Identification of seed storage proteins as the major constituents of the extra virgin olive oil proteome

Identification and semi-quantification of protein allergens in complex mixtures using proteomic and AllerCatPro 2.0 bioinformatic analyses: a proof-of-concept investigation

The demand for botanicals and natural substances in consumer products has increased in recent years. These substances usually contain proteins and these, in turn, can pose a risk for immunoglobulin E (IgE)-mediated sensitization and allergy. However, no method has yet been accepted or validated for assessment of potential allergenic hazards in such materials. In the studies here, a dual proteomic-bioinformatic approach is proposed to evaluate holistically allergenic hazards in complex mixtures of plants, insects, or animal proteins. Twelve commercial preparations of source materials (plant products, dust mite extract, and preparations of animal dander) known to contain allergenic proteins were analyzed by label-free proteomic analyses to identify and semi-quantify proteins. These were then evaluated by bioinformatics using AllerCatPro 2.0 (https://allercatpro.bii.a-star.edu.sg/) to predict no, weak, or strong evidence for allergenicity and similarity to source-specific allergens. In total, 4,586 protein sequences were identified in the 12 source materials combined. Of these, 1,665 sequences were predicted with weak or strong evidence for allergenic potential. This first-tier approach provided top-level information about the occurrence and abundance of proteins and potential allergens. With regards to source-specific allergens, 129 allergens were identified. The sum of the relative abundance of these allergens ranged from 0.8% (lamb's quarters) to 63% (olive pollen). It is proposed here that this dual proteomic-bioinformatic approach has the potential to provide detailed information on the presence and relative abundance of allergens, and can play an important role in identifying potential allergenic hazards in complex protein mixtures for the purposes of safety assessments.

Bone-Marrow-Derived Mesenchymal Stem Cells, Their Conditioned Media, and Olive Leaf Extract Protect against Cisplatin-Induced Toxicity by Alleviating Oxidative Stress, Inflammation, and Apoptosis in Rats

BACKGROUND

Hepatic and renal damage is a cisplatin (Cis)-induced deleterious effect that is a major limiting factor in clinical chemotherapy.

OBJECTIVES

The current study was designed to investigate the influence of pretreatment with olive leaf extract (OLE), bone-marrow-derived mesenchymal stem cells (BM-MSC), and their conditioned media (CM-MSC) against genotoxicity, nephrotoxicity, hepatotoxicity, and immunotoxicity induced by cisplatin in rats.

METHODS

The rats were randomly divided into six groups (six rats each) as follows: Control; OLE group, treated with OLE; Cis group, treated with a single intraperitoneal dose of Cis (7 mg/kg bw); Cis + OLE group, treated with OLE and cisplatin; Cis + CM-MSC group, treated with BM-MSC conditioned media and Cis; and Cis + MSC group, treated with BM-MSC in addition to Cis.

RESULTS

Cis resulted in a significant deterioration in hepatic and renal functions and histological structures. Furthermore, it increased inflammatory markers (TNF-α, IL-6, and IL-1β) and malondialdehyde (MDA) levels and decreased glutathione (GSH) content, total antioxidant capacity (TAC), catalase (CAT), and superoxide dismutase (SOD) activity in hepatic and renal tissues. Furthermore, apoptosis was evident in rat tissues. A significant increase in serum 8-hydroxy-2-deoxyguanosine (8-OH-dG), nitric oxide (NO) and lactate dehydrogenase (LDH), and a decrease in lysozyme activity were detected in Cis-treated rats. OLE, CM-MSC, and BM-MSC have significantly ameliorated Cis-induced deterioration in hepatic and renal structure and function and improved oxidative stress and inflammatory markers, with preference to BM-MSC. Moreover, apoptosis was significantly inhibited, evident from the decreased expression of Bax and caspase-3 genes and upregulation of Bcl-2 proteins in protective groups as compared to Cis group.

CONCLUSIONS

These findings indicate that BM-MSC, CM-MSC, and OLE have beneficial effects in ameliorating cisplatin-induced oxidative stress, inflammation, and apoptosis in the hepatotoxicity, nephrotoxicity, immunotoxicity, and genotoxicity in a rat model.

Microbiological and Enzymatic Activity Modulates the Bitter Taste Reduction in Decanted Coratina Olive Oil

Coratina monocultivar extra virgin olive oil (EVOO) is known for its level of bitterness, which, if too high, can cause consumer acceptance problems. The aim of this study was to modulate the bitter taste of freshly produced olive oil through endogenous enzymatic activity and microbiota during the decantation phase. The opalescent appearance of the newly produced EVOO was substantially reduced during the first three months of decantation due to the deposition of more than 90% of suspended material, consisting of vegetation water and suspended solid particles. The high content of biophenols and the reduction in water concentration in the oil samples negatively affected the survival of yeasts, which were absent in the oil samples at the end of the third month of decantation. The oleuropeinolytic activity was very intense during the first month of decantation, whereas the reduction in the bitter taste associated with the aglycons was consistent only in the second and third months of decantation. At the end of decantation, the sensory notes of bitterness in the Coratina EVOO were reduced by 33%, lowering the position on the value scale without altering the other qualitative parameters whose values fell within the limits of the commercial EVOO class.

Characterisation of Endogenous Peptides Present in Virgin Olive Oil

The low molecular weight peptide composition of virgin olive oil (VOO) is mostly unknown. We aimed to investigate the composition of the endogenous peptides present in VOO, the protein sources from which those peptides originate and their biological activities. A water-soluble extract containing peptides was obtained from VOO. The peptides were separated by size-exclusion using fast protein liquid chromatography, and the low molecular weight fraction (1600–700 kDa) was analysed by nanoscale liquid chromatography Orbitrap coupled with tandem mass spectrometry and de novo sequencing. Nineteen new peptides were identified by Peaks database algorithm, using the available Olea europaea (cv. Farga) genome database. Eight new peptides were also identified by Peaks de novo sequencing. The protein sources of the peptides detected in the database by Peaks DB were identified by BLAST-P search. Seed storage proteins were among the most frequent sources of VOO peptides. BIOPEP software was used to predict the biological activities of peptides and to simulate (in silico) the proteolytic activity of digestive enzymes on the detected peptide sequences. A selection of synthetic peptides was obtained for investigation of their bioactivities. Peptides VCGEAFGKA, NALLCSNS, CPANGFY, CCYSVY and DCHYFL possessed strong ACE-inhibitory and antioxidant activities in vitro. Antioxidant peptides could play a role in VOO quality.

A comprehensive dataset of the extra virgin olive oil (EVOO) proteome

Proteins and peptides are minor components of vegetal oils. The presence of these compounds in virgin olive oil was first reported in 2001, but the nature of the olive oil proteome is still a puzzling question for food science researchers. In this paper, we have compiled for a first time a comprehensive proteomic dataset of olive fruit and fungal proteins that are present at low but measurable concentrations in a vegetable oil from a crop of great agronomical relevance as olive (Olea europaea L.). Accurate mass nLC-MS data were collected in high definition direct data analysis (HD-DDA) mode using the ion mobility separation step. Protein identification was performed using the Mascot Server v2.2.07 software (Matrix Science) against an ad hoc database made of olive protein entries. Starting from this proteomic record, the impact of these proteins on olive oil stability and quality could be tested. Moreover, the effect of olive oil proteins on human health and their potential use as functional food components could be also evaluated. In addition, this dataset provides a resource for use in further functional comparisons across other vegetable oils, and also expands the proteomic resources to non-model species, thus also allowing further comparative inter-species studies. The data presented here are related to the research article of Castro et al. [1].