Non-Targeted Metabolomic Analysis of Arabidopsis thaliana (L.) Heynh: Metabolic Adaptive Responses to Stress Caused by N Starvation

As sessile organisms, plants develop the ability to respond and survive in changing environments. Such adaptive responses maximize phenotypic and metabolic fitness, allowing plants to adjust their growth and development. In this study, we analyzed the metabolic plasticity of Arabidopsis thaliana in response to nitrate deprivation by untargeted metabolomic analysis and using wild-type (WT) genotypes and the loss-of-function nia1/nia2 double mutant. Secondary metabolites were identified using seedlings grown on a hydroponic system supplemented with optimal or limiting concentrations of N (4 or 0.2 mM, respectively) and harvested at 15 and 30 days of age. Then, spectral libraries generated from shoots and roots in both ionization modes (ESI +/-) were compared. Totals of 3407 and 4521 spectral signals (m/z_rt) were obtained in the ESI+ and ESI- modes, respectively. Of these, approximately 50 and 65% were identified as differentially synthetized/accumulated. This led to the presumptive identification of 735 KEGG codes (metabolites) belonging to 79 metabolic pathways. The metabolic responses in the shoots and roots of WT genotypes at 4 mM of N favor the synthesis/accumulation of metabolites strongly related to growth. In contrast, for the nia1/nia2 double mutant (similar as the WT genotype at 0.2 mM N), metabolites identified as differentially synthetized/accumulated help cope with stress, regulating oxidative stress and preventing programmed cell death, meaning that metabolic responses under N starvation compromise growth to prioritize a defensive response.

Antioxidant Effect of the Ethyl Acetate Extract of Potentilla indica on Kidney Mitochondria of Streptozotocin-Induced Diabetic Rats

Diabetes mellitus (DM) is a metabolic disorder characterized by persistent hyperglycemia. This state may lead to an increase in oxidative stress, which contributes to the development of diabetes complications, including diabetic kidney disease. Potentilla indica is a traditional medicinal herb in Asia, employed in the treatment of several diseases, including DM. In this study, we investigated the antioxidant effect of the ethyl acetate extract of Potentilla indica both in vitro and on kidneys of streptozotocin-induced diabetic male rats. Firstly, phytochemicals were identified via UPLC-MS/MS, and their in vitro antioxidant capabilities were evaluated. Subsequently, male Wistar rats were assigned into four groups: normoglycemic control, diabetic control, normoglycemic treated with the extract, and diabetic treated with the extract. At the end of the treatment, fasting blood glucose (FBG) levels, creatinine, blood urea nitrogen (BUN), and uric acid were estimated. Furthermore, the kidneys were removed and utilized for the determination of mitochondrial reactive oxygen species (ROS) production, mitochondrial respiratory chain complex activities, mitochondrial lipid peroxidation, glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) activities. The in vitro findings showed that the major phytochemicals present in the extract were phenolic compounds, which exhibited a potent antioxidant activity. Moreover, the administration of the P. indica extract reduced creatinine and BUN levels, ROS production, and lipid peroxidation and improved mitochondrial respiratory chain complex activity and GSH-Px, SODk, and CAT activities when compared to the diabetic control group. In conclusion, our data suggest that the ethyl acetate extract of Potentilla indica possesses renoprotective effects by reducing oxidative stress on the kidneys of streptozotocin-induced diabetic male rats.

An Ethyl Acetate Extract of Eryngium carlinae Inflorescences Attenuates Oxidative Stress and Inflammation in the Liver of Streptozotocin-Induced Diabetic Rats

Secondary metabolites such as flavonoids are promising in the treatment of non-alcoholic fatty liver disease (NAFLD), which is one of the complications of diabetes due to oxidative stress and inflammation. Some plants, such as Eryngium carlinae, have been investigated regarding their medicinal properties in in vitro and in vivo assays, showing favorable results for the treatment of various diseases such as diabetes and obesity. The present study examined the antioxidant and anti-inflammatory effects of the phenolic compounds present in an ethyl acetate extract of the inflorescences of Eryngium carlinae on liver homogenates and mitochondria from streptozotocin (STZ)-induced diabetic rats. Phenolic compounds were identified and quantified by UHPLC-MS. In vitro assays were carried out to discover the antioxidant potential of the extract. Male Wistar rats were administered with a single intraperitoneal injection of STZ (45 mg/kg) and were given the ethyl acetate extract at a level of 30 mg/kg for 60 days. Phytochemical assays showed that the major constituents of the extract were flavonoids; in addition, the in vitro antioxidant activity was dose dependent with IC50 = 57.97 mg/mL and IC50 = 30.90 mg/mL in the DPPH and FRAP assays, respectively. Moreover, the oral administration of the ethyl acetate extract improved the effects of NAFLD, decreasing serum and liver triacylglycerides (TG) levels and oxidative stress markers and increasing the activity of the antioxidant enzymes. Likewise, it attenuated liver damage by decreasing the expression of NF-κB and iNOS, which lead to inflammation and liver damage. We hypothesize that solvent polarity and consequently chemical composition of the ethyl acetate extract of E. carlinae, exert the beneficial effects due to phenolic compounds. These results suggest that the phenolic compounds of the ethyl acetate extract of E. carlinae have antioxidant, anti-inflammatory, hypolipidemic, and hepatoprotective activity.

Chitosan coatings reduce fruit fly (Anastrepha obliqua) infestation and development of the fungus Colletotrichum gloeosporioides in Manila mangoes

BACKGROUND

Mangoes are tropical fruits appreciated worldwide but are extremely perishable, being susceptible to decay, pest infestation and fungal diseases. Using the flavorful and highly valued 'Manila' cultivar, we examined the effect of second-generation chitosan coatings on shelf-life, phenolic compound variation, phytohormones, pest infestation by fruit flies (Anastrepha obliqua) and anthracnose disease caused by the fungus Colletotrichum gloeosporioides.

RESULTS

We observed almost total elimination of A. obliqua eggs with 10 and 20 g L^-1 chitosan in diluted acetic acid and a five- to sixfold reduction in anthracnose damage. Treatment with 20 g L^-1 chitosan also extended the shelf-life. External (skin) and internal (pulp) discoloration processes were delayed. Fruit firmness was higher when compared with control and acetic acid treatments, and total soluble solids were lower in chitosan-treated fruit. Targeted and non-targeted metabolomics analyses on chitosan-coated fruit identified some phenolic compounds related to the tannin pathway. In addition, abscisic acid and jasmonic acid in the peel were downregulated in chitosan-coated mango peels. Both phytohormones and phenolic content may explain the reduced susceptibility of mangoes to anthracnose development and A. obliqua egg eclosion or larval development.

CONCLUSIONS

We conclude that chitosan coatings represent an effective postharvest treatment that significantly reduces anthracnose disease, inhibits A. obliqua egg eclosion and significantly extends 'Manila' mango shelf-life, a key factor currently inhibiting large-scale commercialization of this valuable fruit. © 2020 Society of Chemical Industry.

Integrated Analysis of the Transcriptome and Metabolome of Cecropia obtusifolia: A Plant with High Chlorogenic Acid Content Traditionally Used to Treat Diabetes Mellitus

This investigation cultured Cecropia obtusifolia cells in suspension to evaluate the effect of nitrate deficiency on the growth and production of chlorogenic acid (CGA), a secondary metabolite with hypoglycemic and hypolipidemic activity that acts directly on type 2 diabetes mellitus. Using cell cultures in suspension, a kinetics time course was established with six time points and four total nitrate concentrations. The metabolites of interest were quantified by high-performance liquid chromatography (HPLC), and the metabolome was analyzed using directed and nondirected approaches. Finally, using RNA-seq methodology, the first transcript collection for C. obtusifolia was generated. HPLC analysis detected CGA at all sampling points, while metabolomic analysis confirmed the identity of CGA and of precursors involved in its biosynthesis. Transcriptome analysis identified differentially expressed genes and enzymes involved in the biosynthetic pathway of CGA. C. obtusifolia probably expresses a key enzyme with bifunctional activity, the hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase and hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HQT/HCT), which recognizes shikimic acid or quinic acid as a substrate and incorporates either into one of the two routes responsible for CGA biosynthesis.

Metabolomic data of phenolic compounds from Acer negundo extracts

Phytochemical and metabolomic data were obtained for the most important phenolic compounds in ethanolic extracts from the endangered Acer negundo tree in Morelia, Michoacan. Samples of leaves and stems were subjected to ethanolic extraction with electric rotavapor. We developed a metabolomic analysis that encompassed the correlation between the leaf and stem extracts through principal component analysis. The data were obtained with an infinity Agilent ultrahigh resolution liquid chromatograph coupled to a Agilent triple quadrupole mass spectrometer. The protocol used was a dynamic MRM (Multiple Reaction Monitoring). Clustering result shown as heatmap (distance measure using euclidean, and clustering algorithm using ward.D).

Novel findings to the biosynthetic pathway of magnoflorine and taspine through transcriptomic and metabolomic analysis of Croton draco (Euphorbiaceae)

BACKGROUND

Croton draco is an arboreal species and its latex as well as some other parts of the plant, are traditionally used in the treatment of a wide range of ailments and diseases. Alkaloids, such as magnoflorine, prevent early atherosclerosis progression while taspine, an abundant constituent of latex, has been described as a wound-healer and antitumor-agent. Despite the great interest for these and other secondary metabolites, no omics resources existed for the species and the biosynthetic pathways of these alkaloids remain largely unknown.

RESULTS

To gain insights into the pathways involved in magnoflorine and taspine biosynthesis by C. draco and identify the key enzymes in these processes, we performed an integrated analysis of the transcriptome and metabolome in the major organs (roots, stem, leaves, inflorescences, and flowers) of this species. Transcript profiles were generated through high-throughput RNA-sequencing analysis while targeted and high resolution untargeted metabolomic profiling was also performed. The biosynthesis of these compounds appears to occur in the plant organs examined, but intermediaries may be translocated from the cells in which they are produced to other cells in which they accumulate.

CONCLUSIONS

Our results provide a framework to better understand magnoflorine and taspine biosynthesis in C. draco. In addition, we demonstrate the potential of multi-omics approaches to identify candidate genes involved in the biosynthetic pathways of interest.