Quantitative analysis of pungent and anti-inflammatory phenolic compounds in olive oil by capillary electrophoresis

The first CE procedure for the quantitative determination of pharmacologically relevant secoiridoids in olive oil, oleocanthal and oleacein, is described. Together with their precursors tyrosol and hydroxytyrosol they could be baseline separated in less than 15 min using a borax buffer with pH 9.5, at 25 kV and 30 °C. Method validation confirmed that the procedure is selective, accurate (recovery rates from 94.0 to 104.6%), reproducible (σmax ≤ 6.8%) and precise (inter-day precision ≤ 6.4%), and that the compounds do not degrade quickly if non-aqueous acetonitrile is used as solvent. Quantitative results indicated a low occurrence of oleocanthal (0.004-0.021%) and oleacein (0.002-0.048%) in olive oil samples, which is in agreement to published HPLC data. The CE method impresses with its simple instrumental and methodological design, combined with reproducible and valid quantitative results. © 2014 Elsevier Ltd. All rights reserved

Recent advances and new strategies in the NMR-based identification of natural products

Nature comprises an untapped pool of unique compounds with high structural uniqueness and exceptional properties. At the core of natural products (NPs) discovery is the identification procedure and NMR remains the most efficient method. Technical improvements such as miniaturized and crycogenic NMR probes along with hyphenation capabilities and computational support are at the center of evolution. Concepts such as dereplication and metabolomics are increasingly adopted in NPs using the power of databases, currently fragmented. The introduction and utilization of these technical and computational implements could lead NPs research to more comprehensive structure identification and new holistic perspectives. © 2013 Elsevier Ltd

Evaluation of estrogenic/antiestrogenic activity of Onobrychis ebenoides extract - Interaction with estrogen receptor subtypes ERα and ERβ

A protective effect of plant extract from Onobrychis ebenoides on ovariectomy-induced bone loss in rats has been shown. To investigate the molecular mechanisms that underly the beneficial effect of O. ebenoides (Onb) on bone loss, we studied its potential to activate ER subtypes (ERα and ERβ) on transiently transfected HeLa cells with HO-hERα or pSG5-hERβ and 3×ERE-TATA-Luc expression vectors. Its impact to stimulate differentiation and mineralization of osteoblasts (KS483 cell line) by Alizarin Red-S staining was also examined. Furthermore we sought to induce for its potential the IGFBP3, a known estrogen-dependent marker in MCF7 breast cancer cells. 17β-Estradiol and the pure antiestrogen ICI182780 were included to serve as control samples of the estrogenic and antiestrogenic activity respectively. Our data revealed: (1) Onb extract displayed a significant estrogenic activity on both ERα and ERβ subtypes. (2) It exhibited direct action on osteoblasts by inducing mineralization. (3) It showed estrogenic activity in MCF7 cells. These findings suggest that the beneficial effect of Onb extract on bone loss is mediated through an estrogen-like action via activation of ERα-ERE and ERβ-ERE pathways and via direct action on the mineralization process of osteoblasts. © 2006 Elsevier Ltd. All rights reserved

Ion tree-based structure elucidation of acetophenone dimers (AtA) from Acronychia pedunculata and their identification in extracts by liquid chromatography electrospray ionization LTQ-Orbitrap mass spectrometry

Acronychia-type acetophenones (AtA) is a chemical group of compounds of important structural and biological interest, abundant in Acronychia species. However, there are no data available for their characterization using mass spectrometry. In the current work, AtA have been investigated by multistage high resolution mass spectrometry and both electrospray ionization and atmospheric pressure chemical ionization, in positive and negative mode, were utilized for their structure elucidation and identification. The analysis of AtA using a linear ion trap-Orbitrap analyzer enabled the structural determination of key fragment ions and cleavages, which can be used for the structural characterization thereof. A systematic nomenclature based on protonated and deprotonated fragment ions under collision-induced dissociation conditions and decision trees for the structural determination of AtA are proposed. Furthermore, taking advantage of the characteristic fragmentation patterns, a selective Ultra High Performance Liquid Chromatography Electrospray Ionization multistage Mass Spectrometry (UHPLC-ESI(-)-MSn) method was developed and successfully applied for the dereplication of known AtA and the identification of potentially new ones in Acronychia extracts. Despite the structure similarity and the presence of isomers, accurate characterization of known and unknown AtA derivatives was possible. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd

Corrigendum to “Oleocanthalic and Oleaceinic acids: New compounds from Extra Virgin Olive Oil (EVOO)” [Phytochem. Lett. 26 (2018) 190–194] (S1874390018301757) (10.1016/j.phytol.2018.06.020))

The authors regret the omission of the optical rotation values for compounds 1 and 2 which are [α]D 20= −1.25 (c = 3.2 mg/mL in ethanol) and [α]D 20= −6.2 (c = 5.0 mg/mL in ethanol) as well as a citation to compound 1(Tsolakou, 2017, https://pergamos.lib.uoa.gr/uoa/dl/object/1708868), which should be added. The authors would like to apologise for any inconvenience caused. © 2018 Phytochemical Society of Europ

The origin of copper-induced medicarpin accumulation and its secretion from roots of young fenugreek seedlings are regulated by copper concentration

Isoflavonoid pterocarpans, like medicarpin (M), are produced by leguminous plants in response to biotic or abiotic elicitation from either their glycosidic conjugate pools or by de novo synthesis. In an attempt to clarify M origin in response to copper elicitation, intact Trigonella foenum-graecum (fenugreek) seedlings and cell suspension cultures were treated with CuCl2, and the accumulated isoflavonoid aglycones and their glycosides were determined by High Performance Liquid Chromatography (HPLC). Our results show that copper induces the de novo synthesis of M in a concentration dependent manner. In roots, where copper accumulated in high amounts, only part of M was formed de novo, while another part was formed at the expense of its malonyl glucoside (MGM). In contrast, when tissue copper concentration was low, like in shoots, or in roots treated with low CuCl2, M was formed only by de novo synthesis. The increase of phenylalanine ammonia lyase activity (PAL) as well as the accumulation of chalcone synthase (CHS) and vestitone reductase (VR) specific transcripts are consistent with the de novo synthesis of M induced by copper. The non-linear negative correlation of the studied copper concentrations to the amount of M excreted in the seedling growth medium suggests the existence of an M secretion process which is regulated by copper concentration. The possible involvement of an ATP-dependent transporter in the copper-induced M excretion is discussed. © 2008 Elsevier Ireland Ltd. All rights reserved