LC-MS and NMR Based Plant Metabolomics: A Comprehensive Phytochemical Investigation of Symphytum anatolicum.

The application of metabolomics to the study of plants is growing because of the current development of analytical techniques. The most commonly used analytical technology driving plant metabolomics studies is Mass Spectrometry (MS) coupled to liquid chromatography (LC). In recent years, Nuclear Magnetic Resonance (NMR) spectroscopy, not requiring a previous chromatographic separation, has been receiving growing attention for metabolite fingerprinting of natural extracts. Herein, an integrated LC-MS and 1H NMR metabolomic approach provided a comprehensive phytochemical characterization of Symphytum anatolicum whole plant, taking into account both primary and specialized metabolites. Moreover, the NMR analyses provided direct quantitative information. Species belonging to the Symphytum genus, known as comfrey, have shown several biological activities including anti-inflammatory, analgesic, hepatoprotective, antifungal, and antibacterial. The LC-MS profile showed the presence of 21 main specialized metabolites, belonging to the classes of flavonoids, phenylpropanoids, salvianols, and oxylipins. The 1H NMR spectrum revealed the occurrence of metabolites including organic acids, phenolics, flavonoids, sugars, and amino acids. A quantitative analysis of these metabolites was performed and their concentration was obtained with respect to the known concentration of TSP, by means of the software package Chenomx which allows quantification of individual components in the NMR spectra. Furthermore, the phenolic content, antioxidant activity, glucosidase, and tyrosinase inhibitory activity of S. anatolicum extract were evaluated. The resulting bioactivity profile suggests how S. anatolicum represents a source of metabolites with health-promoting activity.

Scabiosa atropurpurea: A rich source of iridoids with α-glucosidase inhibitory activity evaluated by in vitro and in silico studies.

Scabiosa atropurpurea L. subsp. maritima (L.) Arc. (Caprifoliaceae) is a plant widely distributed in the Mediterranean region and represented by 32 taxa in the flora of Turkey. In the present study, an in-depth phytochemical investigation of S. atropurpurea methanol extract of the whole plant was carried out using a combination of LC-ESI-FT-MS and NMR analysis. This approach allowed the isolation and structural elucidation of 28 compounds: 17 iridoids, 7 flavonoids, and 4 phenolic acids. Among these compounds, three previously unreported iridoids named secologanin-methyl-hemiacetal, atropurpurin A, and atropurpurin B were identified. The methanol extract of S. atropurpurea was assayed for its antioxidant and antihyperglycemic activity, showing a potent α-glucosidase inhibitory activity (IC50 = 100 µg/mL), higher than that exerted by acarbose (IC50 = 196 µg/mL), used as the positive control. Thus, the most abundant iridoids were selected to be tested for their antihyperglycemic activity, and molecular docking experiments were carried out to assess the possibility for selected compounds to form complexes with α-glucosidase enzyme active site.

Garcinia mangostana L. fruits and derived food supplements: Identification and quantitative determination of bioactive xanthones by NMR analysis.

Mangosteen (Garcinia mangostana L.), known as "the queen of fruits", is one of the most praised tropical fruit due to its delicious taste. In the last years, the use of mangosteen in functional products has been increasing, mainly in food beverages and nutraceutical formulations due to its biological activities related to the content of xanthones. The quantitative Nuclear Magnetic Resonance (qNMR) analysis, a rapid and accurate method used for simultaneous quantification of plant metabolites, was here employed to determine the amount of bioactive xanthones in the extracts of G. mangostana arils and shells obtained by using solvent of increasing polarity along with ''eco-friendly'' solvents like ethanol and ethanol-water. Furthermore, the content of xanthones was compared with that occurring in four selected commercial food supplements, among which tablets and capsules, and two fruit juices, based on mangosteen. Quantitative results highlighted a significant variability: the extracts of the shells displayed a higher amount of bioactive xanthones than those of the arils, in particular, of γ-mangostin and α-mangostin, while ß-mangostin, demethylcalabaxanthone, mangostanin, 8-deoxygartanin occurred in higher amounts in arils. A certain variability in the amount of biologically active xanthones (i.e. α-mangostin and γ-mangostin) could be observed in commercial food supplements.

Phytochemical investigation of Scabiosa sicula guided by a preliminary HPLC-ESIMSn profiling.

The genus Scabiosa (Caprifoliaceae) is represented by 80 species, widely used as medicinal plants for their positive effects on human diseases. On the basis of the interesting biological activity shown by Scabiosa spp., the phytochemical investigation of Scabiosa sicula L., never investigated before, was carried out. An initial LC-MS profile of the MeOH extract of S. sicula whole plant guided the isolation of 34 compounds, of which the structures were unambiguously elucidated by NMR analysis as phenolic compounds and triterpene saponins, among which eight undescribed compounds. Moreover, the total phenolic content of S. sicula methanol extract has been evaluated. On the basis of the pharmacological activities reported for Scabiosa species the antioxidant activity of the methanol extract was tested by TEAC and DPPH assays. Finally, the α-glucosidase inhibitory activity of the methanol extract was assayed, showing an IC50 value (49 µg/mL) comparable to that exerted by acarbose (90 µg/mL), used as positive control.

Chemical constituents of Silene montbretiana.

A new steroidal glycoside, 3- O-ß-d-glucopyranosyl-3ß,25-dihydroxy-5ß-cholest-7-en-6-one 25- O-ß-d-glucopyranoside (1), together with six known steroidal derivatives (2-7), one cerebroside (8) and one flavonoid (9) were isolated from Silene montbretiana Boiss (Caryophyllaceae), a perennial herb growing mainly in the Middle and East Anatolia, Azerbaijan, Iran, and Turkey. Their structures were established by the extensive use of 1D and 2D NMR experiments along with ESI-MS analyses. The cytotoxicity against the cancer A549 (human alveolar basal carcinoma) and Hela (human epitheloid cervix carcinoma) cell lines has been evaluated. None of the tested compounds, in a range of concentrations between 12.5 and 100 µM, caused a significant reduction of the cell number.

Bilateral Choroidal Detachment Induced by Unilateral Application of a Fixed Combination of Topical Timolol Maleate and Brinzolamide.

We describe a 66-year-old man who developed bilateral choroidal detachment that was induced by unilateral topical administration of a fixed combination of 1% brinzolamide and 0.5% timolol maleate the day after an uneventful phacoemulsification surgery and intraocular lens implantation involving his right eye. We believe that the reaction was an idiosyncratic reaction, most likely against brinzolamide. The condition improved rapidly after the cessation of the fixed combination of brinzolamide and timolol maleate and treatment with 1% topical prednisolone acetate every hour and 1% cyclopentolate twice a day bilaterally. Although there are several similar cases involving choroidal detachment after oral acetazolamide and topical dorzolamide treatment mentioned in the literature, the present case is the first case report involving bilateral choroidal detachment after topical treatment with brinzolamide.