Biosynthesis and biomimetic synthesis of alkaloids isolated from plants of the Nitraria and Myrioneuron genera: an unusual lysine-based metabolism

This review describes a wide panel of alkaloids isolated from plants of the Nitraria genus, focusing on their biosynthesis and discussing the resulting biomimetic chemistry in relevant cases. The scope is purposely limited to alkaloids derived at least to some extent from L-lysine, considering that most of these molecules have unique structures and are specific to the genus. Some of the biosynthetic pathways described are taken from the literature, but others are proposed here for the first time. The latter are mostly hypotheses justified by the fact that they are based on metabolic routes frequently encountered for other Nitraria alkaloids, and thus permit unification of the biosynthesis around common pivotal biosynthetic intermediates. Myrioneuron alkaloids are also presented as a newly discovered class with striking similarities to Nitraria alkaloids.