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Publications
Piper nigrum L. (black and white peppercorn) is one of the most common culinary spices used worldwide. The current study aims to dissect pepper metabolome using 1H-NMR targeting of its major primary and secondary metabolites. Eighteen metabolites were identified with piperine detected in black and white pepper at 20.2 and 23.9 mg mg−1, respectively. Aroma profiling using HS-SPME coupled to GC-MS analysis and in the context of autoclave treatment led to the detection of a total of 52 volatiles with an abundance of b-caryophyllene at 82% and 59% in black and white pepper, respectively. Autoclaving of black and white pepper revealed improvement of pepper aroma as manifested by an increase in oxygenated compounds\' level. In vitro remote antimicrobial activity against food-borne Gram-positive and Gram-negative bacteria revealed the highest activity against P. aeruginosa (VP-MIC 16.4 and 12.9 mg mL−1) and a direct effect against Enterobacter cloacae at ca. 11.6 mg mL−1 for both white and black pepper.
Publications
For several sesquiterpene lactones (STLs) found in Asteraceae plants, very interesting biomedical activities have been demonstrated. Chicory roots accumulate the guaianolide STLs 8-deoxylactucin, lactucin, and lactucopicrin predominantly in oxalated forms in the latex. In this work, a supercritical fluid extract fraction of chicory STLs containing 8-deoxylactucin and 11β,13-dihydro-8-deoxylactucin was shown to have anti-inflammatory activity in an inflamed intestinal mucosa model. To increase the accumulation of these two compounds in chicory taproots, the lactucin synthase that takes 8-deoxylactucin as the substrate for the regiospecific hydroxylation to generate lactucin needs to be inactivated. Three candidate cytochrome P450 enzymes of the CYP71 clan were identified in chicory. Their targeted inactivation using the CRISPR/Cas9 approach identified CYP71DD33 to have lactucin synthase activity. The analysis of the terpene profile of the taproots of plants with edits in CYP71DD33 revealed a nearly complete elimination of the endogenous chicory STLs lactucin and lactucopicrin and their corresponding oxalates. Indeed, in the same lines, the interruption of biosynthesis resulted in a strong increase of 8-deoxylactucin and its derivatives. The enzyme activity of CYP71DD33 to convert 8-deoxylactucin to lactucin was additionally demonstrated in vitro using yeast microsome assays. The identified chicory lactucin synthase gene is predominantly expressed in the chicory latex, indicating that the late steps in the STL biosynthesis take place in the latex. This study contributes to further elucidation of the STL pathway in chicory and shows that root chicory can be positioned as a crop from which different health products can be extracted.
Publications
Balanites aegyptiaca (L.) Delile (Zygophyllaceae), also known as the desert date, is an edible fruit-producing tree popular for its nutritional and several health benefits. In this study, multi-targeted comparative metabolic profiling and fingerprinting approaches were conducted for the assessment of the nutrient primary and secondary metabolite heterogeneity in different parts, such as leaves, stems, seeds, unripe, and ripe fruits of B. aegyptiaca using nuclear magnetic resonance (NMR), ultra-performance liquid chromatography (UPLC-MS), and gas chromatography mass-spectrometry (GC-MS) based metabolomics coupled to multivariate analyses and in relation to its cytotoxic activities. NMR-based metabolomic study identified and quantified 15 major primary and secondary metabolites belonging to alkaloids, saponins, flavonoids, sugars, and amino and fatty acids. Principal component analysis (PCA) of the NMR dataset revealed α-glucose, sucrose, and isorhamnetin as markers for fruit and stem and unsaturated fatty acids for predominated seeds. Orthogonal projections to latent structure discriminant analysis (OPLS-DA) revealed trigonelline as a major distinctive metabolite in the immature fruit and isorhamnetin as a major distinct marker in the mature fruit. UPLC-MS/MS analysis using feature-based molecular networks revealed diverse chemical classes viz. steroidal saponins, N-containing metabolites, phenolics, fatty acids, and lipids as the constitutive metabolome in Balanites. Gas chromatography-mass spectroscopy (GC-MS) profiling of primary metabolites led to the detection of 135 peaks belonging to sugars, fatty acids/esters, amino acids, nitrogenous, and organic acids. Monosaccharides were detected at much higher levels in ripe fruit and disaccharides in predominate unripe fruits, whereas B. aegyptiaca vegetative parts (leaves and stem) were rich in amino acids and fatty acids. The antidiabetic compounds, viz, nicotinic acid, and trigonelline, were detected in all parts especially unripe fruit in addition to the sugar alcohol D-pinitol for the first time providing novel evidence for B. aegyptiaca use in diabetes. In vitro cytotoxic activity revealed the potential efficacy of immature fruit and seeds as cytotoxic agents against human prostate cancer (PC3) and human colorectal cancer (HCT-116) cell lines. Collectively, such detailed profiling of parts provides novel evidence for B. aegyptiaca medicinal uses.
Publications
Late blight, caused by the oomycete Phytophthora infestans, is economically the most important foliar disease of potato. To assess the importance of the leaf surface, as the site of the first encounter of pathogen and host, we performed untargeted profiling by liquid chromatography–mass spectrometry of leaf surface metabolites of the susceptible cultivated potato Solanum tuberosum and the resistant wild potato species Solanum bulbocastanum. Hydroxycinnamic acid amides, typical phytoalexins of potato, were abundant on the surface of S. tuberosum, but not on S. bulbocastanum. One of the metabolites accumulating on the surface of the wild potato was identified as lysophosphatidylcholine carrying heptadecenoic acid, LPC17:1. In vitro assays revealed that both spore germination and mycelial growth of P. infestans were efficiently inhibited by LPC17:1, suggesting that leaf surface metabolites from wild potato species could contribute to early defense responses against P. infestans.
Publications
Seeds of domesticated Vicia (vetch) species (family Fabaceae-Faboideae) are produced and consumed worldwide for their nutritional value. Seed accessions belonging to 16 different species of Vicia—both domesticated and wild taxa—were subjected to a chemotaxonomic study using ultraperformance liquid chromatography–mass spectrometry (UPLC-MS) analyzed by chemometrics. A total of 89 metabolites were observed in the examined Vicia accessions. Seventy-eight out of the 89 detected metabolites were annotated. Metabolites quantified belonged to several classes, viz., flavonoids, procyanidins, prodelphinidins, anthocyanins, stilbenes, dihydrochalcones, phenolic acids, coumarins, alkaloids, jasmonates, fatty acids, terpenoids, and cyanogenics, with flavonoids and fatty acids amounting to the major classes. Flavonoids, fatty acids, and anthocyanins showed up as potential chemotaxonomic markers in Vicia species discrimination. Fatty acids were more enriched in Vicia faba specimens, while the abundance of flavonoids was the highest in Vicia parviflora. Anthocyanins allowed for discrimination between Vicia hirsuta and Vicia sepium. To the best of our knowledge, this is the first report on employing UPLC-MS metabolomics to discern the diversity of metabolites at the intrageneric level among Vicia species.
Publications
Herbs of the Umbelliferae family are popular spices valued worldwide for their many nutritional and health benefits. Herein, five chief umbelliferous fruits viz., cumin, fennel, anise, coriander and caraway were assessed for its secondary metabolites diversity along with compositional changes incurring upon roasting as analyzed via ultra-high performance liquid chromatography coupled to photodiode array and electrospray ionization mass detectors UHPLC-qToF/MS. A total of 186 metabolites were annotated, according to metabolomics society guidelines, belonging mainly to flavonoids, fatty acids and phenolic acids. Multivariate models viz., PCA, HCA and OPLS-DA were further employed to assess fruits\' heterogeneity in an untargeted manner and determine mechanistic changes in bioactive makeup post roasting viz., glycosidic cleavage, lipid degradation and Maillard reaction. Finally, the fruits\' antioxidant activity showed decline upon roasting and in correlation with its total phenolic content. This study presents the first complete map of umbelliferous fruit metabolome, compositional differences and its roasting effect.
Publications
Rosemary and sage species from Lamiaceae contain high amounts of structurally related but diverse abietane diterpenes. A number of substances from this compound family have potential pharmacological activities and are used in the food and cosmetic industry. This has raised interest in their biosynthesis. Investigations in Rosmarinus officinalis and some sage species have uncovered two main groups of cytochrome P450 oxygenases that are involved in the oxidation of the precursor abietatriene. CYP76AHs produce ferruginol and 11-hydroxyferruginol, while CYP76AKs catalyze oxidations at the C20 position. Using a modular Golden-Gate-compatible assembly system for yeast expression, these enzymes were systematically tested either alone or in combination. A total of 14 abietane diterpenes could be detected, 8 of which have not been reported thus far. We demonstrate here that yeast is a valid system for engineering and reconstituting the abietane diterpene network, allowing for the discovery of novel compounds with potential bioactivity.
Publications
Lens culinaris and several Lupinus species are two legumes regarded as potential protein resources aside from their richness in phytochemicals. Consequently, characterization of their metabolite composition seems warranted to be considered as a sustainable commercial functional food. This study presents a discriminatory holistic approach for metabolite profiling in accessions of four lentil cultivars and four Lupinus species via gas chromatography/mass spectrometry. A total of 107 metabolites were identified, encompassing organic and amino acids, sugars, and sterols, along with antinutrients, viz., alkaloids and sugar phosphates. Among the examined specimens, four nutritionally valuable accessions ought to be prioritized for future breeding to include Lupinus hispanicus, enriched in organic (ca. 11.7%) and amino acids (ca. 5%), and Lupinus angustifolius, rich in sucrose (ca. 40%), along with two dark-colored lentil cultivars ‘verte du Puy’ and ‘Black Beluga’ enriched in peptides. Antinutrient chemicals were observed in Lupinus polyphyllus, owing to its high alkaloid content. Several species-specific markers were also revealed using multivariate data analyses.
Publications
Ceramides (Cers) are major components of the outermost layer of the skin, the stratum corneum, and play a crucial role in permeability barrier functions. Alterations in Cer composition causing skin diseases are compensated with semisynthetic skin-identical Cers. Plants constitute new resources for Cer production as they contain glucosylceramides (GluCers) as major components. GluCers were purified from industrial waste plant materials, apple pomace (Malus domestica), wheat germs (Triticum sp.), and coffee grounds (Coffea sp.), with GluCer contents of 28.9 mg, 33.7 mg, and 4.4 mg per 100 g of plant material. Forty-five species of GluCers (1–45) were identified with different sphingoid bases, saturated or monounsaturated α-hydroxy fatty acids (C15–28), and β-glucose as polar headgroup. Three main GluCers were hydrolyzed by a recombinant human glucocerebrosidase to produce phyto-Cers (46–48). These studies showed that rare and expensive phyto-Cers can be obtained from industrial food plant residues.
Publications
A methodology that brings together sugar and steroid scaffolds linked by a selenium atom is discussed in this work. A series of 6β and 3α glycoconjugated steroids were achieved by stereoselective nucleophilic substitution of cholesterol, pregnenolone, stigmasterol and sitosterol with different seleno-pyranosides and furanosides.