1 H-NMR metabolomics profiling of recombinant tobacco plants holding a promoter of a sesquiterpene cyclase.

INTRODUCTION: Nicotiana tabacum is a plant model intensively used in the bio-engineering pharmaceutical industry as a platform to produce drugs and therapeutic agents. Currently, no information regarding the non-targeted metabolome of transgenic tobacco containing recombinant regulatory sequences is available. OBJECTIVE: To compare the proton nuclear magnetic resonance (1 H-NMR) metabolomics profiling of a recombinant Nicotiana tabacum strain containing a promoter of a sesquiterpene cyclase from Capsicum annuum driving GUS expression, versus wild-type samples. Methodology The non-targeted 1 H-NMR metabolome was obtained and processed by principal component analysis (PCA) and orthogonal projection to latent structures discriminant analysis (OPLS-DA). The differential metabolites were quantified by quantitative NMR. RESULTS: PCA and OPLS-DA revealed 37 metabolites including 16 discriminant compounds for transgenic samples. Ethanol (0.4 mg g-1 ), the main differential compound, was exclusively detected in transgenic tobacco; however, high levels of formate (0.28 mg g-1 ) and acetate (0.3 mg g-1 ) were simultaneously observed in the same group of samples. Cembratriene-4,6-diol, an antitumour and neuroprotective compound, and capsidiol, a known phytoalexin, increased by about 30% in transgenic samples. In addition, the endogenous levels of the antioxidant caffeoylquinic acid isomers increased by 50% in comparison to those of wild-type tobaccos. CONCLUSION: Our results support the occurrence of metabolic differences between wild type and transgenic tobacco containing a promoter of a Capsicum sesquiterpene cyclase gene. Interestingly, the recombinant transgenic strain studied accumulated high amounts of added value compounds with biological activity.

NMR-based metabonomic analysis of normal rat urine and faeces in response to (±)-venlafaxine treatment.

(±)-Venlafaxine, a bicyclic antidepressant of the serotonin-norepinephrine reuptake inhibitor (SNRI) class, is prescribed for the treatment of depression and anxiety disorders. As is the case with other antidepressants, its precise mechanisms of action are still unknown. Pharmacometabonomic approaches allow for the detection of diverse metabolites, unlike classic methods for analysing drug interaction based on single metabolites and linear pathways. This provides a global view of the state of homeostasis during treatment and an insight into the mechanisms of action of a drug. Accordingly, the final outcome of treatment is characterised by the network of reactome pathways derived from the on-target and off-target effects of the drug. Regarding antidepressants, the drug network may be located in the gut-microbiome-brain-liver-kidney-immune-cardiovascular system axis (GMBLKICA), implying that neurotransmitters participate as signalling molecules in bidirectional communication. If their bioavailability is increased, this communication and the state of homeostasis may be disrupted. With a pharmacometabonomic approach using NMR in combination with different chemometric methods, a determination was made of subtle changes in the metabolic profile (metabotype) of urine and faeces in normal Wistar rats following a single administration of pharmacological doses of (±)-venlafaxine hydrochloride. Based on the drug-response metabotypes observed, (±)-venlafaxine had effects on gut microbial co-metabolites and osmolytes. Hence, it can be hypothesized that bidirectional communication in the multiorgan axis was perturbed by this drug, and very likely by its active metabolite, (±)-desvenlafaxine. This disrupted signalling could be related not only to therapeutic and adverse effects, but also to the lag period in treatment response.