[Preparation and characterization of fenugreek leaf flavonoids and their protective effects against oxidative damage to hepatocytes].

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.

Isolation of oligostilbenes from Iris lactea Pall. var. chinensis (Fisch.) Koidz and their anti-inflammatory activities.

Iris lactea Pall. var. chinensis (Fisch.) Koidz (Iris lactea) is an herbaceous perennial widely distributed in China, India, and South Korea. Iris lactea has been extensively used in traditional Chinese medicine. The present study isolated a new oligostilbene (compound 1), together with three known oligostilbenes (compounds 2, 3 and 4) from the seeds of Iris lactea. The structures of these compounds were elucidated by HRESIMS, NMR, and chemical analyses. The network-based pharmacologic analysis platform was used to predict the target proteins related to inflammation of isolated compounds. Furthermore, the isolated compounds were tested for their anti-inflammatory effects in LPS-stimulated RAW 264.7 cells. In this network, 138 candidate targets of compounds related to its therapeutic effect on inflammation were identified. In addition, compounds 1, 2, 3 and 4 significantly decreased NO content and the IL-6 levels as well as the expression of COX-2 in LPS-stimulated RAW 264.7 cells.