RESUMEN
Searching for new anti-ischemic stroke (anti-IS) drugs has always been a hot topic in the pharmaceutical industry. Natural products are an important source of discovering anti-IS drugs. The aim of the present study is to extract, rapidly prepare and explore the neuroprotective effect of texasin, a main active constituent from Caragana jubata (Pall.) Poir., which is a kind of Tibetan medicine with a clear anti-IS effect. The results showed that 95% ethanol was the optimal extraction solvent. A three-step rapid preparation method for texasin was successfully established, with a purity of 99.2%. Texasin at the concentration of 25-100 µM had no effect on the viability of normal cultured PC12 cells; 12.5 and 25 µM texasin could enhance the viability of PC12 cells damaged by oxygen and glucose deprivation/reoxygenation (OGD/R), and their effects are comparable to the positive drug edaravone at the concentration of 50 µM. Compared with the normal group, the expression of Bcl-2 protein in OGD/R-injured PC12 cells was downregulated (p < 0.01), and that of PERK, eIF2α, ATF4, CHOP, Bax and Cleaved caspase-3 proteins were upregulated (p < 0.01, p < 0.001). Compared with the OGD/R group, 25 µM texasin could upregulate the expression of Bcl-2 protein (p < 0.01), and downregulate that of PERK, eIF2α, ATF4, CHOP, Bax and Cleaved caspase-3 proteins (p < 0.01, p < 0.001). The 7-OH and 1-O of texasin formed H-bonds with residues Cys891 of the hinge ß-strand of PERK, which is crucial for kinase inhibitors. The above results suggest that the method established in the present study achieved rapid preparation of high-purity texasin. Texasin might inhibit neuronal apoptosis via the regulation of endoplasmic reticulum stress PERK/eIF2α/ATF4/CHOP signalling pathway to exert a protective effect on OGD/R-injured PC12 cells. Aiding by molecular docking, texasin was assumed to be a potential PERK inhibitor.
RESUMEN
Books on Chinese herbal medicines have shown that Dendrobium has the effect of nourishing Yin and reinforcing Yin,usually used for constipation induced by spleen Yin deficiency in clinical application. D. huoshanense,as an independent species among many species of Dendrobium,has no experimental studies about its effects on spleen Yin deficiency-type constipation. The purpose of this experiment was to illustrate the therapeutic effect of D. huoshanense on the constipation of spleen Yin deficiency type in rats,investigate its preliminary mechanism,and compare it with the D. officinale and D. nobile contained in the Chinese Pharmacopoeia to clarify its characteristics. The spleen Yin deficiency model was replicated in 70 rats by the composite factor method,and then the model rats were randomly divided into 7 groups: model group,Liuwei Dihuang Pills group( LWDHP),D. huoshanense high( DHS-H),medium( DHS-M),low( DHS-L) dose groups,D. nobile group( DNS),and D. officinale group( DOS),and another 10 rats were used as normal group( Normal). After 7 continuous days of administration,the fecal water content and intestine propulsion rate of each group were detected. HE staining was used to observe the pathological damage of ileum and colon in each group. Immunohistochemistry and Western blot were used to detect aquaporin 3( AQP3) expressions,while the expression levels of the somatostatin( SS) and motilin( MTL) in the ileum of each group were detected by enzyme-linked immunosorbent assay. The results showed that as compared with the model group,the rats in each drug-administered group had increased number of fecal pellets,increased fecal water content,and the increased intestinal propulsion rate( P<0. 01),while the pathological damage of the ileum and colon was significantly reduced; the expression of AQP3 protein was significantly decreased( P<0. 01); the level of MTL was significantly increased and the level of SS was decreased( P<0. 01). All DHS groups showed a good dose-effect relationship,and the same dose treatment effect was equivalent to that of DOS,but it was superior to DNS. Therefore,DHS has a significant therapeutic effect on constipation of spleen Yin deficiency type,and its mechanism may be related to intestinal motility and water-liquid metabolism,with a good therapeutic effect.