Synthesis, Stability, and Antidiabetic Activity Evaluation of (-)-Epigallocatechin Gallate (EGCG) Palmitate Derived from Natural Tea Polyphenols.

This work describes a novel approach for the synthesis of (-)-epigallocatechin gallate (EGCG) palmitate by a chemical-synthesis method, where the elevated stability of the EGCG derivative is achieved. Various parameters affecting the acylation process, such as the base, solvent, as well as the molar ratio of palmitoyl chloride, have been studied to optimize the acylation procedure. The optimized reaction condition was set as follows: EGCG/palmitoyl chloride/sodium acetate was under a molar ratio of 1:2:2, with acetone as the solvent, and the reaction temperature was 40 °C. Under the optimized condition, the yield reached 90.6%. The EGCG palmitate (PEGCG) was isolated and identified as 4'-O-palmitoyl EGCG. Moreover, the stability of PEGCG under different conditions was proved significantly superior to EGCG. Finally, PEGCG showed better inhibition towards α-amylase and α-glucosidase, which was 4.5 and 52 times of EGCG, respectively. Molecular docking simulations confirmed the in vitro assay results. This study set a novel and practical synthetic approach for the derivatization of EGCG, and suggest that PEGCG may act as an antidiabetic agent.

Quantitative Polyunsaturated Fatty Acid Analysis of Chia Seed Oil by High-Performance Liquid Chromatography.

Alpha-linolenic acid (ALA) and linoleic acid (LA), abundant in chia seed oil, are useful polyunsaturated fatty acids (PUFA) with numerous health benefits. The objectives of the present study were to explore the optimum extraction condition of chia seed oil and the possibilities of direct analysis of ALA and LA in chia seed oil by reversed-phase high-performance liquid chromatography with ultraviolet detection (RP-HPLC-UV). The optimized chia seed oil extraction condition was set by the usage of Soxhlet extrator with hexane as a solvent, with the solvent to solid ratio of 8 and the extraction time of 8 h. Prior to HPLC-UV analysis, the oil was saponified in order to get the free fatty acids for detection. The results showed that the proposed HPLC-UV method allowed the quantification of ALA and LA in chia seed oil. The method was simple, rapid (within 18 min) and sensitive (limit of detection 0.006 mg/mL for ALA and 0.02 mg/mL for LA) and precise (RSD ≤ 2%). Thus, the proposed experimental designs were shown to offer considerable advantages over traditional derivatization approaches in the ALA and LA analyses.

Authentication of the Bilberry Extracts by an HPLC Fingerprint Method Combining Reference Standard Extracts.

A simple and fast high-performance liquid chromatography (HPLC) fingerprint method combining reference standard extract for the identification of bilberry extract was developed and validated. Six batches of bilberry extract collected from different manufactures were used to establish the HPLC fingerprint. Other berry extracts-such as blueberry extracts, mulberry extracts, cranberry extracts, and black rice extracts-were also analyzed for their HPLC chromatograms. The fingerprints of five batches of bilberry extract showed high similarities, while one batch was distinguished from others. Additionally, the content of anthocyanin Cyanidin-3-O-glucoside (Cy-3-glc) in each berry extract was analyzed and compared. The results indicate that this HPLC fingerprint method, combining reference standard extracts, could be used for the authentication and quality control of bilberry extracts.

Preparation from Lepidium meyenii Walpers using high-speed countercurrent chromatography and thermal stability of macamides in air at various temperatures.

Originally cultivated in the Peruvian Andes, Maca (Lepidium meyenii) is now widely consumed as functional food which is known for its functional characteristic like relieving fatigue and enhancing stamina. Macamides are the unique fatty acids with long-chain and N-benzylamides among the various constituents extracted from Maca. N-benzyl-(9Z, 12Z, 15Z)-octadecatrienamide, N-benzyl-(9Z, 12Z)-octadecadienamide, N-benzylhexadecanamide and N-benzyl-9Z-octadecenamide were isolated from crude Maca extracts in two steps by using a combination of high-speed countercurrent chromatography (HSCCC) and semi-preparative HPLC. The four macamides were identified by NMR, UV, HRMS and IR spectra. The thermal stability and autoxidative kinetics for N-benzyl-(9Z, 12Z, 15Z)-octadecatrienamide and N-benzyl-(9Z, 12Z)-octadecadienamide in the air were also studied at various temperatures and the apparent activation energies were 28.4 kJ/mol and 29.9 kJ/mol, respectively. The purity of the isolated macamides was up to 98% and the amount was enough for application as a reference substance.

The antiviral activity of arctigenin in traditional Chinese medicine on porcine circovirus type 2.

Arctigenin (ACT) is a phenylpropanoid dibenzylbutyrolactone lignan extracted from the traditional herb Arctium lappa L. (Compositae) with anti-viral and anti-inflammatory effects. Here, we investigated the antiviral activity of ACT found in traditional Chinese medicine on porcine circovirus type 2 (PCV2) in vitro and in vivo. Results showed that dosing of 15.6-62.5µg/mL ACT could significantly inhibit the PCV2 proliferation in PK-15 cells (P<0.01). Dosing of 62.5µg/mL ACT 0, 4 or 8h after challenge inoculation significantly inhibited the proliferation of 1MOI and 10MOI in PK-15 cells (P<0.01), and the inhibitory effect of ACT dosing 4h or 8h post-inoculation was greater than 0h after dosing (P<0.01). In vivo test with mice challenge against PCV2 infection demonstrated that intraperitoneal injection of 200µg/kg ACT significantly inhibited PCV2 proliferation in the lungs, spleens and inguinal lymph nodes, with an effect similar to ribavirin, demonstrating the effectiveness of ACT as an antiviral agent against PCV2 in vitro and in vivo. This compound, therefore, may have the potential to serve as a drug for protection of pigs against the infection of PCV2.

Determination and quality evaluation of green tea extracts through qualitative and quantitative analysis of multi-components by single marker (QAMS).

The quality of tea is mainly attributed to tea polyphenols and caffeine. In this paper, a new strategy for quality evaluation of green tea extracts was explored and verified through qualitative and quantitative analysis of multi-components by single marker (QAMS). Taguchi Design was introduced to evaluate the fluctuations of the relative conversion factors (fx) of tea catechins, gallic acid and caffeine to epigallocatechin gallate. The regression model (Sig.=0.000) and the deviations (R(2)>0.999) between QAMS and normal external standard method proved the consistency of the two methods. Hierarchical cluster analysis and canonical discriminant analysis were employed to classify 26 batches of commercial Longjing green tea extracts (LJGTEs) collected from different producers. The results showed a significant difference in component profile between the samples from different origins. The QAMS method was verified to be an alternative and promising method to comprehensively and effectively control the quality of LJGTEs from different origins.