Phytochemical investigation of Volutaria lippii and evaluation of the antioxidant activity.

Volutaria lippii (L.) Cass. ex Maire, syn. Centaurea lippii (L.), (Asteraceae) is a plant from the central region of Algeria, considerably distributed in all Mediterranean areas. Herein, the antioxidant activity of the three derived fractions [chloroform (CHCl3), ethyl acetate (EtOAc) and n-butanol (n-BuOH)] of the 70% methanol extract of the aerial parts (leaves and flowers), was assessed by using CUPRAC, ABTS, DPPH free radical scavenging, and ß-carotene bleaching methods. The results obtained allowed to guide the fractionation of EtOAc and n-BuOH fractions by CC followed by purification by TLC and reverse phase HPLC. A guaianolide glucoside, 3ß-hydroxy-11ß,13-dihydrodehydrocostuslactone 8α-O-(6'-acetyl-ß-glucopyranoside) (1), never reported in the literature, was isolated together with other known compounds (2-14). Their structures were elucidated by the extensive use of 1 D- and 2 D-NMR experiments along with ESI-MS analyses and with comparison with literature data.

Metabolite profiling and antioxidant activity of the polar fraction of Italian almonds (Toritto and Avola): Analysis of seeds, skins, and blanching water.

The health benefits of almonds along with their ability to prevent atheroschlerosis as well as cardiovascular and diabetes risks are well known. Previous works were focused mainly on the lipid fraction, thus a lack of information about the polar constituents still persists. In order to provide deeper insight into the chemical composition of almond, the polar fraction of Italian almond cultivars (Toritto and Avola) was investigated. The MeOH extract of the Toritto cultivar was submitted to LC-ESI-(HR)MS/MS experiments, highlighting the occurrence of several compounds, mainly cyanogenic glycosides, glycosylated flavonoids, proanthocyanidins, and a diterpene glycoside. EtOH and EtOH:H2O solution were also employed for extractions, resulting selective for flavonoids and proanthocyanidins, while cyanogenic glycosides were mainly detected in EtOH:H2O extract. Almonds were also blanched to afford skins and blanching water which were analyzed by LC-ESI-(HR)MS/MS experiments in order to establish the source of the identified compounds. Cyanogenic glycosides were detected in the peeled almonds, while flavonoids and proanthocyanidins were detected in almond skins and blanching water. The LC-ESI-(HR)MS/MS analyses of the almonds of the Avola cvs (Fascionello, Pizzuta and Romana) were compared with those of the Toritto cv., showing clear differences in their metabolome, probably due to the different growing conditions. Finally, total phenolic content and radical scavenging activity of the extracts and blanching waters were evaluated by Folin-Ciocalteu assay and by DPPH and ABTS+ assays, highlighting interesting antioxidant properties possessed by almond skins and blanching water, suggesting their potential employment in pharmaceutical, cosmetic and nutraceutical formulations.

Plant Specialized Metabolites in Hazelnut (Corylus avellana) Kernel and Byproducts: An Update on Chemistry, Biological Activity, and Analytical Aspects.

Corylus avellana (hazelnut) is one of the most popular tree nuts on a worldwide basis. The main products of C. avellana are kernels, a nutritious food, with a high content of healthy lipids, contained in a hard shell. In recent years, along with the ongoing research carried out on hazelnut kernels, a growing interest has been addressed to the hazelnut byproducts including hazelnut skin, hazelnut hard shell, and hazelnut green leafy cover as well as hazelnut tree leaf. These byproducts deriving from the roasting, cracking, shelling/hulling, and harvesting processes have been found as a source of "phytochemicals" with biological activity. The aim of this review is to provide a comprehensive and critical update on the chemistry and biological activity of specialized metabolites occurring in hazelnut kernels and byproducts. Phenolics are the most abundant phytochemicals not only in the kernels, but also in other processing byproducts. Attention has been also devoted to taxane derivatives isolated from C. avellana leaves. An overview on the biological activity, mainly antioxidant, antiproliferative, and antimicrobial along with less common biological effects, has been provided, contributing to highlight C. avellana as a source of bioactive phytochemicals with the potential to exert beneficial effects on human health. Finally, analytical techniques for the quali-quantitative analysis of specialized metabolites occurring in the different parts of C. avellana have been reviewed.

HR-LC-ESI-Orbitrap-MS based metabolite profiling of Prunus dulcis Mill. (Italian cultivars Toritto and Avola) husks and evaluation of antioxidant activity.

INTRODUCTION: Prunus dulcis Mill. is a plant cultivated for the production of its edible seeds, known as sweet almonds. In the last decades almond demand has highly increased due to their wide use in the industrial manufacturing of almond-based foods; this has led to a huge production of waste materials, mainly corresponding to shells and husks. OBJECTIVE: To achieve a deeper understanding of the chemical composition of almond husks with the aim of exploring these byproducts as a source of bioactives to be used in nutraceutical and cosmetic formulations. METHODS: Methanol, ethanol and ethanol-water extracts of the almond husks were analysed by high-resolution liquid chromatography electrospray ionisation Orbitrap mass spectrometry (HR-LC-ESI-Orbitrap-MS) in negative ion mode. Tandem mass spectrometry (MS/MS) data were acquired by using the Data-Dependent Scan experiment, allowing the precursor ion to be selected as the most intense peak during LC-MS analyses. Nuclear magnetic resonance (NMR) experiments were performed on a Bruker DRX-600 spectrometer. Folin-Ciocalteu, DPPH• (2,2-diphenyl-1-picrylhydrazyl) and TEAC (Trolox equivalent antioxidant capacity) assays were employed to determine the total phenolic content and the radical scavenging activity of the extracts. RESULTS: The LC-MS/MS analysis of the methanol extract guided the isolation of phloroglucinol derivatives, flavonoids and terpenes. Eco-friendly extraction methods showed to be selective in extracting flavonoids while the comparison of the LC-MS profiles of the Italian cultivars Toritto and Avola showed significant differences, confirming how different growing conditions may influence the metabolome of a plant species. CONCLUSION: This study led to a deeper insight into the chemical constituents of almond husks and showed how the eco-friendly extraction resulted in an effective method to obtain extracts rich in antioxidant sources.

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.

Sesquiterpene lactones from Centaurea rhizantha C.A. Meyer.

Two new sesquiterpene lactones, rhizantholide A (1) and rhizantholide B (2), together with five known compounds (3-7) have been isolated from the aerial parts of Centaurea rhizantha (Asteraceae). Sesquiterpene lactones belong to guaianolide class, and rhizantholide B is a rare guaianolide characterized by a free primary alcoholic function at C-10 along with a 3ß,10ß-epoxy function. Their structures have been established on the basis of 1D and 2D NMR experiments, as well as HR-ESIMS. The antimicrobial activity of compounds 1-7 has been evaluated against Gram-positive and Gram-negative strains. Only deacylcynaropicrin 8-O-[3'-hydroxy-2'-methylpropionate] (5) showed moderate antibacterial activity against Staphylococcus aureus with a MIC/MBC value of 500 µg/mL. All isolated compounds have been also evaluated for their cytotoxic activities against cancer cells. Among them, compound 5 showed the highest cytotoxic activity with IC50 values in the range 5.02-16.76 µg/mL.

Metabolomics and antioxidant activity of the leaves of Prunus dulcis Mill. (Italian cvs. Toritto and Avola).

Prunus dulcis leaves have been reported to exert some biological activity, in particular potent free radical-scavenging capacity, but so far there is limited information on their chemical composition. With the aim to achieve deep insight on the chemical constituents of the leaves of P. dulcis cultivars "Toritto" and "Avola", the most appreciated in Italy, an approach based on liquid chromatography-mass spectrometry (LC-MS) combined with isolation and structure elucidation of pure compounds by Nuclear Magnetic Resonance (NMR) analysis was carried out. Results allowed to detect in cv. Toritto leaves phenolics, terpenoids and a cyanogenic glycoside. Successively, various solvent systems were chosen to afford different extracts and an approach based on principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) from LC-MS data sets highlighted eco-friendly methods as selective in extracting phenolics and glycosides. Comparison of LC-MS profiles of the MeOH extracts of cv. Toritto and cvs. Avola (Pizzuta, Fascionello and Romana) leaves and evaluation of their phenolic contents and antioxidant activity were also carried out.

Quali-quantitative analysis of the phenolic fraction of the flowers of Corylus avellana, source of the Italian PGI product "Nocciola di Giffoni": Isolation of antioxidant diarylheptanoids.

There is only limited information available on the chemical composition of the non-edible parts of Corylus avellana, source of the Italian PGI product "Nocciola di Giffoni" (hazelnut). An initial LC-MS profile of the methanolic extract of the male flowers of C. avellana, cultivar 'Tonda di Giffoni' led to the isolation of 12 compounds, of which the structures were elucidated by NMR spectroscopy. These were identified as three previously undescribed diarylheptanoids, named giffonins Q-S, along with nine known compounds. Furthermore, the quantitative determination of the main compounds occurring in the methanolic extract of C. avellana flowers was carried out by an analytical approach based on LC-ESI(QqQ)MS, using the Multiple Reaction Monitoring (MRM) experiment. In order to explore the antioxidant ability of C. avellana flowers, the methanolic extract and the isolated compounds were evaluated for their inhibitory effects on human plasma lipid peroxidation induced by H2O2 and H2O2/Fe(2+), by measuring the concentration of TBARS.