Preparation and characterization of fenugreek leaf flavonoids and their protective effects against oxidative damage to hepatocytes / 中国中药杂志

The present study investigated the main components of fenugreek(Trigonella foenum-graecum L.) leaf flavonoids(FLFs) and their antioxidant activity. FLFs were prepared and enriched by solvent extraction, and the flavonoids were characterized by high-performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry(HPLC-Q-TOF-MS/MS). The protective effect of FLFs against H_2O_2-induced stress damage to L02 hepatocytes was also investigated. Firstly, the cell viability was measured by MTT assay. The oxidative stress injury model was induced by H_2O_2 in L02 cells. The release of lactate dehydrogenase(LDH), the content of reduced glutathione(GSH) and malondialdehyde(MDA), and the activities of superoxide dismutase(SOD) and catalase(CAT) were measured by assay kits. Hoechst fluorescence staining was performed to observe the cell apoptosis. The expression levels of c-Jun N-terminal kinase(JNK), extracellular signal-regulated kinase 1/2(ERK1/2), nuclear factor erythroid-2 related factor 2(Nrf2), heme oxygenase 1(HO-1), and their phosphorylated proteins were detected by Western blot. Based on the MS fragment ion information and data in databases, FLFs contained eight flavonoids with quercetin and kaempferol as the main aglycons. The cell viabi-lity assay revealed that as compared with the conditions in the H_2O_2 treatment group, 3.125-25 μg·mL~(-1) FLFs could increase the viability of L02 cells, reduce LDH release and MDA content in a dose-dependent manner, potentiate the activities of SOD, CAT, and GSH, decrease the phosphorylation of JNK and ERK1/2 proteins, and up-regulate the expression of Nrf2 and HO-1. The results of fluorescence staining showed that the nucleus of the H_2O_2 treatment group showed concentrated and dense strong blue fluorescence, while the blue fluorescence intensity of the FLFs group decreased significantly. FLFs showed a protective effect against H_2O_2-induced oxidative damage in L02 cells, and the underlying mechanism is associated with the enhancement of cell capability in clearing oxygen free radicals and the inhibition of apoptosis by the activation of the MAPKs/Nrf2/HO-1 signaling pathway. The antioxidant effect of fenugreek leaf is related to its rich flavonoids.

Research progress on chemical constituents and pharmacological activities of Trigonella foenum-graecum / 中国中药杂志

Trigonella foenum-graecum is an annual plant of the genus Trigonella in the Leguminosae family. It is widely distributed in China and has a long history of application. According to phytochemistry research, the seeds, stem, and leaves of this herb contain not only a variety of bioactive ingredients, including alkaloids, saponins, polysaccharides, flavonoids, and phenols, but also abundant nutrients such as unsaturated fatty acids and amino acids and various trace elements. Pharmacological studies have shown that both the extract of T. foenum-graecum and its chemical constituents exhibit hypoglycemic, hypolipidemic, antitumor, antioxidative, antimicro-bial, and hepatoprotective activities. This paper reviews the research progress on the chemical constituents and pharmacological effects of T. foenum-graecum, which may contribute to further development, application, and clinical research of this herb.

Extraction technology, composition analysis and antioxidant and antimicrobial activities of volatile oil from fenugreek leaves / 中国中药杂志

To define the extraction process, main components and antioxidative and antimicrobial activities of volatile oil from fenugreek(Trigonella foenum-graecum) leaves and its active substance basis. Response surface methodology was used for optimum supercritical CO_2 extraction conditions of essential oil from fenugreek leaves. The main components of volatile oil were analyzed by GC-MS, its antioxidant activity was evaluated by measuring the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl(DPPH) and 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, ABTS) free radical, and the antimicrobial effect of volatile oil was evaluated by K-B paper AGAR diffusion method. The results showed that the optimal extraction temperature was 50 ℃, the extraction time was 89 min, and the extraction pressure was 35 MPa. Under the conditions, the optimum extracting yield of volatile oil was 1.72%,which was about 1.5 times higher than that of the conventional steam distillation. A total of 52 compounds were found based on reference substance retention time and GC-MS fragmentation information or the existing literatures, and the major compounds were oleic acid(9.65%), carveol(9.41%), n-hexadecanoic acid(9.1%), linoleic acid(6.95%), methyl linolenate(5.4%), petroselinic acid(5.3%), testosterone(3.4%), sotolon(1.75%). The volatile oil of fenugreek showed moderate antioxidant activities in DPPH assay(IC_(50) value of 0.473 mg·mL~(-1)) and ABTS test(IC_(50) value of 0.107 mg·mL~(-1)). The oil had a stronger antimicrobial activity in vitro. MIC of the volatile oil ranged from 0.375 to 1.5 mg·mL~(-1). The results showed that the optimized volatile oil extraction process was stable, and the extraction yield was high. Fenugreek leaves contained a variety of volatile components, with obvious antioxidant and antibacterial activities. This study provides a certain theoretical basis for the comprehensive development and utilization of fenugreek.

Study on content determination of alkaloids and HPLC fingerprint of "Jianlian" Nelumbinis Plumula / 中国中药杂志

This study is to determine the content of three alkaloids and establish the HPLC fingerprint of "Jianlian" Nelumbinis Plumula. The HPLC method of content determination was as follows: Thermo C18 (4. 6 mm x 250 mm, 5 μm) was conducted with acetonitrile-sodium dodecyl sulfonate solution-acetic acid (56: 43: 1) at a flow rate of 1.0 mL x min(-1). The monitoring wavelength was set at 282 nm and the column temperature was 35 degrees C. The method of HPLC fingerprint was as follows: Agilent ZORBAX SB-Aq C18 (4.6 mm x 250 mm, 5 μm) was conducted with gradient elution of methanol and water at a flow rate of 0.8 mL x min(-1), the monitoring wavelength was set at 282 nm and the column temperature was 35 degrees C. Similarities evaluation and hierarchical clustering analysis were applied to demonstrate the variability of 12 batches of "Jianlian" Nelumbinis Plumula samples. The results demonstrated that 11 batches showed good similarity on chemical constituents. The method could well display the chemical information of "Jianlian" Nelumbinis Plumula. It was simple, reliable and could be used for the chemical quality control of "Jianlian" Nelumbinis Plumula.