Analysis of plant secondary metabolism using stable isotope‐labelled precursors

Special issue of Phytochemical Analysis on NMR-based analytical techniques. open access articleIntroduction Analysis of biochemical pathways typically involves feeding a labelled precursor to an organism, and then monitoring the metabolic fate of the label. Initial studies used radioisotopes as a label and then monitored radioactivity in the metabolic products. As analytical equipment improved and became more widely available, preference shifted the use stable ‘heavy’ isotopes like deuterium (2H)‐, carbon‐13 (13C)‐ and nitrogen‐15 (15N)‐atoms as labels. Incorporation of the labels could be monitored by mass spectrometry (MS), as part of a hyphenated tool kits, e.g. Liquid chromatography (LC)–MS, gas chromatography (GC)–MS, LC–MS/MS. MS offers great sensitivity but the exact location of an isotope label in a given metabolite cannot always be unambiguously established. Nuclear magnetic resonance (NMR) can also be used to pick up signals of stable isotopes, and can give information on the precise location of incorporated label in the metabolites. However, the detection limit for NMR is quite a bit higher than that for MS. Objectives A number of experiments involving feeding stable isotope‐labelled precursors followed by NMR analysis of the metabolites is presented. The aim is to highlight the use of NMR analysis in identifying the precise fate of isotope labels after precursor feeding experiments. As more powerful NMR equipment becomes available, applications as described in this review may become more commonplace in pathway analysis. Conclusion and Prospects NMR is a widely accepted tool for chemical structure elucidation and is now increasingly used in metabolomic studies. In addition, NMR, combined with stable isotope feeding, should be considered as a tool for metabolic flux analyses

Phytochemical Analysis, Antispasmodic, Myorelaxant, and Antioxidant Effect of Dysphania ambrosioides (L.) Mosyakin and Clemants Flower Hydroethanolic Extracts and Its Chloroform and Ethyl Acetate Fractions

Dysphania ambrosioides (L.) Mosyakin and Clemants is an annual or ephemeral perennial herb used traditionally in the Mediterranean region in folk medicine to treat various illnesses, including those related to the digestive system. This study aims to assess the antispasmodic, myorelaxant, and antioxidant effects of D. ambrosioides flower hydroethanolic extract and its chloroform and ethyl acetate fractions in a comparative study to evaluate the result of the extraction type on the potential activity of the extract. Both rat and rabbit jejunum were used to evaluate the antispasmodic and myorelaxant effect, while the antioxidant effect was evaluated using DPPH, a ferric reducing power assay, and a beta-carotene bleaching test. LC/MS-MS analysis was carried out to reveal the composition of the different types of extract. Following the results, the hydroethanolic extract showed a significant myorelaxant effect (IC50 = 0.39 ± 0.01 mg/mL). Moreover, it was shown that the hydroethanolic extract demonstrated the best antispasmodic activity (IC50 = 0.51 ± 0.05 mg/mL), followed by the ethyl acetate (IC50 = 4.05 ± 0.32 mg/mL) and chloroform (IC50 = 4.34 ± 0.45 mg/mL) fractions. The antioxidant tests showed that the hydroethanolic extract demonstrated high antioxidant activity, followed by the ethyl acetate and chloroform fractions. The LC/MS-MS analysis indicates that the plant extract was rich in flavonoids, to which the extract activity has been attributed. This study supports the traditional use of this plant to treat digestive problems, especially those with spasms

Thidiazuron-induced efficient biosynthesis of phenolic compounds in callus culture of Ipomoea turbinata Lagasca and Segura

International audienceIpomoea turbinata Lagasca and Segura (Purple Moonflower) belongs to the largest flowering genus Ipomoea in the Convolvulaceae family. Ipomoea turbinata has not been previously explored for its in vitro potential. This is the first study focused on thidiazuron-induced callus culture for efficient biosynthesis of commercially important phenolic compounds in this plant species. Among the two plant growth regulators tested on leaf, stem, and root explants, 5 mg L−1 thidiazuron (TDZ) induced the highest biomass accumulation (61.4 g L−1 fresh weight, 6.3 g L−1 dry weight) in leaf-derived callus cultures after 5 wk of culture. The highest total phenolic and flavonoid contents recorded were 9.04 mg g−1 and 1.16 mg g−1, respectively, in optimized callus cultures. High-performance liquid chromatography analysis indicated high levels of pharmacologically important anticancer compounds such as chlorogenic acid (13.48 mg g−1), arctigenin (11.67 mg g−1), quercetin (6.19 mg g−1), and kaempferol (5.48 mg g−1), along with other phenolic acids. Furthermore, the antioxidant activity was also evaluated, and leaf-derived callus culture displayed a maximum of 62.6% antioxidant potential. The induction of improved biomass accumulation in callus culture and the production of multipotent bioactive metabolites shows the potential of the multifunctional thidiazuron hormone as an efficient elicitation tool in callus culture of I. turbinata