Badiali Camilla, Petruccelli Valerio, Brasili Elisa, Pasqua Gabriella
Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy.
Plants (Basel). 2023 Feb 4;12(4):694. doi: 10.3390/plants12040694.
Xanthones are a class of secondary metabolites produced by plant organisms. They are characterized by a wide structural variety and numerous biological activities that make them valuable metabolites for use in the pharmaceutical field. This review shows the current knowledge of the xanthone biosynthetic pathway with a focus on the precursors and the enzymes involved, as well as on the cellular and organ localization of xanthones in plants. Xanthone biosynthesis in plants involves the shikimate and the acetate pathways which originate in plastids and endoplasmic reticulum, respectively. The pathway continues following three alternative routes, two phenylalanine-dependent and one phenylalanine-independent. All three routes lead to the biosynthesis of 2,3',4,6-tetrahydroxybenzophenone, which is the central intermediate. Unlike plants, the xanthone core in fungi and lichens is wholly derived from polyketide. Although organs and tissues synthesizing and accumulating xanthones are known in plants, no information is yet available on their subcellular and cellular localization in fungi and lichens. This review highlights the studies published to date on xanthone biosynthesis and trafficking in plant organisms, from which it emerges that the mechanisms underlying their synthesis need to be further investigated in order to exploit them for application purposes.
氧杂蒽酮是植物生物体产生的一类次生代谢产物。它们具有结构多样和多种生物活性的特点，这使得它们成为制药领域有价值的代谢产物。本综述展示了目前关于氧杂蒽酮生物合成途径的知识，重点关注其前体和相关酶，以及氧杂蒽酮在植物中的细胞和器官定位。植物中的氧杂蒽酮生物合成涉及莽草酸途径和乙酸途径，它们分别起源于质体和内质网。该途径通过三条替代路线继续进行，两条依赖苯丙氨酸，一条不依赖苯丙氨酸。所有这三条路线都导致2,3',4,6 - 四羟基二苯甲酮的生物合成，它是核心中间体。与植物不同，真菌和地衣中的氧杂蒽酮核心完全源自聚酮化合物。虽然已知植物中合成和积累氧杂蒽酮的器官和组织，但关于它们在真菌和地衣中的亚细胞和细胞定位尚无信息。本综述强调了迄今为止发表的关于植物生物体中氧杂蒽酮生物合成和运输的研究，从中可以看出，为了将其用于应用目的，需要进一步研究其合成的潜在机制。
