Laus Maura N, Soccio Mario
Department of Agriculture, Food, Natural Resources and Engineering (DAFNE), University of Foggia, via Napoli, 25, 71122 Foggia, Italy.
Antioxidants (Basel). 2020 Dec 10;9(12):1256. doi: 10.3390/antiox9121256.
In order to contribute to the understanding of the antioxidant behavior of plant bioactive compounds with respect to specific subcellular targets, in this study, their capability to protect aconitase activity from oxidative-mediated dysfunction was evaluated for the first time in plant mitochondria. Interest was focused on the Krebs cycle enzyme catalyzing the citrate/isocitrate interconversion via -aconitate, as it possesses a [4Fe-4S] cluster at the active site, making it an early and highly sensitive target of reactive oxygen species (ROS)-induced oxidative damage. In particular, the effect on the aconitase reaction of five natural phenols, including ferulic acid, apigenin, quercetin, resveratrol, and curcumin, as well as of the isothiocyanate sulforaphane, was investigated in highly purified mitochondria obtained from durum wheat (DWM). Interestingly, a short-term (10 min) DWM pre-treatment with all investigated compounds, applied at 150 µM (75 µM in the case of resveratrol), completely prevented aconitase damage induced by a 15 min exposure of mitochondria to 500 µM HO. Curcumin and quercetin were also found to completely recover DWM-aconitase activity when phytochemical treatment was performed after HO damage. In addition, all tested phytochemicals (except ferulic) induced a significant increase of aconitase activity in undamaged mitochondria. On the contrary, a relevant protective and recovery effect of only quercetin treatment was observed in terms of the aconitase activity of a commercial purified mammalian isoform, which was used for comparison. Overall, the results obtained in this study may suggest a possible role of phytochemicals in preserving plant mitochondrial aconitase activity, as well as energy metabolism, against oxidative damage that may occur under environmental stress conditions. Further investigations are needed to elucidate the physiological role and the mechanism responsible for this short-term protective effect.
为了有助于理解植物生物活性化合物相对于特定亚细胞靶点的抗氧化行为，在本研究中，首次在植物线粒体中评估了它们保护乌头酸酶活性免受氧化介导功能障碍的能力。研究重点是催化柠檬酸/异柠檬酸通过顺乌头酸相互转化的三羧酸循环酶，因为它在活性位点拥有一个[4Fe-4S]簇，使其成为活性氧（ROS）诱导的氧化损伤的早期且高度敏感的靶点。特别是，研究了包括阿魏酸、芹菜素、槲皮素、白藜芦醇和姜黄素在内的五种天然酚类化合物以及异硫氰酸萝卜硫素对从硬粒小麦（DWM）获得的高度纯化线粒体中乌头酸酶反应的影响。有趣的是，用所有研究化合物在150 μM（白藜芦醇为75 μM）下对DWM进行短期（10分钟）预处理，完全防止了线粒体暴露于500 μM H₂O₂ 15分钟所诱导的乌头酸酶损伤。当在H₂O₂损伤后进行植物化学处理时，还发现姜黄素和槲皮素能完全恢复DWM-乌头酸酶活性。此外，所有测试的植物化学物质（除阿魏酸外）在未受损的线粒体中均诱导乌头酸酶活性显著增加。相反，就用于比较的商业纯化哺乳动物同工型的乌头酸酶活性而言，仅观察到槲皮素处理具有显著的保护和恢复作用。总体而言，本研究获得的结果可能表明植物化学物质在保护植物线粒体乌头酸酶活性以及能量代谢免受环境应激条件下可能发生的氧化损伤方面具有潜在作用。需要进一步研究以阐明这种短期保护作用的生理作用和机制。
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