Biosynthetic origin of the isoprene units in chromenes of Piper aduncum (Piperaceae)

Abstract

Estudos metabólicos envolvendo a incorporação de D-glicose-[1-13 C] em folhas dePiper aduncum (Piperaceae) mostraram que as vias do mevalonato (MVA) e da triose-piruvato (MEP) estão envolvidas na biossíntese da unidade isoprênica presente no 2,2-dimetil-2H-1-cromeno-6-carboxilato de metila (1) e no 2,2-dimetil-8-(3'-metil-2'-butenil)-2H-1-cromeno-6-carboxilato de metila (2). O padrão de incorporação dos carbonos marcados com D-glicose-[1-13 C] destes cromenos foram determinados através de espectroscopia de RMN de 13 C quantitativo. Os resultados confirmaram que o compartimento biossintético de 1 e 2 pode ser o plastídio e/ou citosol, ou possivelmente um compartimento adicional, como o espaço entre a membrana e o plastídio.Metabolic studies involving the incorporation of [1-13 C]-D-glucose into intact leaves of Piper aduncum (Piperaceae) have indicated that both the mevalonate (MVA) and the pyruvate-triose (MEP) non-mevalonate pathways are implicated in the biosynthesis of isoprene moieties present in methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (1) and methyl 2,2-dimethyl-8-(3'-methyl-2'-butenyl)-2H-1-chromene-6-carboxylate (2). The pattern of incorporation of label from [1- 13C]-D-glucose into these chromenes was determined by quantitative 13 C NMR spectroscopy. The results confirmed that biosynthetic compartment of 1 and 2 could either be the plastid and/ or the cytosol or, possibly, an additional compartment such as the plastid inter-membrane space. Keywords:Piper aduncum, chromenes, [1-13 C]-D-glucose, mevalonate pathway, 2-C-methyl-D-erythritol-4-phosphate pathway IntroductionThe isoprenoids constitute a large class of natural products comprising more than 29,000 compounds. 1 In higher plants, isoprenoids play essential roles in membrane structure (sterols), redox chemistry (plastoquinones, ubiquinones), growth regulation (gibberellins, cytokinins, brassinosteroids and abscisic acid), defence mechanisms (phytoalexins) and free radical scavenging (carotenoids and tocopherols). 2 The common building blocks of all isoprenoids, the so-called 'isoprene units', is derived from isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The biosynthesis of IPP can proceed via two different pathways, namely the longestablished mevalonic acid (MVA) and the 2-C-methyl-D-erythritol-4-phosphate (MEP) pathways, the reaction sequence of which has been characterized. 3 In plants, the MEP pathway appears generally operative for formation of monoterpenoids, diterpenoids, phytols and carotenoids. [4][5][6] The key regulatory step of the MVA pathway involves reduction of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) to mevalonate, with this being catalysed by the cytosolic enzyme HMG-CoA reductase (HMGR). Plastidic IPP is derived, however, from MEP formed via the condensation of pyruvate and glyceraldehyde-3-phosphate (G3P) catalysed by 1-deoxy-D-xylulose-5-phosphate synthase (DXS). 2,6 The two pathways to IPP are thus compartmentalized in the cytosol and the plastid, respectively. However, they may function in the for...

The Combined Use of Proteomics and Transcriptomics Reveals a Complex Secondary Metabolite Network in Peperomia obtusifolia

“…It was confirmed by the identification of all the enzymes involved in the production of IPP and DMAPP from both pathways (Figure S9, Supporting Information). This result is in accordance with studies that have suggested the simultaneous operation of these two separate biosynthesis pathways in Piperaceae. , …”

“…This result is in accordance with studies that have suggested the simultaneous operation of these two separate biosynthesis pathways in Piperaceae. 23,24 As observed in the proteome, the transcriptome analysis identified a large number of proteins involved in terpene biosynthesis ( Figure S9−S12, Supporting Information). Important enzymes such as geranyl diphosphate, farnesyl diphosphate, geranylgeranyl diphosphate, and squalene synthases were identified, along with a number of prenyltransferases.…”

Análises filogenéticas e estudo do metabolismo fenilpropanoidico em espécies de Piper

“…O metabolismo secundário da família Piperaceae é caracterizado pela ocorrência de produtos predominantemente oriundos de biossíntese mista (chiquimato/acetato), que resultam na produção de amidas (da Silva et al, 2002;Marques et al, 2008b;Marques et al, 2007;Navickiene et al, 2003;Scott et al, 2008), fenilpropanoides e lignanas (Benevides et al, 1999;Gottlieb et al, 1995;Kato and Furlan, 2007;Martins et al, 2000;Martins et al, 2003;Parmar et al, 1997), ácidos benzóicos (Freitas et al, 2009;Friedrich et al, 2005;Lago et al, 2009;Lago et al, 2004;Morandim et al, 2009), cromenos (Baldoqui et al, 1999;Leite et al, 2007;Lopes et al, 2007;Morandim et al, 2009;Morandim et al, 2005) e alquenilfenóis (Orjala et al, 1998;Parmar et al, 1997;Valdivia et al, 2008). Muitos desses apresentam pronunciadas atividades biológicas, as quais se destacam as atividades antifúngica (Lago et al, 2004;Marques et al, 2007), antiparasitária (Martins et al, 2003;Rapado et al, 2013) e antitumoral (Bezerra et al, 2008a;Bezerra et al, 2008b;Bezerra et al, 2008c).…”

“…Para avaliação da consistência dos clados foi empregado o método bootstrap (Felsenstein, 1985). (Baldoqui et al, 1999;Lago et al, 2009;Morandim et al, 2005;Moreira et al, 1998;Navickiene et al, 2006;Orjala et al, 1993a;Orjala et al, 1993b); (Batista et al, 2008;Leite et al, 2007;Parmar et al, 1997;Parmar et al, 1998) P. aequale -+ ---- (Maxwell et al, 1999) P. amalago + + ---- (Achenbach et al, 1986;Parmar et al, 1997) P P. arboricola + ----- (He, 1981;Ho, 1981) P. argyrophylum + + ---- (Singh et al, 1996) P. argyrophylum + + ---- (Singh et al, 1996) P. arieianum ----+ - (Green et al, 1999) Tabela 4. Continuação.…”