Phytoalexin

About: Phytoalexin is a research topic. Over the lifetime, 1161 publications have been published within this topic receiving 63405 citations. The topic is also known as: phytoalexins.

Enhancement of Phytoalexin Synthesis during Rice Blast Infection of Leaves by Pre-treatment with Carpropamid

Abstract: Carpropamid {(1RS, 3SR)-2,2-dichloro-N-[1-(4-chlorophenyl) ethyl]-1-ethyl-3-methyl cyclo-propanecarboxamide}, which is considered as a melanin biosynthesis inhibitor, enhanced the accumulation of the phytoalexins momilactone A and sakuranetin in the rice leaves subsequently inoculated with the blast pathogen (Pyricularia oryzae). Carpropamid and its two diastereo-isomers, A(1R,3S) and B(1S,3R), did not stimulate phytoalexin production directly, but they potentiated rice plants to produce the two phytoalexins more rapidly and much amounts in response to blast infection. This phenomenon was also observed in rice leaves treated with WL28325 (2,2-dichloro-3,3-dimethylcyclopropane carboxylic acid), a resistance inducer. The calculation data of the correlation among accumulation of phytoalexins, concentrations of chemicals and biological effects suggested that the correlation pattern of isomer A resembled that of WL28325. The main mode of action of isomer A appears to be an enhancement of phytoalexin synthesis during blast infection (EPAS mode) similar to that of WL28325, rather than the inhibition of melanin biosynthesis (MBI mode). In contrast, the main mode of action of isomer B was found to be MBI, although EPAS probably also contributes to its biological activity. Carpropamid is assumed to control rice blast through a combination of MBI and EPAS activities.

In vitro effect of resveratrol against oxidative injury of human coronary artery endothelial cells

Abstract: Reactive oxygen species induce oxidative stress that may contribute to endothelial dysfunction. In addition to endogen antioxidants, adding antioxidants to diet has been used to reduce oxidative-stress-induced endothelial dysfunction. Resveratrol is a natural phytoalexin which has many effects including antioxidant activity. The aim of this study was to investigate whether resveratrol could protect human coronary artery endothelial cells against in vitro oxidative-stress-mediated injury. Materials and methods: Human coronary artery endothelial cells were treated with varying concentrations of hydrogen peroxide for different durations and hydrogen peroxide plus varying concentrations of resveratrol. Then cell death was measured using lactate dehydrogenase release. Human coronary artery endothelial cells were exposed to hydrogen peroxide and resveratrol plus hydrogen peroxide for 15 min, 60 min, and 6 h. Reactive oxygen species was measured using a fluorometric assay. Results: Preincubation of cells with 10 and 50 mM resveratrol for different periods caused a significantly decreased hydrogen-peroxide-induced cell death. Preincubation with resveratrol caused a significant decrease in reactive oxygen species production. Conclusion: Our results demonstrate that resveratrol protects human coronary artery endothelial cells, in vitro, against oxidative-stress-induced injury by decreasing cell death and reactive oxygen species production.