Recent Progress in Amaryllidaceae Biotechnology

Abstract

Plants belonging to the monocotyledonous Amaryllidaceae family include about 1100 species divided among 75 genera. They are well known as medicinal and ornamental plants, producing pharmaceutically important alkaloids, the most intensively investigated of which are galanthamine and lycorine. Amaryllidaceae alkaloids possess various biological activities, the most important one being their anti-acetylcholinesterase activity, used for the treatment of Alzheimer's disease. Due to increased demand for Amaryllidaceae alkaloids (mainly galanthamine) and the limited availability of plant sources, in vitro culture technology has attracted the attention of researchers as a prospective alternative for their sustainable production. Plant in vitro systems have been extensively used for continuous, sustainable, and economically viable production of bioactive plant secondary metabolites. Over the past two decades, a significant success has been demonstrated in the development of in vitro systems synthesizing Amaryllidaceae alkaloids. The present review discusses the state of the art of in vitro Amaryllidaceae alkaloids production, summarizing recently documented plant in vitro systems producing them, as well as the authors' point of view on the development of biotechnological production processes with a focus on the future prospects of in vitro culture technology for the commercial production of these valuable alkaloids.

Keywords: Amaryllidaceae; alkaloids; bioreactors; galanthamine; plant in vitro systems.

Figure 1

Integrated approach to biotechnological production of Amaryllidaceae alkaloids.

Figure 2

Schematic presentation of the proposed biosynthetic pathway of Amaryllidaceae alkaloid biosynthesis in plants. The five stages of the pathway are presented in different colors. The dashed arrows represent multiple reactions. The bold grey arrows indicate specialized pathways leading to the biosynthesis of different types of Amaryllidaceae alkaloids. The known enzymes are written in bold red font. Abbreviations: CM—chorismate mutase; PPA-AT—prephenate aminotransferase; GOGAT—glutamine oxoglutarate aminotransferase; ADH—arogenate dehydrogenase; ADT—arogenate dehydratase; PAL—phenylalanine ammonia-lyase; C4H—cinnamate-4-hydroxylase; C3H—4-coumarate 3-hydroxylase; 4CL—4-coumarate-CoA ligase; HCT—hydroxycinnamoyltransferase; TYDC—tyrosine decarboxylase; NBS—norbelladine synthase; NR—noroxomaritidine reductase; N4OMT—norbelladine 4′-O-methyltransferase; CYP96T1—cytochrome P450 96T1 monooxygenase.