Characterization of Aroma-Active Components and Antioxidant Activity Analysis of E-jiao(Colla CoriiAsini)from Different Geographical Origins

E-jiao(Colla Corii Asini,CCA)has been widely used as a healthy food and Chinese medicine.Although authentic CCA is characterized by its typical sweet and neutral fragrance,its aroma components have been rarely investigated.This work investigated the aroma-active components and antioxidant activity of 19 CCAs from different geographical origins.CCA extracts obtained by simultaneous distillation and extraction were analyzed by gas chromatography-mass spectrometry(GC-MS),gas chromatography-olfactometry(GC-O)and sensory analysis.The antioxidant activity of CCAs was determined by ABTS and DPPH assays.A total of 65 volatile compounds were identified and quantified by GC-MS and 23 aroma-active compounds were identified by GC-O and aroma extract dilution analysis.The most powerful aroma-active compounds were identified based on the flavor dilution factor and their contents were compared among the 19 CCAs.Principal component analysis of the 23 aroma-active components showed 3 significant clusters.Canonical correlation analysis between antioxidant assays and the 23 aroma-active compounds indicates strong correlation(r=0.9776,p=0.0281).Analysis of aroma-active components shows potential for quality evaluation and discrimination of CCAs from different geographical origins.

Rapid recognition of Chinese herbal pieces of Areca catechu by different concocted processes using Fourier transform mid-infrared and near-infrared spectroscopy combined with partial least-squares discriminant analysis

Rapid and sensitive recognition of herbal pieces according to different concocted processing is crucial to quality control and pharmaceutical effect. Near-infrared （NIR） and mid-infrared （MIR） technology combined with supervised pattern recognition based on partial least-squares discriminant analysis （PLSDA） was attempted to classify and recognize six different concocted processing pieces of 600 Areca catechu L. samples and the influence of fingerprint information preprocessing methods on recognition performance was also investigated in this work. Recognition rates of 99.24%, 100% and 99.49% for original fingerprint, multiple scatter correct （MSC） fingerprint and second derivative （2nd derivative） fingerprint of NIR spectra were achieved by PLSDA models, respectively. Meanwhile, a perfect recognition rate of 100% was obtained for the above three fingerprint models of MIR spectra. In conclusion, PLSDA can rapidly and effectively extract otherness of fingerprint information from NIR and MIR spectra to identify different concocted herbal pieces ofA. catechu.

Computational insights into different regioselectivities in the Ir-porphyrin-catalyzed C–H insertion reaction of quinoid carbene

The mechanisms and regioselectivities of the Ir-porphyrin-catalyzed C–H insertion reaction of quinoid carbene(QC)were investigated by density functional theory(DFT)calculations.The competing catalytic cycles were identified as the hydrogen-atom abstraction by quinoid oxygen(HAA-O)and hydrogen-atom abstraction by carbene carbon(HAA-C)catalytic cycles.