groups by colour measurement without more demanding sample treatment.

[Determination of 3 components in Xinjiang Ziziphora bungeana by HPLC]

This study aimed to develop an HPLC method for simultaneous determination of the 3 components in Ziziphora bungeana. The optimum HPLC condition was as follows：ZORBAX SB-C₁₈ column（4.6 mm×250 mm, 5.0 μm）with gradient elution of methanol (A)-0.2% glacial acetic acid (B), detection wavelength 340 nm,column temperature 30 °C, flow rate 1 mL·min⁻¹. There were good linearity between peak areas and injection quantity of caffeic acid, rosmarinic acid, and linarin in the range of 2-40 mg·L⁻¹（r=0.999 9）, 3-60 mg·L⁻¹（r=1）, 7-140 mg·L⁻¹（r=0.999 9）, respectively. The average recoveries were 100.9%（RSD 1.3%）,98.25%（RSD 2.0%）,and 98.73%（RSD 1.5%）, respectively. The HPLC method was stable and accurate, which could be used to detect caffeic acid,rosmarinic acid, and linarin in Ziziphora bungeana.

Theory and practice of pharmacopoeial control of quality of drugs and excipients X. Number of parallel determinations, processing of results and their use in the assessment of the content of active substances and excipients in the European Pharmacopoeia (Ph. Eur.)

In the European Pharmacopoeia (Ph. Eur.) there is no prescribed number of parallel determinations of the content of active substances and excipients. The authors suggest adding at least three determinations. The results of parallel determinations suggest to test for outliers before using test based on the ratio of the range of results (p = 0.95) and not to compare individual results with the tolerance limits given in Ph. Eur., but with their arithmetic mean. Furthermore, they propose to extend the Chapter 5.3. of the European Pharmacopoeia so as to be applicable not only to bioassays, but also to chemical, physicochemical and physical assays and tests, starting with the content of active substances and excipients.

[Analysis on ecological factors and active components content of wild Dipsacus asper in Chongqing Wulong district]

An HPLC method was developed for the determination of iridoid glycosides (loganin acid, loganin, sweroside) and saponins (asperosaponin Ⅵ) in the wild Dipsacus asper. A total of 108 samples consecutive growing 12 month were collected in 9 plots in Wulong district of Chongqing. Subsequent analysis of the content of loganin acid, loganin, sweroside and asperosaponin Ⅵ was performed by HPLC to evaluate the quality. In addition, 20 climate data provided by the world climate database (http://www.worldclim.org/) was analyzed to deduce the correlation between the growing environment factors and the active ingredient content accumulation of D. asperoides and choose the apposite growing environment for D. asper. The range of active ingredient content in wild D. asper were 0.01%-3.80%(loganin acid), 0.08%-0.62%(loganin), 0.12%-0.78%(sweroside), 0.64%-5.26%(asperosaponin Ⅵ). The highest content of these active ingredients was concentrated from February to April, with 2.64% of loganin acid, 0.36% of loganin), 0.57% of sweroside, and 3.09% of asperosaponin Ⅵ. The method used for determination of the active ingredient content in D. asper was simple and convenient with accurate result. The selection of the quadrats is scientific and reasonable and can be used for the analysis of the contents of the wild D. asper, thus provide a reference for quality evaluation of D. asper and protection of D. asper resources.