Planta medica
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Multidrug resistance (MDR) constitutes the major obstacle to the successful treatment of cancer. In several cancer cells, MDR is thought to be mediated by the super-expression of P-glycoprotein (Pgp). Pgp extrudes drugs from the cells, therefore reducing their cytotoxicity, and its activity inhibition may reverse the MDR phenotype. ⋯ Of note, the P. amarus derivatives significantly potentiated 5 microM daunorubicin-induced cell death in Lucena-1 cells (P < 0.01) but not in K562 cells. After treatment only with P. amarus derivatives (100 microg/mL HE, 30 microg/mL LRF, 12.9 microg/mL NIRA, 43.2 microg/mL NIRT, 43 microg/mL PHYLLA or 41.6 microg/mL PHYLT), the Lucena-1 cellular viability was 83.7, 85.3, 101, 69.7, 75.6 or 88.7%, respectively, whereas the in the presence of daunorubincin, which was not cytotoxic PER SE, the cell viability decreased to 42.9, 42.2, 64.2, 35.4, 30.4 or 52.6%, respectively. Together, these results suggest a potential action of P. amarus derivatives as MDR reversing agents, mainly due to their ability to synergize with the action of conventional chemotherapeutics.
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The phenolic glucoside gastrodin (Gas) is a main component extracted from the rhizome of Gastrodia elata, a Chinese herbal medicine, which has long been used for treating dizziness, epilepsy, stroke and dementia. In this study, we investigated the neuroprotective effects of Gas on cerebral ischemic injury in rats caused by transient middle cerebral arterial occlusion (MCAO), oxygen/glucose deprivation (OGD) and glutamate-induced injury in cultured rat hippocampal neurons. Additionally, the effects of Gas on the extracellular glutamate level and changes in intracellular Ca (2+) and the generation of nitric oxide (NO) were examined in cultured hippocampal neurons subjected to OGD in vitro. ⋯ Gas treatment (15 microg/mL, 30 microg/mL) also significantly inhibited OGD- and glutamate-induced neuronal cell death and reduced the extracellular glutamate level following OGD. Moreover, Gas treatment significantly inhibited the OGD-induced Ca (2+) and NO increases. In conclusion, the present study indicates that Gas has a neuroprotective action.