Orychophragmus violaceus (O. violaceus) is a kind of edible wild herb in north China and its seeds have medical potential, however, the effect of O. violaceus seeds on liver injury and the mechanism of action remains poorly understood. Thus, the purpose of the present study is to investigate the effect of O. violaceus seeds on liver injury and further explore the molecular mechanism of the beneficial effects using aqueous extract from the seeds of O. violaceus (AEOV). Mice were orally administrated with saline, AEOV, and biphenyldicarboxylate for 4 days, and were then injected subcutaneously with 0.1% carbon tetrachloride (CCl4) dissolved in corn oil. Sixteen hours later, mice were sacrificed and blood samples were collected. Then, the serum was separated and used for biochemical assay. Livers were excised and were routinely processed for histological examinations. Enzyme activities and protein levels in liver homogenates were detected using commercial kits or by western blot analysis. Additionally, the hepatoprotective effect of AEOV in vitro was evaluated using epigoitrin, the major alkaloid compound isolated from AEOV. We found that AEOV attenuated liver injury induced by CCl4 as evidenced by decreased levels of alanine aminotransferase (ALT) and aminotransferase (AST) in serum, improvement of liver histopathological changes, and substantial attenuation of oxidative stress and inflammation via regulation of nuclear factor-erythroid 2-related factor-2 (Nrf2) and nuclear factor κB (NFκB) pathways. These effects of AEOV were comparable to that of biphenyldicarboxylate which was commonly used as a hepatoprotective reference. Moreover, pretreatment of HepG2 cells with epigoitrin improved cell viability, decreased lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels, increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, attenuated the NFκB pathway, and elevated the Nrf2 pathway after exposure to H2O2. These results suggest that AEOV could effectively prevent CCl4-induced liver injury in mice via regulating the Nrf2 and NFκB pathways, and reveal the cytoprotective effects of epigoitrin against H2O2-induced oxidative stress in HepG2 cells.
One new cassane diterpene possessing an unusual N bridge between C-19 and C-20 named caesalsappanin R (1), as well as another new diterpene caesalsappanin S (2), were isolated from the seeds of Caesalpinia sappanwith methanol extract. Their structures were determined by spectroscopic analysis and examined alongside existing data from prior studies. Their biological activities were profiled by their antiplasmodial activity.
The tea-like beverage Stevia rebaudiana Bertoni (Stevia) is popular in China because it reduces blood glucose and has a sweet taste. In this work, a comprehensive quality assessment of Stevia led to the discovery of five phenylethanoid glycosides, namely steviophethanoside (1), cuchiloside (2), salidroside (3), icariside D (4), and tyrosol (5). Of them, compound 1 is a novel compound. Mass spectrometry and NMR spectroscopy were employed to confirm the absolute configuration. A hydrolytic step with 4 N TFA at 95 °C for 4 h was used to confirm the monosaccharides. In addition, Discovery Studio 4.0 was used to predict the ADME and toxicity activity of compound 1. The results suggested that compound 1 was biocompatible and had poor toxicity, which was verified by rat INS-1 islet β cells through an MTT assay. Meanwhile, a significant stimulatory effect on INS-1 cells was observed, which indicated a hypoglycemic effect of compound 1. This is the first report that describes a natural, novel, and hypoglycemic phenylethanoid glycoside in Stevia.
Three novel meroterpenoids, clavipines A–C (1–3), possessing a benzoquinone fused to an azepine ring and a ten-membered carbocycle with α,β-epoxy/unsaturated-γ-lactone, along with a new natural compound clavilactone F (4) and two known clavilactones D (5) and A (6) were isolated from the basidiomycete Clitocybe clavipes. Their structures with absolute configurations were unambiguously established by extensive spectroscopic analyses, and ECD and X-ray methods. An unusual seven-azepine skeleton was postulated to be formed biosynthetically via a rearrangement of quinone–amino acid conjugates. The biosynthetic origin of meroterpenoids with a benzo-fused 10-membered carbocycle unit was determined by incorporation of 13C-labeled precursors. Compound 1 exhibited significant antiproliferative activity against HepG2 and A549 cells with IC50 values of 4.28 ± 0.26 and 7.49 ± 0.41 μM, respectively.
The seeds of the plant Orychophragmus violaceus yielded eight new spermidine alkaloids, termed orychophragmuspine A–H (1–8). Their structures were elucidated by extensive spectroscopic analysis and comparison with literature data. Compounds 1–8 are unusual natural alkaloids with spermidine moieties and were tested for cytoprotective properties. The results showed that all compounds displayed mild cytoprotective activities compared with the normal and model groups.