Shisheng Wang

Rapid discrimination and quantification of alkaloids in Corydalis Tuber by near-infrared spectroscopy.

With the application of near-infrared spectroscopy (NIRS), a convenient and rapid method for determination of alkaloids in Corydalis Tuber extract and classification for samples from different locations have been developed. Five different samples were collected according to their geographical origin, 2-Der with smoothing point of 17 was applied as the spectral pre-treatment, and the 1st to scaling range algorithm was adjusted to be optimal approach, classification model was constructed over the wavelength range of 4582-4270 cm⁻¹, 5562-4976 cm⁻¹ and 7000-7467 cm⁻¹ with a great recognition rate. For prediction model, partial least squares (PLS) algorithm was utilized referring to HPLC-UV reference method, the optimum models were obtained after adjustment. Pre-processing methods of calibration models were COE for protopine and min-max normalization for palmatine and MSC for tetrahydropalmatine, respectively. The root mean square errors of cross-validation (RMSECV) for protopine, palmatine, tetrahydropalmatine were 0.884, 1.83, 3.23 mg/g. The correlation coefficients (R²) were 99.75, 98.41 and 97.34%. T test was applied, in the model of tetrahydropalmatine; there is no significant difference between NIR prediction and HPLC reference method at 95% confidence interval with t=0.746

Rapid quantification of flavonoids in propolis and previous study for classification of propolis from different origins by using near infrared spectroscopy

A fast, simple and accurate near infrared spectroscopy (NIRs) method was investigated for the geographical origin discrimination and main flavonoid content determination of Chinese propolis. 180 propolis samples from four provinces of China were collected for establishing partial least squares (PLS) models of rutin, myricetin, quercetin, kaempferol, apigenin, izapinin, pinocembrin, chrysin, galangin and total flavonoids. The root mean square error of prediction (RMSEP) and correlation coefficient (R2) in the test set of the optimum models were 0.479 to 1.332% and 76.23 to 96.68%. The residual prediction deviation (RPD) values were all larger than 2.93. A paired t-test result showed that there was no significant difference between NIRs and HPLC methods at a 95% confidence interval. A principal component analysis (PCA)–Mahalanobis distance (MD) method was applied to classify the geographical origin of propolis samples, and 100% accuracy was obtained. Finally, a quality assessment was performed, and the propolis samples from Zhejiang and Liaoning province were classified as good quality. The developed NIRs method was a suitable tool for the rapid analysis of Chinese propolis, and might be also extended to the on-line quality control of propolis raw material in pharmaceutical industries, or monitoring industrial natural products extraction processes.

Discrimination and content analysis of fritillaria using near infrared spectroscopy.

Fritillaria is a traditional Chinese herbal medicine which can be used to moisten the lungs. The objective of this study is to develop simple, accurate, and solvent-free methods to discriminate and quantify Fritillaria herbs from seven different origins. Near infrared spectroscopy (NIRS) methods are established for the rapid discrimination of seven different Fritillaria samples and quantitative analysis of their total alkaloids. The scaling to first range method and the partial least square (PLS) method are used for the establishment of qualitative and quantitative analysis models. As a result of evaluation for the qualitative NIR model, the selectivity values between groups are always above 2, and the mistaken judgment rate of fifteen samples in prediction sets was zero. This means that the NIR model can be used to distinguish different species of Fritillaria herbs. The established quantitative NIR model can accurately predict the content of total alkaloids from Fritillaria samples.

Syntheses of new chlorin derivatives containing maleimide functional group and their photodynamic activity evaluation

Nine new chlorin derivatives containing maleimide functional group and amino acid residue with chlorin e6 scaffold (compounds 1-6) or pheophorbide a scaffold (compounds 7-9) were synthesised from chlorophyll a. The all nine derivatives demonstrated increased photo cytotoxic activity in HepG2 cell (IC50 3.2-20.5 μM) comparing with chlorin e6 and its trimethyl ester. Their photo cytotoxicities were approximately dependent on their abilities to produce singlet oxygen ((1)O2) in the cells.

Screening and identification of natural ligands of tyrosinase from Pueraria lobata Ohwi by a combination of ultrafiltration and LC-MS

Ultrafiltration combined with liquid chromatography-mass spectrometry (UF-LC-MS) is an efficient affinity-based method to screen potential ligands of biomacromolecules from natural sources. In order to investigate the effects of constituents from Pueraria labta Ohwi on tyrosinase, a UF-LC-MS method for screening tyrosinase ligands was established. Seven constituents were screened as tyrosinase ligands with high affinity and their structures were elucidated as isoflavones and isoflavone glycosides by mass spectrum analysis, among which puerarin exhibited much stronger inhibitory activity in vitro than arbutin against tyrosinase. An in silico docking study indicates that the interaction between puerarin and tyrosinase mainly derived from hydrogen bonds and π–cation interaction.

Qualitative and quantitative analysis of effective components in Fructus Ligustri Lucidi by near infrared spectroscopy

In an attempt to establish the qualitative and quantitative analysis of Fructus ligustri lucidi, near-infrared spectroscopy (NIRS) was applied. The qualitative model can identify nine alcohol-broiled products from eight different geographical origins and one crude sample with a factorization algorithm and pretreatment of the second-derivative (2-Der). For the quantitative models, a partial least squares (PLS) algorithm with optimum parameters was applied for determination of oleanolic acid (OA) and ursolic acid (UA) in Fructus ligustri lucidi. There is no significant difference for the observed values between the NIRS and HPLC method since the results of the t-tests are 0.590 and 0.441, respectively, both less than t(0.05,19) = 2.093 with a 95% confidence level. The data obtained revealed the proposed NIRS method is viable for the rapid qualitative and quantitative analysis of the active ingredients in Fructus ligustri lucidi.

Non-destructive geographical traceability of sea cucumber (Apostichopus japonicus) using near infrared spectroscopy combined with chemometric methods

Sea cucumber is the major tonic seafood worldwide, and geographical origin traceability is an important part of its quality and safety control. In this work, a non-destructive method for origin traceability of sea cucumber (Apostichopus japonicus) from northern China Sea and East China Sea using near infrared spectroscopy (NIRS) and multivariate analysis methods was proposed. Total fat contents of 189 fresh sea cucumber samples were determined and partial least-squares (PLS) regression was used to establish the quantitative NIRS model. The ordered predictor selection algorithm was performed to select feasible wavelength regions for the construction of PLS and identification models. The identification model was developed by principal component analysis combined with Mahalanobis distance and scaling to the first range algorithms. In the test set of the optimum PLS models, the root mean square error of prediction was 0.45, and correlation coefficient was 0.90. The correct classification rates of 100% were obtained in both identification calibration model and test model. The overall results indicated that NIRS method combined with chemometric analysis was a suitable tool for origin traceability and identification of fresh sea cucumber samples from nine origins in China.

Synthesis and in vitro phototoxicity of novel π-extension derivatives of chlorin e6

Six novel E-32-aryl substituted chlorins (5a–5f) were synthesized via improved regioselective bromination and Suzuki–Miyaura cross-coupling reactions with chlorin e6 (1) as a starting material. All the π-extension photosensitizers 5a–5f exhibited significant bathochromic-shifts (ca. 10 nm) in the far red part of the spectrum called the phototherapeutic window and decreased photobleaching under irradiation of 660 nm light. Moreover, 5a–5f possessed higher phototoxicity in vitro against HepG2 cells (IC50 = 0.73 ± 0.04, 2.33 ± 0.22, 0.78 ± 0.05, 0.50 ± 0.04, 2.25 ± 0.16 and 0.65 ± 0.11 μM, respectively) compared with chlorin e6 (IC50 = 28.9 ± 1.2 μM). The enhanced cellular uptake and reactive oxygen species (ROS) production of modified chlorins were found to be responsible for their increased in vitro phototoxicity.

Synergistic antiproliferative effect of chemo-phototherapy: Synthesis and photodynamic activity evaluation of novel Chlorin e6-artesunate conjugates as antiproliferative agents

In order to increase the photodynamic effect of Chlorin e6, four Chlorin e6-artesunate conjugates were designed and synthesized. Among them, three conjugates (3, 6, 9) contained single artesunate side chain at 152, 173 and 131 of Chlorin e6, respectively, and one conjugate (11) contained three artesunate side chains. In the in vitro evaluation of photodynamic effect, the four conjugates showed more potent phototoxicity against HepG2 cells than Chlorin e6. The introduction of artesunate side chain significantly increased the intracellular ROS production, although the production of singlet oxygen was not improved. Compound 11 exhibited much more potent phototoxicity than the other conjugates because the three artesunate side chains greatly enhanced the ROS production and cellular uptake. The results demonstrated that the conjugation of Chlorin e6 and artesunate could accomplish synergistic effects of chemo-phototherapy, and finally enhanced their antiproliferative effects.