Pyrroloquinoline quinone is a quinone described as a cofactor for many bacterial dehydrogenases and is reported to exert an effect on metabolism in mammalian cells/tissues.Pyrroloquinoline quinone is present in the diet being available in foodstuffs,conferring the potential of this compound to be supplemented by dietary administration.Pyrroloquinoline quinone’s nutritional role in mammalian health is supported by the extensive deficits in reproduction,growth,and immunity resulting from the dietary absence of pyrroloquinoline quinone,and as such,pyrroloquinoline quinone has been considered as a“new vitamin.”Although the classification of pyrroloquinoline quinone as a vitamin needs to be properly established,the wide range of benefits for health provided has been reported in many studies.In this respect,pyrroloquinoline quinone seems to be particularly involved in regulating cell signaling pathways that promote metabolic and mitochondrial processes in many experimental contexts,thus dictating the rationale to consider pyrroloquinoline quinone as a vital compound for mammalian life.Through the regulation of different metabolic mechanisms,pyrroloquinoline quinone may improve clinical deficits where dysfunctional metabolism and mitochondrial activity contribute to induce cell damage and death.Pyrroloquinoline quinone has been demonstrated to have neuroprotective properties in different experimental models of neurodegeneration,although the link between pyrroloquinoline quinone-promoted metabolism and improved neuronal viability in some of such contexts is still to be fully elucidated.Here,we review the general properties of pyrroloquinoline quinone and its capacity to modulate metabolic and mitochondrial mechanisms in physiological contexts.In addition,we analyze the neuroprotective properties of pyrroloquinoline quinone in different neurodegenerative conditions and consider future perspectives for pyrroloquinoline quinone’s potential in health and disease.
Terpenoids with quinoid structures are found as natural products. This includes steroidal quinones, quinones with a secosteroid structure and meroterpenoid quinones. Importantly, catechol estrogens as endogenous metabolites of estradiol and estrone are precursors of reactive quinones and semiquinones, which are thought to contribute to estrogen-induced carcinogenesis. On the other hand, a number of quinones that include substituted naphthoquinones and anthraquinones are highly cytotoxic and have been used in cancer treatment. This makes the structures interesting synthetic targets. The following is a review of important natural and synthetic terpenoid and steroid quinone hybrids.
A highly efficient,transition-metal-and light-free approach to polyheterocycles via regioselective cascade radical cyclization is developed.The redox-neutral protocol has a broad substrate scope with good functional group tolerance and probably undergoes a SET process,which is initiated by catalytic amounts of quinone in combination with 2.0 equiv.of Cs_(2)CO_(3).
Qijing ZhangPan YueHao LeiCong-Ying ZhouChengming Wang
Photosynthetic carbon fixation by cyanobacteria plays a pivotal role in the global carbon cycle but is threatened by environmental pollutants.To date,the impact of quinones,with electron shuttling properties,on cyanobacterial photosynthesis is unknown.Here,we present the first study investigating the effects of an emerging quinone pollutant,i.e.,6PPD-Q(N-(1,3-dimethylbutyl)-N0-phenyl-p-phenylenediamine-quinone),on the cyanobacterium Synechocystis sp.over a 400-generation exposure period.Synechocystis sp.exhibited distinct sequential phases,including hormesis,toxicity,and eventual recovery,throughout this exposure.Extensive evidence,including results of thylakoid membrane morphological and photosynthetic responses,carbon fixation rate,and key gene/protein analyses,strongly indicates that 6PPD-Q is a potent disruptor of photosynthesis.6PPD-Q accepts photosynthetic electrons at the plastoquinone QB site in photosystem II(PSII)and the phylloquinone A1 site in PSI,leading to a sustained decrease in the carbon fixation of cyanobacteria after an ephemeral increase.This work revealed the specific mechanism by which 6PPD-Q interferes with photosynthetic carbon fixation in cyanobacteria,which is highly important for the global carbon cycle.
Xiuqi YouXimin ChenYi JiangHuan ChenJuan LiuZhen WuWeiling SunJinren Ni
目的探讨吡咯喹啉醌(PQQ)的研究热点与发展趋势,挖掘PQQ的研究及应用价值。方法本研究以Web of Science为检索的数据库,检索1985年至2022年发表的关于PQQ的文献,采用VOSviewer纳入文献的关键词、国家及地区、期刊等,对这些文献进行文献计量学分析。结果共纳入1512篇文献,年发文量整体呈现上升的趋势。发文量排名最高的期刊类别为Biochemistry Molecular Biology;引文期刊Journal of Biological Chemistry总链接强度最大;高频关键词主要包括膳食营养补充剂、线粒体、抗氧化等;国家及地区可视化结果显示中国虽然研究开始的时间较晚,但是与其他国家链接强度较大。结论近年来,对于PQQ的研究热度逐渐上升,其抗氧化作用、改善线粒体功能以及作用靶点可能是未来研究的热点。PQQ仍然具有广阔的发展前景,为医药健康产业注入新的活力。
