Phenolic composition, antioxidant, cytotoxic activities and cardioprotective effect of hydroalcoholic extract from aerial-parts of Hypericum attenuatum Fisch. ex Choisy.

This study investigated phenolic metabolites, antioxidant, cytotoxic and cardioprotective effects of the hydroalcoholic extract from the aerial parts of Hypericum attenuatum Fisch. ex Choisy. The total phenolic and flavonoid contents of the extract were 132.40 ± 2.06 mg GAE/g and 101.46 ± 1.47 mg QE/g respectively. The extract exhibited antioxidant activities with an EC50 value against DPPH radical of 0.099 ± 0.03 mg/mL and a FRAP value of 1.22 ± 0.086 mmol/L Fe2+. The extract could protect H9c2 cardiomyoblasts from the injury of H2O2, while it restored the H9c2 cell viability to 82.69 ± 2.33% at 100 µg/mL. The extract possessed cytotoxicity on MGC803, C666-1 and SW620 cells with IC50 values of 69.77 ± 2.43 µg/mL, 74.97 ± 1.08 µg/mL and 58.91 ± 1.81 µg/mL, respectively. Moreover, it could promote apoptosis of the tested cancer cells. This research provided useful information for the utilization of H. attenuatum as herbal medicine.

α-Glucosidase Inhibition Action of Major Flavonoids Identified from Hypericum Attenuatum Choisy and Their Synergistic Effects.

Hypericum attenuatum Choisy is a traditional Chinese herbal plant with multiple therapeutic effects. In this study, bioactivity-guided fractionation of Hypericum attenuatum Choisy extracts afforded three major flavonoids (including astragalin, guaijaverin and quercetin), which possessed α-Glucosidase inhibitory activity with IC50 values of 33.90±0.68 µM, 17.23±0.75 µM and 31.90±0.34 µM, respectively. Circular dichroism analysis revealed that all the three compounds could interact with α-glucosidase by inducing conformational changes of the enzyme. Molecular docking results indicated that they could bind to the active site in α-glucosidase, and the binding force was driven mainly by hydrogen bond. Additionally, isobolographic analysis of the interactions between two compounds showed that all the combinations presented a synergistic α-glucosidase inhibitory effect at lower concentrations, and the combination between quercetin and guaijaverin or astragalin exhibited the best synergistic effect. This research might provide a theoretical basis for the application of Hypericum attenuatum Choisy in treating hyperglycemia.

EtOAc extract of H. attenuatum Choisy inhibits inflammation by suppressing the NF-κB and MAPK pathways and modulating the gut microbiota.

BACKGROUND: Hypericum attenuatum Choisy, a traditional Chinese herb, has been shown to be effective in the treatment of diseases associated with inflammation and has been used to treat rheumatic arthritis in China for centuries. However, the underlying mechanism of its anti-inflammatory effect is poorly understood. HYPOTHESIS/PURPOSE: In this study, we aimed to investigate the anti-inflammatory mechanisms of EtOAc fractions of H. attenuatum Choisy (Ha-EtOAc) on lipopolysaccharide (LPS)-induced RAW264.7 macrophage inflammation and hypothesized that Ha-EtOAc could attenuate inflammation in the colon. STUDY DESIGN: LPS was utilized to induce RAW264.7 cells inflammation. The anti-inflammatory effect of Ha-EtOAc in RAW264.7 cells was evaluated by measuring the inhibition ratio of nitric oxide (NO) production. Murine ulcerative colitis (UC) was induced by treatment with 2.5% dextran sulfate sodium (DSS). The basic indexes of the mice, including body weight, food intake and hematochezia, were recorded during mice experiments. METHODS: The expression levels of pro-inflammatory cytokines, including TNF-α, IL-6 and IL-1ß, were measured by quantitative real-time PCR and western blot. Additionally, the influences of Ha-EtOAc on the NF-κB and MAPK signaling pathways were determined by western blot and immunofluorescence assays. In addition, the impact of Ha-EtOAc on gut microbiota of mice with UC was detected by 16S rDNA sequencing. RESULTS: Ha-EtOAc inhibited the LPS-induced production of NO and decreased the release of TNF-α, IL-6 and IL-1ß in RAW264.7 cells in a dose-dependent manner. In addition, pretreatment with Ha-EtOAc could suppress the nuclear translocation of p65 and the phosphorylation of Erk1/2, p38 and JNK. Ha-EtOAc treatment ameliorated murine UC, as reflected by a reduced body weight loss, improved colon shortening, alleviated mucosal damage and decreased releases of pro-inflammatory cytokines. Furthermore, Ha-EtOAc could modulate the composition of microbial communities. CONCLUSION: Our results demonstrated that Ha-EtOAc exhibited anti-inflammatory effects mainly by suppressing the NF-κB and MAPK pathways, and Ha-EtOAc treatment may be a potent therapy for the treatment of ulcerative colitis.

Antibacterial active compounds from Hypericum ascyron L. induce bacterial cell death through apoptosis pathway.

Hypericum ascyron L. has been used as a traditional medicine for the treatment of wounds, swelling, headache, nausea and abscesses in China for thousands of years. However, modern pharmacological studies are still necessary to provide a scientific basis to substantiate their traditional use. In this study, the mechanism underlying the antimicrobial effect of the antibacterial activity compounds from H. ascyron L. was investigated. Bioguided fractionation of the extract from H. ascyron L. afforded antibacterial activity fraction 8. The results of cup plate analysis and MTT assay showed that the MIC and MBC of fraction 8 is 5 mg/mL. Furthermore, using Annexin V-FITC/PI, TUNEL labeling and DNA gel electrophoresis, we found that cell death with apoptosis features similar to those in eucaryon could be induced in bacteria strains after exposure to the antibacterial activity compounds from H. ascyron L. at moderate concentration. In addition, we further found fraction 8 could disrupt the cell membrane potential indicate that fraction 8 exerts pro-apoptotic effects through a membrane-mediated apoptosis pathway. Finally, quercetin and kaempferol 3-O-ß-(2″-acetyl)-galactopyranoside, were identified from fraction 8 by means of Mass spectrometry and Nuclear magnetic resonance. To our best knowledge, this study is the first to show that Kaempferol 3-O-ß-(2″-acetyl)-galactopyranoside coupled with quercetin had significant antibacterial activity via apoptosis pathway, and it is also the first report that Kaempferol 3-O-ß-(2″-acetyl)-galactopyranoside was found in clusiacea. Our data might provide a rational base for the use of H. ascyron L. in clinical, and throw light on the development of novel antibacterial drugs.